TransDigm (TDG) 10-K16 Nov 212021 FY Annual reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Sep. 30, 2021	Nov. 03, 2021	Mar. 31, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-32833
Entity Registrant Name	TransDigm Group Incorporated
Entity Central Index Key	0001260221
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	41-2101738
Entity Address, Address Line One	1301 East 9th Street,
Entity Address, Address Line Two	Suite 3000,
Entity Address, City or Town	Cleveland,
Entity Address, State or Province	OH
Entity Address, Postal Zip Code	44114
City Area Code	216
Local Phone Number	706-2960
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	TDG
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 32,940,645,808
Entity Common Stock, Shares Outstanding		55,248,901
Documents Incorporated by Reference	Certain sections of the registrant’s definitive Proxy Statement to be filed in connection with its 2022 Annual Meeting of Shareholders expected to be held in March 2022 are incorporated by reference into Part III of this Annual Report on Form 10-K.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
CURRENT ASSETS:
Cash and cash equivalents	$ 4,787	$ 4,717
Trade accounts receivable—Net	791	720
Inventories—Net	1,185	1,283
Prepaid expenses and other	267	240
Total current assets	7,030	6,960
PROPERTY, PLANT AND EQUIPMENT—NET	770	752
GOODWILL	8,568	7,889
Total	2,791	2,610
DEFERRED INCOME TAXES	0	17
OTHER	156	167
TOTAL ASSETS	19,315	18,395
CURRENT LIABILITIES:
Current portion of long-term debt	277	276
Short-term borrowings—trade receivable securitization facility	349	349
Accounts payable	227	218
Accrued and other current liabilities	810	773
LONG-TERM DEBT	19,372	19,384
Total current liabilities	1,663	1,616
DEFERRED INCOME TAXES	485	430
OTHER NON-CURRENT LIABILITIES	705	933
Total liabilities	22,225	22,363
TD GROUP STOCKHOLDERS’ DEFICIT:
Common stock - $.01 par value; authorized 224,400,000 shares; issued 59,403,100 and 58,612,028 at September 30, 2021 and September 30, 2020, respectively	1	1
Additional paid-in capital	1,830	1,581
Accumulated deficit	(3,705)	(4,359)
Accumulated other comprehensive loss	(248)	(401)
Treasury stock, at cost; 4,198,226 shares at September 30, 2021 and September 30, 2020, respectively	(794)	(794)
Total TD Group stockholders’ deficit	(2,916)	(3,972)
NONCONTROLLING INTERESTS	6	4
Total stockholders’ deficit	(2,910)	(3,968)
TOTAL LIABILITIES AND STOCKHOLDERS’ DEFICIT	$ 19,315	$ 18,395

Consolidated Balance Sheets Par

Consolidated Balance Sheets Parenthetical - $ / shares	Sep. 30, 2021	Sep. 30, 2020
Statement of Financial Position [Abstract]
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	224,400,000	224,400,000
Common Stock, Shares, Issued	59,403,100	58,612,028
Treasury Stock, Shares	4,198,226	4,198,226

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Revenues	$ 4,798	$ 5,103	$ 5,223
COST OF SALES	2,285	2,456	2,414
GROSS PROFIT	2,513	2,647	2,809
SELLING AND ADMINISTRATIVE EXPENSES	685	727	748
AMORTIZATION OF INTANGIBLE ASSETS	137	169	135
INCOME FROM OPERATIONS	1,691	1,751	1,926
INTEREST EXPENSE—NET	1,059	1,029	859
REFINANCING COSTS	37	28	3
OTHER (INCOME) EXPENSE	(51)	(46)	1
GAIN ON SALE OF BUSINESSES—NET	(69)	0	0
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	715	740	1,063
INCOME TAX PROVISION	34	87	222
Income from continuing operations	681	653	841
Income from discontinued operations, net of tax	0	47	51
Net income	681	700	892
LESS: NET INCOME ATTRIBUTABLE TO NONCONTROLLING INTERESTS	(1)	(1)	(2)
Net Income (Loss) Attributable to Parent	680	699	890
NET INCOME APPLICABLE TO TD GROUP COMMON STOCKHOLDERS	$ 607	$ 514	$ 779
Earnings Per Share [Abstract]
Earnings per share from continuing operations—basic and diluted	$ 10.41	$ 8.14	$ 12.94
Earnings per share from discontinued operations—basic and diluted	0	0.82	0.90
Earnings per share	10.41	8.96	13.84
Cash dividends paid per common share	$ 0	$ 32.50	$ 30
Weighted-average shares outstanding:
Basic and diluted	58.4	57.3	56.3

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Net income	$ 681	$ 700	$ 892
Less: Net income attributable to noncontrolling interests	1	1	2
Net Income (Loss) Attributable to Parent	680	699	890
Other comprehensive income (loss), net of tax:
Other comprehensive income (loss), net of tax, attributable to TD Group	153	(22)	(383)
TOTAL COMPREHENSIVE INCOME ATTRIBUTABLE TO TD GROUP	833	677	507
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent	90	76	(115)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax, Parent	73	(130)	(239)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent	$ (10)	$ 32	$ (29)

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Deficit - USD ($) $ in Millions	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Non-controlling Interests
NONCONTROLLING INTERESTS							$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total stockholders’ deficit	$ (1,808)
BALANCE (in shares) at Sep. 30, 2019		57,623,311
BALANCE (in shares) at Sep. 30, 2018						(4,161,326)
BALANCE at Sep. 30, 2018		$ 1	$ 1,209	$ (2,247)	$ 4	$ (775)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Changes in noncontrolling interest of consolidated subsidiaries, net	8						8
Accrued unvested dividend equivalents and other	(1,688)			(1,688)
Accrued unvested dividend equivalents and other	(80)			(80)
Compensation expense recognized for employee stock options	88		88
Exercise of employee stock options	82		82
Exercise of employee stock options		726,750
Common stock issued		875
Net income	892
Net Income (Loss) Attributable to Parent	890			890
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent	(115)
Less: Net income attributable to noncontrolling interests							(2)
Foreign currency translation adjustments					(115)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax, Parent	(239)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax	(237)				(237)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent	29
Pensions and other postretirement benefits adjustments, net of tax					(29)
BALANCE (in shares) at Sep. 30, 2018		56,895,686
BALANCE (in shares) at Sep. 30, 2019						(4,161,326)
BALANCE at Sep. 30, 2019		$ 1	1,379	(3,120)	(379)	$ (775)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative Effect of ASC 606, adopted October 1, 2018 \| Accounting Standards Update 2014-09 [Member]	3			(3)
Cumulative Effect of ASU 2018-02, adopted October 1, 2018 \| Accounting Standards Update 2018-02 [Member]	0			(2)	2
NONCONTROLLING INTERESTS							10
Total stockholders’ deficit	$ (2,884)
BALANCE (in shares) at Sep. 30, 2020	58,612,028	58,612,028
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Changes in noncontrolling interest of consolidated subsidiaries, net	$ (6)						(6)
Accrued unvested dividend equivalents and other	(1,864)			(1,864)
Accrued unvested dividend equivalents and other	(74)			(74)
Compensation expense recognized for employee stock options	86		86
Exercise of employee stock options	116		116
Exercise of employee stock options		988,717
Net income	700
Treasury Stock, Shares, Acquired						(36,900)
Treasury Stock, Value, Acquired, Cost Method	(19)					$ (19)
Net Income (Loss) Attributable to Parent	699			699
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent	76
Foreign currency translation adjustments					76
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax, Parent	(130)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent	$ (32)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax					(130)
Pensions and other postretirement benefits adjustments, net of tax					32
BALANCE (in shares) at Sep. 30, 2019		57,623,311
BALANCE (in shares) at Sep. 30, 2020	(4,198,226)					(4,198,226)
BALANCE at Sep. 30, 2020	$ (3,972)	$ 1	1,581	(4,359)	(401)	$ (794)
NONCONTROLLING INTERESTS	4						4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total stockholders’ deficit	$ (3,968)
BALANCE (in shares) at Sep. 30, 2021	59,403,100	59,403,100
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Changes in noncontrolling interest of consolidated subsidiaries, net	$ 2						2
Accrued unvested dividend equivalents and other	(26)			(26)
Compensation expense recognized for employee stock options	121		121
Exercise of employee stock options	128		128
Exercise of employee stock options		791,072
Net income	681
Net Income (Loss) Attributable to Parent	680			680
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent	90
Foreign currency translation adjustments					90
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax, Parent	73
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent	$ 10
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax					73
Pensions and other postretirement benefits adjustments, net of tax					(10)
BALANCE (in shares) at Sep. 30, 2020	58,612,028	58,612,028
BALANCE (in shares) at Sep. 30, 2021	(4,198,226)					(4,198,226)
BALANCE at Sep. 30, 2021	$ (2,916)	$ 1	$ 1,830	$ (3,705)	$ (248)	$ (794)
NONCONTROLLING INTERESTS	6						$ 6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total stockholders’ deficit	$ (2,910)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
OPERATING ACTIVITIES:
Net income	$ 681	$ 700	$ 892
Income from discontinued operations, net of tax	0	(47)	(51)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	115	114	91
Amortization of intangible assets and product certification costs	138	169	135
Amortization of debt issuance costs, original issue discount and premium	34	33	28
Amortization of inventory step-up	6	0	77
Amortization of loss contract reserves	(55)	(36)	(38)
Refinancing costs	37	28	3
GAIN ON SALE OF BUSINESSES—NET	(69)	0	0
Non-cash stock compensation expense	129	93	93
Deferred income taxes	34	24	0
Foreign currency exchange loss (gain)	11	22	(5)
Gain on insurance proceeds from fire	(24)	0	0
Changes in assets/liabilities, net of effects from acquisitions and sales of businesses:
Trade accounts receivable	(78)	352	(82)
Inventories	79	(62)	(36)
Income taxes receivable	(63)	(144)	(3)
Other assets	(33)	(16)	(27)
Accounts payable	3	(62)	(1)
Accrued interest	14	85	(4)
Accrued and other liabilities	(46)	(40)	(57)
Net cash provided by operating activities	913	1,213	1,015
INVESTING ACTIVITIES:
Capital expenditures	(105)	(105)	(102)
Acquisition of businesses, net of cash acquired	(963)	0	(3,976)
Net proceeds from sale of businesses	259	904	189
Proceeds from Insurance Settlement, Investing Activities	24	0	0
Net cash (used in) provided by investing activities	(785)	799	(3,889)
FINANCING ACTIVITIES:
Proceeds from exercise of stock options	128	116	82
Dividends and dividend equivalent payments	(73)	(1,928)	(1,712)
Treasury stock purchases	0	(19)	0
Proceeds from issuances of senior secured and subordinated notes, net	1,932	4,114	4,480
Repayments of senior subordinated notes, net	(1,982)	(1,167)	(550)
Proceeds from revolving credit facility	200	200	0
Repayment on revolving credit facility	(200)	0	0
Proceeds from trade receivable securitization facility, net	0	0	49
Repayment on term loans	75	75	77
Financing costs and other, net	0	(11)	(1)
Net cash (used in) provided by financing activities	(70)	1,230	2,271
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	12	8	(3)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	70	3,250	(606)
Cash and cash equivalents	4,787	4,717	1,467
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid during the period for interest	1,008	923	878
Cash paid during the period for income taxes, net of refunds	$ 83	$ 223	$ 215

DESCRIPTION OF THE BUSINESS AND

DESCRIPTION OF THE BUSINESS AND IMPACT OF COVID-19 PANDEMIC	12 Months Ended
DESCRIPTION OF THE BUSINESS AND IMPACT OF COVID-19 PANDEMIC	Sep. 30, 2021
Accounting Policies [Abstract]
DESCRIPTION OF THE BUSINESS AND IMPACT OF COVID-19	DESCRIPTION OF THE BUSINESS AND IMPACT OF COVID-19 PANDEMIC Description of the Business – TD Group, through its wholly-owned subsidiary, TransDigm Inc., is a leading global designer, producer and supplier of highly engineered aircraft components for use on nearly every commercial and military aircraft in service today. TransDigm Inc., along with TransDigm Inc.’s direct and indirect wholly-owned operating subsidiaries (collectively, with TD Group, the “Company” or “TransDigm”), offers a broad range of proprietary aerospace products. TD Group has no significant assets or operations other than its 100% ownership of TransDigm Inc. TD Group’s common stock is listed on the New York Stock Exchange, or the NYSE, under the trading symbol “TDG.” TransDigm's major product offerings, substantially all of which are ultimately provided to end-users in the aerospace industry, include mechanical/electro-mechanical actuators and controls, ignition systems and engine technology, specialized pumps and valves, power conditioning devices, specialized AC/DC electric motors and generators, batteries and chargers, engineered latching and locking devices, engineered rods, engineered connectors and elastomer sealing solutions, databus and power controls, cockpit security components and systems, specialized and advanced cockpit displays, engineered audio, radio and antenna systems, specialized lavatory components, seat belts and safety restraints, engineered and customized interior surfaces and related components, advanced sensor products, switches and relay panels, thermal protection and insulation, lighting and control technology, parachutes, high performance hoists, winches and lifting devices, and cargo loading, handling and delivery systems. COVID-19 Pandemic Restructuring Costs – The commercial aerospace industry continues to be significantly disrupted, both domestically and internationally, by the COVID-19 pandemic resulting in ongoing business challenges. While global vaccination efforts are underway and commercial air travel demand has shown slight signs of recovery in recent months, the continued impact of COVID-19, including any increases in infection rates, new variants, vaccination efficacy and renewed governmental action to slow the spread of COVID-19 cannot be estimated. Material actions to reduce costs in response to the impact that the pandemic has had on operating results include: (1) reducing the Company's workforce to align operations with customer demand through a reduction in force or through a realignment of certain business units; (2) implementing unpaid furloughs and salary reductions; (3) delaying non-essential capital projects and (4) minimizing discretionary spending. For the fiscal year ended September 30, 2021, COVID-19 restructuring costs of approximately $36 million were incurred, of which $26 million was recorded in cost of sales and $10 million was recorded in selling and administrative expenses on the consolidated statements of income. For the fiscal year ended September 30, 2020, COVID-19 restructuring costs of approximately $46 million were incurred, of which $37 million was recorded in cost of sales and $9 million was recorded in selling and administrative expenses in the consolidated statements of income. These costs are primarily related to the Company's actions to reduce its workforce and consolidate certain facilities to align with customer demand. Additionally, for the fiscal years ended September 30, 2021 and September 30, 2020, the Company incurred approximately $4 million and $5 million, respectively, in incremental costs related to the pandemic that are not expected to recur once the pandemic has subsided and are clearly separable from normal operations (e.g., additional cleaning and disinfecting of facilities by contractors above and beyond normal requirements, personal protective equipment).

ACQUISITIONS AND DIVESTITURES

ACQUISITIONS AND DIVESTITURES	12 Months Ended
ACQUISITIONS AND DIVESTITURES	Sep. 30, 2021
Business Combinations [Abstract]
ACQUISITIONS AND DIVESTITURES	ACQUISITIONS AND DIVESTITURES Acquisitions Cobham Aero Connectivity – On November 24, 2020, the Company entered into a definitive agreement to acquire all the outstanding stock of Chelton Limited, Chelton Avionics Holdings, Inc. and Mastsystem Int'l Oy, collectively, Cobham Aero Connectivity (“CAC”), for a total purchase price of $945 million. The acquisition was substantially completed on January 5, 2021 and financed through existing cash on hand. The Company completed the remainder of the acquisition of CAC on February 12, 2021, also through existing cash on hand. CAC operates from two primary facilities (Marlow, United Kingdom and Prescott, Arizona) and is a leading provider of highly engineered antennas and radios for the aerospace end market. The products are primarily proprietary with significant aftermarket content and have a strong presence across major defense platforms as well as select commercial applications. CAC's operating results are included in TransDigm's Airframe segment. The acquisition strengthens and expands the Company’s position to design, produce and supply highly engineered proprietary aerospace components in niche markets with significant aftermarket content and provide opportunities to create value through the application of our three core value-driven operating strategies (obtaining profitable new business, continually improving our cost structure, and providing highly engineered value-added products to customers). The purchase price paid for the acquisition reflects the current earnings before interest, taxes, depreciation and amortization ("EBITDA") and cash flows, as well as the future EBITDA and cash flows expected to be generated by the business, which are driven in most cases by the recurring aftermarket consumption over the life of a particular aircraft, estimated to be approximately 25 to 30 years. The Company accounted for the CAC acquisition using the acquisition method and included the results of operations of the acquisition in its consolidated financial statements from the effective dates of the acquisition. The Company made an initial allocation of the purchase price at the date of acquisition based upon its understanding of the fair value of the acquired assets and assumed liabilities. As of September 30, 2021, the measurement period (not to exceed one year) is open; therefore, the assets acquired and liabilities assumed related to the CAC acquisition are subject to adjustment until the end of the measurement period. The allocation of the purchase price is preliminary and will likely change in future periods, perhaps materially, as fair value estimates of the assets acquired and liabilities assumed are finalized during the allowable one year measurement period. The Company is in the process of finalizing a third-party valuation of certain intangible assets, tangible assets and liabilities of CAC. The fair values of acquired intangibles and certain liabilities, such as loss contract reserves, are determined based on estimates and assumptions that are deemed reasonable by the Company. Significant assumptions used to determine the fair values of acquired intangible assets include the discount rates and certain assumptions that form the basis of the forecasted results of the acquired business including revenue growth rates, EBITDA margins, royalty rates and technology obsolescence rates. Significant assumptions used to determine the fair value of the loss contract reserves using the discounted cash flow model include discount rates and forecasted costs to be incurred under the long-term contracts and at-market bid prices for respective contracts. These assumptions are forward looking and could be affected by future economic and market conditions. Pro forma net sales and results of operations for the acquisition had it occurred at the beginning of the applicable the fiscal years ended September 30, 2021 or September 30, 2020 are not material and, accordingly, are not provided. The preliminary allocation of the estimated fair value of assets acquired and liabilities assumed in the CAC acquisition as of the acquisition date, as well as measurement period adjustments recorded as of September 30, 2021, are summarized in the table below (in millions): Preliminary Measurement Period Adjusted Preliminary Allocation Adjustments Allocation Assets acquired (excluding cash): Trade accounts receivable $ 31 $ 1 $ 32 Inventories 27 2 29 Prepaid expenses and other 10 (3) 7 Property, plant and equipment 18 3 21 Goodwill 636 58 694 (1) Other intangible assets 309 16 325 (1) Other 34 (2) 32 Total assets acquired (excluding cash) 1,065 75 1,140 Liabilities assumed: Accounts payable 15 3 18 Accrued and other current liabilities 38 5 (2) 43 Deferred income taxes 38 (7) 31 Other non-current liabilities 29 74 (2) 103 Total liabilities assumed 120 75 195 Net assets acquired $ 945 $ — $ 945 (1) The Company expects that of the approximately $694 million of goodwill recognized for the acquisition, approximately $57 million will be deductible for tax purposes. The Company also expects that of the approximately $325 million of other intangible assets recognized for the acquisition, approximately $108 million will be deductible for tax purposes. The goodwill and intangible assets will be deductible over 15 years. (2) Primarily relates to the recording of loss contract reserves associated with acquired ongoing long-term contracts with customers that were incurring negative gross margins as of the date of acquisition. Based on our review of these contracts, we concluded that the terms of certain contracts were unfavorable when compared to market terms as of the acquisition date. The loss contract reserves are preliminarily estimated to be $80.6 million and will be released over a three to five year period. Esterline Technologies Corporation – On March 14, 2019, TransDigm completed the acquisition of all the outstanding stock of Esterline Technologies Corporation (“Esterline”) for $122.50 per share in cash, plus the repayment of Esterline debt. The purchase price, net of cash acquired of approximately $398.2 million, totaled approximately $3,923.9 million. Of the $3,923.9 million purchase price, $3,536.3 million was paid at closing and the remaining $387.6 million was classified as restricted cash for the redemption of Esterline’s senior notes outstanding due 2023 (the "2023 Notes"). The 2023 Notes were redeemed on April 15, 2019. Esterline, through its subsidiaries, was an industry leader in specialized manufacturing for the aerospace and defense industry primarily within three core disciplines: advanced materials, avionics and controls and sensors and systems. The acquisition of Esterline expands TransDigm's platform of proprietary and sole source content for the aerospace and defense industry. TransDigm evaluated the strategic fit and description of each Esterline reporting unit to determine the appropriate business segment for the reporting unit. Each Esterline reporting unit is included in one of TransDigm's segments: Power and Control, Airframe, or Non-aviation. The total purchase price of Esterline was allocated to the underlying assets acquired and liabilities assumed based upon the respective fair value at the date of acquisition. To the extent the purchase price exceeded the fair value of the net identifiable tangible and intangible assets acquired, such excess was allocated to goodwill. Allocations were based on the acquisition method of accounting and third-party valuation appraisals. The allocation of the fair value of the assets acquired and liabilities assumed in the Esterline acquisition as of the acquisition date of March 14, 2019 is summarized in the table below (in millions): Adjusted Final Allocation Assets acquired (excluding cash): Trade accounts receivable $ 384 Inventories 583 Prepaid expenses and other 423 Property, plant and equipment 469 Goodwill 2,256 Other intangible assets 1,301 Other 20 Total assets acquired (excluding cash) 5,436 Liabilities assumed: Accounts payable 146 Accrued and other current liabilities 751 Deferred income taxes 181 Other non-current liabilities 434 Total liabilities assumed 1,512 Net assets acquired $ 3,924 Of the approximately $2.3 billion of goodwill recognized for the acquisition, approximately $25.6 million is deductible for tax purposes. Also, of the approximately $1.3 billion of other intangible assets recognized for the acquisition, approximately $48.9 million is deductible for tax purposes. In connection with the Esterline acquisition, we acquired existing long-term contracts with customers that were incurring negative gross margins as of the date of acquisition. Based on our review of these contracts, we concluded that the terms of certain of these loss-making contracts were unfavorable when compared to market terms as of the acquisition date. As a result, we recognized loss contract reserves of $267.9 million as of the acquisition date based on the present value of the difference between the contractual cash flows of the existing long-term contracts and the estimated cash flows had the contracts been executed at market terms as of the acquisition date. These adjustments applied only to contracts generating a negative margin as of the date of acquisition. Significant assumptions used to determine the fair value of the loss contract reserves using the discounted cash flow model include discount rates, forecasted quantities of products to be sold under the long-term contracts and market prices for respective products. These were forward looking assumptions and could be affected by future economic and market conditions. Loss contract reserves are amortized and recorded as an offset to cost of sales over the life of the contracts as actual sales occur under the long-term contracts. The remaining loss contract reserves related to the Esterline acquisition were $160.1 million and $201.3 million at September 30, 2021 and 2020, respectively, of which $14.5 million and $31.9 million was classified in accrued and other current liabilities and $145.6 million and $169.4 million was classified in other non-current liabilities in the consolidated balance sheets at September 30, 2021 and 2020, respectively. Loss contract reserves of approximately $41.8 million, $29.5 million and $27.3 million were amortized and recorded as an offset to cost of sales in the consolidated statements of income for the fiscal years ended September 30, 2021, 2020 and 2019, respectively. Esterline acquisition costs were expensed as incurred and totaled $26.9 million and $85.1 million for the fiscal years ended September 30, 2020 and 2019, respectively. Divestitures Third Quarter Fiscal 2021 ScioTeq and TREALITY Simulation Visual Systems – On June 30, 2021, TransDigm completed the divestiture of its ScioTeq and TREALITY Simulation Visual Systems businesses (“ScioTeq and TREALITY”) to OpenGate Capital for approximately $200 million in cash. ScioTeq and TREALITY were acquired by TransDigm as part of its acquisition of Esterline in March 2019 and were included in TransDigm’s Airframe segment. Technical Airborne Components – On April 27, 2021, TransDigm completed the divestiture of the Technical Airborne Components business (“TAC”) to Searchlight Capital Partners for approximately $40 million in cash. TAC was included in TransDigm’s Airframe segment. The net gain on sale recognized in fiscal 2021 as a result of the ScioTeq and TREALITY and TAC divestitures was approximately $68 million, which is classified as a component of gain on sale of businesses-net within the consolidated statements of income. Second Quarter Fiscal 2021 Racal Acoustics – On January 29, 2021, TransDigm completed the divestiture of the Racal Acoustics business (“Racal”) to Invisio Communications AB ("Invisio") for approximately $20 million in cash. The gain on sale recognized as a result of the divestiture was immaterial and classified as a component of gain on sale of businesses-net within the consolidated statements of income. Racal was acquired by TransDigm as part of its acquisition of Esterline in March 2019 and was included in TransDigm's Non-aviation segment. First Quarter Fiscal 2021 Avista Inc. – On November 17, 2020, TransDigm completed the divestiture of the Avista, Inc. business ("Avista") to Belcan, LLC ("Belcan") for approximately $8 million in cash. Avista was acquired by TransDigm as part of its acquisition of Esterline in March 2019 and was included in TransDigm's Airframe segment. The gain on sale recognized as a result of the divestiture was immaterial and classified as a component of gain on sale of businesses-net within the consolidated statements of income. During the fourth quarter of fiscal 2020, the Company determined Avista met the criteria to be classified as held for sale. Therefore, the assets and liabilities of Avista, which were not material, have been presented as held for sale in other assets, accrued and other current liabilities and other non-current liabilities, respectively, in the consolidated balance sheets as of September 30, 2020. Fiscal 2020 Souriau-Sunbank Connection Technologies – On December 20, 2019, TransDigm completed the divestiture of the Souriau-Sunbank Connection Technologies business (“Souriau-Sunbank”) to Eaton Corporation plc (“Eaton”) for approximately $920 million. Souriau-Sunbank was acquired by TransDigm as part of its acquisition of Esterline in March 2019 and was included in TransDigm's Non-aviation segment. The results of operations of Souriau-Sunbank are presented in discontinued operations in the accompanying consolidated financial statements for all periods presented since the date acquired. Refer to Note 23, “Discontinued Operations” for additional information. Fiscal 2019 Esterline Interface Technology Group – On September 20, 2019, TransDigm completed the divestiture of its EIT group of businesses to an affiliate of KPS Capital Partners, LP for approximately $190 million. EIT was acquired by TransDigm as part of its acquisition of Esterline in March 2019. The results of operations of EIT are presented in discontinued operations in the accompanying consolidated financial statements for all periods presented since the date acquired. Refer to Note 23, “Discontinued Operations” for additional information. Each divestiture was executed with unrelated third parties.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	Sep. 30, 2021
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation and Consolidation —The accompanying consolidated financial statements were prepared in conformity with U.S. GAAP and include the accounts of TD Group and subsidiaries. All significant intercompany balances and transactions have been eliminated. Certain reclassifications have been made to the prior year amounts to conform to the current year presentation, none of which are material. Revenue Recognition —Revenue is recognized from the sale of products when control transfers to the customer, which is demonstrated by our right to payment, a transfer of title, a transfer of the risk and rewards of ownership, or the customer acceptance, but most frequently upon shipment where the customer obtains physical possession of the goods. The majority of the Company's revenue is recorded at a point in time. Sales recognized over time are generally accounted for using an input measure to determine progress completed at the end of the period. Sales for service contracts generally are recognized as the services are provided. Refer to Note 5, “Revenue Recognition,” for further details. Shipping and Handling Costs —Shipping and handling costs are included in cost of sales in the consolidated statements of income. Research and Development Costs —The Company expenses research and development costs as incurred and classifies such amounts in selling and administrative expenses. The expense recognized for research and development costs for the fiscal years ended September 30, 2021, 2020 and 2019 was approximately $105.6 million, $130.9 million, and $116.8 million, respectively. Cash Equivalents —The Company considers all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. Allowance for Credit Losses —The Company's allowance for credit losses is the allowance for uncollectible accounts. The allowance for uncollectible accounts reduces the trade accounts receivable balance to the estimated net realizable value equal to the amount that is expected to be collected. The Company’s method for developing its allowance for credit losses is based on historical write-off experience, the aging of receivables, an assessment of the creditworthiness of customers, economic conditions and other external market information. The allowance also incorporates a provision for the estimated impact of disputes with customers. All provisions for allowances for uncollectible accounts are included in selling and administrative expenses. The determination of the amount of the allowance for uncollectible accounts is subject to judgment and estimation by management. If circumstances change or economic conditions deteriorate or improve, the allowance for uncollectible accounts could increase or decrease. Refer to Note 7, “Trade Accounts Receivable,” for further details. Inventories —Inventories are stated at the lower of cost or net realizable value. Cost of inventories is generally determined by the average cost and the first-in, first-out (“FIFO”) methods and includes material, labor and overhead related to the manufacturing process. Provision for potentially obsolete or slow-moving inventory is made based on management’s analysis of inventory levels and future sales forecasts. Refer to Note 8, “Inventories,” for further details. Property, Plant and Equipment —Property, plant and equipment are stated at cost and include improvements which significantly increase capacities or extend the useful lives of existing plant and equipment. Depreciation is computed using the straight-line method over the following estimated useful lives: land improvements from 10 to 20 years, buildings and improvements from 5 to 30 years, machinery and equipment from 2 to 10 years and furniture and fixtures from 3 to 10 years. Net gains or losses related to asset dispositions are recognized in earnings in the period in which dispositions occur. Routine maintenance, repairs and replacements are expensed as incurred. Amortization expense of assets accounted for as finance leases is included within depreciation expense. Property, plant and equipment is assessed for potential impairment whenever indicators of impairment are present by determining whether the carrying value of the property can be recovered through projected, undiscounted cash flows from future operations over the property’s remaining estimated useful life. Any impairment recognized is the amount by which the carrying amount exceeds the fair value of the asset. Fair value is measured based on quoted market prices in active markets, if available. If quoted market prices are not available, the estimate of fair value is based on various valuation techniques, including the discounted value of estimated future cash flows. Refer to Note 9, “Property, Plant and Equipment,” for further details. Debt Issuance Costs, Premiums and Discounts —The cost of obtaining financing as well as premiums and discounts are amortized using the effective interest method over the terms of the respective obligations as a component of interest expense within the consolidated statements of income. Debt issuance costs are presented in the consolidated balance sheets as a direct reduction from the carrying amount of the related debt liabilities. Refer to Note 12, “Debt,” for further details. Financial Instruments —Interest rate swap and cap agreements are used to manage interest rate risk associated with floating-rate borrowings under our credit facility. The interest rate swap and cap agreements utilized by the Company effectively modify the Company’s exposure to interest rate risk by converting a portion of the Company’s variable rate debt to a fixed rate basis through the expiration date of the interest rate swap and cap agreements, thereby reducing the impact of interest rate volatility on future interest expense. These agreements involve the receipt of variable rate amounts in exchange for fixed rate interest payments over the term of the agreements without an exchange of the underlying principal amount. These derivative instruments qualify as effective cash flow hedges under U.S. GAAP. The Company transacts business in various foreign currencies, which subjects the Company’s cash flows and results of operations to exposure related to changes in foreign currency exchange rates. These exposures arise primarily from purchases or sales of products and services from third parties. Foreign currency forward exchange contracts provide for the purchase or sale of foreign currencies at specified future dates at specified exchange rates, and are used to offset changes in the fair value of certain assets or liabilities or forecasted cash flows resulting from transactions denominated in foreign currencies. For the interest rate swap and cap agreements and the foreign currency forward contracts designated as cash flow hedges, the effective portion of the gain or loss from the financial instruments is reported as a component of accumulated other comprehensive loss in stockholders’ deficit and subsequently reclassified into earnings in the same line as the hedged item in the same period or periods during which the hedged item affected earnings. As the interest rate swap and cap agreements are used to manage interest rate risk, any gains or losses from the derivative instruments that are reclassified into earnings are recognized in interest expense - net in the consolidated statements of income. As the foreign currency forward exchange contracts are used to manage foreign currency exposure primarily arising from purchases or sales from third parties, any gains or losses from the derivative instruments that are reclassified into earnings are recognized in cost of sales or net sales in the consolidated statements of income. Refer to Note 21, “Derivatives and Hedging Activities,” for further details. Goodwill and Other Intangible Assets —In accordance with ASC 805, “Business Combinations,” the Company uses the acquisition method of accounting to allocate costs of acquired businesses to the assets acquired and liabilities assumed based on their estimated fair values at the dates of acquisition. The excess costs of acquired businesses over the fair values of the assets acquired and liabilities assumed were recognized as goodwill. The valuations of the acquired assets and liabilities assumed will impact the determination of future operating results. Determining the fair value of assets acquired and liabilities assumed requires management’s judgment and often involves the use of significant estimates and assumptions, including assumptions with respect to future cash inflows and outflows, revenue growth rates and EBITDA margins, discount rates, customer attrition rates, royalty rates, asset lives and market multiples, among other items. We determine the fair values of intangible assets acquired generally in consultation with third-party valuation advisors. Fair value adjustments to the Company’s assets and liabilities are recognized and the results of operations of the acquired business are included in our consolidated financial statements from the effective date of the merger or acquisition. Intangible assets other than goodwill are recognized if the benefit of the intangible asset is obtained through contractual or other legal rights, or if the intangible asset can be sold, transferred, licensed or exchanged, regardless of the Company’s intent to do so. Goodwill is the excess of the purchase price paid over the estimated fair value of the net assets of a business acquired. Other intangible assets consist of identifiable intangibles acquired or recognized in accounting for the acquisitions (trademarks, trade names, technology, customer relationships, order backlog and other intangible assets). Goodwill and intangible assets that have indefinite useful lives (i.e., trademarks and trade names) are subject to annual impairment testing. Management determines fair value using a discounted future cash flow analysis or other accepted valuation techniques. The Company performs an annual impairment test for goodwill and other intangible assets as of the first day of the fourth fiscal quarter of each year, or more frequently, if an event occurs or circumstances change that would more likely than not reduce fair value below carrying value. At the time of goodwill impairment testing, the Company first assesses qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value, and whether it is therefore necessary to perform the quantitative goodwill impairment test. If, after considering all events and circumstances that support a qualitative evaluation the Company determines that it is not more-likely-than-not that the goodwill and/or indefinite-lived intangible assets are impaired, then performing the single-step quantitative analysis to determine if there is impairment would be unnecessary. Conversely, if it is more-likely-than-not that the goodwill and/or indefinite-lived intangible assets are impaired, then the Company would proceed with the single-step quantitative analysis to determine if there is a goodwill and/or indefinite-lived intangible asset impairment loss. In this application, the definition of “more-likely-than-not” is interpreted as a likelihood of more than 50%. U.S. GAAP requires that the annual, and any interim, impairment assessment be performed at the reporting unit level. The reporting unit level is one level below an operating segment. Substantially all goodwill was determined and recognized for each reporting unit pursuant to the accounting for the merger or acquisition as of the date of each transaction. With respect to acquisitions integrated into an existing reporting unit, any acquired goodwill is combined with the goodwill of the reporting unit. The impairment test for indefinite lived intangible assets consists of a comparison between their fair values and carrying values. If the carrying amounts of intangible assets that have indefinite useful lives exceed their fair values, an impairment loss will be recognized in an amount equal to the sum of any such excesses. The Company had 46 reporting units with goodwill and 43 reporting units with indefinite-lived intangible assets as of the first day of the fourth quarter of fiscal 2021, the date of the annual impairment test. Based on its initial qualitative assessment over each of the reporting units, the Company identified 16 reporting units to test for impairment using a quantitative test for both goodwill and indefinite-lived intangible assets. In addition to the key assumptions reviewed summarized above, a key assumption used in response to the COVID-19 pandemic was the estimated length of time for the commercial aerospace sector to rebound to pre-pandemic levels. The estimated fair value of each of these reporting units was in excess of its respective carrying value, and therefore, no impairment was recorded on goodwill or indefinite-lived intangible assets. The Company performed a sensitivity analysis on the discount rate, which is a significant assumption in the calculation of fair values. With a one percentage point increase in the discount rate, all of the reporting units would continue to have fair values in excess of their respective carrying values. As a result of the impairment testing performed as of the first day of the fourth quarter, no indefinite-lived intangible assets or goodwill was determined to be impaired. As economic and market conditions have not changed significantly since the first day of the fourth quarter, this conclusion remains appropriate as of September 30, 2021. The Company assesses the recoverability of its amortizable intangible assets only when indicators of impairment are present by determining whether the amortization over their remaining lives can be recovered through projected, undiscounted cash flows from future operations. Amortization of amortizable intangible assets is computed using the straight-line method over the following estimated useful lives: technology from 20 to 22 years, order backlog from 1 to 1.5 years, customer relationships over 20 years and other intangible assets over 20 years. No indicators of impairment on the amortizable intangible assets were identified in fiscal 2021. Stock-Based Compensation —The Company records stock-based compensation expense using the Black-Scholes pricing model based on certain valuation assumptions. Compensation expense is recorded over the vesting periods of the stock options, adjusted for expected forfeitures. The Company has classified stock-based compensation primarily within selling and administrative expenses to correspond with the classification of employees that receive stock option grants. The Company also evaluates any subsequent changes to the respective option holders terms under the modification rules of ASC 718. If determined to be a modification, the Black-Scholes pricing model is updated as of the date of the modification resulting in a cumulative catch up to expense, if necessary. Refer to Note 18, “Stock-Based Compensation,” for further details. Income Taxes —The provision for income taxes is calculated using the asset and liability method. Under the asset and liability method, deferred income taxes are recognized for the tax effect of temporary differences between the financial statement carrying amount of assets and liabilities and the amounts used for income tax purposes and for certain changes in valuation allowances. Valuation allowances are recorded to reduce certain deferred tax assets when, in our estimation, it is more likely than not that a tax benefit will not be realized. We recognize uncertain tax positions when we have determined it is more likely than not that a tax position will be sustained upon examination. However, new information may become available, or applicable laws or regulations may change, thereby resulting in a favorable or unfavorable adjustment to amounts recorded. Refer to Note 14, “Income Taxes,” for further details. Estimates —The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Comprehensive Income (Loss) —The term “comprehensive income (loss)” represents the change in stockholders’ equity (deficit) from transactions and other events and circumstances resulting from non-stockholder sources. The Company’s accumulated other comprehensive income or loss, consisting principally of fair value adjustments to its interest rate swap and cap agreements (net of tax), cumulative foreign currency translation adjustments and pension liability adjustments (net of tax), is reported separately in the accompanying consolidated statements of comprehensive income. Foreign Currency Translation and Transactions —The assets and liabilities of subsidiaries located outside the United States are translated into U.S. dollars at the rates of exchange in effect at the balance sheet dates. Revenue and expense items are translated at the average monthly exchange rates prevailing during the period. Gains and losses resulting from foreign currency transactions are recognized currently in income, and those resulting from translation of financial statements are accumulated as a separate component of other comprehensive income (loss) for the period. Foreign currency gains or losses recognized currently in income from changes in exchange rates were immaterial to our results of operations. Earnings per Share —Earnings per share information is determined using the two-class method, which includes the weighted-average number of common shares outstanding during the period and other securities that participate in dividends (“participating securities”). Our vested stock options are considered “participating securities” because they include non-forfeitable rights to dividends. In applying the two-class method, earnings are allocated to both common stock shares and participating securities based on their respective weighted-average shares outstanding for the period. Diluted earnings per share information may include the additional effect of other securities, if dilutive, in which case the dilutive effect of such securities is calculated using the treasury stock method. Contingently issuable shares are not included in earnings per share until the period in which the contingency is satisfied. Refer to Note 6, “Earnings Per Share,” for further details. Pension Benefits —The Company accounts for net periodic pension benefit cost using the end of the fiscal year as our measurement date. Management selects appropriate assumptions including the discount rate, rate of increase in future compensation levels and assumed long-term rate of return on plan assets. The assumptions are based upon historical results, the current economic environment and reasonable expectations of future events. Actual results which vary from our assumptions are accumulated and amortized over future periods, and accordingly, are recognized in expense in these periods. Significant differences between the assumptions and actual experience or significant changes in assumptions could impact the pension costs and the pension obligation. Refer to Note 13, “Retirement Plans,” for further details.

RECENT ACCOUNTING PRONOUNCEMENT

RECENT ACCOUNTING PRONOUNCEMENTS	12 Months Ended
RECENT ACCOUNTING PRONOUNCEMENTS	Sep. 30, 2021
Accounting Standards Update and Change in Accounting Principle [Abstract]
RECENT ACCOUNTING PRONOUNCEMENTS	RECENT ACCOUNTING PRONOUNCEMENTS In June 2016, the FASB issued ASU 2016-13, "Financial Instruments—Credit Losses: Measurement of Credit Losses on Financial Instruments (ASU 2016-13)," which changes the impairment model for most financial assets. The new model uses a forward-looking expected loss method, which generally results in earlier recognition of allowances for losses. The Company adopted ASU 2016-13 on October 1, 2020. The adoption of this standard did not have a material impact on our consolidated financial statements and disclosures. Refer to Note 5, “Revenue Recognition,” for additional disclosures. In January 2017, the FASB issued ASU 2017-04, “Simplifying the Test for Goodwill Impairment,” to eliminate Step 2 from the goodwill impairment test in order to simplify the subsequent measurement of goodwill. The Company adopted ASU 2017-04 on October 1, 2020. The adoption of this standard did not have a material impact on our consolidated financial statements and disclosures. In December 2019, the FASB issued ASU 2019-12, “Income Taxes (ASC 740) - Simplifying the Accounting for Income Taxes,” which simplifies the accounting for income taxes by removing certain exceptions to the general principles in ASC 740. The amendments also improve consistent application of and simplify U.S. GAAP for other areas of ASC 740 by clarifying and amending existing guidance. This guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption of the amendments is permitted, including adoption in any interim period for which financial statements have not yet been issued. Depending on the amendment, adoption may be applied on the retrospective, modified retrospective or prospective basis. The adoption of this standard is not expected to have a material impact on our consolidated financial statements and disclosures. We will adopt as required on October 1, 2021. In March 2020, the FASB issued ASU 2020-04, “Reference Rate Reform." Certain amendments were provided for in ASU 2021-01, "Reference Rate Reform (ASC 848): Scope," which was issued in January 2021. This ASU provides optional guidance for a limited period of time to ease potential accounting impacts associated with transitioning away from reference rates that are expected to be discontinued, such as the London Interbank Offered Rate ("LIBOR"). The amendments in this ASU apply only to contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued. The amendments in this ASU are effective through December 31, 2022. The Company is currently evaluating the impact of adopting this standard on our consolidated financial statements and disclosures.

REVENUE RECOGNITION

REVENUE RECOGNITION	12 Months Ended
REVENUE RECOGNITION	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
REVENUE RECOGNITION	REVENUE RECOGNITION TransDigm's sales are concentrated in the aerospace and defense industry. The Company’s customers include: distributors of aerospace components, commercial airlines, large commercial transport and regional and business aircraft OEMs, various armed forces of the United States and friendly foreign governments, defense OEMs, system suppliers, and various other industrial customers. The majority of the Company's revenue is recorded at a point in time. Revenue is recognized from the sale of products when control transfers to the customer, which is demonstrated by our right to payment, a transfer of title, a transfer of the risk and rewards of ownership, or the customer acceptance, but most frequently upon shipment where the customer obtains physical possession of the goods. In some contracts, control transfers to the customer over time, primarily in contracts where the customer is required to pay for the cost of both the finished and unfinished goods at the time of cancellation plus a reasonable profit relative to the work performed for products that were customized for the customer. Therefore, we recognize revenue over time for those agreements that have a right to margin and where the products being produced have no alternative use. Based on our production cycle, it is generally expected that goods related to the revenue will be shipped and billed within the current year. For revenue recognized over time, we estimate the amount of revenue attributable to a contract earned at a given point during the production cycle based on certain costs, such as materials and labor incurred to date, plus the expected profit, which is a cost-to-cost input method. We consider the contractual consideration payable by the customer and assess variable consideration that may affect the total transaction price. Variable consideration is included in the estimated transaction price when there is a basis to reasonably estimate the amount, including whether the estimate should be constrained in order to avoid a significant reversal of revenue in a future period. These estimates are based on historical experience, anticipated performance under the terms of the contract and our best judgment at the time. When contracts are modified to account for changes in contract specifications and requirements, the Company considers whether the modification either creates new or changes the existing enforceable rights and obligations. Contract modifications that are for goods or services that are not distinct from the existing contract, due to the significant integration with the original good or service provided, are accounted for as if they were part of that existing contract. The effect of a contract modification to an existing contract on the transaction price and our measure of progress for the performance obligation to which it relates, is recognized as an adjustment to revenue on a cumulative catch-up basis. When the modifications include additional performance obligations that are distinct and at relative stand-alone selling price, they are accounted for as a new contract and performance obligation, which are recognized prospectively. The Company’s payment terms vary by the type and location of the customer and the products or services offered. The Company does not offer any payment terms that would meet the requirements for consideration as a significant financing component. Shipping and handling fees and costs incurred in connection with products sold are recorded in cost of sales in the consolidated statements of income, and are not considered a performance obligation to our customers. The Company pays sales commissions that relate to contracts for products or services that are satisfied at a point in time or over a period of one year or less and are expensed as incurred. These costs are reported as a component of selling and administrative expenses in the consolidated statements of income. In fiscal 2021 and 2020, no customer individually accounted for 10% or more of the Company’s net sales. In fiscal 2019, one customer accounted for approximately 11% of the Company’s net sales, which were split approximately 60% and 40% between the Airframe and Power & Control segments, respectively. Net sales to foreign customers, primarily in Western Europe, Canada and Asia, were $1.7 billion during the fiscal years ended 2021 and 2020, respectively, and $1.8 billion during the fiscal year ended 2019. Contract Assets and Liabilities - Contract assets reflect revenue recognized and performance obligations satisfied in advance of customer billing or reimbursable costs related to a specific contract. Contract liabilities relate to payments received in advance of the satisfaction of performance under the contract. We receive payments from customers based on the terms established in our contracts. The following table summarizes our contract assets and liabilities balances (in millions): September 30, 2021 September 30, 2020 Change Contract assets, current (1) $ 70 $ 36 $ 34 Contract assets, non-current (2) 2 6 (4) Total contract assets 72 42 30 Contract liabilities, current (3) 25 18 7 Contract liabilities, non-current (4) 5 9 (4) Total contract liabilities 30 27 3 Net contract assets $ 42 $ 15 $ 27 (1) Included in prepaid expenses and other on the consolidated balance sheets. (2) Included in other non-current assets on the consolidated balance sheets. (3) Included in accrued and other current liabilities on the consolidated balance sheets. (4) Included in other non-current liabilities on the consolidated balance sheets. For the fiscal year ended September 30, 2021, the revenue recognized that was previously included in contract liabilities was not material. Refer to Note 17, “Segments,” for disclosures related to the disaggregation of revenue.

EARNINGS PER SHARE

EARNINGS PER SHARE	12 Months Ended
EARNINGS PER SHARE	Sep. 30, 2021
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHARE The following table sets forth the computation of basic and diluted earnings per share (in millions, except per share data) using the two-class method: Fiscal Years Ended September 30, 2021 2020 2019 Numerator for earnings per share: Income from continuing operations $ 681 $ 653 $ 841 Less: Net income attributable to noncontrolling interests (1) (1) (2) Net income from continuing operations attributable to TD Group 680 652 839 Less: Special dividends declared or paid on participating securities, including dividend equivalent payments (73) (185) (111) Income from discontinued operations, net of tax — 47 51 Net income applicable to TD Group common stockholders - basic and diluted $ 607 $ 514 $ 779 Denominator for basic and diluted earnings per share under the two-class method: Weighted-average common shares outstanding 54.8 53.9 53.1 Vested options deemed participating securities 3.6 3.4 3.2 Total shares for basic and diluted earnings per share 58.4 57.3 56.3 Earnings per share from continuing operations—basic and diluted $ 10.41 $ 8.14 $ 12.94 Earnings per share from discontinued operations—basic and diluted — 0.82 0.90 Earnings per share $ 10.41 $ 8.96 $ 13.84

TRADE ACCOUNTS RECEIVABLE

TRADE ACCOUNTS RECEIVABLE	12 Months Ended
TRADE ACCOUNTS RECEIVABLE	Sep. 30, 2021
Receivables [Abstract]
TRADE ACCOUNTS RECEIVABLE	TRADE ACCOUNTS RECEIVABLE Trade accounts receivable consist of the following (in millions): September 30, 2021 September 30, 2020 Trade accounts receivable—gross $ 821 $ 757 Allowance for uncollectible accounts (30) (37) Trade accounts receivable—Net $ 791 $ 720 At September 30, 2021, one customer individually accounted for approximately 10% of the Company’s trade accounts receivable-gross. In addition, approximately 38% of the Company’s trade accounts receivable-gross was due from entities that operate principally outside of the United States. Credit is extended based on an evaluation of each customer’s financial condition and collateral is generally not required. The decrease in the allowance for uncollectible accounts for the fiscal year ended September 30, 2021 is primarily driven by a decrease in estimated losses from certain commercial aerospace customers that were more adversely affected by the COVID-19 pandemic. The allowance for uncollectible accounts is assessed individually at each operating unit by the operating unit’s management team.

INVENTORIES

INVENTORIES	12 Months Ended
INVENTORIES	Sep. 30, 2021
Inventory Disclosure [Abstract]
INVENTORIES	INVENTORIES Inventories consist of the following (in millions): September 30, 2021 September 30, 2020 Raw materials and purchased component parts $ 850 $ 881 Work-in-progress 322 358 Finished goods 207 222 Total 1,379 1,461 Reserves for excess and obsolete inventory (194) (178) Inventories—Net $ 1,185 $ 1,283

PROPERTY, PLANT AND EQUIPMENT

PROPERTY, PLANT AND EQUIPMENT	12 Months Ended
PROPERTY, PLANT AND EQUIPMENT	Sep. 30, 2021
Property, Plant and Equipment [Abstract]
PROPERTY, PLANT AND EQUIPMENT	PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment consist of the following (in millions): September 30, 2021 September 30, 2020 Land and improvements $ 103 $ 103 Buildings and improvements 409 350 Machinery, equipment and other 832 782 Construction-in-progress 61 57 Total 1,405 1,292 Accumulated depreciation (635) (540) Property, plant and equipment—Net $ 770 $ 752

INTANGIBLE ASSETS

INTANGIBLE ASSETS	12 Months Ended
INTANGIBLE ASSETS	Sep. 30, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
INTANGIBLE ASSETS	INTANGIBLE ASSETS Other intangible assets - net in the consolidated balance sheets consist of the following at September 30 (in millions): 2021 2020 Gross Carrying Accumulated Net Gross Carrying Accumulated Net Trademarks & trade names $ 983 $ — $ 983 $ 958 $ — $ 958 Technology 2,009 679 1,330 1,842 589 1,253 Order backlog (1) 16 11 5 93 93 — Customer relationships 545 78 467 443 52 391 Other 18 12 6 18 10 8 Total $ 3,571 $ 780 $ 2,791 $ 3,354 $ 744 $ 2,610 (1) Fully amortized order backlog associated with the Esterline acquisition was written down from the gross carrying amount and accumulated amortization in the second quarter of fiscal 2021 due to being fully amortized. There was no impact on the net balance. As disclosed in Note 2, "Acquisitions and Divestitures," the estimated fair value of the net identifiable tangible and intangible assets acquired is based on the acquisition method of accounting and is subject to adjustment upon completion of the third-party valuation. Material adjustments may occur. The fair value of the net identifiable tangible and intangible assets acquired will be finalized within the measurement period (not to exceed one year). Intangible assets acquired during the fiscal year ended September 30, 2021 are summarized in the table below (in millions), principally all relate to the CAC acquisition: Gross Amount Amortization Intangible assets not subject to amortization: Goodwill $ 703 Trademarks and trade names 35 738 Intangible assets subject to amortization: Technology 178 20 years Order backlog 16 1 year Customer relationships 101 20 years 295 Total $ 1,033 Information regarding the amortization expense of amortizable intangible assets is detailed below (in millions): Annual Amortization Expense: Fiscal years ended September 30, 2021 $ 137 2020 169 2019 135 Estimated Amortization Expense: Fiscal years ending September 30, 2022 $ 143 2023 143 2024 143 2025 143 2026 143 The following is a summary of changes in the carrying value of goodwill by segment for the fiscal years ended September 30, 2020 and 2021 were as follows (in millions): Power & Airframe Non- Total Balance at September 30, 2019 $ 4,121 $ 3,598 $ 101 $ 7,820 Purchase price allocation adjustments (1) (1) 39 — 38 Currency translation adjustments 21 10 — 31 Balance at September 30, 2020 4,141 3,647 101 7,889 Goodwill acquired during the period 9 694 — 703 Goodwill divested during the period (4) (32) (8) (44) Currency translation adjustments 3 17 — 20 Balance at September 30, 2021 $ 4,149 $ 4,326 $ 93 $ 8,568 (1) Primarily relates to opening balance sheet adjustments recorded by the reporting units acquired from Esterline up to the expiration of the one year measurement period in March 2020.

ACCRUED AND OTHER CURRENT LIABI

ACCRUED AND OTHER CURRENT LIABILITIES	12 Months Ended
ACCRUED AND OTHER CURRENT LIABILITIES	Sep. 30, 2021
Payables and Accruals [Abstract]
ACCRUED AND OTHER CURRENT LIABILITIES	ACCRUED AND OTHER CURRENT LIABILITIES Accrued and other current liabilities consist of the following (in millions): September 30, 2021 September 30, 2020 Interest $ 191 $ 178 Compensation and related benefits 167 173 Interest rate swap agreements (Note 21) 100 56 Dividend equivalent payments—current (Note 18) 46 72 Loss contract reserves 46 42 Product warranties 29 32 Contract liabilities, current (Note 5) 25 18 Current operating lease liabilities (Note 19) 20 22 Environmental and other litigation reserves 14 15 Other 172 165 Accrued and other current liabilities $ 810 $ 773

DEBT

DEBT	12 Months Ended
DEBT	Sep. 30, 2021
Debt Disclosure [Abstract]
DEBT	DEBT The Company’s debt consists of the following (in millions): September 30, 2021 Gross Amount Debt Issuance Costs Original Issue Discount or Premium Net Amount Short-term borrowings—trade receivable securitization facility $ 350 $ (1) $ — $ 349 Term loans $ 7,374 $ (39) $ (17) $ 7,318 Revolving credit facility 200 — — 200 8.00% senior secured notes due 2025 (“2025 Secured Notes”) 1,100 (7) — 1,093 6.375% senior subordinated notes due 2026 (“6.375% 2026 Notes”) 950 (5) — 945 6.875% senior subordinated notes due 2026 (“6.875% 2026 Notes”) 500 (4) (2) 494 6.25% secured notes due 2026 (“2026 Secured Notes”) 4,400 (45) 4 4,359 7.50% senior subordinated notes due 2027 (“7.50% 2027 Notes”) 550 (4) — 546 5.50% senior subordinated notes due 2027 (“5.50% 2027 Notes”) 2,650 (18) — 2,632 4.625% senior subordinated notes due 2029 (“4.625% 2029 Notes”) 1,200 (10) — 1,190 4.875% senior subordinated notes due 2029 (“4.875% 2029 Notes”) 750 (7) — 743 Government refundable advances 29 — — 29 Finance lease obligations 100 — — 100 19,803 (139) (15) 19,649 Less: current portion 278 (1) — 277 Long-term debt $ 19,525 $ (138) $ (15) $ 19,372 September 30, 2020 Gross Amount Debt Issuance Costs Original Issue Discount or Premium Net Amount Short-term borrowings—trade receivable securitization facility $ 350 $ (1) $ — $ 349 Term loans $ 7,449 $ (48) $ (23) $ 7,378 Revolving credit facility 200 — — 200 6.50% senior subordinated notes due 2024 (“2024 Notes”) 1,200 (5) — 1,195 6.50% senior subordinated notes due 2025 (“2025 Notes”) 750 (3) 3 750 2025 Secured Notes 1,100 (9) — 1,091 6.375% 2026 Notes 950 (6) — 944 6.875% 2026 Notes 500 (4) (3) 493 2026 Secured Notes 4,400 (55) 5 4,350 7.50% 2027 Notes 550 (5) — 545 5.50% 2027 Notes 2,650 (21) — 2,629 Government refundable advances 28 — — 28 Finance lease obligations 57 — — 57 19,834 (156) (18) 19,660 Less: current portion 277 (1) — 276 Long-term debt $ 19,557 $ (155) $ (18) $ 19,384 Fiscal 2021 Activity Issuance of 4.625% Senior Subordinated Notes due 2029 – On January 14, 2021, the Company entered into a purchase agreement in connection with a private offering of $1,200 million of 4.625% Senior Subordinated Notes due 2029 at an issue price of 100% of the principal amount. The 4.625% 2029 Notes were issued pursuant to an indenture, dated January 20, 2021, among TransDigm Inc., as issuer, TransDigm Group, TransDigm UK and the other subsidiaries of TransDigm Inc. named therein, as guarantors. The 4.625% 2029 Notes bear interest at the rate of 4.625% per annum, which accrues from January 14, 2021 and is payable in arrears on January 15th and July 15th of each year, commencing on July 15, 2021. The 4.625% 2029 Notes mature on January 15, 2029, unless earlier redeemed or repurchased, and are subject to the terms and conditions set forth in the indenture. The Company capitalized $11.3 million and expensed $0.1 million representing debt issuance costs associated with the 4.625% 2029 Notes during the fiscal year ended September 30, 2021. Repurchase of 6.50% Senior Subordinated Notes due 2024 – On January 14, 2021, the Company announced a cash tender offer for any and all of its outstanding 6.50% Senior Subordinated Notes due 2024. On February 16, 2021, the Company redeemed the principal amount of $1,200 million, plus accrued interest of approximately $6.3 million and early redemption premium of $19.5 million. The Company expensed refinancing costs of $23.6 million, consisting of the $19.5 million early redemption premium and the write off of $4.1 million in unamortized debt issuance costs during the fiscal year ended September 30, 2021 in conjunction with the redemption of the 2024 Notes. Issuance of 4.875% Senior Subordinated Notes due 2029 – On April 12, 2021, the Company entered into a purchase agreement in connection with a private offering of $750 million in 4.875% Senior Subordinated Notes due 2029 at an issue price of 100% of the principal amount. The 4.875% 2029 Notes were issued pursuant to an indenture, dated April 21, 2021, among TransDigm Inc., as issuer, TransDigm Group, TransDigm UK and the other subsidiaries of TransDigm Inc. named therein, as guarantors. The 4.875% 2029 Notes bear interest at a rate of 4.875% per annum, which accrues from April 12, 2021 and is payable in arrears on May 1st and November 1st of each year, commencing on November 1, 2021. The 4.875% 2029 Notes mature on May 1, 2029, unless earlier redeemed or repurchased, and are subject to the terms and conditions set forth in the indenture. The Company capitalized $7.1 million representing debt issuance costs associated with the 4.875% 2029 Notes during the fiscal year ended September 30, 2021. Repurchase of 6.50% Senior Subordinated Notes due 2025 – On April 12, 2021, the Company announced a cash tender offer for any and all of its outstanding 6.50% Senior Subordinated Notes due 2025. On May 14, 2021, the Company redeemed the principal amount of $750 million, plus accrued interest of approximately $24.4 million and an early redemption premium of $12.2 million. The Company expensed refinancing costs of $12.1 million, consisting of the $12.2 million early redemption premium and the write off of $2.1 million in unamortized debt issuance costs, offset by the write off of $2.2 million in unamortized premiums during the fiscal year ended September 30, 2021 in conjunction with the redemption of the 2025 Notes. Amendment No. 8 and Loan Modification Agreement – On May 24, 2021, the Company entered into Amendment No. 8 and Loan Modification Agreement (herein, "Amendment No. 8") to the Second Amended and Restated Credit Agreement dated as of June 4, 2014 (the "Credit Agreement"). Amendment No. 8, among other things, (i) extends the maturity date of the revolving credit commitments and revolving loans under its existing Credit Agreement to May 24, 2026, and (ii) the LIBOR interest rate per annum applicable to the revolving loans under its existing Credit Agreement is 2.50%, a decrease from the 3.00% rate that applied previously to the amendment . The other terms and conditions that apply to the revolving loans are substantially the same as the terms and conditions that applied to the revolving loans immediately prior to Amendment No. 8. The Company expensed $0.7 million in refinancing costs associated with Amendment No. 8 during the fiscal year ended September 30, 2021. Revolving Credit Facility The revolving credit facility bears interest at a rate of 2.50% plus LIBOR. At September 30, 2021, the applicable interest rate was 2.58%. As of September 30, 2021, the Company had $31.1 million in letters of credit outstanding and $528.9 million of borrowings available under the revolving credit facility. On October 6, 2021, the Company repaid $200 million of the revolving credit facility, in addition to $0.1 million of accrued interest, increasing the borrowings available under the revolving commitments to $728.9 million. Trade Receivable Securitization Facility During fiscal 2014, the Company established a trade receivable securitization facility (the “Securitization Facility”). The Securitization Facility effectively increases the Company’s borrowing capacity depending on the amount of the domestic operations’ trade accounts receivable. The Securitization Facility includes the right for the Company to exercise annual one year extensions as long as there have been no termination events as defined by the agreement. The Company uses the proceeds from the Securitization Facility as an alternative to other forms of debt, effectively reducing borrowing costs. On July 27, 2021, the Company amended the Securitization Facility to extend the maturity date to July 26, 2022. As of September 30, 2021, the Company has borrowed $350 million under the Securitization Facility, which bears interest at a rate of 1.20% plus LIBOR. At September 30, 2021, the applicable interest rate was 1.33%. The Securitization Facility is collateralized by substantially all of the Company’s domestic operations’ trade accounts receivable. Government Refundable Advances Government refundable advances consist of payments received from the Canadian government to assist in research and development related to commercial aviation. The requirement to repay this advance is based on year-over-year commercial aviation revenue growth for certain product lines at CMC Electronics, which is a wholly-owned subsidiary of TransDigm. As of September 30, 2021 and 2020, the outstanding balance of these advances were $28.9 million and $28.4 million, respectively. Obligations under Finance Leases The Company leases certain buildings and equipment under finance leases. The present value of the minimum finance lease payments, net of the current portion, represents a balance of $100.4 million and $56.8 million at September 30, 2021 and 2020, respectively. Refer to Note 19, “Leases,” for further disclosure of the Company’s lease obligations. Term Loans As of September 30, 2021 and 2020, TransDigm had $7,374 million and $7,449 million in fully drawn term loans and $760 million in revolving commitments, of which $529 million and $521 million was available to the Company as of September 30, 2021 and 2020, respectively. The term loans consist of three tranches as follows (in millions): Term Loan Facility Maturity Date Interest Rate Aggregate Principal as of September 30, 2021 2020 Tranche E May 30, 2025 LIBOR + 2.25% $ 2,177 $ 2,199 Tranche F December 9, 2025 LIBOR + 2.25% $ 3,454 $ 3,489 Tranche G August 22, 2024 LIBOR + 2.25% $ 1,743 $ 1,761 The interest rates per annum applicable to all of the existing tranches of term loans are, at TransDigm’s option, equal to either an alternate base rate or an adjusted LIBOR for one, two, three or six-month (or to the extent agreed to by each relevant lender, nine or twelve-month) interest periods chosen by TransDigm, in each case plus an applicable margin percentage. The adjusted LIBOR is not subject to a floor. At September 30, 2021 and 2020, the applicable interest rates for all existing tranches were 2.33% and 2.41%, respectively. Refinancing Costs During the fiscal year ended September 30, 2021, the Company expensed refinancing costs of $37 million, primarily representing the early redemption premium paid in connection with the repurchase of the $1,200 million 6.50% 2024 Notes and $750 million 6.50% 2025 Notes, and also the execution of Amendment No. 8 and Loan Modification Agreement. During the fiscal year ended September 30, 2020, the Company expensed refinancing costs of $28 million primarily representing the early redemption premium paid in connection with the repurchase of the $1,150 million 6.00% 2022 Notes, and also the execution of Amendment No. 7 and the Refinancing Facility Agreement. During the fiscal year ended September 30, 2019, the Company expensed refinancing costs of $3 million representing the early redemption premium paid in connection with the repurchase of the $550 million 2020 Senior Subordinated Notes and issuance of the $4.0 billion 2026 Senior Secured Notes. Interest Rate Swap and Cap Agreements Refer to Note 21, “Derivatives and Hedging Activities,” for information about how our interest rate swap and cap agreements are used to manage interest rate risk associated with floating-rate borrowings under our credit facilities. Secured Notes TransDigm Inc.’s 2025 Secured Notes and 2026 Secured Notes jointly and severally guaranteed, on a senior basis, by TD Group, TransDigm UK and all of TransDigm Inc.'s Domestic Restricted Subsidiaries, as defined in the applicable Indentures. The Secured Notes contain many of the restrictive covenants included in the Credit Agreement. TransDigm is in compliance with all the covenants contained in the notes. Subordinated Notes TransDigm Inc.'s 6.375% 2026 Notes, 7.50% 2027 Notes, 5.50% 2027 Notes, 4.625% 2029 Notes, and 4.875% 2029 Notes are jointly and severally guaranteed, on a senior subordinated basis, by TD Group, TransDigm UK and all of TransDigm Inc.'s Domestic Restricted Subsidiaries, as defined in the applicable Indenture. TransDigm UK's 6.875% 2026 Notes are jointly and severally guaranteed, on a senior subordinated basis, by TD Group, TransDigm Inc. and all of TransDigm Inc.'s Domestic Restricted Subsidiaries, as defined in the applicable Indenture. The Notes contain many of the restrictive covenants included in the Credit Agreement. TransDigm is in compliance with all the covenants contained in the notes. Debt Repayment Schedule At September 30, 2021, future maturities of long-term debt (includes finance leases) are as follows (in millions): Fiscal years ending September 30, 2022 $ 277 2023 80 2024 1,770 2025 2,151 2026 10,268 Thereafter 5,257 Total $ 19,803

RETIREMENT PLANS

RETIREMENT PLANS	12 Months Ended
RETIREMENT PLANS	Sep. 30, 2021
Retirement Benefits [Abstract]
RETIREMENT PLANS	RETIREMENT PLANS The Company maintains certain non-contributory defined benefit pension plans (collectively, referred to as the “pension plans”). The pension plans provide benefits of stated amounts for each year of service. The Company’s funding policy is to contribute actuarially determined amounts allowable under tax and statutory regulations for the qualified plans. The Company uses a September 30th measurement date for its defined benefit pension plans. In addition, the Company makes actuarially computed contributions to these plans as necessary to adequately fund benefits. The Company’s funding policy is consistent with the minimum funding requirements of the Employee Retirement Income Security Act of 1974 (“ERISA”). The Company sponsors a number of U.S. defined benefit pension plans (collectively, referred to as the “U.S. plans”), with the largest plan being the Esterline Technologies Retirement Plan (the “ERP”). The ERP’s pension benefits are primarily earned under a cash balance formula with annual pay credits ranging from 2% to 6%. During the first quarter of fiscal 2021, the Company announced of its intent to freeze the ERP effective December 31, 2020, and amended the plan to, among other things, close participation by new or rehired employees and freeze all future benefit accruals as of the effective date. On March 30, 2021, the Company approved an amendment of its intent to terminate the ERP effective June 30, 2021. The weighted-average interest crediting rate decreased from 5.50% in fiscal year 2020 to a fixed rate of 4.71% as of the Plan’s effective termination date, in accordance with IRS regulations. The Company anticipates the termination process to be completed within the next 12 months, with the ERP expected to be fully liquidated by the end of fiscal year 2022. As of September 30, 2021, the ERP’s pension obligation decreased by lump-sum settlement payments of $7.9 million that were distributed to participants from pension plan assets. As a result of the settlement, we were required to remeasure the ERP’s pension obligation. In connection with the remeasurement, we updated the effective discount rate assumption for the ERP’s pension obligation from 2.47% to 2.56% as of September 30, 2021. The increase in unrecognized actuarial losses from the remeasurement due to settlement payments that occurred during fiscal year 2021 was offset by increases to unrecognized actuarial gains from the freezing of all future benefit accruals of the ERP. During fiscal year 2021, the net amount of unrecognized actuarial losses recorded in accumulated other comprehensive loss on the Company’s consolidated balance sheets reclassified to other (income) expense on the consolidated statements of income related to the remeasurement was immaterial. The Company also sponsors a number of non-U.S. defined benefit pension plans (collectively, referred to as the “non-U.S. plans”), primarily in Canada, France, Germany and the United Kingdom. These defined benefit plans generally provide benefits to employees based on formulas recognizing length of service and earnings. The Company also sponsors other retirement benefit plans for its employees in Canada. Other retirement benefit plans are non-contributory health care and life insurance plans. The accumulated benefit obligation and projected benefit obligation for the U.S. plans are $350.6 million and $350.9 million, respectively, with plan assets of $341.1 million as of September 30, 2021. The underfunded status for the Company’s U.S. plans is $9.8 million at September 30, 2021. As of September 30, 2021, a $7.9 million decrease to the projected benefit obligation resulted from settlements that occurred in fiscal 2021 . Contributions to the Company’s qualified U.S. plans totaled $1.4 million in fiscal 2021. No contributions were made to non-qualified U.S. plans in fiscal 2021. Contributions to the Company’s qualified and non-qualified U.S. plans totaled $1.7 million and $19.8 million, respectively, in fiscal 2020. There is an expected funding requirement of $0.6 million in fiscal 2022 for the qualified U.S. pension plans maintained by the Company. The accumulated benefit obligation and projected benefit obligation for the non-U.S. plans are $217.2 million and $224.1 million, respectively, with plan assets of $205.9 million as of September 30, 2021. The underfunded status for these non-U.S. plans is $18.2 million at September 30, 2021. As of September 30, 2021, a $20.4 million decrease to the projected benefit obligation is due to divestitures that occurred in fiscal 2021. Contributions to the non-U.S. plans totaled $8.6 million and $8.3 million in fiscal 2021 and 2020, respectively. The expected funding requirement for fiscal 2022 for the non-U.S. plans is $2.3 million. U.S. Defined Benefit Pension Plans Non-U.S. Defined Benefit Pension Plans Principal assumptions as of year end 2021 2020 2021 2020 Discount rate 2.56% 2.47% 2.40% 1.90% Rate of increase in future compensation levels N/A (1) 4.45% 3.06% 2.90% Assumed long-term rate of return on plan assets 5.74% 5.99% 3.20% 3.69% (1) As a result of the plan freeze to the ERP for all future benefit accruals and participation by new or rehired employees on or after January 1, 2021, the assumed rate of increase in future compensation levels is not applicable as of September 30, 2021, as pay increases are not valued once a defined benefit pension plan is frozen . U.S. Post-Retirement Pension Plans Non-U.S. Post-Retirement Pension Plans Principal assumptions as of year end 2021 2020 2021 2020 Discount rate 2.36% 1.99% 2.87% 2.28% Initial weighted average health care trend rate 7.30% 7.27% 5.70% 5.50% Ultimate weighted average health care trend rate 6.00% 6.00% 4.20% 4.10% The Company uses discount rates developed from a yield curve established from high-quality corporate bonds and matched to plan-specific projected benefit payments. Although future changes to the discount rate are unknown, had the discount rate increased or decreased by 25 basis points, pension liabilities in total would have decreased $8.4 million or increased $9.0 million, respectively. Had the discount rate increased or decreased by 25 basis points, fiscal 2021 net periodic benefit income for the pension plans would have decreased $0.4 million or increased $0.6 million, respectively. In determining the expected long-term rate of return on the defined benefit pension plans’ assets, the Company considers the historical rates of return, the nature of investments, the asset allocation, and expectations of future investment strategies. Had the expected return on assets increased or decreased by 25 basis points, fiscal 2021 net periodic benefit income would have increased $1.3 million or decreased $1.4 million, respectively. Other than the expected settlement of the ERP in fiscal 2022 , m anagement is not aware of any legislative or other initiatives or circumstances that will significantly impact the Company’s pension obligations in fiscal 2022. Plan assets are invested in a diversified portfolio of equity and debt securities consisting primarily of common stocks, bonds and government securities. The objective of these investments is to maintain sufficient liquidity to fund current benefit payments and achieve targeted risk-adjusted returns. Management periodically reviews allocations of plan assets by investment type and evaluates external sources of information regarding the long-term historical returns and expected future returns for each investment type. Due to the freeze and subsequent termination of the ERP that occurred during fiscal 2021 , management approved changes to the Plan’s investment policy to align our pension plan assets with our projected benefit obligation to reduce volatility by targeting an investment strategy of approximately 85 to 95% in fixed-income securities and up to approximately 20% in return-seeking assets, consisting of primarily equity securities and real estate. Allocations by investment type are as follows : Actual Plan assets allocation as of fiscal year end: Target 2021 2020 Return-seeking assets (e.g., equity securities and real estate) 0%-20% 20.7% 39.1% Fixed-income securities (e.g., debt securities) 85%- 95% 78.3% 57.0% Cash —% 1.0% 3.9% Total 100.0% 100.0% The following table presents the fair value of the Company’s pension plan assets as of September 30, 2021, by asset category segregated by level within the fair value hierarchy, as described in Note 20, “Fair Value Measurements” (in millions): Fair Value Hierarchy Level 1 Level 2 Total Investments measured at fair value by category: (5) Return-seeking assets: (1) U.S. equity securities $ 6 $ — $ 6 Non-U.S. equity securities 34 — 34 Fixed-income securities: (2) Non-U.S. foreign commercial and government bonds — 53 53 Cash and cash equivalents (3) 5 — 5 $ 45 $ 53 $ 98 Investments measured at net asset value by category: (4) Return-seeking assets: (1) Commingled trust funds - Non-U.S. securities 65 Non-U.S. equity securities 9 Fixed-income securities: (2) U.S. government bonds and securities 91 U.S corporate bonds 223 Non-U.S. corporate bonds 20 Non-U.S. foreign commercial and government bonds 41 Total $ 547 The following table presents the fair value of the Company’s pension plan assets as of September 30, 2020, by asset category segregated by level within the fair value hierarchy, as described in Note 20, “Fair Value Measurements” (in millions): Fair Value Hierarchy Level 1 Level 2 Total Investments measured at fair value by category: (5) Return-seeking assets: (1) U.S. equity securities $ 4 $ — $ 4 Non-U.S. equity securities 48 — 48 Fixed-income securities: (2) Non-U.S. foreign commercial and government bonds — 58 58 Cash and cash equivalents (3) 22 — 22 $ 74 $ 58 $ 132 Investments measured at net asset value by category: (4) Return-seeking assets: (1) Commingled trust funds - Non-U.S. securities 153 Non-U.S. equity securities 9 Fixed-income securities: (2) U.S. government bonds and securities 80 U.S corporate bonds 123 Non-U.S. corporate bonds 18 Non-U.S. foreign commercial and government bonds 31 Total $ 546 (1) Level 1 return-seeking assets, which are primarily equity securities and real estate, are actively traded on U.S. and non-U.S. exchanges and are either valued using the market approach at quoted market prices on the measurement date or at the net asset value of the shares held by the plan on the measurement date based on quoted market prices. (2) Level 2 fixed-income securities, which are primarily debt securities, are primarily valued using the market approach at either quoted market prices, pricing models that use observable market data, or bids provided by independent investment brokerage firms. (3) Cash and cash equivalents include cash which is used to pay benefits and cash invested in a short-term investment fund that holds securities with values based on quoted market prices, but for which the funds are not valued on quoted market basis. (4) These investments are valued at the net asset value (“NAV”) of units held. The NAV is used to estimate fair value and is based on the fair value of the underlying investments held by the fund less its liability. (5) No investments measured using Level 3 inputs. Net periodic pension benefit (income) cost for the Company’s U.S. and non-U.S. defined benefit pension plans at the end of each fiscal year consisted of the following (in millions): Defined Benefit Pension Plans 2021 2020 2019 U.S. Pension Plans Non-U.S. Pension Plans U.S. Pension Plans Non-U.S. Pension Plans U.S. Pension Plans Non-U.S. Pension Plans Service cost $ 2 $ 5 $ 9 $ 6 $ 5 $ 3 Interest cost 6 5 10 5 7 5 Expected return on plan assets (19) (7) (19) (8) (10) (6) Amortization of net loss 1 2 1 1 — — Curtailment/settlements (gain) loss — (2) (1) (1) — — Net periodic pension benefit (income) cost $ (10) $ 3 $ — $ 3 $ 2 $ 2 Net periodic pension benefit cost for the Company’s U.S. and non-U.S. post-retirement pension plans was less than $1 million for each of the fiscal years ended 2021, 2020 and 2019. The components of net periodic pension benefit cost other than service cost are included in other (income) expense in the consolidated statements of income. The funded status of the defined benefit pension and post-retirement plans at the end of fiscal 2021 and 2020 were as follows (in millions): Defined Benefit Pension Plans Post-Retirement Pension Plans September 30, 2021 September 30, 2020 September 30, 2021 September 30, 2020 U.S. Pension Plans Non-U.S. Pension Plans U.S. Pension Plans Non-U.S. Pension Plans U.S. Pension Plans Non-U.S. Pension Plans U.S. Pension Plans Non-U.S. Pension Plans Benefit Obligations Beginning balance $ 366 $ 248 $ 379 $ 270 $ 1 $ 14 $ 1 $ 14 Currency translation adjustment — 10 — 5 — 1 — — Service cost 2 5 9 6 — 1 — — Interest cost 6 5 10 5 — — — — Plan participant contributions — 1 — 1 — — — — Actuarial (gain) loss — (11) 10 13 — (3) — 1 Curtailments — (4) — (2) — — — — Settlements (8) (1) (20) (40) — — — — Divestitures — (20) — — — — — — Other adjustments 1 — — — 1 — — — Benefits paid (16) (9) (22) (10) — (1) — (1) Ending balance $ 351 $ 224 $ 366 $ 248 $ 2 $ 12 $ 1 $ 14 Plan Assets - Fair Value Beginning balance $ 342 $ 204 $ 318 $ 234 $ — $ — $ — $ — Currency translation adjustment — 9 — 3 — — — — Realized and unrealized gain on plan assets 22 14 44 8 — — — — Plan participant contributions — 1 — 1 — — — — Company contributions — 8 21 8 — 1 — 1 Settlements (8) (1) (19) (40) — — — — Divestitures — (20) — — — — — — Other adjustments 1 — — — — — — — Benefits paid (16) (9) (22) (10) — (1) — (1) Ending balance $ 341 $ 206 $ 342 $ 204 $ — $ — $ — $ — Funded Status Fair value of plan assets $ 341 $ 206 $ 342 $ 204 $ — $ — $ — $ — Benefit obligations (351) (224) (366) (248) (2) (12) (1) (14) Net amount recognized $ (10) $ (18) $ (24) $ (44) $ (2) $ (12) $ (1) $ (14) Amount Recognized on Consolidated Balance Sheet Other (non-current assets) $ — $ 6 $ — $ 4 $ — $ — $ — $ — Accrued liabilities (current) (3) — (1) (1) — (1) — (1) Other non-current liabilities (7) (24) (23) (47) (2) (11) (1) (13) Net amount recognized $ (10) $ (18) $ (24) $ (44) $ (2) $ (12) $ (1) $ (14) Amounts Recognized in Accumulated Other Comprehensive Income Net actuarial loss (gain) $ 10 $ 14 $ 12 $ 35 $ (1) $ (2) $ — $ 2 Prior service cost 1 1 1 1 1 — — — Ending balance $ 11 $ 15 $ 13 $ 36 $ — $ (2) $ — $ 2 The accumulated benefit obligation for all pension plans wa s $567.8 million and $595.3 million as of September 30, 2021 and September 30, 2020, respectively. Estimated future benefit payments expected to be paid from the pension and post-retirement benefit plans or from the Company’s assets are as follows (in millions): Fiscal years ending September 30, 2022 (1) $ 350 2023 12 2024 12 2025 12 2026 13 2027 - 2031 65 (1) Expected benefit payments in fiscal year 2022 primarily relates to the expected liquidation of the ERP. Defined Contribution Plans The Company sponsors certain defined contribution employee savings plans that cover substantially all of the Company’s U.S. employees. Under certain plans, the Company contributes a percentage of employee compensation and matches a portion of employee contributions. The cost recognized for such contributions for the fiscal years ended September 30, 2021, 2020 and 2019 was approximately $28.3 million, $25.3 million and $24.5 million, respectively.

INCOME TAXES

INCOME TAXES	12 Months Ended
INCOME TAXES	Sep. 30, 2021
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The Company’s income from continuing operations before income taxes includes the following components for the periods shown below (in millions): Fiscal Years Ended September 30, 2021 2020 2019 United States $ 516 $ 635 $ 878 Foreign 199 105 185 $ 715 $ 740 $ 1,063 The Company’s income tax provision (benefit) on income from continuing operations consists of the following for the periods shown below (in millions): Fiscal Years Ended September 30, 2021 2020 2019 Current Federal $ (21) $ 26 $ 154 State 14 3 15 Foreign 7 34 54 — 63 223 Deferred Federal 7 29 15 State (2) 3 2 Foreign 29 (8) (18) 34 24 (1) $ 34 $ 87 $ 222 A reconciliation of the federal statutory income tax rate to the effective income tax rate for the periods shown below is as follows: Fiscal Years Ended September 30, 2021 2020 2019 Federal statutory income tax rate 21.0 % 21.0 % 21.0 % Provision to return adjustments 2.2 % (0.4) % (0.3) % Remeasurement of deferred tax assets and liabilities related to enacted statutory rate changes 2.1 % 0.4 % (0.5) % Gain on sale of businesses 1.4 % — % — % Global intangible low-taxed income 1.3 % 0.4 % 1.0 % Foreign tax credits (1.2) % (0.6) % (1.7) % Research and development credits (1.2) % (0.6) % (0.6) % Foreign-derived intangible income (1.5) % (2.8) % (1.5) % Resolution and settlements to uncertain tax positions (3.2) % (0.3) % (0.3) % Changes in valuation allowances impacting results (1) (8.2) % 4.2 % 6.2 % Stock compensation (8.7) % (10.7) % (5.4) % Other—net 0.7 % 1.1 % 3.0 % Effective income tax rate 4.7 % 11.7 % 20.9 % (1) Primarily relates to the Company’s business interest expense limitation pursuant to IRC §163(j) as modified by the Tax Cuts and Jobs Act. Such provision, as modified, was effective for the Company beginning in fiscal 2019. In general, the deduction for interest expense is limited to 30% (50% as modified by the CARES Act for the Company’s fiscal 2020 and 2021) of the sum of the Company’s adjusted taxable income (“ATI”) and its business interest income. Interest expense disallowed by such limitation, in a taxable year, may be carried forward indefinitely. Based upon available evidence, a valuation allowance was recorded for the resulting carryforward to reflect the Company’s belief that it is more likely than not that such deferred tax assets will not be realized. In fiscal 2021, the Company made a tax election on its most recently filed U.S. federal income tax return allowing for the utilization of its net interest limitation carryforward. The Company recognized approximately $69.0 million of benefit from the release of the valuation allowance, applicable to such carryforward, for the fiscal year ended September 30, 2021. The components of the deferred taxes consist of the following (in millions): September 30, 2021 September 30, 2020 Deferred tax assets (liabilities): Intangible assets $ (814) $ (730) Property, plant and equipment (32) (59) Employee benefits 107 110 Interest rate swaps and caps 69 92 Net operating losses 58 54 Loss contract reserves 51 55 Inventories 45 41 U.S. income tax credits 31 17 Interest expense limitation 28 87 Non-U.S. income tax credits 20 21 Environmental reserves 11 12 Product warranty reserves 7 10 Other 8 9 Total (411) (281) Add: Valuation allowance (74) (132) Total net deferred tax assets (liabilities) $ (485) $ (413) At September 30, 2021, the Company has state net operating loss carryforwards of approximately $1,491.8 million, German net operating loss carryforwards of $41.2 million and United Kingdom net operating loss carryforwards of approximately $39.6 million that expire in various tax years from 2021 to 2039. The Company has U.S. and non-U.S. tax credit carryforwards of $50.7 million that expire beginning in 2025. The deferred tax assets for the interest expense limitation, net operating losses, and tax credit carryforwards are reduced by a valuation allowance for the amount of such assets that the Company believes will not be realized. The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction and various state, local and foreign jurisdictions. The Company is no longer subject to U.S. federal examinations for years before fiscal 2017. The Company is currently under examination for its federal income taxes in Canada for fiscal years 2013 through 2019, in France for fiscal years 2018 through 2019 and in Germany for fiscal years 2014 through 2017. The Company expects the examinations in France to be completed during fiscal 2022. In addition, the Company is subject to state income tax examinations for fiscal years 2015 and later. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in millions): 2021 2020 Balance at October 1 $ 41 $ 37 Additions based on tax positions related to the prior year — 7 Additions based on tax positions related to the current year 2 2 Reductions based on tax positions related to the prior year (18) (1) Settlement with tax authorities (4) (2) Lapse in statute of limitations (2) (2) Balance at September 30 $ 19 $ 41 Unrecognized tax benefits at September 30, 2021 and 2020, the recognition of which would have an effect on the effective tax rate for each fiscal year, amounted to $19.1 million and $40.9 million, respectively. The Company classifies all income tax-related interest and penalties as income tax expense, which were not significant for the years ended September 30, 2021 and 2020. As of September 30, 2021 and 2020, the Company accrued $4.9 million and $8.7 million, respectively, for the potential payment of interest and penalties. Within the next 12 months, it is reasonably possible that unrecognized tax benefits could be reduced by approximately $3.0 million resulting from the resolution or closure of tax examinations. Any increase in the amount of unrecognized tax benefits within the next 12 months is not expected to be material.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
COMMITMENTS AND CONTINGENCIES	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES During the ordinary course of business, the Company is from time to time threatened with, or may become a party to, legal actions and other proceedings. While the Company is currently involved in certain legal proceedings, it believes the results of these proceedings will not have a material adverse effect on its financial condition, results of operations, or cash flows. Litigation Claims – We, as a nominal defendant, and certain of our current or former directors, are defendants in a shareholder derivative action captioned Sciabacucchi v Howley, et al. (Del. Chancery Court). The case was filed on November 1, 2021. The plaintiff alleges that the defendants breached their fiduciary duties, that the directors engaged in corporate waste and that the directors and our former Executive Chair and Chief Executive Officer were unjustly enriched in connection with the compensation paid to them. The plaintiff seeks attorney fees and equitable remedies such as rescission of compensation and changes in corporate policies, as well as unspecified monetary damages. Although we are only a nominal defendant in the derivative action, we could have indemnification obligations and/or be required to advance the costs and expenses of the officer and director defendants in the action. We do not expect this matter to have a material adverse impact on our financial condition or results of operations. Environmental Liabilities – Our operations and facilities are subject to a number of federal, state, local and foreign environmental laws and regulations that govern, among other things, discharges of pollutants into the air and water, the generation, handling, storage and disposal of hazardous materials and wastes, the remediation of contamination and the health and safety of our employees. Environmental laws and regulations may require that the Company investigate and remediate the effects of the release or disposal of materials at sites associated with past and present operations. Certain facilities and third-party sites utilized by the Company have been identified as potentially responsible parties under the federal superfund laws and comparable state laws. The Company is currently involved in the investigation and remediation of a number of sites under applicable laws. Estimates of the Company’s environmental liabilities are based on current facts, laws, regulations and technology. These estimates take into consideration the Company’s prior experience and professional judgment of the Company’s environmental advisors. Estimates of the Company’s environmental liabilities are further subject to uncertainties regarding the nature and extent of site contamination, the range of remediation alternatives available, evolving remediation standards, imprecise engineering evaluations and cost estimates, the extent of corrective actions that may be required and the number and financial condition of other potentially responsible parties, as well as the extent of their responsibility for the remediation. Accordingly, as investigation and remediation proceed, it is likely that adjustments in the Company’s accruals will be necessary to reflect new information. The amounts of any such adjustments could have a material adverse effect on the Company’s results of operations or cash flows in a given period. Based on currently available information, however, the Company does not believe that future environmental costs in excess of those accrued with respect to sites for which the Company has been identified as a potentially responsible party are likely to have a material adverse effect on the Company’s financial condition or results of operations. Environmental liabilities are recorded when the liability is probable and the costs are reasonably estimable, which generally is not later than at completion of a feasibility study or when the Company has recommended a remedy or has committed to an appropriate plan of action. The Company also takes into consideration the estimated period of time in which payments will be required. The liabilities are reviewed periodically and, as investigation and remediation proceed, adjustments are made as necessary. Liabilities for losses from environmental remediation obligations do not consider the effects of inflation and anticipated expenditures are not discounted to their present value. The liabilities are not offset by possible recoveries from insurance carriers or other third parties, but do reflect anticipated allocations among potentially responsible parties at federal superfund sites or similar state-managed sites, third party indemnity obligations, and an assessment of the likelihood that such parties will fulfill their obligations at such sites. The Company’s consolidated balance sheets includes current environmental remediation obligations at September 30, 2021 and 2020 of $8.2 million and $7.9 million classified as a component of accrued and other current liabilities, respectively, and non-current environmental remediation obligations at September 30, 2021 and 2020 of $40.7 million and $43.1 million classified as a component of other non-current liabilities, respectively. Leach International Europe (Facility Fire) – On August 8, 2019, a fire caused significant damage to the Niort, France operating facility of the Leach International Europe subsidiary, which is reported within the Company’s Power & Control segment. The facility as well as certain machinery, equipment and inventory sustained damage. The Company suspended operations at the Niort facility as a result of the fire; however, had transferred certain operations to temporary facilities until operations were fully restored at the rebuilt facility. The new facility was completed in December 2020 and was fully operational as of March 2021. The Company’s insurance covers damage to the facility, equipment, inventory, and other assets, at replacement cost, as well as business interruption losses and other incremental costs resulting from the disruption of operations caused by the fire, subject to a $1 million deductible and certain sub-limits based on the nature of the covered item. Anticipated insurance recoveries related to losses and incremental costs incurred were recognized when receipt was probable. Anticipated insurance recoveries in excess of net book value of the damaged property and inventory were recorded once all contingencies relating to the claim had been resolved. During fiscal 2021, the insurance claim, inclusive of property, business interruption and incremental costs of working, was settled for $88 million, net of the $1 million deductible. A gain of $24 million was recorded to other income during fiscal 2021, of which $19 million represents the insurance proceeds received in excess of the carrying value of the damaged fixed assets and inventory and $5 million represents the insurance proceeds received in excess of previously recorded receivables for business interruption and incremental costs of working.

CAPITAL STOCK

CAPITAL STOCK	12 Months Ended
CAPITAL STOCK	Sep. 30, 2021
Equity [Abstract]
CAPITAL STOCK	TD Group consists of 224,400,000 shares of $.01 par value common stock and 149,600,000 shares of $.01 par value preferred stock. The total number of shares of common stock issued at September 30, 2021 and 2020 was 59,403,100 and 58,612,028, respectively. The total number of shares held in treasury was 4,198,226 at September 30, 2021 and 2020. There were no shares of preferred stock outstanding at September 30, 2021 and 2020. The terms of the preferred stock have not been established.On November 8, 2017, our Board of Directors, authorized a stock repurchase program permitting repurchases of our outstanding shares not to exceed $650 million in the aggregate, subject to any restrictions specified in the Credit Agreement and/or Indentures governing the existing Notes. During March 2020, the Company repurchased 36,900 shares of its common stock at a gross cost of $18.9 million at the weighted average cost of $512.67 under the program. No repurchases were made under the program during the fiscal year ended September 30, 2021. As of September 30, 2021, the remaining amount of repurchases allowable under the program was $631.1 million subject to any restrictions specified in the Credit Agreement and/or Indentures governing the existing Notes.

SEGMENTS

SEGMENTS	12 Months Ended
SEGMENTS	Sep. 30, 2021
Segment Reporting [Abstract]
SEGMENTS	SEGMENTS The Company’s businesses are organized and managed in three reporting segments: Power & Control, Airframe and Non-aviation. The Power & Control segment includes operations that primarily develop, produce and market systems and components that predominately provide power to or control power of the aircraft utilizing electronic, fluid, power and mechanical motion control technologies. Major product offerings include mechanical/electro-mechanical actuators and controls, ignition systems and engine technology, specialized pumps and valves, power conditioning devices, specialized AC/DC electric motors and generators, batteries and chargers, databus and power controls, advanced sensor products, switches and relay panels, high performance hoists, winches and lifting devices, and cargo loading, handling and delivery systems. Primary customers of this segment are engine and power system and subsystem suppliers, airlines, third party maintenance suppliers, military buying agencies and repair depots. Products are sold in the original equipment and aftermarket market channels. The Airframe segment includes operations that primarily develop, produce and market systems and components that are used in non-power airframe applications utilizing airframe and cabin structure technologies. Major product offerings include engineered latching and locking devices, engineered rods, engineered connectors and elastomer sealing solutions, cockpit security components and systems, specialized and advanced cockpit displays, engineered audio, radio and antenna systems, specialized lavatory components, seat belts and safety restraints, engineered and customized interior surfaces and related components, thermal protection and insulation, lighting and control technology and parachutes. Primary customers of this segment are airframe manufacturers and cabin system suppliers and subsystem suppliers, airlines, third party maintenance suppliers, military buying agencies and repair depots. Products are sold in the original equipment and aftermarket market channels. The Non-aviation segment includes operations that primarily develop, produce and market products for non-aviation markets. Major product offerings include seat belts and safety restraints for ground transportation applications, mechanical/electro-mechanical actuators and controls for space applications, hydraulic/electromechanical actuators and fuel valves for land based gas turbines, and refueling systems for heavy equipment used in mining, construction and other industries and turbine controls for the energy and oil and gas markets. Primary customers of this segment are off-road vehicle suppliers and subsystem suppliers, child restraint system suppliers, satellite and space system suppliers, manufacturers of heavy equipment used in mining, construction and other industries and turbine original equipment manufacturers, gas pipeline builders and electric utilities. The primary measurement used by management to review and assess the operating performance of each segment is EBITDA As Defined. The Company defines EBITDA As Defined as earnings before interest, taxes, depreciation and amortization plus certain non-operating items recorded as corporate expenses including non-cash compensation charges incurred in connection with the Company’s stock incentive plans, restructuring costs related to the Company's cost reduction measures in response to the COVID-19 pandemic, foreign currency gains and losses, acquisition-integration costs, acquisition and divestiture transaction-related expenses, and refinancing costs. COVID-19 restructuring costs represent actions taken by the Company to reduce its workforce to align with customer demand, as well as incremental costs related to the pandemic that are not expected to recur once the pandemic has subsided and are clearly separable from normal operations (e.g., additional cleaning and disinfecting of facilities by contractors above and beyond normal requirements, personal protective equipment). Acquisition and divestiture-related costs represent accounting adjustments to inventory associated with acquisitions of businesses and product lines that were charged to cost of sales when the inventory was sold; costs incurred to integrate acquired businesses and product lines into the Company’s operations, facility relocation costs and other acquisition-related costs; transaction-related costs for both acquisitions and divestitures comprising deal fees; legal, financial and tax diligence expenses and valuation costs that are required to be expensed as incurred and other acquisition accounting adjustments. EBITDA As Defined is not a measurement of financial performance under U.S. GAAP. Although the Company uses EBITDA As Defined to assess the performance of its business and for various other purposes, the use of this non-GAAP financial measure as an analytical tool has limitations, and it should not be considered in isolation or as a substitute for analysis of the Company’s results of operations as reported in accordance with U.S. GAAP. The Company’s segments are reported on the same basis used internally for evaluating performance and for allocating resources. The accounting policies for each segment are the same as those described in the summary of significant accounting policies in the Company’s consolidated financial statements. Intersegment sales and transfers are recorded at values based on market prices, which creates intercompany profit on intersegment sales or transfers that is eliminated in consolidation. Intersegment sales were immaterial for the periods presented below. Corporate consists of our corporate offices. Corporate office expenses consist primarily of compensation, benefits, professional services and other administrative costs incurred by the corporate offices. Corporate assets consist primarily of cash and cash equivalents. Corporate expenses and assets reconcile reportable segment data to the consolidated totals. An immaterial amount of corporate expenses are allocated to the operating segments. The following table presents net sales by reportable segment (in millions): Fiscal Years Ended September 30, 2021 2020 2019 Net sales to external customers Power & Control Commercial and non-aerospace OEM $ 527 $ 623 $ 686 Commercial and non-aerospace aftermarket 576 673 769 Defense 1,447 1,399 1,281 Total Power & Control 2,550 2,695 2,736 Airframe Commercial and non-aerospace OEM 591 783 836 Commercial and non-aerospace aftermarket 550 689 865 Defense 942 781 628 Total Airframe 2,083 2,253 2,329 Total Non-aviation 165 155 158 Net sales $ 4,798 $ 5,103 $ 5,223 The following table reconciles EBITDA As Defined by segment to consolidated income from continuing operations before income taxes (in millions): Fiscal Years Ended September 30, 2021 2020 2019 EBITDA As Defined Power & Control $ 1,319 $ 1,345 $ 1,395 Airframe 878 955 1,063 Non-aviation 62 54 51 Total segment EBITDA As Defined 2,259 2,354 2,509 Less: Unallocated corporate expenses 70 76 90 Total Company EBITDA As Defined 2,189 2,278 2,419 Depreciation and amortization expense 253 283 225 Interest expense, net 1,059 1,029 859 Acquisition and divestiture-related costs 35 31 169 Non-cash stock compensation expense 129 93 93 Refinancing costs 37 28 3 COVID-19 pandemic restructuring costs 40 54 — Gain on sale of businesses, net (69) — — Other, net (10) 20 7 Income from continuing operations before income taxes $ 715 $ 740 $ 1,063 The following table presents capital expenditures and depreciation and amortization by segment (in millions): Fiscal Years Ended September 30, 2021 2020 2019 Capital expenditures Power & Control $ 65 $ 89 $ 50 Airframe 37 10 48 Non-aviation 2 4 3 Corporate 1 2 1 $ 105 $ 105 $ 102 Depreciation and amortization Power & Control $ 107 $ 117 $ 99 Airframe 139 157 119 Non-aviation 6 7 6 Corporate 1 2 2 $ 253 $ 283 $ 226 The following table presents total assets by segment (in millions): September 30, 2021 September 30, 2020 Total assets Power & Control $ 6,980 $ 7,005 Airframe 7,472 6,575 Non-aviation 229 251 Corporate 4,634 4,564 $ 19,315 $ 18,395 Geographic Area Information Net sales are measured based on the geographic destination of sales. Long-lived assets consist of property, plant and equipment - net and operating lease right-of-use assets. Net sales and long-lived assets of individual countries outside of the United States are not material. The following table presents net sales by geographic area (in millions): September 30, 2021 September 30, 2020 Net sales United States $ 3,096 $ 3,407 Foreign Countries 1,702 1,696 $ 4,798 $ 5,103 The following table presents long-lived assets by geographic area (in millions): September 30, 2021 September 30, 2020 Long-lived assets United States $ 608 $ 600 Foreign Countries 256 255 $ 864 $ 855

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	12 Months Ended
STOCK-BASED COMPENSATION	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION The Company’s equity compensation plans are designed to assist the Company in attracting, retaining, motivating and rewarding key employees, directors or consultants, and promoting the creation of long-term value for stockholders by closely aligning the interests of these individuals with those of the Company’s stockholders. The Company’s equity compensation plans provide for the granting of stock options. Non-cash stock compensation expense recognized by the Company during the fiscal years ended September 30, 2021, 2020 and 2019 was $128.9 million, $92.7 million and $93.4 million, respectively. The weighted-average grant date fair value of options granted during the fiscal years ended September 30, 2021, 2020 and 2019 was $193.47, $157.41 and $114.43, respectively. Compensation expense is recognized based upon probability assessments of awards that are expected to vest in future periods, adjusted for expected forfeitures. Such probability assessments are subject to revision and, therefore, unrecognized compensation expense is subject to future changes in estimate. As of September 30, 2021, there was approximately $55.0 million of total unrecognized compensation expense related to non-vested awards expected to vest, which is expected to be recognized over a weighted-average period of 1.3 years. On September 25, 2020, the Compensation Committee of the Board of Directors determined to allow the portion of options granted in fiscal 2020 with a scheduled vesting date in 2020 to vest, effective September 30, 2020, notwithstanding that performance criteria for such options would not be met. This action impacted options granted to approximately 85 individuals, including all of the independent directors and certain executive officers. This action was treated as a modification for accounting purposes under ASC 718. An additional $2.5 million of stock compensation expense for fiscal 2020 resulted from this modification. On November 10, 2020, the Compensation Committee of the Board of Directors approved the Company’s established performance criteria required to be achieved for the options granted in fiscal 2020 and in fiscal 2021 with a scheduled vesting date of September 30, 2021. This action resulted in a modification for accounting purposes under ASC 718 for the options granted in fiscal 2020, consisting of 64 individuals, including all of the independent directors and certain executive officers. An additional $8.5 million of stock compensation expense for fiscal 2021 resulted from this modification. The fair value of the Company’s employee stock options was estimated at the date of grant or modification using a Black-Scholes option-pricing model with the following weighted average assumptions for all options granted during the fiscal years ended: Fiscal Years Ended September 30, 2021 2020 2019 Risk-free interest rate 0.42% to 0.86% 0.26% to 1.65% 2.33% to 3.03% Expected life of options 5.5 years 5 to 5.5 years 5.5 years Expected dividend yield of stock — — — Expected volatility of stock 36% 25% to 39% 25% The risk-free interest rate is based upon the U.S. Treasury bond rates as of the grant or modification date. The average expected life of stock-based awards is based on the Company’s actual historical exercise experience. Expected volatility of stock was calculated using a rate based upon the historical volatility of TransDigm’s common stock up to the date of grant or date of modification. The Company estimates stock option forfeitures based on historical data. The total number of stock options expected to vest is adjusted by actual and estimated forfeitures. Changes to the actual and estimated forfeitures will result in a cumulative adjustment in the period of change. Notwithstanding the special cash dividends declared and paid from time to time, the Company historically has not declared and paid regular cash dividends and does not anticipate declaring and paying regular cash dividends in future periods; thus, no dividend rate assumption is used. The total fair value of options vested during fiscal years ended September 30, 2021, 2020 and 2019 was $92.0 million, $97.2 million and $37.7 million, respectively. The significant increase in the total fair value of options vested during fiscal years 2021 and 2020 compared to fiscal year 2019 resulted from substantially more options vesting and increase in the grant date fair value, particularly between fiscal 2019 and fiscal 2020. 2019 Stock Option Plan In August 2019, the Board of Directors of TD Group adopted a new stock option plan, which was subsequently approved by stockholders on October 3, 2019. The 2019 stock option plan permits TD Group to award stock options to our key employees, directors or consultants. The total number shares of TD Group common stock reserved for issuance or delivery under the 2019 stock option plan is 4,000,000, subject to adjustment in the event of any stock dividend or split, reorganization, recapitalization, merger, share exchange or any other similar corporate transaction or event. No grants have been made from TD Group’s 2019 stock option plan as of September 30, 2021. 2014 Stock Option Plan In July 2014, the Board of Directors of TD Group adopted the 2014 stock option plan, which was subsequently approved by stockholders on October 2, 2014. The 2014 stock option plan permits TD Group to award our key employees, directors or consultants stock options. The total number of shares of TD Group common stock reserved for issuance or delivery under the 2014 stock option plan is 5,000,000, subject to adjustment in the event of any stock dividend or split, reorganization, recapitalization, merger, share exchange or any other similar corporate transaction or event. Performance Vested Stock Options —Generally all of the options granted through September 30, 2021 under the 2014 stock option plan have been pursuant to an equity incentive program adopted by the Company in 2008. Under the 2008 equity incentive program, generally all of the options granted will vest based on the Company’s achievement of established operating performance goals. As of September 30, 2021, the operating performance goals have not been determined on the portion of options granted in fiscal 2021 and 2020 with a scheduled vesting date of September 30, 2022 and beyond due to the uncertainty on the Company’s financial results from the COVID-19 pandemic. The following table summarizes the activity, pricing and other information for the Company’s performance vested stock-based award activity during the fiscal year ended September 30, 2021: Number of Weighted-Average Weighted-Average Aggregate Outstanding at September 30, 2020 3,613,857 $ 364.79 Granted 811,308 573.65 Exercised (101,638) 328.42 Forfeited (120,604) 464.43 Expired — — Outstanding at September 30, 2021 4,202,923 $ 403.12 7.1 years $ 930,737,298 Expected to vest 725,302 $ 351.88 6.9 years $ 197,784,390 Exercisable at September 30, 2021 2,458,305 $ 352.13 6.5 years $ 669,740,614 At September 30, 2021, there were 626,294 remaining shares available for award under TD Group’s 2014 stock option plan. 2006 Stock Incentive Plan In conjunction with the consummation of the Company’s initial public offering, a 2006 stock incentive plan was adopted by TD Group. In July 2008 and March 2011, the plan was amended to increase the number of shares available for issuance thereunder. TD Group reserved 8,119,668 shares of its common stock for issuance to key employees, directors or consultants under the plan. Awards under the plan were in the form of options, restricted stock or other stock-based awards. Options granted under the plan expire no later than the tenth anniversary of the applicable date of grant of the options, and have an exercise price of not less than the fair market value of our common stock on the date of grant. Restricted stock granted under the plan vested over three years. No restricted stock units remained outstanding as of September 30, 2018. Performance Vested Stock Options —All of the options granted under the 2006 stock incentive plan have been pursuant to an equity incentive program adopted by the Company in 2008. Under the 2008 equity incentive program, all of the options granted vest based on the Company’s achievement of established operating performance goals. The following table summarizes the activity, pricing and other information for the Company’s performance vested stock-based award activity during the fiscal year ended September 30, 2021: Number of Weighted-Average Weighted-Average Aggregate Outstanding at September 30, 2020 2,235,680 $ 170.97 Granted — — Exercised (687,075) 137.75 Forfeited — — Expired — — Outstanding at September 30, 2021 1,548,605 $ 185.71 2.9 years $ 679,627,029 Exercisable at September 30, 2021 1,548,605 $ 185.71 2.9 years $ 679,627,029 The 2006 stock incentive plan expired on March 14, 2016 and no further shares were granted under the plan thereafter. 2003 Stock Option Plan Certain executives and key employees of the Company were granted stock options under TD Group’s 2003 stock option plan. All shares had been issued as of September 30, 2013. As of September 30, 2020, 829 options were outstanding and exercisable at a weighted average price per option of $130.09. As of September 30, 2021, no shares were outstanding or exercisable under our 2003 stock incentive plan. The total intrinsic value of performance options exercised during the fiscal years ended September 30, 2021, 2020 and 2019 was $355.3 million, $394.2 million and $240.2 million, respectively. Dividend Equivalent Plans Pursuant to the Third Amended and Restated TransDigm Group Incorporated 2003 Stock Option Plan Dividend Equivalent Plan, the Second Amended and Restated TransDigm Group Incorporated 2006 Stock Incentive Plan Dividend Equivalent Plan and the 2014 Stock Option Plan Dividend Equivalent Plan, all of the options granted under the existing stock option plans are entitled to certain dividend equivalent payments in the event of the declaration of a dividend by the Company. Dividend equivalent payments on vested options were $72.5 million, $184.9 million and $111.0 million during the fiscal years ended September 30, 2021, 2020 and 2019, respectively. At September 30, 2021, there was $45.9 million recorded in accrued and other current liabilities and $30.9 million accrued in other non-current liabilities on the consolidated balance sheets related to future dividend equivalent payments.

LEASES

LEASES	12 Months Ended
LEASES	Sep. 30, 2021
Leases [Abstract]
Lessee, Operating and Finance Leases	LEASES The Company leases certain manufacturing facilities, offices, land, equipment and vehicles. Such leases, some of which are noncancellable and, in many cases, include renewals, expire at various dates. Such options to renew are included in the lease term when it is reasonably certain that the option will be exercised. The Company’s lease agreements typically do not contain any significant residual value guarantees or restrictive covenants, and payments within certain lease agreements are adjusted periodically for changes in an index or rate. The Company determines if an arrangement is a lease at inception. Operating lease assets and liabilities are recognized at the commencement date of the lease based on the present value of lease payments over the lease term. Lease assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. The discount rate implicit within our leases is generally not determinable and therefore we determine the discount rate based on our incremental borrowing rate. The incremental borrowing rate for our leases is determined based on the lease term and the currency in which lease payments are made. The length of a lease term includes options to extend or terminate the lease when it is reasonably certain that the Company will exercise those options. The Company made an accounting policy election to not recognize lease assets or liabilities for leases with a term of 12 months or less. Additionally, when accounting for leases, the Company combines payments for leased assets, related services and other components of a lease. The components of lease expense for the fiscal years ended September 30, 2021 and 2020 are as follows (in millions): Fiscal Years Ended September 30, Classification 2021 2020 Operating lease cost Cost of Sales or Selling and Administrative Expenses $ 29 $ 29 Finance lease cost Amortization of leased assets Cost of Sales 4 3 Interest on lease liabilities Interest Expense - Net 6 4 Total lease cost $ 39 $ 36 Supplemental cash flow information related to leases for the fiscal years ended September 30, 2021 and 2020 is as follows (in millions): Fiscal Years Ended September 30, 2021 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash outflows from operating leases $ 29 $ 29 Operating cash outflows from finance leases 6 4 Financing cash outflows from finance leases 2 2 Lease assets obtained in exchange for new lease obligations: Operating leases $ 41 $ 32 Financing leases 25 — Supplemental balance sheet information related to leases is as follows (in millions): Classification September 30, 2021 September 30, 2020 Operating Leases Operating lease right-of-use assets Other assets $ 94 $ 103 Current operating lease liabilities Accrued and other current liabilities 20 22 Long-term operating lease liabilities Other non-current liabilities 79 87 Total operating lease liabilities $ 99 $ 109 Finance Leases Finance lease right-of-use assets, net Property, plant and equipment - net $ 104 $ 67 Current finance lease liabilities Accrued and other current liabilities 2 2 Long-term finance lease liabilities Other non-current liabilities 98 55 Total finance lease liabilities $ 100 $ 57 As of September 30, 2021, the Company has the following remaining lease term and weighted average discount rates: Weighted-average remaining lease term Operating leases 8.1 years Finance leases 21.7 years Weighted-average discount rate Operating leases 6.0% Finance leases 7.2% Maturities of lease liabilities at September 30, 2021 are as follows (in millions): Operating Leases Finance Leases 2022 $ 24 $ 8 2023 19 9 2024 16 9 2025 13 9 2026 10 9 Thereafter 45 171 Total future minimum lease payments 127 215 Less: imputed interest 28 115 Present value of lease liabilities reported $ 99 $ 100

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
FAIR VALUE MEASUREMENTS	Sep. 30, 2021
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS The following table presents our assets and liabilities that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy. The fair value hierarchy has three levels based on the reliability of the inputs used to determine fair value. Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 2 inputs are quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, and inputs (other than quoted prices) that are observable for the asset or liability, either directly or indirectly. Level 3 inputs are unobservable inputs for the asset or liability. A financial asset or liability’s classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. The following summarizes the carrying amounts and fair values of financial instruments (in millions): September 30, 2021 September 30, 2020 Level Carrying Fair Value Carrying Fair Value Assets: Cash and cash equivalents 1 $ 4,787 $ 4,787 $ 4,717 $ 4,717 Interest rate cap agreements (1) 2 8 8 — — Liabilities: Interest rate swap agreements (2) 2 100 100 56 56 Interest rate swap agreements (3) 2 180 180 328 328 Foreign currency forward exchange contracts (2) 2 4 4 1 1 Short-term borrowings - trade receivable securitization facility (4) 2 349 349 349 349 Long-term debt, including current portion: Term loans (4) 2 7,318 7,268 7,378 7,004 Revolving credit facility (4) 2 200 200 200 200 2024 Notes (4) 1 — — 1,195 1,194 2025 Notes (4) 1 — — 750 743 2025 Secured Notes (4) 1 1,093 1,170 1,091 1,194 6.375% 2026 Notes (4) 1 945 981 944 948 6.875% 2026 Notes (4) 1 494 527 493 500 2026 Secured Notes (4) 1 4,359 4,593 4,350 4,604 7.50% 2027 Notes (4) 1 546 578 545 569 5.50% 2027 Notes (4) 1 2,632 2,730 2,629 2,554 4.625% 2029 Notes (4) 1 1,190 1,196 — — 4.875% 2029 Notes (4) 1 743 751 — — Government refundable advances 2 29 29 28 28 Finance lease obligations 2 100 100 57 57 (1) Included in other assets on the consolidated balance sheets. (2) Included in accrued and other current liabilities on the consolidated balance sheets. (3) Included in other non-current liabilities on the consolidated balance sheets. (4) The carrying amount of the debt instrument is presented net of the debt issuance costs, premium and discount. Refer to Note 12, “Debt,” for gross carrying amounts. The Company values its financial instruments using an industry standard market approach, in which prices and other relevant information are generated by market transactions involving identical or comparable assets or liabilities. No financial instruments were recognized or disclosed using unobservable inputs (i.e., Level 3). Interest rate swaps were measured at fair value using quoted market prices for the swap interest rate indexes over the term of the swap discounted to present value versus the fixed rate of the contract. The interest rate caps were measured at fair value using implied volatility rates of each individual caplet and the yield curve for the related periods. The Company’s derivative contracts consist of foreign currency exchange contracts and interest rate swap and cap agreements. These derivative contracts are over-the-counter, and their fair value is determined using modeling techniques that include market inputs such as interest rates, yield curves, and currency exchange rates. These contracts are categorized as Level 2 in the fair value hierarchy. The estimated fair value of the Company’s term loans was based on information provided by the agent under the Company’s senior secured credit facility. The estimated fair values of the Company’s notes were based upon quoted market prices. There has not been any impact to the fair value of derivative liabilities due to the Company's own credit risk. Similarly, there has not been any significant impact to the fair value of derivative assets based on the Company's evaluation of counterparties' credit risks.

DERIVATIVES AND HEDGING ACTIVIT

DERIVATIVES AND HEDGING ACTIVITIES	12 Months Ended
DERIVATIVES AND HEDGING ACTIVITIES	Sep. 30, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVES AND HEDGING ACTIVITIES	DERIVATIVES AND HEDGING ACTIVITIES The Company is exposed to, among other things, the impact of changes in foreign currency exchange rates and interest rates in the normal course of business. The Company’s risk management program is designed to manage the exposure and volatility arising from these risks, and utilizes derivative financial instruments to offset a portion of these risks. The Company uses derivative financial instruments only to the extent necessary to hedge identified business risks and does not enter into such transactions for trading purposes. The Company generally does not require collateral or other security with counterparties to these financial instruments and is therefore subject to credit risk in the event of nonperformance; however, the Company monitors credit risk and currently does not anticipate nonperformance by other parties. These derivative financial instruments do not subject the Company to undue risk, as gains and losses on these instruments generally offset gains and losses on the underlying assets, liabilities, or anticipated transactions that are being hedged. The Company has agreements with each of its swap and cap counterparties that contain a provision whereby if the Company defaults on the credit facility the Company could also be declared in default on its swaps and caps, resulting in an acceleration of payment under the swaps and caps. All derivative financial instruments are recorded at fair value in the consolidated balance sheets. For a derivative that has not been designated as an accounting hedge, the change in the fair value is recognized immediately through earnings. For a derivative that has been designated as an accounting hedge of an existing asset or liability (a fair value hedge), the change in the fair value of both the derivative and underlying asset or liability is recognized immediately through earnings. For a derivative designated as an accounting hedge of an anticipated transaction (a cash flow hedge), the change in the fair value is recorded on the consolidated balance sheets in accumulated other comprehensive loss to the extent the derivative is effective in mitigating the exposure related to the anticipated transaction. The change in the fair value related to the ineffective portion of the hedge, if any, is immediately recognized in earnings. The amount recorded within accumulated other comprehensive loss is reclassified into earnings in the same period during which the underlying hedged transaction affects earnings. Interest Rate Swap and Cap Agreements – Interest rate swap and cap agreements are used to manage interest rate risk associated with floating-rate borrowings under our credit facility. The interest rate swap and cap agreements utilized by the Company effectively modify the Company’s exposure to interest rate risk by converting a portion of the Company’s floating-rate debt to a fixed rate basis through the expiration date of the interest rate swap and cap agreements, thereby reducing the impact of interest rate changes on future interest expense. These agreements involve the receipt of floating rate amounts in exchange for fixed rate interest payments over the term of the agreements without an exchange of the underlying principal amount. These derivative instruments qualify as effective cash flow hedges under U.S. GAAP. For these cash flow hedges, the effective portion of the gain or loss from the financial instruments was initially reported as a component of accumulated other comprehensive loss in stockholders’ deficit and subsequently reclassified into earnings in the same line as the hedged item in the same period or periods during which the hedged item affected earnings. As the interest rate swap and cap agreements are used to manage interest rate risk, any gains or losses from the derivative instruments that are reclassified into earnings are recognized in interest expense-net in the consolidated statements of income. The following table summarizes the Company’s interest rate swap agreements: Aggregate Notional Amount Start Date End Date Related Term Loans Conversion of Related Variable Rate Debt to $500 6/29/2018 3/31/2025 Tranche E 5.25% (3.0% plus the 2.25% margin percentage) $750 6/30/2020 6/30/2022 Tranche E 4.75% (2.5% plus the 2.25% margin percentage) $1,500 6/30/2022 3/31/2025 Tranche E 5.35% (3.1% plus the 2.25% margin percentage) $700 3/31/2023 9/30/2025 Tranche F 3.55% (1.3% plus the 2.25% margin percentage) $1,400 6/30/2021 3/31/2023 Tranche F 5.25% (3.0% plus the 2.25% margin percentage) $500 12/30/2016 12/31/2021 Tranche G 4.15% (1.9% plus the 2.25% margin percentage) $400 9/30/2017 9/30/2022 Tranche G 4.15% (1.9% plus the 2.25% margin percentage) $900 12/31/2021 6/28/2024 Tranche G 5.35% (3.1% plus the 2.25% margin percentage) $400 9/30/2022 6/28/2024 Tranche G 5.25% (3.0% plus the 2.25% margin percentage) The following table summarizes the Company’s interest rate cap agreements: Aggregate Notional Amount Start Date End Date Related Debt Offsets Variable Rate Debt Attributable to $750 6/30/2020 6/30/2022 Tranche E Three month LIBOR rate of 2.50% $700 3/31/2023 9/30/2025 Tranche F Three month LIBOR rate of 1.25% $400 12/30/2016 12/31/2021 Tranche G Three month LIBOR rate of 2.50% Certain derivative asset and liability balances are offset where master netting agreements provide for the legal right of setoff. For classification purposes, we record the net fair value of each type of derivative position that is expected to settle in less than one year with each counterparty as a net current asset or liability and each type of long-term position as a net non-current asset or liability. The amounts shown in the table below represent the gross amounts of recognized assets and liabilities, the amounts offset in the consolidated balance sheets and the net amounts of assets and liabilities presented therein (in millions): September 30, 2021 September 30, 2020 Asset Liability Asset Liability Interest rate cap agreements $ 8 $ — $ — $ — Interest rate swap agreements — (280) — (384) Net derivatives as classified in the consolidated balance sheet (1) $ 8 $ (280) $ — $ (384) (1) Refer to Note 20, "Fair Value Measurements," for the consolidated balance sheets classification of our interest rate swap agreements. Based on the fair value amounts of the interest rate swap and cap agreements determined as of September 30, 2021, the estimated net amount of existing gains and losses and caplet amortization expected to be reclassified into interest expense-net within the next 12 months is approximately $101.8 million. On June 18, 2021, the Company entered into two interest rate cap agreements and one interest rate swap agreement. The agreements each have an effective date of March 31, 2023 and mature on September 30, 2025. The two interest rate cap agreements will offset the variable interest rates on the Company's floating rate debt exposures based on an aggregate notional amount of $700 million. The two interest rate caps offset the variability in expected future cash flows on the Company's variable rate debt attributable to fluctuations above the three month LIBOR of 1.25%. The interest rate swap agreement hedges the variable interest rates on the Company's floating rate debt exposures for a fixed rate based on a notional amount of $700 million. The interest rate swap agreement converts the variable interest rate on the aggregate notional amount of the Company's floating rate debt to a fixed rate of 3.55% (1.3% plus the 2.25% margin percentage) over the term of the interest rate swap agreement. Foreign Currency Forward Exchange Contracts – The Company transacts business in various foreign currencies, which subjects the Company’s cash flows and earnings to exposure related to changes in foreign currency exchange rates. These exposures arise primarily from purchases or sales of products and services from third parties. Foreign currency forward exchange contracts provide for the purchase or sale of foreign currencies at specified future dates at specified exchange rates, and are used to offset changes in the fair value of certain assets or liabilities or forecasted cash flows resulting from transactions denominated in foreign currencies. At September 30, 2021, the Company had outstanding foreign currency forward exchange contracts to sell U.S. dollars with notional amounts of $125.7 million. The maximum duration of the Company’s foreign currency cash flow hedge contracts at September 30, 2021 is 12 months. These notional values consist of contracts for the Canadian dollar and the European euro and are stated in U.S. dollar equivalents at spot exchange rates at the respective trade dates. Amounts related to foreign currency forward exchange contracts included in accumulated other comprehensive loss in stockholders' deficit are reclassified into net sales when the hedged transaction settles. During the fiscal year ended September 30, 2021, the gains reclassified on settlements of foreign currency forward exchange contracts designated as cash flow hedges into net sales in the consolidated statements of income was $3.6 million. The gains were previously recorded as a component of accumulated other comprehensive loss in stockholders' deficit. During the fiscal year ended September 30, 2021, the gains recorded as a component of other (income) expense related to the ineffective portion of the foreign currency forward exchange contracts designated as cash flow hedges were immaterial.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	12 Months Ended
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	Sep. 30, 2021
Equity [Abstract]
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	ACCUMULATED OTHER COMPREHENSIVE LOSS The following table presents the components of accumulated other comprehensive loss, net of taxes, for the fiscal years ended September 30, 2021, 2020 and 2019 (in millions): Unrealized (losses) gains on derivatives designated and qualifying as cash flow hedges (1) Defined benefit pension plan activity (2) Currency translation adjustment Total Balance at September 30, 2019 $ (172) $ (40) $ (167) $ (379) Current-period other comprehensive (loss) gain (130) 32 76 (22) Balance at September 30, 2020 (302) (8) (91) (401) Current-period other comprehensive gain (loss) before reclassification 68 (10) 90 148 Amounts reclassified from AOCI related to derivative instruments 5 — — 5 Net current-period other comprehensive gain (loss) 73 (10) 90 153 Balance at September 30, 2021 $ (229) $ (18) $ (1) $ (248) (1) Represents unrealized (losses) gains on derivatives designated and qualifying as cash flow hedges, net of tax (benefit) expense of $(23) million, $36 million and $70 million for the fiscal years ended September 30, 2021, 2020 and 2019, respectively. (2) Defined benefit pension plan and other post-retirement plan activity represents pension liability adjustments, net of tax (benefit) expense of $(8) million, $(1) million and $9 million for the fiscal years ended September 30, 2021, 2020 and 2019, respectively. Amounts reclassified from AOCI related to defined benefit pension plan and other post-retirement plan activity were immaterial for the fiscal year ended September 30, 2021. A summary of reclassifications out of accumulated other comprehensive loss for the fiscal year ended September 30, 2021 is provided below (in millions): Description of reclassifications out of accumulated other comprehensive loss Amount Reclassified Amortization from redesignated interest rate swap and cap agreements (1) $ 2 Gains from settlement of foreign currency forward exchange contracts (2) 4 Deferred tax expense on reclassifications out of accumulated other comprehensive loss (1) Amounts reclassified into earnings, net of tax $ 5 (1) This component of accumulated other comprehensive loss is included in interest expense-net. Refer to Note 21, “Derivatives and Hedging Activities,” for additional information. (2) This component of accumulated other comprehensive loss is included in net sales. Refer to Note 21, “Derivatives and Hedging Activities,” for additional information.

DISCONTINUED OPERATIONS

DISCONTINUED OPERATIONS	12 Months Ended
DISCONTINUED OPERATIONS	Sep. 30, 2021
DISCONTINUED OPERATIONS [Abstract]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	DISCONTINUED OPERATIONS The table below summarizes income from discontinued operations, net of tax, for the fiscal years ended September 30, 2020 and 2019 (in millions): Fiscal Years Ended September 30, 2020 2019 Net sales $ 79 $ 294 Income from discontinued operations, before income taxes 11 — Income tax provision (benefit) 4 (13) Income from discontinued operations, net of tax 7 13 Gain from sale of discontinued operations, net of tax 40 38 Income from discontinued operations, net of tax (1) $ 47 $ 51 (1) No divestitures occurring in the fiscal year ended September 30, 2021 met the criteria to qualify as discontinued operations under U.S. GAAP as none represented a strategic shift that has or will have a major affect on TransDigm's operations and financial results. Refer to Note 2, "Acquisitions and Divestitures," for additional disclosures on the Company's fiscal 2021 divestitures. Fiscal Year 2020 Divestitures & Discontinued Operations – On December 20, 2019, TransDigm completed the divestiture of Souriau-Sunbank to Eaton for approximately $920 million. Souriau-Sunbank was acquired by TransDigm as part of its acquisition of Esterline in March 2019 and was included in TransDigm’s Non-aviation segment. The divestiture represented a strategic shift in TransDigm’s business and, in accordance with U.S. GAAP, qualified as discontinued operations. Therefore, the results of operations of Souriau-Sunbank are presented in discontinued operations in the accompanying consolidated financial statements for all periods presented since the date acquired. Income from discontinued operations, net of tax, for the fiscal year ended September 30, 2020 was $47 million and included $7 million from the results of operations of Souriau-Sunbank and a gain on the sale of Souriau-Sunbank, net of tax, of $40 million. Fiscal Year 2019 Divestitures & Discontinued Operations – On September 20, 2019, TransDigm completed the divestiture of its EIT group of businesses to an affiliate of KPS Capital Partners, LP for approximately $190 million. EIT was acquired by TransDigm as part of its acquisition of Esterline Technologies Corporation in March 2019 and was included in TransDigm’s Non-aviation segment. The divestiture represented a strategic shift in TransDigm’s business and, in accordance with U.S. GAAP, qualified as discontinued operations. Therefore, the results of operations of EIT were presented in discontinued operations in the accompanying consolidated financial statements for all periods presented since the date acquired. Income from discontinued operations, net of tax, for the fiscal year ended September 30, 2019 was $51 million and included $13 million from the results of operations of Souriau-Sunbank and the EIT group of businesses and a gain on the sale of the EIT group of businesses, net of tax, of $38 million. Souriau-Sunbank’s net sales, (loss) from discontinued operations, before income taxes, and income tax (benefit) were $199 million, $(17) million and $(14) million, respectively, for the fiscal year ended September 30, 2019. The EIT group of businesses net sales, income from discontinued operations, before income taxes, and income tax expense were $95 million, $17 million and $1 million, respectively, for the fiscal year ended September 30, 2019.

VALUATION AND QUALIFYING ACCOUN

VALUATION AND QUALIFYING ACCOUNTS	12 Months Ended
VALUATION AND QUALIFYING ACCOUNTS	Sep. 30, 2021
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
VALUATION AND QUALIFYING ACCOUNTS	TRANSDIGM GROUP INCORPORATED VALUATION AND QUALIFYING ACCOUNTS FOR THE FISCAL YEARS ENDED SEPTEMBER 30, 2021, 2020, AND 2019 (Amounts in millions) Column A Column B Column C Column D Column E Balance at Additions Divestitures & Deductions from Reserve (1) Balance at Description Charged to Costs Acquisitions & Purchase Price Adjustments Year Ended September 30, 2021 Allowance for uncollectible accounts $ 37 $ — $ — $ (7) $ 30 Inventory valuation reserves 178 42 10 (36) 194 Valuation allowance for deferred tax assets 132 (58) — — 74 Year Ended September 30, 2020 Allowance for uncollectible accounts $ 17 $ 21 $ 3 $ (4) $ 37 Inventory valuation reserves 124 34 37 (17) 178 Valuation allowance for deferred tax assets 118 15 (1) — 132 Year Ended September 30, 2019 Allowance for uncollectible accounts $ 5 $ 5 $ 9 $ (2) $ 17 Inventory valuation reserves 99 17 17 (9) 124 Valuation allowance for deferred tax assets 47 40 31 — 118 (1) The amounts in this column represent the impact from divestitures, charge-offs net of recoveries and the impact of foreign currency translation adjustments.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation—The accompanying consolidated financial statements were prepared in conformity with U.S. GAAP and include the accounts of TD Group and subsidiaries. All significant intercompany balances and transactions have been eliminated. Certain reclassifications have been made to the prior year amounts to conform to the current year presentation, none of which are material.
Revenue Recognition, Shipping and Handling Costs	Revenue Recognition —Revenue is recognized from the sale of products when control transfers to the customer, which is demonstrated by our right to payment, a transfer of title, a transfer of the risk and rewards of ownership, or the customer acceptance, but most frequently upon shipment where the customer obtains physical possession of the goods. The majority of the Company's revenue is recorded at a point in time. Sales recognized over time are generally accounted for using an input measure to determine progress completed at the end of the period. Sales for service contracts generally are recognized as the services are provided. Refer to Note 5, “Revenue Recognition,” for further details. Shipping and Handling Costs —Shipping and handling costs are included in cost of sales in the consolidated statements of income.
Research and Development Expense	Research and Development Costs —The Company expenses research and development costs as incurred and classifies such amounts in selling and administrative expenses. The expense recognized for research and development costs for the fiscal years ended September 30, 2021, 2020 and 2019 was approximately $105.6 million, $130.9 million, and $116.8 million, respectively.
Cash and Cash Equivalents, Policy	Cash Equivalents —The Company considers all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents.
Receivables, Trade and Other Accounts Receivable, Allowance for Doubtful Accounts, Policy	Allowance for Credit Losses —The Company's allowance for credit losses is the allowance for uncollectible accounts. The allowance for uncollectible accounts reduces the trade accounts receivable balance to the estimated net realizable value equal to the amount that is expected to be collected. The Company’s method for developing its allowance for credit losses is based on historical write-off experience, the aging of receivables, an assessment of the creditworthiness of customers, economic conditions and other external market information. The allowance also incorporates a provision for the estimated impact of disputes with customers. All provisions for allowances for uncollectible accounts are included in selling and administrative expenses. The determination of the amount of the allowance for uncollectible accounts is subject to judgment and estimation by management. If circumstances change or economic conditions deteriorate or improve, the allowance for uncollectible accounts could increase or decrease. Refer to Note 7, “Trade Accounts Receivable,” for further details.
Inventories	Inventories —Inventories are stated at the lower of cost or net realizable value. Cost of inventories is generally determined by the average cost and the first-in, first-out (“FIFO”) methods and includes material, labor and overhead related to the manufacturing process. Provision for potentially obsolete or slow-moving inventory is made based on management’s analysis of inventory levels and future sales forecasts. Refer to Note 8, “Inventories,” for further details.
Property, Plant and Equipment	Property, Plant and Equipment —Property, plant and equipment are stated at cost and include improvements which significantly increase capacities or extend the useful lives of existing plant and equipment. Depreciation is computed using the straight-line method over the following estimated useful lives: land improvements from 10 to 20 years, buildings and improvements from 5 to 30 years, machinery and equipment from 2 to 10 years and furniture and fixtures from 3 to 10 years. Net gains or losses related to asset dispositions are recognized in earnings in the period in which dispositions occur. Routine maintenance, repairs and replacements are expensed as incurred. Amortization expense of assets accounted for as finance leases is included within depreciation expense. Property, plant and equipment is assessed for potential impairment whenever indicators of impairment are present by determining whether the carrying value of the property can be recovered through projected, undiscounted cash flows from future operations over the property’s remaining estimated useful life. Any impairment recognized is the amount by which the carrying amount exceeds the fair value of the asset. Fair value is measured based on quoted market prices in active markets, if available. If quoted market prices are not available, the estimate of fair value is based on various valuation techniques, including the discounted value of estimated future cash flows. Refer to Note 9, “Property, Plant and Equipment,” for further details.
Debt Issue Costs, Premiums and Discounts	Debt Issuance Costs, Premiums and Discounts —The cost of obtaining financing as well as premiums and discounts are amortized using the effective interest method over the terms of the respective obligations as a component of interest expense within the consolidated statements of income. Debt issuance costs are presented in the consolidated balance sheets as a direct reduction from the carrying amount of the related debt liabilities. Refer to Note 12, “Debt,” for further details.
Financial Instruments	Financial Instruments —Interest rate swap and cap agreements are used to manage interest rate risk associated with floating-rate borrowings under our credit facility. The interest rate swap and cap agreements utilized by the Company effectively modify the Company’s exposure to interest rate risk by converting a portion of the Company’s variable rate debt to a fixed rate basis through the expiration date of the interest rate swap and cap agreements, thereby reducing the impact of interest rate volatility on future interest expense. These agreements involve the receipt of variable rate amounts in exchange for fixed rate interest payments over the term of the agreements without an exchange of the underlying principal amount. These derivative instruments qualify as effective cash flow hedges under U.S. GAAP. The Company transacts business in various foreign currencies, which subjects the Company’s cash flows and results of operations to exposure related to changes in foreign currency exchange rates. These exposures arise primarily from purchases or sales of products and services from third parties. Foreign currency forward exchange contracts provide for the purchase or sale of foreign currencies at specified future dates at specified exchange rates, and are used to offset changes in the fair value of certain assets or liabilities or forecasted cash flows resulting from transactions denominated in foreign currencies. For the interest rate swap and cap agreements and the foreign currency forward contracts designated as cash flow hedges, the effective portion of the gain or loss from the financial instruments is reported as a component of accumulated other comprehensive loss in stockholders’ deficit and subsequently reclassified into earnings in the same line as the hedged item in the same period or periods during which the hedged item affected earnings. As the interest rate swap and cap agreements are used to manage interest rate risk, any gains or losses from the derivative instruments that are reclassified into earnings are recognized in interest expense - net in the consolidated statements of income. As the foreign currency forward exchange contracts are used to manage foreign currency exposure primarily arising from purchases or sales from third parties, any gains or losses from the derivative instruments that are reclassified into earnings are recognized in cost of sales or net sales in the consolidated statements of income. Refer to Note 21, “Derivatives and Hedging Activities,” for further details.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets —In accordance with ASC 805, “Business Combinations,” the Company uses the acquisition method of accounting to allocate costs of acquired businesses to the assets acquired and liabilities assumed based on their estimated fair values at the dates of acquisition. The excess costs of acquired businesses over the fair values of the assets acquired and liabilities assumed were recognized as goodwill. The valuations of the acquired assets and liabilities assumed will impact the determination of future operating results. Determining the fair value of assets acquired and liabilities assumed requires management’s judgment and often involves the use of significant estimates and assumptions, including assumptions with respect to future cash inflows and outflows, revenue growth rates and EBITDA margins, discount rates, customer attrition rates, royalty rates, asset lives and market multiples, among other items. We determine the fair values of intangible assets acquired generally in consultation with third-party valuation advisors. Fair value adjustments to the Company’s assets and liabilities are recognized and the results of operations of the acquired business are included in our consolidated financial statements from the effective date of the merger or acquisition. Intangible assets other than goodwill are recognized if the benefit of the intangible asset is obtained through contractual or other legal rights, or if the intangible asset can be sold, transferred, licensed or exchanged, regardless of the Company’s intent to do so. Goodwill is the excess of the purchase price paid over the estimated fair value of the net assets of a business acquired. Other intangible assets consist of identifiable intangibles acquired or recognized in accounting for the acquisitions (trademarks, trade names, technology, customer relationships, order backlog and other intangible assets). Goodwill and intangible assets that have indefinite useful lives (i.e., trademarks and trade names) are subject to annual impairment testing. Management determines fair value using a discounted future cash flow analysis or other accepted valuation techniques. The Company performs an annual impairment test for goodwill and other intangible assets as of the first day of the fourth fiscal quarter of each year, or more frequently, if an event occurs or circumstances change that would more likely than not reduce fair value below carrying value. At the time of goodwill impairment testing, the Company first assesses qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value, and whether it is therefore necessary to perform the quantitative goodwill impairment test. If, after considering all events and circumstances that support a qualitative evaluation the Company determines that it is not more-likely-than-not that the goodwill and/or indefinite-lived intangible assets are impaired, then performing the single-step quantitative analysis to determine if there is impairment would be unnecessary. Conversely, if it is more-likely-than-not that the goodwill and/or indefinite-lived intangible assets are impaired, then the Company would proceed with the single-step quantitative analysis to determine if there is a goodwill and/or indefinite-lived intangible asset impairment loss. In this application, the definition of “more-likely-than-not” is interpreted as a likelihood of more than 50%. U.S. GAAP requires that the annual, and any interim, impairment assessment be performed at the reporting unit level. The reporting unit level is one level below an operating segment. Substantially all goodwill was determined and recognized for each reporting unit pursuant to the accounting for the merger or acquisition as of the date of each transaction. With respect to acquisitions integrated into an existing reporting unit, any acquired goodwill is combined with the goodwill of the reporting unit. The impairment test for indefinite lived intangible assets consists of a comparison between their fair values and carrying values. If the carrying amounts of intangible assets that have indefinite useful lives exceed their fair values, an impairment loss will be recognized in an amount equal to the sum of any such excesses. The Company had 46 reporting units with goodwill and 43 reporting units with indefinite-lived intangible assets as of the first day of the fourth quarter of fiscal 2021, the date of the annual impairment test. Based on its initial qualitative assessment over each of the reporting units, the Company identified 16 reporting units to test for impairment using a quantitative test for both goodwill and indefinite-lived intangible assets. In addition to the key assumptions reviewed summarized above, a key assumption used in response to the COVID-19 pandemic was the estimated length of time for the commercial aerospace sector to rebound to pre-pandemic levels. The estimated fair value of each of these reporting units was in excess of its respective carrying value, and therefore, no impairment was recorded on goodwill or indefinite-lived intangible assets. The Company performed a sensitivity analysis on the discount rate, which is a significant assumption in the calculation of fair values. With a one percentage point increase in the discount rate, all of the reporting units would continue to have fair values in excess of their respective carrying values. As a result of the impairment testing performed as of the first day of the fourth quarter, no indefinite-lived intangible assets or goodwill was determined to be impaired. As economic and market conditions have not changed significantly since the first day of the fourth quarter, this conclusion remains appropriate as of September 30, 2021.
Stock-Based Compensation	Stock-Based Compensation —The Company records stock-based compensation expense using the Black-Scholes pricing model based on certain valuation assumptions. Compensation expense is recorded over the vesting periods of the stock options, adjusted for expected forfeitures. The Company has classified stock-based compensation primarily within selling and administrative expenses to correspond with the classification of employees that receive stock option grants. The Company also evaluates any subsequent changes to the respective option holders terms under the modification rules of ASC 718. If determined to be a modification, the Black-Scholes pricing model is updated as of the date of the modification resulting in a cumulative catch up to expense, if necessary. Refer to Note 18, “Stock-Based Compensation,” for further details.
Income Taxes	Income Taxes —The provision for income taxes is calculated using the asset and liability method. Under the asset and liability method, deferred income taxes are recognized for the tax effect of temporary differences between the financial statement carrying amount of assets and liabilities and the amounts used for income tax purposes and for certain changes in valuation allowances. Valuation allowances are recorded to reduce certain deferred tax assets when, in our estimation, it is more likely than not that a tax benefit will not be realized. We recognize uncertain tax positions when we have determined it is more likely than not that a tax position will be sustained upon examination. However, new information may become available, or applicable laws or regulations may change, thereby resulting in a favorable or unfavorable adjustment to amounts recorded. Refer to Note 14, “Income Taxes,” for further details.
Estimates	Estimates —The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Comprehensive Income (Loss)	Comprehensive Income (Loss) —The term “comprehensive income (loss)” represents the change in stockholders’ equity (deficit) from transactions and other events and circumstances resulting from non-stockholder sources. The Company’s accumulated other comprehensive income or loss, consisting principally of fair value adjustments to its interest rate swap and cap agreements (net of tax), cumulative foreign currency translation adjustments and pension liability adjustments (net of tax), is reported separately in the accompanying consolidated statements of comprehensive income.
Foreign Currency Translations and Transactions	Foreign Currency Translation and Transactions —The assets and liabilities of subsidiaries located outside the United States are translated into U.S. dollars at the rates of exchange in effect at the balance sheet dates. Revenue and expense items are translated at the average monthly exchange rates prevailing during the period. Gains and losses resulting from foreign currency transactions are recognized currently in income, and those resulting from translation of financial statements are accumulated as a separate component of other comprehensive income (loss) for the period. Foreign currency gains or losses recognized currently in income from changes in exchange rates were immaterial to our results of operations.
Earnings per Share (two-class method)	Earnings per Share —Earnings per share information is determined using the two-class method, which includes the weighted-average number of common shares outstanding during the period and other securities that participate in dividends (“participating securities”). Our vested stock options are considered “participating securities” because they include non-forfeitable rights to dividends. In applying the two-class method, earnings are allocated to both common stock shares and participating securities based on their respective weighted-average shares outstanding for the period. Diluted earnings per share information may include the additional effect of other securities, if dilutive, in which case the dilutive effect of such securities is calculated using the treasury stock method. Contingently issuable shares are not included in earnings per share until the period in which the contingency is satisfied. Refer to Note 6, “Earnings Per Share,” for further details.
Pension Benefits	Pension Benefits —The Company accounts for net periodic pension benefit cost using the end of the fiscal year as our measurement date. Management selects appropriate assumptions including the discount rate, rate of increase in future compensation levels and assumed long-term rate of return on plan assets. The assumptions are based upon historical results, the current economic environment and reasonable expectations of future events. Actual results which vary from our assumptions are accumulated and amortized over future periods, and accordingly, are recognized in expense in these periods. Significant differences between the assumptions and actual experience or significant changes in assumptions could impact the pension costs and the pension obligation. Refer to Note 13, “Retirement Plans,” for further details.

ACQUISITIONS AND DIVESTITURES (

ACQUISITIONS AND DIVESTITURES (Tables)	Jan. 05, 2021
Business Acquisition [Line Items]
Schedule of Business Acquisitions, by Acquisition	Cobham Aero Connectivity – On November 24, 2020, the Company entered into a definitive agreement to acquire all the outstanding stock of Chelton Limited, Chelton Avionics Holdings, Inc. and Mastsystem Int'l Oy, collectively, Cobham Aero Connectivity (“CAC”), for a total purchase price of $945 million. The acquisition was substantially completed on January 5, 2021 and financed through existing cash on hand. The Company completed the remainder of the acquisition of CAC on February 12, 2021, also through existing cash on hand. CAC operates from two primary facilities (Marlow, United Kingdom and Prescott, Arizona) and is a leading provider of highly engineered antennas and radios for the aerospace end market. The products are primarily proprietary with significant aftermarket content and have a strong presence across major defense platforms as well as select commercial applications. CAC's operating results are included in TransDigm's Airframe segment. The acquisition strengthens and expands the Company’s position to design, produce and supply highly engineered proprietary aerospace components in niche markets with significant aftermarket content and provide opportunities to create value through the application of our three core value-driven operating strategies (obtaining profitable new business, continually improving our cost structure, and providing highly engineered value-added products to customers). The purchase price paid for the acquisition reflects the current earnings before interest, taxes, depreciation and amortization ("EBITDA") and cash flows, as well as the future EBITDA and cash flows expected to be generated by the business, which are driven in most cases by the recurring aftermarket consumption over the life of a particular aircraft, estimated to be approximately 25 to 30 years. The Company accounted for the CAC acquisition using the acquisition method and included the results of operations of the acquisition in its consolidated financial statements from the effective dates of the acquisition. The Company made an initial allocation of the purchase price at the date of acquisition based upon its understanding of the fair value of the acquired assets and assumed liabilities. As of September 30, 2021, the measurement period (not to exceed one year) is open; therefore, the assets acquired and liabilities assumed related to the CAC acquisition are subject to adjustment until the end of the measurement period. The allocation of the purchase price is preliminary and will likely change in future periods, perhaps materially, as fair value estimates of the assets acquired and liabilities assumed are finalized during the allowable one year measurement period. The Company is in the process of finalizing a third-party valuation of certain intangible assets, tangible assets and liabilities of CAC. The fair values of acquired intangibles and certain liabilities, such as loss contract reserves, are determined based on estimates and assumptions that are deemed reasonable by the Company. Significant assumptions used to determine the fair values of acquired intangible assets include the discount rates and certain assumptions that form the basis of the forecasted results of the acquired business including revenue growth rates, EBITDA margins, royalty rates and technology obsolescence rates. Significant assumptions used to determine the fair value of the loss contract reserves using the discounted cash flow model include discount rates and forecasted costs to be incurred under the long-term contracts and at-market bid prices for respective contracts. These assumptions are forward looking and could be affected by future economic and market conditions. Pro forma net sales and results of operations for the acquisition had it occurred at the beginning of the applicable the fiscal years ended September 30, 2021 or September 30, 2020 are not material and, accordingly, are not provided. The preliminary allocation of the estimated fair value of assets acquired and liabilities assumed in the CAC acquisition as of the acquisition date, as well as measurement period adjustments recorded as of September 30, 2021, are summarized in the table below (in millions): Preliminary Measurement Period Adjusted Preliminary Allocation Adjustments Allocation Assets acquired (excluding cash): Trade accounts receivable $ 31 $ 1 $ 32 Inventories 27 2 29 Prepaid expenses and other 10 (3) 7 Property, plant and equipment 18 3 21 Goodwill 636 58 694 (1) Other intangible assets 309 16 325 (1) Other 34 (2) 32 Total assets acquired (excluding cash) 1,065 75 1,140 Liabilities assumed: Accounts payable 15 3 18 Accrued and other current liabilities 38 5 (2) 43 Deferred income taxes 38 (7) 31 Other non-current liabilities 29 74 (2) 103 Total liabilities assumed 120 75 195 Net assets acquired $ 945 $ — $ 945 (1) The Company expects that of the approximately $694 million of goodwill recognized for the acquisition, approximately $57 million will be deductible for tax purposes. The Company also expects that of the approximately $325 million of other intangible assets recognized for the acquisition, approximately $108 million will be deductible for tax purposes. The goodwill and intangible assets will be deductible over 15 years. (2) Primarily relates to the recording of loss contract reserves associated with acquired ongoing long-term contracts with customers that were incurring negative gross margins as of the date of acquisition. Based on our review of these contracts, we concluded that the terms of certain contracts were unfavorable when compared to market terms as of the acquisition date. The loss contract reserves are preliminarily estimated to be $80.6 million and will be released over a three to five year period. Esterline Technologies Corporation – On March 14, 2019, TransDigm completed the acquisition of all the outstanding stock of Esterline Technologies Corporation (“Esterline”) for $122.50 per share in cash, plus the repayment of Esterline debt. The purchase price, net of cash acquired of approximately $398.2 million, totaled approximately $3,923.9 million. Of the $3,923.9 million purchase price, $3,536.3 million was paid at closing and the remaining $387.6 million was classified as restricted cash for the redemption of Esterline’s senior notes outstanding due 2023 (the "2023 Notes"). The 2023 Notes were redeemed on April 15, 2019. Esterline, through its subsidiaries, was an industry leader in specialized manufacturing for the aerospace and defense industry primarily within three core disciplines: advanced materials, avionics and controls and sensors and systems. The acquisition of Esterline expands TransDigm's platform of proprietary and sole source content for the aerospace and defense industry. TransDigm evaluated the strategic fit and description of each Esterline reporting unit to determine the appropriate business segment for the reporting unit. Each Esterline reporting unit is included in one of TransDigm's segments: Power and Control, Airframe, or Non-aviation. The total purchase price of Esterline was allocated to the underlying assets acquired and liabilities assumed based upon the respective fair value at the date of acquisition. To the extent the purchase price exceeded the fair value of the net identifiable tangible and intangible assets acquired, such excess was allocated to goodwill. Allocations were based on the acquisition method of accounting and third-party valuation appraisals. The allocation of the fair value of the assets acquired and liabilities assumed in the Esterline acquisition as of the acquisition date of March 14, 2019 is summarized in the table below (in millions): Adjusted Final Allocation Assets acquired (excluding cash): Trade accounts receivable $ 384 Inventories 583 Prepaid expenses and other 423 Property, plant and equipment 469 Goodwill 2,256 Other intangible assets 1,301 Other 20 Total assets acquired (excluding cash) 5,436 Liabilities assumed: Accounts payable 146 Accrued and other current liabilities 751 Deferred income taxes 181 Other non-current liabilities 434 Total liabilities assumed 1,512 Net assets acquired $ 3,924

REVENUE RECOGNITION (Tables)

REVENUE RECOGNITION (Tables)	12 Months Ended
REVENUE RECOGNITION (Tables)	Sep. 30, 2021
Schedule of Contract Assets and Liabilities [Line Items]
Contract with Customer, Asset and Liability [Table Text Block]	The following table summarizes our contract assets and liabilities balances (in millions): September 30, 2021 September 30, 2020 Change Contract assets, current (1) $ 70 $ 36 $ 34 Contract assets, non-current (2) 2 6 (4) Total contract assets 72 42 30 Contract liabilities, current (3) 25 18 7 Contract liabilities, non-current (4) 5 9 (4) Total contract liabilities 30 27 3 Net contract assets $ 42 $ 15 $ 27 (1) Included in prepaid expenses and other on the consolidated balance sheets. (2) Included in other non-current assets on the consolidated balance sheets. (3) Included in accrued and other current liabilities on the consolidated balance sheets. (4) Included in other non-current liabilities on the consolidated balance sheets.

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
EARNINGS PER SHARE (Tables)	Sep. 30, 2021
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings Per Share (two-class method)	The following table sets forth the computation of basic and diluted earnings per share (in millions, except per share data) using the two-class method: Fiscal Years Ended September 30, 2021 2020 2019 Numerator for earnings per share: Income from continuing operations $ 681 $ 653 $ 841 Less: Net income attributable to noncontrolling interests (1) (1) (2) Net income from continuing operations attributable to TD Group 680 652 839 Less: Special dividends declared or paid on participating securities, including dividend equivalent payments (73) (185) (111) Income from discontinued operations, net of tax — 47 51 Net income applicable to TD Group common stockholders - basic and diluted $ 607 $ 514 $ 779 Denominator for basic and diluted earnings per share under the two-class method: Weighted-average common shares outstanding 54.8 53.9 53.1 Vested options deemed participating securities 3.6 3.4 3.2 Total shares for basic and diluted earnings per share 58.4 57.3 56.3 Earnings per share from continuing operations—basic and diluted $ 10.41 $ 8.14 $ 12.94 Earnings per share from discontinued operations—basic and diluted — 0.82 0.90 Earnings per share $ 10.41 $ 8.96 $ 13.84

TRADE ACCOUNTS RECEIVABLE (Tabl

TRADE ACCOUNTS RECEIVABLE (Tables)	12 Months Ended
TRADE ACCOUNTS RECEIVABLE (Tables)	Sep. 30, 2021
Receivables [Abstract]
Schedule of Trade Accounts Receivable	Trade accounts receivable consist of the following (in millions): September 30, 2021 September 30, 2020 Trade accounts receivable—gross $ 821 $ 757 Allowance for uncollectible accounts (30) (37) Trade accounts receivable—Net $ 791 $ 720

INVENTORIES (Tables)

INVENTORIES (Tables)	12 Months Ended
INVENTORIES (Tables)	Sep. 30, 2021
Inventory Disclosure [Abstract]
Schedule of Inventory	Inventories consist of the following (in millions): September 30, 2021 September 30, 2020 Raw materials and purchased component parts $ 850 $ 881 Work-in-progress 322 358 Finished goods 207 222 Total 1,379 1,461 Reserves for excess and obsolete inventory (194) (178) Inventories—Net $ 1,185 $ 1,283

PROPERTY, PLANT AND EQUIPMENT (

PROPERTY, PLANT AND EQUIPMENT (Tables)	12 Months Ended
PROPERTY, PLANT AND EQUIPMENT (Tables)	Sep. 30, 2021
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, plant and equipment consist of the following (in millions): September 30, 2021 September 30, 2020 Land and improvements $ 103 $ 103 Buildings and improvements 409 350 Machinery, equipment and other 832 782 Construction-in-progress 61 57 Total 1,405 1,292 Accumulated depreciation (635) (540) Property, plant and equipment—Net $ 770 $ 752

INTANGIBLE ASSETS (Tables)

INTANGIBLE ASSETS (Tables)	12 Months Ended
INTANGIBLE ASSETS (Tables)	Sep. 30, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets	Other intangible assets - net in the consolidated balance sheets consist of the following at September 30 (in millions): 2021 2020 Gross Carrying Accumulated Net Gross Carrying Accumulated Net Trademarks & trade names $ 983 $ — $ 983 $ 958 $ — $ 958 Technology 2,009 679 1,330 1,842 589 1,253 Order backlog (1) 16 11 5 93 93 — Customer relationships 545 78 467 443 52 391 Other 18 12 6 18 10 8 Total $ 3,571 $ 780 $ 2,791 $ 3,354 $ 744 $ 2,610 (1) Fully amortized order backlog associated with the Esterline acquisition was written down from the gross carrying amount and accumulated amortization in the second quarter of fiscal 2021 due to being fully amortized. There was no impact on the net balance.
Schedule of Acquired Indefinite-lived Intangible Assets by Major Class	Intangible assets acquired during the fiscal year ended September 30, 2021 are summarized in the table below (in millions), principally all relate to the CAC acquisition: Gross Amount Amortization Intangible assets not subject to amortization: Goodwill $ 703 Trademarks and trade names 35 738 Intangible assets subject to amortization: Technology 178 20 years Order backlog 16 1 year Customer relationships 101 20 years 295 Total $ 1,033
Schedule of Aggregate Amortization Expense	Information regarding the amortization expense of amortizable intangible assets is detailed below (in millions): Annual Amortization Expense: Fiscal years ended September 30, 2021 $ 137 2020 169 2019 135
Schedule of Finite-Lived Intangible Assets, Future Amortization	Estimated Amortization Expense: Fiscal years ending September 30, 2022 $ 143 2023 143 2024 143 2025 143 2026 143
Summary of Changes in Carrying Value of Goodwill	the fiscal years ended September 30, 2020 and 2021 were as follows (in millions): Power & Airframe Non- Total Balance at September 30, 2019 $ 4,121 $ 3,598 $ 101 $ 7,820 Purchase price allocation adjustments (1) (1) 39 — 38 Currency translation adjustments 21 10 — 31 Balance at September 30, 2020 4,141 3,647 101 7,889 Goodwill acquired during the period 9 694 — 703 Goodwill divested during the period (4) (32) (8) (44) Currency translation adjustments 3 17 — 20 Balance at September 30, 2021 $ 4,149 $ 4,326 $ 93 $ 8,568 (1) Primarily relates to opening balance sheet adjustments recorded by the reporting units acquired from Esterline up to the expiration of the one year measurement period in March 2020.

ACCRUED AND OTHER CURRENT LIA_2

ACCRUED AND OTHER CURRENT LIABILITIES (Tables)	12 Months Ended
ACCRUED AND OTHER CURRENT LIABILITIES (Tables)	Sep. 30, 2021
Payables and Accruals [Abstract]
ACCRUED AND OTHER CURRENT LIABILITIES	Accrued and other current liabilities consist of the following (in millions): September 30, 2021 September 30, 2020 Interest $ 191 $ 178 Compensation and related benefits 167 173 Interest rate swap agreements (Note 21) 100 56 Dividend equivalent payments—current (Note 18) 46 72 Loss contract reserves 46 42 Product warranties 29 32 Contract liabilities, current (Note 5) 25 18 Current operating lease liabilities (Note 19) 20 22 Environmental and other litigation reserves 14 15 Other 172 165 Accrued and other current liabilities $ 810 $ 773

DEBT (Tables)

DEBT (Tables)	12 Months Ended
DEBT (Tables)	Sep. 30, 2021
Debt Disclosure [Abstract]
Schedule of Debt	The Company’s debt consists of the following (in millions): September 30, 2021 Gross Amount Debt Issuance Costs Original Issue Discount or Premium Net Amount Short-term borrowings—trade receivable securitization facility $ 350 $ (1) $ — $ 349 Term loans $ 7,374 $ (39) $ (17) $ 7,318 Revolving credit facility 200 — — 200 8.00% senior secured notes due 2025 (“2025 Secured Notes”) 1,100 (7) — 1,093 6.375% senior subordinated notes due 2026 (“6.375% 2026 Notes”) 950 (5) — 945 6.875% senior subordinated notes due 2026 (“6.875% 2026 Notes”) 500 (4) (2) 494 6.25% secured notes due 2026 (“2026 Secured Notes”) 4,400 (45) 4 4,359 7.50% senior subordinated notes due 2027 (“7.50% 2027 Notes”) 550 (4) — 546 5.50% senior subordinated notes due 2027 (“5.50% 2027 Notes”) 2,650 (18) — 2,632 4.625% senior subordinated notes due 2029 (“4.625% 2029 Notes”) 1,200 (10) — 1,190 4.875% senior subordinated notes due 2029 (“4.875% 2029 Notes”) 750 (7) — 743 Government refundable advances 29 — — 29 Finance lease obligations 100 — — 100 19,803 (139) (15) 19,649 Less: current portion 278 (1) — 277 Long-term debt $ 19,525 $ (138) $ (15) $ 19,372 September 30, 2020 Gross Amount Debt Issuance Costs Original Issue Discount or Premium Net Amount Short-term borrowings—trade receivable securitization facility $ 350 $ (1) $ — $ 349 Term loans $ 7,449 $ (48) $ (23) $ 7,378 Revolving credit facility 200 — — 200 6.50% senior subordinated notes due 2024 (“2024 Notes”) 1,200 (5) — 1,195 6.50% senior subordinated notes due 2025 (“2025 Notes”) 750 (3) 3 750 2025 Secured Notes 1,100 (9) — 1,091 6.375% 2026 Notes 950 (6) — 944 6.875% 2026 Notes 500 (4) (3) 493 2026 Secured Notes 4,400 (55) 5 4,350 7.50% 2027 Notes 550 (5) — 545 5.50% 2027 Notes 2,650 (21) — 2,629 Government refundable advances 28 — — 28 Finance lease obligations 57 — — 57 19,834 (156) (18) 19,660 Less: current portion 277 (1) — 276 Long-term debt $ 19,557 $ (155) $ (18) $ 19,384
Schedule of Term Loans	As of September 30, 2021 and 2020, TransDigm had $7,374 million and $7,449 million in fully drawn term loans and $760 million in revolving commitments, of which $529 million and $521 million was available to the Company as of September 30, 2021 and 2020, respectively. The term loans consist of three tranches as follows (in millions): Term Loan Facility Maturity Date Interest Rate Aggregate Principal as of September 30, 2021 2020 Tranche E May 30, 2025 LIBOR + 2.25% $ 2,177 $ 2,199 Tranche F December 9, 2025 LIBOR + 2.25% $ 3,454 $ 3,489 Tranche G August 22, 2024 LIBOR + 2.25% $ 1,743 $ 1,761 The interest rates per annum applicable to all of the existing tranches of term loans are, at TransDigm’s option, equal to either an alternate base rate or an adjusted LIBOR for one, two, three or six-month (or to the extent agreed to by each relevant lender, nine or twelve-month) interest periods chosen by TransDigm, in each case plus an applicable margin percentage. The adjusted LIBOR is not subject to a floor. At September 30, 2021 and 2020, the applicable interest rates for all existing tranches were 2.33% and 2.41%, respectively.
Future Maturities of Long-Term Debt	At September 30, 2021, future maturities of long-term debt (includes finance leases) are as follows (in millions): Fiscal years ending September 30, 2022 $ 277 2023 80 2024 1,770 2025 2,151 2026 10,268 Thereafter 5,257 Total $ 19,803
Schedule of Senior Secured and Senior Subordinated Debt	Secured Notes TransDigm Inc.’s 2025 Secured Notes and 2026 Secured Notes jointly and severally guaranteed, on a senior basis, by TD Group, TransDigm UK and all of TransDigm Inc.'s Domestic Restricted Subsidiaries, as defined in the applicable Indentures. The Secured Notes contain many of the restrictive covenants included in the Credit Agreement. TransDigm is in compliance with all the covenants contained in the notes. Subordinated Notes TransDigm Inc.'s 6.375% 2026 Notes, 7.50% 2027 Notes, 5.50% 2027 Notes, 4.625% 2029 Notes, and 4.875% 2029 Notes are jointly and severally guaranteed, on a senior subordinated basis, by TD Group, TransDigm UK and all of TransDigm Inc.'s Domestic Restricted Subsidiaries, as defined in the applicable Indenture. TransDigm UK's 6.875% 2026 Notes are jointly and severally guaranteed, on a senior subordinated basis, by TD Group, TransDigm Inc. and all of TransDigm Inc.'s Domestic Restricted Subsidiaries, as defined in the applicable Indenture. The Notes contain many of the restrictive covenants included in the Credit Agreement. TransDigm is in compliance with all the covenants contained in the notes.

RETIREMENT PLANS (Tables)

RETIREMENT PLANS (Tables)	12 Months Ended
RETIREMENT PLANS (Tables)	Sep. 30, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Assumptions [Table Text Block]	U.S. Defined Benefit Pension Plans Non-U.S. Defined Benefit Pension Plans Principal assumptions as of year end 2021 2020 2021 2020 Discount rate 2.56% 2.47% 2.40% 1.90% Rate of increase in future compensation levels N/A (1) 4.45% 3.06% 2.90% Assumed long-term rate of return on plan assets 5.74% 5.99% 3.20% 3.69% (1) As a result of the plan freeze to the ERP for all future benefit accruals and participation by new or rehired employees on or after January 1, 2021, the assumed rate of increase in future compensation levels is not applicable as of September 30, 2021, as pay increases are not valued once a defined benefit pension plan is frozen . U.S. Post-Retirement Pension Plans Non-U.S. Post-Retirement Pension Plans Principal assumptions as of year end 2021 2020 2021 2020 Discount rate 2.36% 1.99% 2.87% 2.28% Initial weighted average health care trend rate 7.30% 7.27% 5.70% 5.50% Ultimate weighted average health care trend rate 6.00% 6.00% 4.20% 4.10%
Defined Benefit Plan, Plan Assets, Allocation [Table Text Block]	Allocations by investment type are as follows : Actual Plan assets allocation as of fiscal year end: Target 2021 2020 Return-seeking assets (e.g., equity securities and real estate) 0%-20% 20.7% 39.1% Fixed-income securities (e.g., debt securities) 85%- 95% 78.3% 57.0% Cash —% 1.0% 3.9% Total 100.0% 100.0%
Defined Benefit Plan, Plan Assets, Category [Table Text Block]	The following table presents the fair value of the Company’s pension plan assets as of September 30, 2021, by asset category segregated by level within the fair value hierarchy, as described in Note 20, “Fair Value Measurements” (in millions): Fair Value Hierarchy Level 1 Level 2 Total Investments measured at fair value by category: (5) Return-seeking assets: (1) U.S. equity securities $ 6 $ — $ 6 Non-U.S. equity securities 34 — 34 Fixed-income securities: (2) Non-U.S. foreign commercial and government bonds — 53 53 Cash and cash equivalents (3) 5 — 5 $ 45 $ 53 $ 98 Investments measured at net asset value by category: (4) Return-seeking assets: (1) Commingled trust funds - Non-U.S. securities 65 Non-U.S. equity securities 9 Fixed-income securities: (2) U.S. government bonds and securities 91 U.S corporate bonds 223 Non-U.S. corporate bonds 20 Non-U.S. foreign commercial and government bonds 41 Total $ 547 The following table presents the fair value of the Company’s pension plan assets as of September 30, 2020, by asset category segregated by level within the fair value hierarchy, as described in Note 20, “Fair Value Measurements” (in millions): Fair Value Hierarchy Level 1 Level 2 Total Investments measured at fair value by category: (5) Return-seeking assets: (1) U.S. equity securities $ 4 $ — $ 4 Non-U.S. equity securities 48 — 48 Fixed-income securities: (2) Non-U.S. foreign commercial and government bonds — 58 58 Cash and cash equivalents (3) 22 — 22 $ 74 $ 58 $ 132 Investments measured at net asset value by category: (4) Return-seeking assets: (1) Commingled trust funds - Non-U.S. securities 153 Non-U.S. equity securities 9 Fixed-income securities: (2) U.S. government bonds and securities 80 U.S corporate bonds 123 Non-U.S. corporate bonds 18 Non-U.S. foreign commercial and government bonds 31 Total $ 546 (1) Level 1 return-seeking assets, which are primarily equity securities and real estate, are actively traded on U.S. and non-U.S. exchanges and are either valued using the market approach at quoted market prices on the measurement date or at the net asset value of the shares held by the plan on the measurement date based on quoted market prices. (2) Level 2 fixed-income securities, which are primarily debt securities, are primarily valued using the market approach at either quoted market prices, pricing models that use observable market data, or bids provided by independent investment brokerage firms. (3) Cash and cash equivalents include cash which is used to pay benefits and cash invested in a short-term investment fund that holds securities with values based on quoted market prices, but for which the funds are not valued on quoted market basis. (4) These investments are valued at the net asset value (“NAV”) of units held. The NAV is used to estimate fair value and is based on the fair value of the underlying investments held by the fund less its liability. (5) No investments measured using Level 3 inputs.
Schedule of Net Benefit Costs [Table Text Block]	Net periodic pension benefit (income) cost for the Company’s U.S. and non-U.S. defined benefit pension plans at the end of each fiscal year consisted of the following (in millions): Defined Benefit Pension Plans 2021 2020 2019 U.S. Pension Plans Non-U.S. Pension Plans U.S. Pension Plans Non-U.S. Pension Plans U.S. Pension Plans Non-U.S. Pension Plans Service cost $ 2 $ 5 $ 9 $ 6 $ 5 $ 3 Interest cost 6 5 10 5 7 5 Expected return on plan assets (19) (7) (19) (8) (10) (6) Amortization of net loss 1 2 1 1 — — Curtailment/settlements (gain) loss — (2) (1) (1) — — Net periodic pension benefit (income) cost $ (10) $ 3 $ — $ 3 $ 2 $ 2
Schedule of Net Funded Status [Table Text Block]	The funded status of the defined benefit pension and post-retirement plans at the end of fiscal 2021 and 2020 were as follows (in millions): Defined Benefit Pension Plans Post-Retirement Pension Plans September 30, 2021 September 30, 2020 September 30, 2021 September 30, 2020 U.S. Pension Plans Non-U.S. Pension Plans U.S. Pension Plans Non-U.S. Pension Plans U.S. Pension Plans Non-U.S. Pension Plans U.S. Pension Plans Non-U.S. Pension Plans Benefit Obligations Beginning balance $ 366 $ 248 $ 379 $ 270 $ 1 $ 14 $ 1 $ 14 Currency translation adjustment — 10 — 5 — 1 — — Service cost 2 5 9 6 — 1 — — Interest cost 6 5 10 5 — — — — Plan participant contributions — 1 — 1 — — — — Actuarial (gain) loss — (11) 10 13 — (3) — 1 Curtailments — (4) — (2) — — — — Settlements (8) (1) (20) (40) — — — — Divestitures — (20) — — — — — — Other adjustments 1 — — — 1 — — — Benefits paid (16) (9) (22) (10) — (1) — (1) Ending balance $ 351 $ 224 $ 366 $ 248 $ 2 $ 12 $ 1 $ 14 Plan Assets - Fair Value Beginning balance $ 342 $ 204 $ 318 $ 234 $ — $ — $ — $ — Currency translation adjustment — 9 — 3 — — — — Realized and unrealized gain on plan assets 22 14 44 8 — — — — Plan participant contributions — 1 — 1 — — — — Company contributions — 8 21 8 — 1 — 1 Settlements (8) (1) (19) (40) — — — — Divestitures — (20) — — — — — — Other adjustments 1 — — — — — — — Benefits paid (16) (9) (22) (10) — (1) — (1) Ending balance $ 341 $ 206 $ 342 $ 204 $ — $ — $ — $ — Funded Status Fair value of plan assets $ 341 $ 206 $ 342 $ 204 $ — $ — $ — $ — Benefit obligations (351) (224) (366) (248) (2) (12) (1) (14) Net amount recognized $ (10) $ (18) $ (24) $ (44) $ (2) $ (12) $ (1) $ (14) Amount Recognized on Consolidated Balance Sheet Other (non-current assets) $ — $ 6 $ — $ 4 $ — $ — $ — $ — Accrued liabilities (current) (3) — (1) (1) — (1) — (1) Other non-current liabilities (7) (24) (23) (47) (2) (11) (1) (13) Net amount recognized $ (10) $ (18) $ (24) $ (44) $ (2) $ (12) $ (1) $ (14) Amounts Recognized in Accumulated Other Comprehensive Income Net actuarial loss (gain) $ 10 $ 14 $ 12 $ 35 $ (1) $ (2) $ — $ 2 Prior service cost 1 1 1 1 1 — — — Ending balance $ 11 $ 15 $ 13 $ 36 $ — $ (2) $ — $ 2
Schedule of Expected Benefit Payments [Table Text Block]	Estimated future benefit payments expected to be paid from the pension and post-retirement benefit plans or from the Company’s assets are as follows (in millions): Fiscal years ending September 30, 2022 (1) $ 350 2023 12 2024 12 2025 12 2026 13 2027 - 2031 65 (1) Expected benefit payments in fiscal year 2022 primarily relates to the expected liquidation of the ERP.

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
INCOME TAXES (Tables)	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]	The Company’s income from continuing operations before income taxes includes the following components for the periods shown below (in millions): Fiscal Years Ended September 30, 2021 2020 2019 United States $ 516 $ 635 $ 878 Foreign 199 105 185 $ 715 $ 740 $ 1,063
Income Tax Provision on Income Before Income Taxes	The Company’s income tax provision (benefit) on income from continuing operations consists of the following for the periods shown below (in millions): Fiscal Years Ended September 30, 2021 2020 2019 Current Federal $ (21) $ 26 $ 154 State 14 3 15 Foreign 7 34 54 — 63 223 Deferred Federal 7 29 15 State (2) 3 2 Foreign 29 (8) (18) 34 24 (1) $ 34 $ 87 $ 222
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of the federal statutory income tax rate to the effective income tax rate for the periods shown below is as follows: Fiscal Years Ended September 30, 2021 2020 2019 Federal statutory income tax rate 21.0 % 21.0 % 21.0 % Provision to return adjustments 2.2 % (0.4) % (0.3) % Remeasurement of deferred tax assets and liabilities related to enacted statutory rate changes 2.1 % 0.4 % (0.5) % Gain on sale of businesses 1.4 % — % — % Global intangible low-taxed income 1.3 % 0.4 % 1.0 % Foreign tax credits (1.2) % (0.6) % (1.7) % Research and development credits (1.2) % (0.6) % (0.6) % Foreign-derived intangible income (1.5) % (2.8) % (1.5) % Resolution and settlements to uncertain tax positions (3.2) % (0.3) % (0.3) % Changes in valuation allowances impacting results (1) (8.2) % 4.2 % 6.2 % Stock compensation (8.7) % (10.7) % (5.4) % Other—net 0.7 % 1.1 % 3.0 % Effective income tax rate 4.7 % 11.7 % 20.9 % (1)
Components of Deferred Taxes	The components of the deferred taxes consist of the following (in millions): September 30, 2021 September 30, 2020 Deferred tax assets (liabilities): Intangible assets $ (814) $ (730) Property, plant and equipment (32) (59) Employee benefits 107 110 Interest rate swaps and caps 69 92 Net operating losses 58 54 Loss contract reserves 51 55 Inventories 45 41 U.S. income tax credits 31 17 Interest expense limitation 28 87 Non-U.S. income tax credits 20 21 Environmental reserves 11 12 Product warranty reserves 7 10 Other 8 9 Total (411) (281) Add: Valuation allowance (74) (132) Total net deferred tax assets (liabilities) $ (485) $ (413)
Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in millions): 2021 2020 Balance at October 1 $ 41 $ 37 Additions based on tax positions related to the prior year — 7 Additions based on tax positions related to the current year 2 2 Reductions based on tax positions related to the prior year (18) (1) Settlement with tax authorities (4) (2) Lapse in statute of limitations (2) (2) Balance at September 30 $ 19 $ 41

SEGMENTS (Tables)

SEGMENTS (Tables)	12 Months Ended
SEGMENTS (Tables)	Sep. 30, 2021
Segment Reporting [Abstract]
Net Sales by Reportable Segment	The following table presents net sales by reportable segment (in millions): Fiscal Years Ended September 30, 2021 2020 2019 Net sales to external customers Power & Control Commercial and non-aerospace OEM $ 527 $ 623 $ 686 Commercial and non-aerospace aftermarket 576 673 769 Defense 1,447 1,399 1,281 Total Power & Control 2,550 2,695 2,736 Airframe Commercial and non-aerospace OEM 591 783 836 Commercial and non-aerospace aftermarket 550 689 865 Defense 942 781 628 Total Airframe 2,083 2,253 2,329 Total Non-aviation 165 155 158 Net sales $ 4,798 $ 5,103 $ 5,223
EBITDA Defined by Segment to Consolidated Income Before Taxes Operations	The following table reconciles EBITDA As Defined by segment to consolidated income from continuing operations before income taxes (in millions): Fiscal Years Ended September 30, 2021 2020 2019 EBITDA As Defined Power & Control $ 1,319 $ 1,345 $ 1,395 Airframe 878 955 1,063 Non-aviation 62 54 51 Total segment EBITDA As Defined 2,259 2,354 2,509 Less: Unallocated corporate expenses 70 76 90 Total Company EBITDA As Defined 2,189 2,278 2,419 Depreciation and amortization expense 253 283 225 Interest expense, net 1,059 1,029 859 Acquisition and divestiture-related costs 35 31 169 Non-cash stock compensation expense 129 93 93 Refinancing costs 37 28 3 COVID-19 pandemic restructuring costs 40 54 — Gain on sale of businesses, net (69) — — Other, net (10) 20 7 Income from continuing operations before income taxes $ 715 $ 740 $ 1,063
Capital Expenditures and Depreciation and Amortization by Segment	The following table presents capital expenditures and depreciation and amortization by segment (in millions): Fiscal Years Ended September 30, 2021 2020 2019 Capital expenditures Power & Control $ 65 $ 89 $ 50 Airframe 37 10 48 Non-aviation 2 4 3 Corporate 1 2 1 $ 105 $ 105 $ 102 Depreciation and amortization Power & Control $ 107 $ 117 $ 99 Airframe 139 157 119 Non-aviation 6 7 6 Corporate 1 2 2 $ 253 $ 283 $ 226
Total Assets by Segment	The following table presents total assets by segment (in millions): September 30, 2021 September 30, 2020 Total assets Power & Control $ 6,980 $ 7,005 Airframe 7,472 6,575 Non-aviation 229 251 Corporate 4,634 4,564 $ 19,315 $ 18,395
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas	Geographic Area Information Net sales are measured based on the geographic destination of sales. Long-lived assets consist of property, plant and equipment - net and operating lease right-of-use assets. Net sales and long-lived assets of individual countries outside of the United States are not material. The following table presents net sales by geographic area (in millions): September 30, 2021 September 30, 2020 Net sales United States $ 3,096 $ 3,407 Foreign Countries 1,702 1,696 $ 4,798 $ 5,103 The following table presents long-lived assets by geographic area (in millions): September 30, 2021 September 30, 2020 Long-lived assets United States $ 608 $ 600 Foreign Countries 256 255 $ 864 $ 855

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	12 Months Ended
STOCK-BASED COMPENSATION (Tables)	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Weighted Average Assumptions for all Options Granted Estimated at Grant Date Using Black-Scholes-Merton Option-Pricing Model	The fair value of the Company’s employee stock options was estimated at the date of grant or modification using a Black-Scholes option-pricing model with the following weighted average assumptions for all options granted during the fiscal years ended: Fiscal Years Ended September 30, 2021 2020 2019 Risk-free interest rate 0.42% to 0.86% 0.26% to 1.65% 2.33% to 3.03% Expected life of options 5.5 years 5 to 5.5 years 5.5 years Expected dividend yield of stock — — — Expected volatility of stock 36% 25% to 39% 25%
Summary of Activity, Pricing and Other Information for Performance Vested Stock-Based Award Activity	The following table summarizes the activity, pricing and other information for the Company’s performance vested stock-based award activity during the fiscal year ended September 30, 2021: Number of Weighted-Average Weighted-Average Aggregate Outstanding at September 30, 2020 3,613,857 $ 364.79 Granted 811,308 573.65 Exercised (101,638) 328.42 Forfeited (120,604) 464.43 Expired — — Outstanding at September 30, 2021 4,202,923 $ 403.12 7.1 years $ 930,737,298 Expected to vest 725,302 $ 351.88 6.9 years $ 197,784,390 Exercisable at September 30, 2021 2,458,305 $ 352.13 6.5 years $ 669,740,614 Number of Weighted-Average Weighted-Average Aggregate Outstanding at September 30, 2020 2,235,680 $ 170.97 Granted — — Exercised (687,075) 137.75 Forfeited — — Expired — — Outstanding at September 30, 2021 1,548,605 $ 185.71 2.9 years $ 679,627,029 Exercisable at September 30, 2021 1,548,605 $ 185.71 2.9 years $ 679,627,029

Leases, Codification Topic 840

Leases, Codification Topic 840 (Tables)	12 Months Ended
Leases, Codification Topic 840 (Tables)	Sep. 30, 2021
Leases [Abstract]
Lease, Cost	The components of lease expense for the fiscal years ended September 30, 2021 and 2020 are as follows (in millions): Fiscal Years Ended September 30, Classification 2021 2020 Operating lease cost Cost of Sales or Selling and Administrative Expenses $ 29 $ 29 Finance lease cost Amortization of leased assets Cost of Sales 4 3 Interest on lease liabilities Interest Expense - Net 6 4 Total lease cost $ 39 $ 36
Schedule of Cash Flow, Supplemental Disclosures	Supplemental cash flow information related to leases for the fiscal years ended September 30, 2021 and 2020 is as follows (in millions): Fiscal Years Ended September 30, 2021 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash outflows from operating leases $ 29 $ 29 Operating cash outflows from finance leases 6 4 Financing cash outflows from finance leases 2 2 Lease assets obtained in exchange for new lease obligations: Operating leases $ 41 $ 32 Financing leases 25 —
Operating Leases, Supplemental Balance Sheet Information	Supplemental balance sheet information related to leases is as follows (in millions): Classification September 30, 2021 September 30, 2020 Operating Leases Operating lease right-of-use assets Other assets $ 94 $ 103 Current operating lease liabilities Accrued and other current liabilities 20 22 Long-term operating lease liabilities Other non-current liabilities 79 87 Total operating lease liabilities $ 99 $ 109 Finance Leases Finance lease right-of-use assets, net Property, plant and equipment - net $ 104 $ 67 Current finance lease liabilities Accrued and other current liabilities 2 2 Long-term finance lease liabilities Other non-current liabilities 98 55 Total finance lease liabilities $ 100 $ 57
Leases, Weighted-Average Term and Discount Rate Remaining	As of September 30, 2021, the Company has the following remaining lease term and weighted average discount rates: Weighted-average remaining lease term Operating leases 8.1 years Finance leases 21.7 years Weighted-average discount rate Operating leases 6.0% Finance leases 7.2%
Finance Lease, Liability, Maturity	Maturities of lease liabilities at September 30, 2021 are as follows (in millions): Operating Leases Finance Leases 2022 $ 24 $ 8 2023 19 9 2024 16 9 2025 13 9 2026 10 9 Thereafter 45 171 Total future minimum lease payments 127 215 Less: imputed interest 28 115 Present value of lease liabilities reported $ 99 $ 100
Lessee, Operating Lease, Liability, Maturity	Maturities of lease liabilities at September 30, 2021 are as follows (in millions): Operating Leases Finance Leases 2022 $ 24 $ 8 2023 19 9 2024 16 9 2025 13 9 2026 10 9 Thereafter 45 171 Total future minimum lease payments 127 215 Less: imputed interest 28 115 Present value of lease liabilities reported $ 99 $ 100

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
FAIR VALUE MEASUREMENTS (Tables)	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Carrying Amounts and Fair Values of Financial Instruments	instruments (in millions): September 30, 2021 September 30, 2020 Level Carrying Fair Value Carrying Fair Value Assets: Cash and cash equivalents 1 $ 4,787 $ 4,787 $ 4,717 $ 4,717 Interest rate cap agreements (1) 2 8 8 — — Liabilities: Interest rate swap agreements (2) 2 100 100 56 56 Interest rate swap agreements (3) 2 180 180 328 328 Foreign currency forward exchange contracts (2) 2 4 4 1 1 Short-term borrowings - trade receivable securitization facility (4) 2 349 349 349 349 Long-term debt, including current portion: Term loans (4) 2 7,318 7,268 7,378 7,004 Revolving credit facility (4) 2 200 200 200 200 2024 Notes (4) 1 — — 1,195 1,194 2025 Notes (4) 1 — — 750 743 2025 Secured Notes (4) 1 1,093 1,170 1,091 1,194 6.375% 2026 Notes (4) 1 945 981 944 948 6.875% 2026 Notes (4) 1 494 527 493 500 2026 Secured Notes (4) 1 4,359 4,593 4,350 4,604 7.50% 2027 Notes (4) 1 546 578 545 569 5.50% 2027 Notes (4) 1 2,632 2,730 2,629 2,554 4.625% 2029 Notes (4) 1 1,190 1,196 — — 4.875% 2029 Notes (4) 1 743 751 — — Government refundable advances 2 29 29 28 28 Finance lease obligations 2 100 100 57 57 (1) Included in other assets on the consolidated balance sheets. (2) Included in accrued and other current liabilities on the consolidated balance sheets. (3) Included in other non-current liabilities on the consolidated balance sheets. (4) The carrying amount of the debt instrument is presented net of the debt issuance costs, premium and discount. Refer to Note 12, “Debt,” for gross carrying amounts.

DERIVATIVES AND HEDGING ACTIV_2

DERIVATIVES AND HEDGING ACTIVITIES (Tables)	12 Months Ended
DERIVATIVES AND HEDGING ACTIVITIES (Tables)	Sep. 30, 2021
Derivative [Line Items]
Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]	The following table summarizes the Company’s interest rate swap agreements: Aggregate Notional Amount Start Date End Date Related Term Loans Conversion of Related Variable Rate Debt to $500 6/29/2018 3/31/2025 Tranche E 5.25% (3.0% plus the 2.25% margin percentage) $750 6/30/2020 6/30/2022 Tranche E 4.75% (2.5% plus the 2.25% margin percentage) $1,500 6/30/2022 3/31/2025 Tranche E 5.35% (3.1% plus the 2.25% margin percentage) $700 3/31/2023 9/30/2025 Tranche F 3.55% (1.3% plus the 2.25% margin percentage) $1,400 6/30/2021 3/31/2023 Tranche F 5.25% (3.0% plus the 2.25% margin percentage) $500 12/30/2016 12/31/2021 Tranche G 4.15% (1.9% plus the 2.25% margin percentage) $400 9/30/2017 9/30/2022 Tranche G 4.15% (1.9% plus the 2.25% margin percentage) $900 12/31/2021 6/28/2024 Tranche G 5.35% (3.1% plus the 2.25% margin percentage) $400 9/30/2022 6/28/2024 Tranche G 5.25% (3.0% plus the 2.25% margin percentage) The following table summarizes the Company’s interest rate cap agreements: Aggregate Notional Amount Start Date End Date Related Debt Offsets Variable Rate Debt Attributable to $750 6/30/2020 6/30/2022 Tranche E Three month LIBOR rate of 2.50% $700 3/31/2023 9/30/2025 Tranche F Three month LIBOR rate of 1.25% $400 12/30/2016 12/31/2021 Tranche G Three month LIBOR rate of 2.50%
Schedule of Interest Rate Derivatives	The amounts shown in the table below represent the gross amounts of recognized assets and liabilities, the amounts offset in the consolidated balance sheets and the net amounts of assets and liabilities presented therein (in millions): September 30, 2021 September 30, 2020 Asset Liability Asset Liability Interest rate cap agreements $ 8 $ — $ — $ — Interest rate swap agreements — (280) — (384) Net derivatives as classified in the consolidated balance sheet (1) $ 8 $ (280) $ — $ (384) (1) Refer to Note 20, "Fair Value Measurements," for the consolidated balance sheets classification of our interest rate swap agreements.

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE LOSS (Tables)	12 Months Ended
ACCUMULATED OTHER COMPREHENSIVE LOSS (Tables)	Sep. 30, 2021
Equity [Abstract]
Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]	A summary of reclassifications out of accumulated other comprehensive loss for the fiscal year ended September 30, 2021 is provided below (in millions): Description of reclassifications out of accumulated other comprehensive loss Amount Reclassified Amortization from redesignated interest rate swap and cap agreements (1) $ 2 Gains from settlement of foreign currency forward exchange contracts (2) 4 Deferred tax expense on reclassifications out of accumulated other comprehensive loss (1) Amounts reclassified into earnings, net of tax $ 5 (1) This component of accumulated other comprehensive loss is included in interest expense-net. Refer to Note 21, “Derivatives and Hedging Activities,” for additional information. (2) This component of accumulated other comprehensive loss is included in net sales. Refer to Note 21, “Derivatives and Hedging Activities,” for additional information.
Schedule of Accumulated Other Comprehensive Loss	The following table presents the components of accumulated other comprehensive loss, net of taxes, for the fiscal years ended September 30, 2021, 2020 and 2019 (in millions): Unrealized (losses) gains on derivatives designated and qualifying as cash flow hedges (1) Defined benefit pension plan activity (2) Currency translation adjustment Total Balance at September 30, 2019 $ (172) $ (40) $ (167) $ (379) Current-period other comprehensive (loss) gain (130) 32 76 (22) Balance at September 30, 2020 (302) (8) (91) (401) Current-period other comprehensive gain (loss) before reclassification 68 (10) 90 148 Amounts reclassified from AOCI related to derivative instruments 5 — — 5 Net current-period other comprehensive gain (loss) 73 (10) 90 153 Balance at September 30, 2021 $ (229) $ (18) $ (1) $ (248) (1) Represents unrealized (losses) gains on derivatives designated and qualifying as cash flow hedges, net of tax (benefit) expense of $(23) million, $36 million and $70 million for the fiscal years ended September 30, 2021, 2020 and 2019, respectively. (2) Defined benefit pension plan and other post-retirement plan activity represents pension liability adjustments, net of tax (benefit) expense of $(8) million, $(1) million and $9 million for the fiscal years ended September 30, 2021, 2020 and 2019, respectively. Amounts reclassified from AOCI related to defined benefit pension plan and other post-retirement plan activity were immaterial for the fiscal year ended September 30, 2021.

DISCONTINUED OPERATIONS (Tables

DISCONTINUED OPERATIONS (Tables)	12 Months Ended
DISCONTINUED OPERATIONS (Tables)	Sep. 30, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Groups, Including Discontinued Operations [Table Text Block]	The table below summarizes income from discontinued operations, net of tax, for the fiscal years ended September 30, 2020 and 2019 (in millions): Fiscal Years Ended September 30, 2020 2019 Net sales $ 79 $ 294 Income from discontinued operations, before income taxes 11 — Income tax provision (benefit) 4 (13) Income from discontinued operations, net of tax 7 13 Gain from sale of discontinued operations, net of tax 40 38 Income from discontinued operations, net of tax (1) $ 47 $ 51 (1) No divestitures occurring in the fiscal year ended September 30, 2021 met the criteria to qualify as discontinued operations under U.S. GAAP as none represented a strategic shift that has or will have a major affect on TransDigm's operations and financial results. Refer to Note 2, "Acquisitions and Divestitures," for additional disclosures on the Company's fiscal 2021 divestitures.

DESCRIPTION OF THE BUSINESS A_2

DESCRIPTION OF THE BUSINESS AND IMPACT OF COVID-19 PANDEMIC - Narratives (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Transdigm Inc [Member]
Accounting Policies [Abstract]
Percentage of ownership in subsidiary	100.00%
Restructuring Cost and Reserve [Line Items]
Percentage of ownership in subsidiary	100.00%
COVID-19 [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Costs	$ 36	$ 46
Restructuring and Related Cost, Expected Cost Remaining	19	13
COVID-19 [Member] \| Unusual or Infrequent Item, or Both
Restructuring Cost and Reserve [Line Items]
Restructuring Costs	4	5
COVID-19 [Member] \| Cost of Sales
Restructuring Cost and Reserve [Line Items]
Restructuring Costs	26	37
COVID-19 [Member] \| Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Costs	$ 10	$ 9

ACQUISITIONS AND DIVESTITURES -

ACQUISITIONS AND DIVESTITURES - Narratives (Details) - USD ($) $ / shares in Units, $ in Millions		Jun. 30, 2021	Apr. 27, 2021	Jan. 29, 2021	Jan. 05, 2021	Nov. 17, 2020	Dec. 20, 2019	Sep. 20, 2019	Mar. 14, 2019	Sep. 30, 2021		Sep. 30, 2020	Sep. 30, 2019
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired										$ 963		$ 0	$ 3,976
GOODWILL										8,568		7,889	7,820
Purchase price allocation adjustments (1)	[1]											38
Loss contract reserves										46		42
Gain on sale of businesses, net										$ 69		0	0
Souriau Sunbank [Member]
Business Acquisition [Line Items]
Divestiture, Sale Price							$ 920
Racal
Business Acquisition [Line Items]
Divestiture, Sale Price				$ 20
Avista
Business Acquisition [Line Items]
Divestiture, Sale Price						$ 8
TAC
Business Acquisition [Line Items]
Divestiture, Sale Price			$ 40
ScioTeq and TREALITY
Business Acquisition [Line Items]
Divestiture, Sale Price		$ 200
Esterline Interface Technology Group [Member]
Business Acquisition [Line Items]
Divestiture, Sale Price								$ 190
Scioteq, Treality, and TAC
Business Acquisition [Line Items]
Gain on sale of businesses, net		$ 68
Minimum [Member]
Business Acquisition [Line Items]
Estimated useful life of aircraft (in years)										25 years
Maximum [Member]
Business Acquisition [Line Items]
Estimated useful life of aircraft (in years)										30 years
Cobham [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired					$ 945
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables					31					$ 32
Business Combination Provisional Information Initial Accounting Incomplete Adjustment Current Assets, Receivable										1
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory					27					29
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Inventory										2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets					10					7
Business Combination Provisional Information Initial Accounting Incomplete Adjustment Current Assets, Prepaid Expenses and Other										(3)
Property, plant, and equipment					18					21
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment										3
GOODWILL					636					694	[2]
Purchase price allocation adjustments (1)										58
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill					309					325	[2]
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles										16
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets					34					32
Business Combination Provisional Information Initial Accounting Incomplete Adjustment Other Assets										(2)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets					1,065					1,140
Business Combination Provisional Information Initial Accounting Incomplete Adjustment Total Assets Acquired										75
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable					15					18
Business Combination Provisional Information Initial Accounting Incomplete Adjustment Accounts Payable										3
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other					38					43
Business Combination Provisional Information Initial Accounting Incomplete Adjustment Accrued and Other Current Liabilities	[3]									5
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities					38					31
Business Combination Provisional Information Initial Accounting Incomplete Adjustment Deferred Income Taxes										(7)
Other noncurrent liabilities					29					103
Business Combination Provisional Information Initial Accounting Incomplete Adjustment Other Non-Current Liabilities	[3]									74
Business acquisition, assumption of net indebtedness					120					195
Business Combination Provisional Information Initial Accounting Incomplete Adjustment Total Liabilities Assumed										75
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net					945					945
Business Combination Provisional Information Initial Accounting Incomplete Adjustment Net Assets Acquired										0
Business acquisition, Goodwill, Tax Deductible Amount					$ 57
Tax benefit recognition period (in years)					15 years
Loss Contingency, Estimate of Possible Loss									$ 80.6
Business acquisition, Intangibles, Tax Deductible Amount					$ 108
Esterline [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired									3,536.3
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables									384
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory									583
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets									423
Property, plant, and equipment									469
GOODWILL									2,256
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill									1,301
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets									20
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets									5,436
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable									146
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other									751
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities									181
Other noncurrent liabilities									434
Business acquisition, assumption of net indebtedness									1,512
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net									$ 3,924
Business Acquisition, Share Price									$ 122.50
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents									$ 398.2
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net									3,923.9
Restricted Cash, Current									387.6
Amount of goodwill expected to be tax deductible									25.6
Business acquisition, Intangibles, Tax Deductible Amount									48.9
Loss Contingency Accrual									$ 267.9	160.1		201.3
Loss contract reserves										14.5		31.9
Loss Contingency, Accrual, Noncurrent										145.6		169.4
Loss Contingency Accrual, Period Increase (Decrease)										$ 41.8		29.5	27.3
Business Combination, Acquisition Related Costs												$ 26.9	$ 85.1

[1]	Primarily relates to opening balance sheet adjustments recorded by the reporting units acquired from Esterline up to the expiration of the one year measurement period in March 2020.
[2]	The Company expects that of the approximately $694 million of goodwill recognized for the acquisition, approximately $57 million will be deductible for tax purposes. The Company also expects that of the approximately $325 million of other intangible assets recognized for the acquisition, approximately $108 million will be deductible for tax purposes. The goodwill and intangible assets will be deductible over 15 years.
[3]	Primarily relates to the recording of loss contract reserves associated with acquired ongoing long-term contracts with customers that were incurring negative gross margins as of the date of acquisition. Based on our review of these contracts, we concluded that the terms of certain contracts were unfavorable when compared to market terms as of the acquisition date. The loss contract reserves are preliminarily estimated to be $80.6 million and will be released over a three to five year period.

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narratives (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Summary Of Significant Accounting Policies [Line Items]
Research and development expense	$ 105.6	$ 130.9	$ 116.8
Land Improvements \| Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	10 years
Land Improvements \| Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	20 years
Building and improvements \| Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	5 years
Building and improvements \| Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	30 years
Machinery and equipment \| Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	2 years
Machinery and equipment \| Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	10 years
Furniture and Fixtures \| Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	3 years
Furniture and Fixtures \| Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	10 years
Technology Intangible Assets \| Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite lived intangible asset useful life	20 years
Technology Intangible Assets \| Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite lived intangible asset useful life	22 years
Order Backlog
Summary Of Significant Accounting Policies [Line Items]
Finite lived intangible asset useful life	1 year
Order Backlog \| Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite lived intangible asset useful life	1 year
Order Backlog \| Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite lived intangible asset useful life	1 year 6 months
Customer Relationships \| Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite lived intangible asset useful life	20 years
Other Intangible Assets \| Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite lived intangible asset useful life	20 years

REVENUE RECOGNITION (Details)

REVENUE RECOGNITION (Details) - USD ($) $ in Millions		12 Months Ended
REVENUE RECOGNITION (Details) - USD ($) $ in Millions		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Revenues		$ 4,798	$ 5,103	$ 5,223
Contract with Customer, Asset, Net, Current	[1]	70	36
Contract with Customer, Asset, Current, Increase or Decrease	[1]	34
Contract with Customer, Asset, Net, Noncurrent	[2]	2	6
Contract with customer, Asset, Non-current, Increase or Decrease	[2]	(4)
Contract with Customer, Asset, after Allowance for Credit Loss		72	42
Contract assets, Increase or Decrease		30
Contract with Customer, Liability, Current	[3]	25	18
Contract liabilities, Current, Increase or Decrease	[3]	7
Contract with Customer, Liability, Noncurrent	[4]	5	9
Contract liabilities, Non-current, Increase or Decrease	[4]	(4)
Contract with Customer, Liability		30	27
Contract Liabilities, Increase or Decrease		3
Net Contract Asset		42	$ 15
Net Contract Asset, Increase or Decrease		$ 27
Revenue Benchmark [Member] \| Customer Concentration Risk \| Customer 1
Percentage of net sales from one customer		10.00%		11.00%
Revenue Benchmark [Member] \| Customer Concentration Risk \| Customer 1 \| Airframe
Percentage of net sales from one customer				60.00%
Revenue Benchmark [Member] \| Customer Concentration Risk \| Customer 1 \| Power & Control
Percentage of net sales from one customer				40.00%
Geographic Distribution, Foreign
Revenues		$ 1,700		$ 1,800

[1]	Included in prepaid expenses and other on the consolidated balance sheets
[2]	Included in other non-current assets on the consolidated balance sheets.
[3]	Included in accrued and other current liabilities on the consolidated balance sheets.
[4]	Included in other non-current liabilities on the consolidated balance sheets.

EARNINGS PER SHARE - Computatio

EARNINGS PER SHARE - Computation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Numerator for earnings per share:
Income from continuing operations	$ 681	$ 653	$ 841
Less: Net income attributable to noncontrolling interests	1	1	2
Net income from continuing operations attributable to TD Group	680	652	839
Less: Special dividends declared or paid on participating securities, including dividend equivalent payments	(73)	(185)	(111)
Income from discontinued operations, net of tax	0	47	51
NET INCOME APPLICABLE TO TD GROUP COMMON STOCKHOLDERS	$ 607	$ 514	$ 779
Denominator for basic and diluted earnings per share under the two-class method:
Weighted-average common shares outstanding	54.8	53.9	53.1
Vested options deemed participating securities	3.6	3.4	3.2
Total shares for basic and diluted earnings per share	58.4	57.3	56.3
Earnings per share from continuing operations—basic and diluted	$ 10.41	$ 8.14	$ 12.94
Earnings per share from discontinued operations—basic and diluted	0	0.82	0.90
Earnings per share	$ 10.41	$ 8.96	$ 13.84

TRADE ACCOUNTS RECEIVABLE - Nar

TRADE ACCOUNTS RECEIVABLE - Narratives (Detail)	12 Months Ended
TRADE ACCOUNTS RECEIVABLE - Narratives (Detail)	Sep. 30, 2021
Trade Accounts Receivable Securitization and Sale Program [Line Items]
TRADE ACCOUNTS RECEIVABLE	TRADE ACCOUNTS RECEIVABLE Trade accounts receivable consist of the following (in millions): September 30, 2021 September 30, 2020 Trade accounts receivable—gross $ 821 $ 757 Allowance for uncollectible accounts (30) (37) Trade accounts receivable—Net $ 791 $ 720 At September 30, 2021, one customer individually accounted for approximately 10% of the Company’s trade accounts receivable-gross. In addition, approximately 38% of the Company’s trade accounts receivable-gross was due from entities that operate principally outside of the United States. Credit is extended based on an evaluation of each customer’s financial condition and collateral is generally not required. The decrease in the allowance for uncollectible accounts for the fiscal year ended September 30, 2021 is primarily driven by a decrease in estimated losses from certain commercial aerospace customers that were more adversely affected by the COVID-19 pandemic. The allowance for uncollectible accounts is assessed individually at each operating unit by the operating unit’s management team.
Trade Accounts Receivable \| Customer Concentration Risk \| Customer 1
Trade Accounts Receivable Securitization and Sale Program [Line Items]
Concentration Risk, Percentage, Accounts Receivable	10.00%
Trade Accounts Receivable \| Geographic Concentration Risk \| Geographic Distribution, Foreign
Trade Accounts Receivable Securitization and Sale Program [Line Items]
Concentration Risk, Percentage, Accounts Receivable	38.00%

TRADE ACCOUNTS RECEIVABLE - Con

TRADE ACCOUNTS RECEIVABLE - Content Trade Accounts Receivable (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Receivables [Abstract]
Trade accounts receivable—gross	$ 821	$ 757
Allowance for uncollectible accounts	(30)	(37)
Trade accounts receivable—Net	$ 791	$ 720

INVENTORIES - Schedule of Inven

INVENTORIES - Schedule of Inventories (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Inventory Disclosure [Abstract]
Raw materials and purchased component parts	$ 850	$ 881
Work-in-progress	322	358
Finished goods	207	222
Total	1,379	1,461
Reserves for excess and obsolete inventory	(194)	(178)
Inventories—Net	$ 1,185	$ 1,283

PROPERTY, PLANT AND EQUIPMENT -

PROPERTY, PLANT AND EQUIPMENT - Schedule of Property, Plant and Equipment (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Property, Plant and Equipment [Abstract]
Land and improvements	$ 103	$ 103
Buildings and improvements	409	350
Machinery, equipment and other	832	782
Construction-in-progress	61	57
Total	1,405	1,292
Accumulated depreciation	(635)	(540)
Property, plant and equipment—Net	$ 770	$ 752

INTANGIBLE ASSETS - Schedule of

INTANGIBLE ASSETS - Schedule of Intangible Assets (Detail) - USD ($) $ in Millions		Sep. 30, 2021	Sep. 30, 2020
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)		$ 3,571	$ 3,354
Intangible Assets, Accumulated Amortization		780	744
Total		2,791	2,610
Technology
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		2,009	1,842
Accumulated Amortization		679	589
Net		1,330	1,253
Order Backlog
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	[1]	16	93
Accumulated Amortization	[1]	11	93
Net	[1]	5	0
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		545	443
Accumulated Amortization		78	52
Net		467	391
Other Intangible Assets
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		18	18
Accumulated Amortization		12	10
Net		6	8
Trademarks and trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets (Excluding Goodwill), Gross		983	958
Indefinite-Lived Intangible Assets, Accumulated Amortization		0	0
Intangible Assets (Excluding Goodwill), Net		$ 983	$ 958

[1]	Fully amortized order backlog associated with the Esterline acquisition was written down from the gross carrying amount and accumulated amortization in the second quarter of fiscal 2021 due to being fully amortized. There was no impact on the net balance.

INTANGIBLE ASSETS - Schedule _2

INTANGIBLE ASSETS - Schedule of Intangible Assets Acquired (Detail) $ in Thousands	12 Months Ended
	Sep. 30, 2021USD ($)
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 703,000
Intangible assets not subject to amortization	738,000
Intangible assets subject to amortization	295,000
intangible Assets, Acquired During the Period	1,033,000
Goodwill
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill	703,000
Trademarks and trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets not subject to amortization	35,000
Technology
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization	$ 178,000
Amortization Period (in years)	20 years
Order Backlog
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization	$ 16,000
Amortization Period (in years)	1 year
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization	$ 101,000
Amortization Period (in years)	20 years

INTANGIBLE ASSETS - Schedule _3

INTANGIBLE ASSETS - Schedule of Aggregate Amortization Expense (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of intangible assets	$ 137	$ 169	$ 135

INTANGIBLE ASSETS - Schedule _4

INTANGIBLE ASSETS - Schedule of Finite-Lived Assets, Future Amortization (Details) $ in Millions	Sep. 30, 2021USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	$ 143
Finite-Lived Intangible Assets, Amortization Expense, Year Two	143
Finite-Lived Intangible Assets, Amortization Expense, Year Three	143
Finite-Lived Intangible Assets, Amortization Expense, Year Four	143
Finite-Lived Intangible Assets, Amortization Expense, Year Five	$ 143

INTANGIBLE ASSETS - Summary of

INTANGIBLE ASSETS - Summary of Changes in Carrying Value of Goodwill (Detail) - USD ($) $ in Thousands		12 Months Ended
		Sep. 30, 2021	Sep. 30, 2020
Goodwill [Line Items]
Goodwill, Beginning Balance		$ 7,889,000	$ 7,820,000
Purchase price allocation adjustments (1)	[1]		38,000
Goodwill acquired during the period		703,000
Currency translation adjustments		20,000	31,000
Goodwill divested during the period		(44,000)
Goodwill, Ending Balance		8,568,000	7,889,000
Power & Control
Goodwill [Line Items]
Goodwill, Beginning Balance		4,141,000	4,121,000
Purchase price allocation adjustments (1)	[1]		(1,000)
Goodwill acquired during the period		9,000
Currency translation adjustments		3,000	21,000
Goodwill divested during the period		(4,000)
Goodwill, Ending Balance		4,149,000	4,141,000
Airframe
Goodwill [Line Items]
Goodwill, Beginning Balance		3,647,000	3,598,000
Purchase price allocation adjustments (1)	[1]		39,000
Goodwill acquired during the period		694,000
Currency translation adjustments		17,000	10,000
Goodwill divested during the period		(32,000)
Goodwill, Ending Balance		4,326,000	3,647,000
Non-aviation
Goodwill [Line Items]
Goodwill, Beginning Balance		101,000	101,000
Purchase price allocation adjustments (1)	[1]		0
Goodwill acquired during the period		0
Currency translation adjustments		0	0
Goodwill divested during the period		(8,000)
Goodwill, Ending Balance		$ 93,000	$ 101,000

[1]	Primarily relates to opening balance sheet adjustments recorded by the reporting units acquired from Esterline up to the expiration of the one year measurement period in March 2020.

ACCRUED AND OTHER CURRENT LIA_3

ACCRUED AND OTHER CURRENT LIABILITIES - Schedule of Accrued and Other Current Liabilities (Detail) - USD ($) $ in Millions		Sep. 30, 2021	Sep. 30, 2020
Payables and Accruals [Abstract]
Interest		$ 191	$ 178
Compensation and related benefits		167	173
Interest rate swap agreements (Note 21)		100	56
Dividend equivalent payments—current (Note 18)		45.9	72
Loss contract reserves		46	42
Product warranties		29	32
Contract with Customer, Liability, Current	[1]	25	18
Current operating lease liabilities (Note 19)		20	22
Environmental and other litigation reserves		14	15
Other		172	165
Accrued and other current liabilities		$ 810	$ 773

[1]	Included in accrued and other current liabilities on the consolidated balance sheets.

DEBT - Narratives (Detail)

DEBT - Narratives (Detail) - USD ($) $ in Millions		12 Months Ended
DEBT - Narratives (Detail) - USD ($) $ in Millions		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2015	Oct. 06, 2021	May 24, 2021	Oct. 29, 2019	Mar. 15, 2019	Feb. 01, 2019
Debt Instrument [Line Items]
Debt instrument, face amount		$ 19,803
Refinancing costs		37	$ 28	$ 3
Long-term Debt, Gross		19,803	19,834
Debt Issuance Costs, Net		(139)	(156)
Debt Instrument, Unamortized Discount (Premium), Net		(15)	(18)
Short-term borrowings—trade receivable securitization facility		349	349
Long-term Debt		19,649	19,660
Current portion of long-term debt		277	276
Long-term Debt, Gross and Lease Obligation		19,525	19,557
Deferred Finance Costs, Excluding Current Maturities		(138)	(155)
Debt Instrument, Unamortized Discount, Excluding Current Maturities		(15)	(18)
LONG-TERM DEBT		19,372	19,384
Finance Lease, Liability		100	57
Asset-backed Securities [Member]
Debt Instrument [Line Items]
Debt Instrument, Term					1 year
Short-term Bank Loans and Notes Payable, Gross		$ 350	350
Debt Instrument, Interest Rate, Stated Percentage		1.20%
Debt Instrument, Interest Rate, Effective Percentage		1.33%
Debt Issuance Costs, Net		$ (1)	(1)
Debt Instrument, Unamortized Discount (Premium), Net		0	0
Short-term borrowings—trade receivable securitization facility	[1]	349	349
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 760
Debt Instrument, Interest Rate, Stated Percentage		2.50%					3.00%
Debt Instrument, Interest Rate, Effective Percentage		2.58%
Line of Credit Facility, Remaining Borrowing Capacity		$ 529	$ 521
Refinancing Costs Recorded in Connection with Amendment No. 8		0.7
Trade Receivable Securitization Facility \| Asset-backed Securities [Member]
Debt Instrument [Line Items]
Short-term Bank Loans and Notes Payable, Gross		$ 350
Term Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage		2.33%	2.41%
Long-term Debt, Gross		$ 7,374	$ 7,449
Debt Issuance Costs, Net		(39)	(48)
Debt Instrument, Unamortized Discount (Premium), Net		(17)	(23)
Long-term Debt	[1]	7,318	7,378
Term Loans [Member] \| Tranche E
Debt Instrument [Line Items]
Long-term Debt, Gross		2,177	2,199
Term Loans [Member] \| Tranche F
Debt Instrument [Line Items]
Long-term Debt, Gross		3,454	3,489
Term Loans [Member] \| Tranche G [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		1,743	1,761
Senior Subordinated Notes [Member] \| Senior Subordinated Notes $1,200M due 2024 6.50%
Debt Instrument [Line Items]
Write-off of debt issuance costs		$ 4.1
Debt Instrument, Interest Rate, Stated Percentage		6.50%
Debt Instrument, Repurchased Face Amount		$ 1,200
Debt Instrument, Repurchase Amount		6.3
Long-term Debt, Gross			1,200
Early Redemption Premium		19.5
Debt Issuance Costs, Net			(5)
Debt Instrument, Unamortized Discount (Premium), Net			0
Long-term Debt	[1]	0	1,195
Refinancing Costs Recorded in Connection with the 2024 Notes Redemption		23.6
Senior Subordinated Notes [Member] \| Senior Subordinated Notes $1,200M due 2029 4.625%
Debt Instrument [Line Items]
Debt Issuance Costs, Gross		$ 11.3
Debt Instrument, Redemption Price, Percentage		100.00%
Debt Instrument, Interest Rate, Stated Percentage		4.625%
Debt Instrument, Repurchase Amount		$ 0.1
Long-term Debt, Gross		1,200
Debt Issuance Costs, Net		(10)
Debt Instrument, Unamortized Discount (Premium), Net		0
Long-term Debt	[1]	1,190	0
Senior Subordinated Notes [Member] \| Senior Subordinated Notes Due 2020 5.50%
Debt Instrument [Line Items]
Debt Instrument, Repurchased Face Amount									$ 550
Senior Subordinated Notes [Member] \| 6.00% Senior Subordinated Notes, Due 2022
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage								6.00%
Debt Instrument, Repurchased Face Amount								$ 1,150
Senior Subordinated Notes [Member] \| 6.50% Senior Subordinated Notes, Due 2025
Debt Instrument [Line Items]
Long-term Debt	[1]	0	750
Senior Subordinated Notes [Member] \| 6.375% Senior Subordinated Notes, Due 2026
Debt Instrument [Line Items]
Long-term Debt	[1]	$ 945	944
Senior Subordinated Notes [Member] \| Senior Subordinated Notes $950M due 2026 6.375%
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.375%
Long-term Debt, Gross		$ 950	950
Debt Issuance Costs, Net		(5)	(6)
Debt Instrument, Unamortized Discount (Premium), Net		0	0
Long-term Debt		$ 945	944
Senior Subordinated Notes [Member] \| Senior Subordinated Notes $500M due 2026 6.875%
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.875%
Long-term Debt, Gross		$ 500	500
Debt Issuance Costs, Net		(4)	(4)
Debt Instrument, Unamortized Discount (Premium), Net		(2)	(3)
Long-term Debt	[1]	$ 494	493
Senior Subordinated Notes [Member] \| Senior Subordinated Notes $550M due 2027 7.50%
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		7.50%
Long-term Debt, Gross		$ 550	550
Debt Issuance Costs, Net		(4)	(5)
Debt Instrument, Unamortized Discount (Premium), Net		0	0
Long-term Debt	[1]	$ 546	545
Senior Subordinated Notes [Member] \| Senior Subordinated Notes $2,650M due 2027 5.50%
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.50%
Long-term Debt, Gross		$ 2,650	2,650
Debt Issuance Costs, Net		(18)	(21)
Debt Instrument, Unamortized Discount (Premium), Net		0	0
Long-term Debt	[1]	2,632	2,629
Senior Subordinated Notes [Member] \| Senior Subordinated Notes $750M due 2029 4.875%
Debt Instrument [Line Items]
Debt Issuance Costs, Gross		$ 7.1
Debt Instrument, Redemption Price, Percentage		100.00%
Debt Instrument, Interest Rate, Stated Percentage		4.875%
Long-term Debt, Gross		$ 750
Debt Issuance Costs, Net		(7)
Debt Instrument, Unamortized Discount (Premium), Net		0
Long-term Debt	[1]	743	0
Senior Subordinated Notes [Member] \| Senior Subordinated Notes $750M due 2025 6.50%
Debt Instrument [Line Items]
Write-off of debt issuance costs		$ 2.1
Debt Instrument, Interest Rate, Stated Percentage		6.50%
Debt Instrument, Repurchased Face Amount		$ 750
Debt Instrument, Repurchase Amount		24.4
Long-term Debt, Gross			750
Early Redemption Premium		12.2
Debt Issuance Costs, Net			(3)
Debt Instrument, Unamortized Discount (Premium), Net			3
Long-term Debt			750
Refinancing Costs Recorded in Connection with the 2025 Notes Redemption		12.1
Write Off of Unamortized Premium		2.2
Senior Notes [Member] \| Senior Secured Notes $4B Due 2026 6.25%
Debt Instrument [Line Items]
Long-term Debt, Gross										$ 4,000
Government Refundable Advances [Member]
Debt Instrument [Line Items]
Government refundable advances		28.9	28.4
Debt Issuance Costs, Net		0	0
Debt Instrument, Unamortized Discount (Premium), Net		0	0
Long-term Debt		29	28
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Net		0	0
Debt Instrument, Unamortized Discount (Premium), Net		0	0
Long-term Debt		100	57
Finance Lease, Liability		100.4	56.8
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		31.1
Line of Credit Facility, Remaining Borrowing Capacity		528.9
Long-term Debt, Gross		200	200
Debt Issuance Costs, Net		0	0
Debt Instrument, Unamortized Discount (Premium), Net		0	0
Long-term Debt	[1]	$ 200	200
Secured Debt [Member] \| Senior Secured Notes $1,100M due 2025 8.00%
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		8.00%
Long-term Debt, Gross		$ 1,100	1,100
Debt Issuance Costs, Net		(7)	(9)
Debt Instrument, Unamortized Discount (Premium), Net		0	0
Long-term Debt	[1]	1,093	1,091
Secured Debt [Member] \| Senior Secured Notes $4.4B Due 2026 6.25%
Debt Instrument [Line Items]
Long-term Debt	[1]	$ 4,359	4,350
Secured Debt [Member] \| Senior Secured Notes $4,400M due 2026 6.25%
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.25%
Long-term Debt, Gross		$ 4,400	4,400
Debt Issuance Costs, Net		(45)	(55)
Debt Instrument, Unamortized Discount (Premium), Net		4	5
Long-term Debt		4,359	4,350
Long-term Debt, Current Maturities [Member]
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount		0
Debt Issuance Costs, Net		(1)	(1)
Debt Instrument, Unamortized Discount (Premium), Net			0
Long-term Debt, Current Maturities, Gross		278	277
Current portion of long-term debt		$ 277	$ 276
Subsequent Event [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity						$ 728.9
Long-term Debt, Gross						$ 200

[1]	The carrying amount of the debt instrument is presented net of the debt issuance costs, premium and discount. Refer to Note 12, “Debt,” for gross carrying amounts.

DEBT - Schedule of Debt (Detail

DEBT - Schedule of Debt (Detail) - USD ($) $ in Millions		12 Months Ended
DEBT - Schedule of Debt (Detail) - USD ($) $ in Millions		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019	Oct. 06, 2021	Oct. 29, 2019	Mar. 15, 2019	Feb. 01, 2019
Debt Instrument [Line Items]
Debt Issuance Costs, Net		$ (139)	$ (156)
Debt Instrument, Unamortized Discount (Premium), Net		15	18
Short-term borrowings—trade receivable securitization facility		349	349
Long-term Debt, Gross		19,803	19,834
Long-term Debt		19,649	19,660
Less current portion		277	276
Deferred Finance Costs, Excluding Current Maturities		(138)	(155)
Debt Instrument, Unamortized Discount, Excluding Current Maturities		(15)	(18)
Long-term Debt, Gross and Lease Obligation		19,525	19,557
LONG-TERM DEBT		19,372	19,384
REFINANCING COSTS		$ 37	$ 28	$ 3
Term Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage		2.33%	2.41%
Debt Issuance Costs, Net		$ (39)	$ (48)
Debt Instrument, Unamortized Discount (Premium), Net		17	23
Long-term Debt, Gross		7,374	7,449
Long-term Debt	[1]	7,318	7,378
Government Refundable Advances [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Net		0	0
Debt Instrument, Unamortized Discount (Premium), Net		0	0
Long-term Debt		29	28
Government refundable advances		28.9	28.4
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Net		0	0
Debt Instrument, Unamortized Discount (Premium), Net		0	0
Long-term Debt		100	57
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Net		0	0
Debt Instrument, Unamortized Discount (Premium), Net		0	0
Long-term Debt, Gross		200	200
Long-term Debt	[1]	200	200
Line of Credit Facility, Remaining Borrowing Capacity		528.9
Letters of Credit Outstanding, Amount		$ 31.1
Revolving Credit Facility [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross					$ 200
Line of Credit Facility, Remaining Borrowing Capacity					728.9
Interest Payable					$ 0.1
Asset-backed Securities [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage		1.33%
Short-term Bank Loans and Notes Payable, Gross		$ 350	350
Debt Issuance Costs, Net		(1)	(1)
Debt Instrument, Unamortized Discount (Premium), Net		0	0
Short-term borrowings—trade receivable securitization facility	[1]	$ 349	349
Debt Instrument, Interest Rate, Stated Percentage		1.20%
6.50% Senior Subordinated Notes, Due 2025 \| Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Long-term Debt	[1]	$ 0	750
6.375% Senior Subordinated Notes, Due 2026 \| Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Long-term Debt	[1]	945	944
6.00% Senior Subordinated Notes, Due 2022 \| Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage						6.00%
Debt Instrument, Repurchased Face Amount						$ 1,150
Senior Subordinated Notes Due 2020 5.50% \| Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchased Face Amount							$ 550
Senior Secured Notes $4B Due 2026 6.25% \| Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross								$ 4,000
Senior Secured Notes $4.4B Due 2026 6.25% \| Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt	[1]	4,359	4,350
Senior Secured Notes $1,100M due 2025 8.00% \| Secured Debt [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Net		(7)	(9)
Debt Instrument, Unamortized Discount (Premium), Net		0	0
Long-term Debt, Gross		$ 1,100	1,100
Debt Instrument, Interest Rate, Stated Percentage		8.00%
Long-term Debt	[1]	$ 1,093	1,091
Senior Subordinated Notes $950M due 2026 6.375% \| Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Net		(5)	(6)
Debt Instrument, Unamortized Discount (Premium), Net		0	0
Long-term Debt, Gross		$ 950	950
Debt Instrument, Interest Rate, Stated Percentage		6.375%
Long-term Debt		$ 945	944
Senior Subordinated Notes $500M due 2026 6.875% \| Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Net		(4)	(4)
Debt Instrument, Unamortized Discount (Premium), Net		2	3
Long-term Debt, Gross		$ 500	500
Debt Instrument, Interest Rate, Stated Percentage		6.875%
Long-term Debt	[1]	$ 494	493
Senior Secured Notes $4,400M due 2026 6.25% \| Secured Debt [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Net		(45)	(55)
Debt Instrument, Unamortized Discount (Premium), Net		(4)	(5)
Long-term Debt, Gross		$ 4,400	4,400
Debt Instrument, Interest Rate, Stated Percentage		6.25%
Long-term Debt		$ 4,359	4,350
Senior Subordinated Notes $550M due 2027 7.50% \| Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Net		(4)	(5)
Debt Instrument, Unamortized Discount (Premium), Net		0	0
Long-term Debt, Gross		$ 550	550
Debt Instrument, Interest Rate, Stated Percentage		7.50%
Long-term Debt	[1]	$ 546	545
Senior Subordinated Notes $2,650M due 2027 5.50% \| Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Net		(18)	(21)
Debt Instrument, Unamortized Discount (Premium), Net		0	0
Long-term Debt, Gross		$ 2,650	2,650
Debt Instrument, Interest Rate, Stated Percentage		5.50%
Long-term Debt	[1]	$ 2,632	2,629
Senior Subordinated Notes $1,200M due 2029 4.625% \| Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Net		(10)
Debt Instrument, Unamortized Discount (Premium), Net		0
Long-term Debt, Gross		$ 1,200
Debt Instrument, Interest Rate, Stated Percentage		4.625%
Long-term Debt	[1]	$ 1,190	0
Debt Instrument, Redemption Price, Percentage		100.00%
Debt Issuance Costs, Gross		$ 11.3
Debt Instrument, Repurchase Amount		0.1
Senior Subordinated Notes $750M due 2029 4.875% \| Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Net		(7)
Debt Instrument, Unamortized Discount (Premium), Net		0
Long-term Debt, Gross		$ 750
Debt Instrument, Interest Rate, Stated Percentage		4.875%
Long-term Debt	[1]	$ 743	0
Debt Instrument, Redemption Price, Percentage		100.00%
Debt Issuance Costs, Gross		$ 7.1
Senior Subordinated Notes $1,200M due 2024 6.50% \| Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Net			(5)
Debt Instrument, Unamortized Discount (Premium), Net			0
Long-term Debt, Gross			1,200
Debt Instrument, Interest Rate, Stated Percentage		6.50%
Long-term Debt	[1]	$ 0	1,195
Refinancing Costs Recorded in Connection with the 2024 Notes Redemption		23.6
Early Redemption Premium		19.5
Debt Instrument, Repurchase Amount		6.3
Debt Instrument, Repurchased Face Amount		1,200
Write-off of debt issuance costs		$ 4.1
Senior Subordinated Notes $750M due 2025 6.50% \| Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Net			(3)
Debt Instrument, Unamortized Discount (Premium), Net			(3)
Long-term Debt, Gross			750
Debt Instrument, Interest Rate, Stated Percentage		6.50%
Long-term Debt			$ 750
Early Redemption Premium		$ 12.2
Debt Instrument, Repurchase Amount		24.4
Debt Instrument, Repurchased Face Amount		750
Write-off of debt issuance costs		2.1
Refinancing Costs Recorded in Connection with the 2025 Notes Redemption		12.1
Write Off of Unamortized Premium		$ 2.2

[1]	The carrying amount of the debt instrument is presented net of the debt issuance costs, premium and discount. Refer to Note 12, “Debt,” for gross carrying amounts.

DEBT - Schedule of Term Loans (

DEBT - Schedule of Term Loans (Details) - USD ($) $ in Millions	Sep. 30, 2021	May 24, 2021	Sep. 30, 2020
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 19,803		$ 19,834
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.50%	3.00%
Debt Instrument, Interest Rate, Effective Percentage	2.58%
Senior Subordinated Notes [Member] \| Senior Subordinated Notes $950M due 2026 6.375%
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 950		950
Debt Instrument, Interest Rate, Stated Percentage	6.375%
Senior Subordinated Notes [Member] \| Senior Subordinated Notes $500M due 2026 6.875%
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 500		500
Debt Instrument, Interest Rate, Stated Percentage	6.875%
Senior Subordinated Notes [Member] \| Senior Subordinated Notes $550M due 2027 7.50%
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 550		550
Debt Instrument, Interest Rate, Stated Percentage	7.50%
Senior Subordinated Notes [Member] \| Senior Subordinated Notes $2,650M due 2027 5.50%
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 2,650		2,650
Debt Instrument, Interest Rate, Stated Percentage	5.50%
Senior Subordinated Notes [Member] \| Senior Subordinated Notes $1,200M due 2029 4.625%
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 1,200
Debt Instrument, Interest Rate, Stated Percentage	4.625%
Senior Subordinated Notes [Member] \| Senior Subordinated Notes $750M due 2029 4.875%
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 750
Debt Instrument, Interest Rate, Stated Percentage	4.875%
Senior Subordinated Notes [Member] \| Senior Subordinated Notes $1,200M due 2024 6.50%
Debt Instrument [Line Items]
Long-term Debt, Gross			1,200
Debt Instrument, Interest Rate, Stated Percentage	6.50%
Senior Subordinated Notes [Member] \| Senior Subordinated Notes $750M due 2025 6.50%
Debt Instrument [Line Items]
Long-term Debt, Gross			750
Debt Instrument, Interest Rate, Stated Percentage	6.50%
Secured Debt [Member] \| Senior Secured Notes $1,100M due 2025 8.00%
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 1,100		1,100
Debt Instrument, Interest Rate, Stated Percentage	8.00%
Secured Debt [Member] \| Senior Secured Notes $4,400M due 2026 6.25%
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 4,400		$ 4,400
Debt Instrument, Interest Rate, Stated Percentage	6.25%

DEBT - Future Maturities of Lon

DEBT - Future Maturities of Long-Term Debt (Detail) $ in Millions	Sep. 30, 2021USD ($)
Debt Disclosure [Abstract]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	$ 277
Long-term Debt, Maturities, Repayments of Principal in Year Two	80
Long-term Debt, Maturities, Repayments of Principal in Year Three	1,770
Long-term Debt, Maturities, Repayments of Principal in Year Four	2,151
Long-term Debt, Maturities, Repayments of Principal in Year Five	10,268
Long-term Debt, Maturities, Repayments of Principal after Year Five	5,257
Debt Instrument, Face Amount	$ 19,803

DEBT -Schedule of Subordinated

DEBT -Schedule of Subordinated Borrowings (Details) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020	Oct. 29, 2019
Subordinated Borrowing [Line Items]
Long-term Debt, Gross	$ 19,803	$ 19,834
Senior Subordinated Notes [Member] \| 6.00% Senior Subordinated Notes, Due 2022
Subordinated Borrowing [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			6.00%

RETIREMENT PLANS - Narratives (

RETIREMENT PLANS - Narratives (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Discount rate decrease by 25 basis points, change in pension obligation	$ 8.4
Discount rate increase by 25 basis points, change in pension obligation	9
Change in Net Periodic Benefit Cost, if 25 basis point decrease in discount rate	0.6
Increase in expected return on assets by 25 basis points, change in net periodic benefit cost	1.3
Decrease in expected return on assets by 25 basis points, change in net periodic benefit costs	1.4
Defined contribution plan, cost recognized	28.3	$ 25.3	$ 24.5
Defined benefit plan, accumulated benefit obligation	567.8	595.3
Change in Net Periodic Benefit Cost, if 25 basis point increase in discount rate	$ 0.4
Equity Securities [Member] \| Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	0.00%
Equity Securities [Member] \| Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	20.00%
Debt Securities [Member] \| Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	85.00%
Debt Securities [Member] \| Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	95.00%
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	0.00%
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Payment for Settlement	$ 7.9
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	1
UNITED STATES \| Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	341.1	342	318
Defined benefit plan, accumulated benefit obligation	350.6
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(10)	0	2
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(9.8)	(24)
Defined Benefit Plan, Plan Assets, Contributions by Employer	0	21
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement	$ 7.9	$ 20
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Weighted-Average Interest Crediting Rate	4.71%	5.50%
Defined Benefit Plan, Plan Assets, Payment for Settlement	$ 8	$ 19
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.56%	2.47%
Defined Benefit Plan, Pension Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation	$ 350.9
Defined Benefit Plan, Benefit Obligation, Divestiture	0	$ 0
UNITED STATES \| Qualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer	1.4	1.7
Defined Benefit Plan, Plan Assets, Expected Contributions by Employer	0.6
UNITED STATES \| Unqualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer		19.8
UNITED STATES \| Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0	0
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(2)	(1)
Defined Benefit Plan, Plan Assets, Contributions by Employer	0	0
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement	0	0
Defined Benefit Plan, Plan Assets, Payment for Settlement	$ 0	$ 0
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.36%	1.99%
Defined Benefit Plan, Benefit Obligation, Divestiture	$ 0	$ 0
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer	8.6
Foreign Plan [Member] \| Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	205.9	204	234
Defined benefit plan, accumulated benefit obligation	217.2
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	3	3	2
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation	224.1
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(18)	(44)
Defined Benefit Plan, Plan Assets, Contributions by Employer	8	8.3
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement	1	40
Defined Benefit Plan, Unfunded Status of Plan	(18.2)
Defined Benefit Plan, Plan Assets, Payment for Settlement	$ 1	$ 40
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.40%	1.90%
Defined Benefit Plan, Benefit Obligation, Divestiture	$ 20.4	$ 0
Defined Benefit Plan, Plan Assets, Expected Contributions by Employer	2.3
Foreign Plan [Member] \| Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0	$ 0
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(12)	(14)
Defined Benefit Plan, Plan Assets, Contributions by Employer	1	1
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement	0	0
Defined Benefit Plan, Plan Assets, Payment for Settlement	$ 0	$ 0
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.87%	2.28%
Defined Benefit Plan, Benefit Obligation, Divestiture	$ 0	$ 0

RETIREMENT PLANS Tables (Detail

RETIREMENT PLANS Tables (Details) - USD ($) $ in Millions		12 Months Ended
RETIREMENT PLANS Tables (Details) - USD ($) $ in Millions		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage		100.00%	100.00%
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	[1]	$ 350
Defined Benefit Plan, Expected Future Benefit Payment, Year Two		12
Defined Benefit Plan, Expected Future Benefit Payment, Year Three		12
Defined Benefit Plan, Expected Future Benefit Payment, Year Four		12
Defined Benefit Plan, Expected Future Benefit Payment, Year Five		13
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter		65
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		45	$ 74
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		$ 53	$ 58
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage		20.70%	39.10%
Defined Benefit Plan, Equity Securities, US [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		$ 6	$ 4
Defined Benefit Plan, Equity Securities, US [Member] \| Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		6	4
Defined Benefit Plan, Equity Securities, US [Member] \| Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0	0
Defined Benefit Plan, Equity Securities, Non-US [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		34	48
Defined Benefit Plan, Equity Securities, Non-US [Member] \| Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		34	48
Defined Benefit Plan, Equity Securities, Non-US [Member] \| Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0	0
Defined Benefit Plan, Equity Securities, Non-US [Member] \| Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		9	9
US Treasury and Government [Member] \| Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		91	80
Defined Benefit Plan, Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		5	22
Defined Benefit Plan, Cash and Cash Equivalents [Member] \| Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		5	22
Defined Benefit Plan, Cash and Cash Equivalents [Member] \| Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0	0
Debt Security, Corporate, US [Member] \| Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		223	123
Debt Security, Corporate, Non-US [Member] \| Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		20	18
Debt Security, Government, Non-US [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		53	58
Debt Security, Government, Non-US [Member] \| Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0	0
Debt Security, Government, Non-US [Member] \| Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		53	58
Debt Security, Government, Non-US [Member] \| Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		$ 41	$ 31
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage		78.30%	57.00%
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage		1.00%	3.90%
Defined Benefit Plan, Commingled Equity Securities, Non-US \| Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		$ 65	$ 153
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer		8.6
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)		$ 1
Other Postretirement Benefits Plan [Member] \| UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		2.36%	1.99%
Defined Benefit Plan, Benefit Obligation		$ 2	$ 1	$ 1
Defined Benefit Plan, Benefit Obligation, Foreign Currency Translation Gain (Loss)		0	0
Defined Benefit Plan, Service Cost		0	0
Defined Benefit Plan, Interest Cost		0	0
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant		0	0
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		0	0
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment		0	0
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Other Change		1	0
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement		0	0
Defined Benefit Plan, Benefit Obligation, Divestiture		0	0
Defined Benefit Plan, Benefit Obligation, Benefits Paid		0	0
Defined Benefit Plan, Plan Assets, Amount		0	0	0
Defined Benefit Plan, Benefit Obligations		(2)	(1)
Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss)		0	0
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)		0	0
Defined Benefit Plan, Plan Assets, Contributions by Plan Participant		0	0
Defined Benefit Plan, Plan Assets, Contributions by Employer		0	0
Defined Benefit Plan, Plan Assets, Payment for Settlement		0	0
Defined Benefit Plan, Plan Assets, Divestiture		0	0
Defined benefit plan, Plan assets, Other change		0	0
Defined Benefit Plan, Plan Assets, Benefits Paid		0	0
Defined Benefit Plan, Funded (Unfunded) Status of Plan		(2)	(1)
Assets for Plan Benefits, Defined Benefit Plan		0	0
Liability, Defined Benefit Plan, Current		0	0
Liability, Defined Benefit Plan, Noncurrent		(2)	(1)
Liability, Defined Benefit Plan		(2)	(1)
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax		(1)	0
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax		1	0
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax		$ 0	$ 0
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year		7.30%	7.27%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate		6.00%	6.00%
Other Postretirement Benefits Plan [Member] \| Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		2.87%	2.28%
Defined Benefit Plan, Benefit Obligation		$ 12	$ 14	14
Defined Benefit Plan, Benefit Obligation, Foreign Currency Translation Gain (Loss)		1	0
Defined Benefit Plan, Service Cost		1	0
Defined Benefit Plan, Interest Cost		0	0
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant		0	0
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		(3)	1
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment		0	0
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Other Change		0	0
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement		0	0
Defined Benefit Plan, Benefit Obligation, Divestiture		0	0
Defined Benefit Plan, Benefit Obligation, Benefits Paid		(1)	(1)
Defined Benefit Plan, Plan Assets, Amount		0	0	0
Defined Benefit Plan, Benefit Obligations		(12)	(14)
Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss)		0	0
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)		0	0
Defined Benefit Plan, Plan Assets, Contributions by Plan Participant		0	0
Defined Benefit Plan, Plan Assets, Contributions by Employer		1	1
Defined Benefit Plan, Plan Assets, Payment for Settlement		0	0
Defined Benefit Plan, Plan Assets, Divestiture		0	0
Defined benefit plan, Plan assets, Other change		0	0
Defined Benefit Plan, Plan Assets, Benefits Paid		(1)	(1)
Defined Benefit Plan, Funded (Unfunded) Status of Plan		(12)	(14)
Assets for Plan Benefits, Defined Benefit Plan		0	0
Liability, Defined Benefit Plan, Current		(1)	(1)
Liability, Defined Benefit Plan, Noncurrent		(11)	(13)
Liability, Defined Benefit Plan		(12)	(14)
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax		(2)	2
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax		0	0
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax		$ (2)	$ 2
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year		5.70%	5.50%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate		4.20%	4.10%
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Payment for Settlement		$ (7.9)
Pension Plan [Member] \| UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		2.56%	2.47%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase		100.00%	4.45%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets		5.74%	5.99%
Defined Benefit Plan, Benefit Obligation		$ 351	$ 366	379
Defined Benefit Plan, Benefit Obligation, Foreign Currency Translation Gain (Loss)		0	0
Defined Benefit Plan, Service Cost		2	9	5
Defined Benefit Plan, Interest Cost		6	10	7
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant		0	0
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		0	10
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment		0	0
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Other Change		1	0
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement		(7.9)	(20)
Defined Benefit Plan, Benefit Obligation, Divestiture		0	0
Defined Benefit Plan, Benefit Obligation, Benefits Paid		(16)	(22)
Defined Benefit Plan, Plan Assets, Amount		341.1	342	318
Defined Benefit Plan, Benefit Obligations		(351)	(366)
Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss)		0	0
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)		22	44
Defined Benefit Plan, Plan Assets, Contributions by Plan Participant		0	0
Defined Benefit Plan, Plan Assets, Contributions by Employer		0	21
Defined Benefit Plan, Plan Assets, Payment for Settlement		(8)	(19)
Defined Benefit Plan, Plan Assets, Divestiture		0	0
Defined benefit plan, Plan assets, Other change		1	0
Defined Benefit Plan, Plan Assets, Benefits Paid		(16)	(22)
Defined Benefit Plan, Funded (Unfunded) Status of Plan		(9.8)	(24)
Assets for Plan Benefits, Defined Benefit Plan		0	0
Liability, Defined Benefit Plan, Current		(3)	(1)
Liability, Defined Benefit Plan, Noncurrent		(7)	(23)
Liability, Defined Benefit Plan		(10)	(24)
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax		10	12
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax		1	1
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax		11	13
Defined Benefit Plan, Expected Return (Loss) on Plan Assets		(19)	(19)	(10)
Defined Benefit Plan, Amortization of Gain (Loss)		1	1	0
Defined Benefit Plan, Benefit Obligation, Payment for Settlement		0	(1)	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)		$ (10)	$ 0	2
Pension Plan [Member] \| Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		2.40%	1.90%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase		3.06%	2.90%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets		3.20%	3.69%
Defined Benefit Plan, Benefit Obligation		$ 224	$ 248	270
Defined Benefit Plan, Benefit Obligation, Foreign Currency Translation Gain (Loss)		10	5
Defined Benefit Plan, Service Cost		5	6	3
Defined Benefit Plan, Interest Cost		5	5	5
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant		1	1
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		(11)	13
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment		(4)	(2)
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Other Change		0	0
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement		(1)	(40)
Defined Benefit Plan, Benefit Obligation, Divestiture		(20.4)	0
Defined Benefit Plan, Benefit Obligation, Benefits Paid		(9)	(10)
Defined Benefit Plan, Plan Assets, Amount		205.9	204	234
Defined Benefit Plan, Benefit Obligations		(224)	(248)
Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss)		9	3
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)		14	8
Defined Benefit Plan, Plan Assets, Contributions by Plan Participant		1	1
Defined Benefit Plan, Plan Assets, Contributions by Employer		8	8.3
Defined Benefit Plan, Plan Assets, Payment for Settlement		(1)	(40)
Defined Benefit Plan, Plan Assets, Divestiture		(20)	0
Defined benefit plan, Plan assets, Other change		0	0
Defined Benefit Plan, Plan Assets, Benefits Paid		(9)	(10)
Defined Benefit Plan, Funded (Unfunded) Status of Plan		(18)	(44)
Assets for Plan Benefits, Defined Benefit Plan		6	4
Liability, Defined Benefit Plan, Current		0	(1)
Liability, Defined Benefit Plan, Noncurrent		(24)	(47)
Liability, Defined Benefit Plan		(18)	(44)
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax		14	35
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax		1	1
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax		15	36
Defined Benefit Plan, Expected Return (Loss) on Plan Assets		(7)	(8)	(6)
Defined Benefit Plan, Amortization of Gain (Loss)		2	1	0
Defined Benefit Plan, Benefit Obligation, Payment for Settlement		(2)	(1)	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)		3	3	$ 2
Fair Value Measured at Net Asset Value Per Share [Member] \| Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		547	546
Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		$ 98	$ 132

[1]	Expected benefit payments in fiscal year 2022 primarily relates to the expected liquidation of the ERP.

INCOME TAXES - Narratives (Deta

INCOME TAXES - Narratives (Detail) - USD ($)	12 Months Ended
INCOME TAXES - Narratives (Detail) - USD ($)	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Income Tax Contingency [Line Items]
Statutory tax rate	21.00%	21.00%	21.00%
Net operating loss carryforward	$ 58,000,000	$ 54,000,000
US and non-US Tax Credit Carryforward	$ 50,700,000
US and non-US tax credit carryforward expiration period	2025
Effect of unrecognized tax benefits on effective tax rate	$ 19,100,000	40,900,000
Accrual for income tax penalties and interest	4,900,000	8,700,000
Deferred Federal Income Tax Expense (Benefit)	7,000,000	$ 29,000,000	$ 15,000,000
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	3,000,000
Release of Valuation Allowance	69,000,000
State
Income Tax Contingency [Line Items]
Net operating loss carryforward	$ 1,491,800,000
Minimum [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards, Expiration Year	2021
Maximum [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards, Expiration Year	2039
UNITED KINGDOM \| Foreign Country Jurisdiction
Income Tax Contingency [Line Items]
Net operating loss carryforward	$ 39,600,000
GERMANY \| Foreign Country Jurisdiction
Income Tax Contingency [Line Items]
Net operating loss carryforward	$ 41,200,000

INCOME TAXES - Income Tax Provi

INCOME TAXES - Income Tax Provision on Income Before Income Taxes (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Current
Federal	$ (21)	$ 26	$ 154
State	14	3	15
Foreign	7	34	54
Total Current	0	63	223
Deferred Federal Income Tax Expense (Benefit)	7	29	15
Deferred State and Local Income Tax Expense (Benefit)	(2)	3	2
Deferred Foreign Income Tax Expense (Benefit)	29	(8)	(18)
Deferred	34	24	(1)
INCOME TAX PROVISION	$ 34	$ 87	$ 222

INCOME TAXES - Income Tax Expen

INCOME TAXES - Income Tax Expense Reconciliation (Detail)	12 Months Ended
INCOME TAXES - Income Tax Expense Reconciliation (Detail)	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, Prior Year Income Taxes, Percent	2.20%	(0.40%)	(0.30%)
Effective Income Tax Rate Reconciliation, Tax Credit, Research, Percent	(1.20%)	(0.60%)	(0.60%)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amortization, Percent	(1.50%)	(2.80%)	(1.50%)
Effective Income Tax Rate Reconciliation, Disposition of Business, Percent	1.40%	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act, Percent	(0.082)	0.042	0.062
Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Percent	(1.20%)	(0.60%)	(1.70%)
Effective Income Tax Rate Reconciliation, Tax Settlement, Percent	(3.20%)	(0.30%)	(0.30%)
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent	2.10%	0.40%	(0.50%)
Effective Income Tax Rate Reconciliation, Tax Expense (Benefit), Share-based Payment Arrangement, Percent	(8.70%)	(10.70%)	(5.40%)
Effective Income Tax Rate Reconciliation,Other Reconciling Items, Percent	0.70%	1.10%	3.00%
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent	1.30%	0.40%	1.00%
Effective Income Tax Rate Reconciliation, Percent	4.70%	11.70%	20.90%
Statutory tax rate	21.00%	21.00%	21.00%

INCOME TAXES - Components of De

INCOME TAXES - Components of Deferred Taxes (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Intangible assets	$ (814)	$ (730)
Property, plant and equipment	(32)	(59)
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Benefits	107	110
Deferred Tax Assets, Derivative Instruments	69	92
Net operating loss carryforward	58	54
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	51	55
Inventory	45	41
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	20	21
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Reserves	11	12
Deferred Tax Assets, Tax Credit Carryforwards	31	17
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Warranty Reserves	7	10
Deferred Tax Asset, Interest Carryforward	28	87
Other	8	9
Total deferred tax liabilities	(411)	(281)
Add: Valuation allowance	(74)	(132)
Total net deferred tax liabilities	$ (485)	$ (413)

INCOME TAXES - Reconciliation o

INCOME TAXES - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	$ 41	$ 37
Additions based on tax positions related to the prior year	0	7
Additions based on tax positions related to the current year	2	2
Reductions based on tax positions related to the prior year	(18)	(1)
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities	4	2
Lapse in statute of limitations	(2)	(2)
Balance at end of period	$ 19	$ 41

INCOME TAXES Income before Tax

INCOME TAXES Income before Tax from Continuing Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Income before Tax from Continuing Operations [Abstract]
Income (Loss) from Continuing Operations before Income Taxes, Domestic	$ 516	$ 635	$ 878
Income (Loss) from Continuing Operations before Income Taxes, Foreign	199	105	185
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	$ 715	$ 740	$ 1,063

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) - USD ($)	12 Months Ended
COMMITMENTS AND CONTINGENCIES (Details) - USD ($)	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Accrued Environmental Loss Contingencies, Current	$ 8,200,000	$ 7,900,000
Accrued Environmental Loss Contingencies, Noncurrent	40,700,000	43,100,000
Insurance deductible	1,000,000
Unusual or Infrequent Item, or Both, Insurance Proceeds	88,000,000
Proceeds from Insurance Settlement, Operating Activities	34,000,000	28,000,000
Unusual or Infrequent Item, or Both, Net of Insurance Proceeds	24,000,000	0	$ 0
Proceeds from Insurance Premiums Collected	58,000,000
Proceeds from Insurance Settlement, Investing Activities	24,000,000	0	0
Business Interruption Loss [Line Items]
Gain on insurance proceeds from fire	(24,000,000)	0	0
Proceeds from Insurance Settlement, Investing Activities	24,000,000	0	$ 0
Proceeds from Insurance Settlement, Operating Activities	34,000,000	$ 28,000,000
Insurance Claims
Commitments and Contingencies Disclosure [Abstract]
Unusual or Infrequent Item, or Both, Net of Insurance Proceeds	19,000,000
Business Interruption Loss [Line Items]
Gain on insurance proceeds from fire	(19,000,000)
Corporate and Other
Commitments and Contingencies Disclosure [Abstract]
Unusual or Infrequent Item, or Both, Net of Insurance Proceeds	5,000,000
Business Interruption Loss [Line Items]
Gain on insurance proceeds from fire	$ (5,000,000)

CAPITAL STOCK - Narratives (Det

CAPITAL STOCK - Narratives (Detail) - USD ($) $ / shares in Units, $ in Millions	Mar. 28, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019	Nov. 08, 2017
Shareholders Equity [Line Items]
Common Stock, Shares Authorized		224,400,000	224,400,000
Common Stock, Par or Stated Value Per Share		$ 0.01	$ 0.01
Preferred stock, shares authorized		149,600,000
Preferred stock, par value		$ 0.01
Common Stock, Shares, Issued		59,403,100	58,612,028
Treasury Stock, Shares		4,198,226	4,198,226
Preferred stock, shares outstanding		0
Payments for Repurchase of Common Stock		$ 0	$ 19	$ 0
November 8, 2017 Stock Repurchase Program [Member]
Shareholders Equity [Line Items]
Stock Repurchase Program, Authorized Amount					$ 650
Stock Repurchased and Retired During Period, Shares	36,900
Payments for Repurchase of Common Stock	$ 18.9
Treasury Stock Acquired, Average Cost Per Share	$ 512.67
Stock Repurchase Program, Remaining Authorized Repurchase Amount		$ 631.1

SEGMENTS - Narratives (Detail)

SEGMENTS - Narratives (Detail)	12 Months Ended
SEGMENTS - Narratives (Detail)	Sep. 30, 2021Segment
Segment Reporting [Abstract]
Number of reporting segments	3

SEGMENTS - Net Sales by Reporta

SEGMENTS - Net Sales by Reportable Segment (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Revenues	$ 4,798	$ 5,103	$ 5,223
Operating Segments \| Power & Control
Segment Reporting Information [Line Items]
Revenues	2,550	2,695	2,736
Operating Segments \| Airframe
Segment Reporting Information [Line Items]
Revenues	2,083	2,253	2,329
Operating Segments \| Non-aviation
Segment Reporting Information [Line Items]
Revenues	165	155	158
Commercial OEM [Member] \| Operating Segments \| Power & Control
Segment Reporting Information [Line Items]
Revenues	527	623	686
Commercial OEM [Member] \| Operating Segments \| Airframe
Segment Reporting Information [Line Items]
Revenues	591	783	836
Commercial Aftermarket [Member] \| Operating Segments \| Power & Control
Segment Reporting Information [Line Items]
Revenues	576	673	769
Commercial Aftermarket [Member] \| Operating Segments \| Airframe
Segment Reporting Information [Line Items]
Revenues	550	689	865
Defense [Member] \| Operating Segments \| Power & Control
Segment Reporting Information [Line Items]
Revenues	1,447	1,399	1,281
Defense [Member] \| Operating Segments \| Airframe
Segment Reporting Information [Line Items]
Revenues	$ 942	$ 781	$ 628

SEGMENTS - EBITDA Defined by Se

SEGMENTS - EBITDA Defined by Segment to Consolidated Income Before Taxes Operations (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Earnings before interest taxes depreciation and amortization	$ 2,189	$ 2,278	$ 2,419
Depreciation and amortization expense	253	283	226
Interest expense, net	(1,059)	(1,029)	(859)
Non-cash stock compensation expense	129	93	93
Refinancing costs	37	28	3
Gain on sale of businesses, net	69	0	0
Income from continuing operations before income taxes	715	740	1,063
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Earnings before interest taxes depreciation and amortization	2,259	2,354	2,509
Operating Segments \| Power & Control
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Earnings before interest taxes depreciation and amortization	1,319	1,345	1,395
Depreciation and amortization expense	107	117	99
Operating Segments \| Airframe
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Earnings before interest taxes depreciation and amortization	878	955	1,063
Depreciation and amortization expense	139	157	119
Operating Segments \| Non-aviation
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Earnings before interest taxes depreciation and amortization	62	54	51
Depreciation and amortization expense	6	7	6
Corporate, Non-Segment [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Earnings before interest taxes depreciation and amortization	70	76	90
Depreciation and amortization expense	1	2	2
Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Depreciation and amortization expense	253	283	225
Interest expense, net	1,059	1,029	859
Acquisition and divestiture-related costs	35	31	169
Non-cash stock compensation expense	129	93	93
Refinancing costs	37	28	3
COVID-19 pandemic restructuring costs	40	54	0
Gain on sale of businesses, net	(69)	0	0
Other, net	$ (10)	$ 20	$ 7

SEGMENTS - Capital Expenditures

SEGMENTS - Capital Expenditures and Depreciation and Amortization by Segment (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Capital expenditures	$ 105	$ 105	$ 102
Depreciation and amortization expense	$ 253	283	226
Capital Expenditures and Depreciation and Amortization by Segment	The following table presents capital expenditures and depreciation and amortization by segment (in millions): Fiscal Years Ended September 30, 2021 2020 2019 Capital expenditures Power & Control $ 65 $ 89 $ 50 Airframe 37 10 48 Non-aviation 2 4 3 Corporate 1 2 1 $ 105 $ 105 $ 102 Depreciation and amortization Power & Control $ 107 $ 117 $ 99 Airframe 139 157 119 Non-aviation 6 7 6 Corporate 1 2 2 $ 253 $ 283 $ 226
Operating Segments \| Power & Control
Segment Reporting Information [Line Items]
Capital expenditures	$ 65	89	50
Depreciation and amortization expense	107	117	99
Operating Segments \| Airframe
Segment Reporting Information [Line Items]
Capital expenditures	37	10	48
Depreciation and amortization expense	139	157	119
Operating Segments \| Non-aviation
Segment Reporting Information [Line Items]
Capital expenditures	2	4	3
Depreciation and amortization expense	6	7	6
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Capital expenditures	1	2	1
Depreciation and amortization expense	$ 1	$ 2	$ 2

SEGMENTS - Total Assets by Segm

SEGMENTS - Total Assets by Segment (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 19,315	$ 18,395
Operating Segments \| Power & Control
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	6,980	7,005
Operating Segments \| Airframe
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	7,472	6,575
Operating Segments \| Non-aviation
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	229	251
Corporate, Non-Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 4,634	$ 4,564

SEGMENTS (Details)

SEGMENTS (Details) - USD ($) $ in Millions	12 Months Ended
SEGMENTS (Details) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 4,798	$ 5,103
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	3,096	3,407
Non-US
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 1,702	$ 1,696

SEGMENTS - Geographic Informati

SEGMENTS - Geographic Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 4,798	$ 5,103
Long-Lived Assets	864	855
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	3,096	3,407
Long-Lived Assets	608	600
Non-US
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,702	1,696
Long-Lived Assets	$ 256	$ 255

STOCK-BASED COMPENSATION - Narr

STOCK-BASED COMPENSATION - Narratives (Detail)	1 Months Ended	12 Months Ended
STOCK-BASED COMPENSATION - Narratives (Detail)	Mar. 31, 2011shares	Sep. 30, 2021USD ($)numberOfGrantees$ / sharesshares	Sep. 30, 2020USD ($)numberOfGrantees$ / shares	Sep. 30, 2019USD ($)$ / shares	Oct. 03, 2019shares	Oct. 02, 2014shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-cash stock compensation expense		$ 129,000,000	$ 93,000,000	$ 93,000,000
Stock option weighted-average grant date fair value \| $ / shares		$ 193.47	$ 157.41	$ 114.43
Unrecognized compensation cost related to non-vested awards expected to vest		$ 55,000,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition		1 year 3 months 18 days
Share-based Payment Arrangement, Plan Modification, Incremental Cost		$ 8,500,000	$ 2,500,000
Fair value of options vested		92,000,000	97,200,000	$ 37,700,000
Cash dividend and dividend equivalents paid		26,000,000	74,000,000	80,000,000
Payments of Dividends		73,000,000	1,928,000,000	1,712,000,000
Dividend equivalent payments—current (Note 18)		45,900,000	$ 72,000,000
Dividend Equivalent Payments on Certain Stock Options, Non-current		$ 30,900,000
Share-based Payment Arrangement, Plan Modification, Number of Grantees Affected \| numberOfGrantees		64	85
Non-cash Stock Compensation Expense		$ 128,900,000	$ 92,700,000	93,400,000
2019 Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock \| shares					4,000,000
2014 Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock \| shares						5,000,000
2006 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock \| shares	8,119,668
Restricted stock grant period in years	3 years
2003 Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of options exercised		$ 355,300,000	394,200,000	240,200,000
2014 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for award \| shares		626,294
Vested Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend, Share-based Payment Arrangement, Cash		$ 72,500,000	$ 184,900,000	$ 111,000,000
Performance Vested Stock Options \| 2014 Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for award \| shares		811,308
Number of Options, Exercised \| shares		101,638
Weighted-Average Exercise Price Per Option, Exercised \| $ / shares		$ 328.42
Number of Options Exercisable at end of period \| shares		2,458,305
Weighted-Average Exercise Price Per Option, Exercisable \| $ / shares		$ 352.13
Weighted-Average Remaining Contractual Term, Exercisable, years		6 years 6 months
Aggregate Intrinsic Value, Exercisable		$ 669,740,614
Performance Vested Stock Options \| 2006 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for award \| shares		0
Number of Options, Exercised \| shares		687,075
Weighted-Average Exercise Price Per Option, Exercised \| $ / shares		$ 137.75
Number of Options Exercisable at end of period \| shares		1,548,605
Weighted-Average Exercise Price Per Option, Exercisable \| $ / shares		$ 185.71
Weighted-Average Remaining Contractual Term, Exercisable, years		2 years 10 months 24 days
Aggregate Intrinsic Value, Exercisable		$ 679,627,029
Performance Vested Stock Options \| 2003 Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options Exercisable at end of period \| shares		829
Weighted-Average Exercise Price Per Option, Exercisable \| $ / shares		$ 130.09

STOCK-BASED COMPENSATION - Weig

STOCK-BASED COMPENSATION - Weighted Average Assumptions used to Estimate Fair Value of all Options at Grant Date using Black-Scholes-Merton Option-Pricing Model (Detail)	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Risk-free interest rate, minimum		0.26%	2.33%
Risk-free interest rate, maximum		1.65%	3.03%
Expected dividend yield of stock	0.00%	0.00%	0.00%
Expected volatility of stock	36.00%		25.00%
Expected life of options	5 years 6 months		5 years 6 months
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum		0.26%	2.33%
Risk-free interest rate, maximum		1.65%	3.03%
Expected life of options	5 years 6 months		5 years 6 months
Expected dividend yield of stock	0.00%	0.00%	0.00%
Expected volatility of stock	36.00%		25.00%
Minimum [Member]
Share-based Payment Arrangement [Abstract]
Risk-free interest rate, minimum	0.42%
Expected volatility of stock		25.00%
Expected life of options		5 years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum	0.42%
Expected life of options		5 years
Expected volatility of stock		25.00%
Maximum [Member]
Share-based Payment Arrangement [Abstract]
Risk-free interest rate, maximum	0.86%
Expected volatility of stock		39.00%
Expected life of options		5 years 6 months
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, maximum	0.86%
Expected life of options		5 years 6 months
Expected volatility of stock		39.00%

STOCK-BASED COMPENSATION - Summ

STOCK-BASED COMPENSATION - Summary of Activity, Pricing and Other Information for Performance Vested Stock-Based Award Activity (Detail) - Performance Vested Stock Options	12 Months Ended
	Sep. 30, 2021USD ($)$ / sharesshares
2014 Stock Option Plan
Number of Options
Number of Options, Outstanding, beginning of period \| shares	3,613,857
Number of Options, Granted \| shares	811,308
Number of Options, Exercised \| shares	(101,638)
Number of Options, Forfeited \| shares	(120,604)
Number of Options, Expired \| shares	0
Number of Options, Outstanding, end of period \| shares	4,202,923
Number of Options, Expected to vest \| shares	725,302
Number of Options Exercisable at end of period \| shares	2,458,305
Weighted average exercise price per option
Weighted-Average Exercise Price Per Option, Outstanding, beginning of period \| $ / shares	$ 364.79
Weighted-Average Exercise Price Per Option, Granted \| $ / shares	573.65
Weighted-Average Exercise Price Per Option, Exercised \| $ / shares	328.42
Weighted-Average Exercise Price Per Option, Forfeited \| $ / shares	464.43
Weighted-Average Exercise Price Per Option, Expired \| $ / shares	0
Weighted-Average Exercise Price Per Option, Outstanding, end of period \| $ / shares	403.12
Weighted-Average Exercise Price Per Option, Expected to vest \| $ / shares	351.88
Weighted-Average Exercise Price Per Option, Exercisable \| $ / shares	$ 352.13
Weighted average remaining contractual term
Weighted-Average Remaining Contractual Term, Outstanding, years	7 years 1 month 6 days
Weighted-Average Remaining Contractual Term, Expected to vest, years	6 years 10 months 24 days
Weighted-Average Remaining Contractual Term, Exercisable, years	6 years 6 months
Aggregate intrinsic value
Aggregate Intrinsic Value, Outstanding \| $	$ 930,737,298
Aggregate Intrinsic Value, Expected to vest \| $	197,784,390
Aggregate Intrinsic Value, Exercisable \| $	$ 669,740,614
2006 Stock Incentive Plan
Number of Options
Number of Options, Outstanding, beginning of period \| shares	2,235,680
Number of Options, Granted \| shares	0
Number of Options, Exercised \| shares	(687,075)
Number of Options, Forfeited \| shares	0
Number of Options, Expired \| shares	0
Number of Options, Outstanding, end of period \| shares	1,548,605
Number of Options Exercisable at end of period \| shares	1,548,605
Weighted average exercise price per option
Weighted-Average Exercise Price Per Option, Outstanding, beginning of period \| $ / shares	$ 170.97
Weighted-Average Exercise Price Per Option, Granted \| $ / shares	0
Weighted-Average Exercise Price Per Option, Exercised \| $ / shares	137.75
Weighted-Average Exercise Price Per Option, Forfeited \| $ / shares	0
Weighted-Average Exercise Price Per Option, Expired \| $ / shares	0
Weighted-Average Exercise Price Per Option, Outstanding, end of period \| $ / shares	185.71
Weighted-Average Exercise Price Per Option, Exercisable \| $ / shares	$ 185.71
Weighted average remaining contractual term
Weighted-Average Remaining Contractual Term, Outstanding, years	2 years 10 months 24 days
Weighted-Average Remaining Contractual Term, Exercisable, years	2 years 10 months 24 days
Aggregate intrinsic value
Aggregate Intrinsic Value, Outstanding \| $	$ (679,627,029)
Aggregate Intrinsic Value, Exercisable \| $	$ 679,627,029
2003 Stock Option Plan
Number of Options
Number of Options Exercisable at end of period \| shares	829
Weighted average exercise price per option
Weighted-Average Exercise Price Per Option, Exercisable \| $ / shares	$ 130.09

LEASES - Components of Lease Ex

LEASES - Components of Lease Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Lease, Cost	$ 39	$ 36
Lessee, Lease, Description [Line Items]
Lease, Cost	39	36
Operating Expense
Leases [Abstract]
Operating Lease, Cost	29	29
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	29	29
Cost of Sales
Leases [Abstract]
Finance Lease, Right-of-Use Asset, Amortization	4	3
Lessee, Lease, Description [Line Items]
Finance Lease, Right-of-Use Asset, Amortization	4	3
Interest Expense
Leases [Abstract]
Finance Lease, Interest Expense	6	4
Lessee, Lease, Description [Line Items]
Finance Lease, Interest Expense	$ 6	$ 4

LEASES - Supplemental Cash Flow

LEASES - Supplemental Cash Flow Information Related to Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Operating Lease, Payments	$ 29	$ 29
Finance Lease, Interest Payment on Liability	6	4
Finance Lease, Principal Payments	2	2
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	41	32
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	$ 25	$ 0

LEASES - Operating Leases, Supp

LEASES - Operating Leases, Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Operating Leased Assets [Line Items]
Current operating lease liabilities (Note 19)	$ 20	$ 22
Operating Lease, Liability	99	109
Finance Lease, Right-of-Use Asset	104
Finance Lease, Liability, Current	2
Finance Lease, Liability, Noncurrent	98
Finance Lease, Liability	100	57
Other Assets [Member]
Operating Leased Assets [Line Items]
Operating Lease, Right-of-Use Asset	94	103
Accrued Liabilities
Operating Leased Assets [Line Items]
Current operating lease liabilities (Note 19)	20	22
Finance Lease, Liability, Current		2
Other Non-Current Liabilities
Operating Leased Assets [Line Items]
Operating Lease, Liability, Noncurrent	$ 79	87
Finance Lease, Liability, Noncurrent		55
Property, Plant and Equipment
Operating Leased Assets [Line Items]
Finance Lease, Right-of-Use Asset		$ 67

LEASES - Finance Leases, Supple

LEASES - Finance Leases, Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Capital Leased Assets [Line Items]
Finance Lease, Right-of-Use Asset	$ 104
Finance Lease, Liability, Current	2
Finance Lease, Liability, Noncurrent	98
Finance Lease, Liability	100	$ 57
Current operating lease liabilities (Note 19)	20	22
Property, Plant and Equipment
Capital Leased Assets [Line Items]
Finance Lease, Right-of-Use Asset		67
Accrued Liabilities
Capital Leased Assets [Line Items]
Finance Lease, Liability, Current		2
Current operating lease liabilities (Note 19)	$ 20	22
Other Non-Current Liabilities
Capital Leased Assets [Line Items]
Finance Lease, Liability, Noncurrent		$ 55

LEASES - Weighted-Average Term

LEASES - Weighted-Average Term and Discount Rate Remaining (Details)	Sep. 30, 2021
Leases [Abstract]
Operating Lease, Weighted Average Remaining Lease Term	8 years 1 month 6 days
Finance Lease, Weighted Average Remaining Lease Term	21 years 8 months 12 days
Operating Lease, Weighted Average Discount Rate, Percent	6.00%
Finance Lease, Weighted Average Discount Rate, Percent	7.20%

LEASES - Maturities of Lease Li

LEASES - Maturities of Lease Liabilities Operating and Financing (Details) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months	$ 24
Lessee, Operating Lease, Liability, Payments, Due Year Two	19
Lessee, Operating Lease, Liability, Payments, Due Year Three	16
Lessee, Operating Lease, Liability, Payments, Due Year Four	13
Lessee, Operating Lease, Liability, Payments, Due Year Five	10
Lessee, Operating Lease, Liability, Payments, Due after Year Five	45
Lessee, Operating Lease, Liability, Payments, Due	127
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	28
Operating Lease, Liability	99	$ 109
Finance Lease, Liability, Payments, Due Next Twelve Months	8
Finance Lease, Liability, Payments, Due Year Two	9
Finance Lease, Liability, Payments, Due Year Three	9
Finance Lease, Liability, Payments, Due Year Four	9
Finance Lease, Liability, Payments, Due Year Five	9
Finance Lease, Liability, Payments, Due after Year Five	171
Finance Lease, Liability, Payment, Due	215
Finance Lease, Liability, Undiscounted Excess Amount	115
Finance Lease, Liability	$ 100	$ 57

FAIR VALUE MEASUREMENTS Carryin

FAIR VALUE MEASUREMENTS Carrying Amounts and Fair Values of Financial Instruments (Detail) - USD ($) $ in Millions		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, Assets, Carrying Amount		$ 4,787	$ 4,717	$ 1,467	$ 2,073
Short-term borrowings - trade receivable securitization facility, Carrying Amount		349	349
Long-term Debt		19,649	19,660
Other Noncurrent Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest Rate Cap Assets	[1]	8	0
Accrued Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap agreements, Liabilities, Carrying Amount	[2]	100	56
Foreign Currency Contract, Asset	[2]	4	1
Other Non-Current Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap agreements, Liabilities, Carrying Amount	[3]	180	328
Term Loans [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	[4]	7,318	7,378
Revolving Credit Facility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	[4]	200	200
Government Refundable Advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt		29	28
Capital Lease Obligations [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt		100	57
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, Assets, Fair Value		4,787	4,717
Fair Value, Inputs, Level 2 [Member] \| Other Noncurrent Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest Rate Cap Assets	[1]	8	0
Fair Value, Inputs, Level 2 [Member] \| Accrued Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest Rate Cash Flow Hedge Liability at Fair Value	[2]	100	56
Foreign Currency Contract, Asset	[2]	4	1
Fair Value, Inputs, Level 2 [Member] \| Other Non-Current Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest Rate Cash Flow Hedge Liability at Fair Value	[3]	180	328
Fair Value, Inputs, Level 2 [Member] \| Term Loans [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, Fair Value	[4]	7,268	7,004
Fair Value, Inputs, Level 2 [Member] \| Revolving Credit Facility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, Fair Value	[4]	200	200
Fair Value, Inputs, Level 2 [Member] \| Government Refundable Advances [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, Fair Value		29	28
Fair Value, Inputs, Level 2 [Member] \| Capital Lease Obligations [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, Fair Value		100	57
Senior Subordinated Notes $1,200M due 2024 6.50% \| Senior Subordinated Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	[4]	0	1,195
Senior Subordinated Notes $1,200M due 2024 6.50% \| Fair Value, Inputs, Level 1 [Member] \| Senior Subordinated Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, Fair Value	[4]	0	1,194
6.50% Senior Subordinated Notes, Due 2025 \| Senior Subordinated Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	[4]	0	750
6.50% Senior Subordinated Notes, Due 2025 \| Fair Value, Inputs, Level 1 [Member] \| Senior Subordinated Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, Fair Value	[4]	0	743
Senior Secured Notes $1,100M due 2025 8.00% \| Secured Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	[4]	1,093	1,091
Senior Secured Notes $1,100M due 2025 8.00% \| Fair Value, Inputs, Level 1 [Member] \| Secured Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, Fair Value	[4]	1,170	1,194
6.375% Senior Subordinated Notes, Due 2026 \| Senior Subordinated Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	[4]	945	944
6.375% Senior Subordinated Notes, Due 2026 \| Fair Value, Inputs, Level 1 [Member] \| Senior Subordinated Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, Fair Value	[4]	981	948
Senior Subordinated Notes $500M due 2026 6.875% \| Senior Subordinated Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	[4]	494	493
Senior Subordinated Notes $500M due 2026 6.875% \| Fair Value, Inputs, Level 1 [Member] \| Senior Subordinated Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, Fair Value	[4]	527	500
Senior Secured Notes $4.4B Due 2026 6.25% \| Secured Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	[4]	4,359	4,350
Senior Secured Notes $4.4B Due 2026 6.25% \| Fair Value, Inputs, Level 1 [Member] \| Secured Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, Fair Value	[4]	4,593	4,604
Senior Subordinated Notes $550M due 2027 7.50% \| Senior Subordinated Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	[4]	546	545
Senior Subordinated Notes $550M due 2027 7.50% \| Fair Value, Inputs, Level 1 [Member] \| Senior Subordinated Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, Fair Value	[4]	578	569
Senior Subordinated Notes $2,650M due 2027 5.50% \| Senior Subordinated Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	[4]	2,632	2,629
Senior Subordinated Notes $2,650M due 2027 5.50% \| Fair Value, Inputs, Level 1 [Member] \| Senior Subordinated Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, Fair Value	[4]	2,730	2,554
Senior Subordinated Notes $1,200M due 2029 4.625% \| Senior Subordinated Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	[4]	1,190	0
Senior Subordinated Notes $1,200M due 2029 4.625% \| Fair Value, Inputs, Level 1 [Member] \| Senior Subordinated Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, Fair Value	[4]	1,196	0
Senior Subordinated Notes $750M due 2029 4.875% \| Senior Subordinated Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	[4]	743	0
Senior Subordinated Notes $750M due 2029 4.875% \| Fair Value, Inputs, Level 1 [Member] \| Senior Subordinated Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, Fair Value	[4]	751	0
Asset-backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term borrowings - trade receivable securitization facility, Carrying Amount	[4]	349	349
Asset-backed Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term borrowings - trade receivable securitization facility, Fair Value	[4]	$ 349	$ 349

[1]	Included in other assets on the consolidated balance sheets.
[2]	Included in accrued and other current liabilities on the consolidated balance sheets.
[3]	Included in other non-current liabilities on the consolidated balance sheets.
[4]	The carrying amount of the debt instrument is presented net of the debt issuance costs, premium and discount. Refer to Note 12, “Debt,” for gross carrying amounts.

DERIVATIVES AND HEDGING ACTIV_3

DERIVATIVES AND HEDGING ACTIVITIES - Narratives (Detail) $ in Millions	12 Months Ended
	Sep. 30, 2021USD ($)
Interest Rate Swap and Cap
Derivative [Line Items]
Derivative loss to be recognized	$ 101.8
Foreign Exchange Forward [Member]
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Tax to be Transferred	3.6
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Gross Amount to be Transferred	3.6
Derivative, Notional Amount	$ 125.7
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimate of Time to Transfer	12 months
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member]
Derivative [Line Items]
Interest Expense	$ 2	[1]
Tranche F \| Interest rate swap beginning June 30, 2021 [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	5.25%
Derivative, Notional Amount	$ 1,400
Derivative, Variable Interest Rate	3.00%
Derivative, Basis Spread on Variable Rate	2.25%
Tranche F \| Interest rate swap beginning March 31, 2023
Derivative [Line Items]
Derivative, Fixed Interest Rate	3.55%
Derivative, Notional Amount	$ 700
Derivative, Variable Interest Rate	1.30%
Derivative, Basis Spread on Variable Rate	2.25%
Tranche F \| Interest rate cap beginning March 31, 2023
Derivative [Line Items]
Derivative, Cap Interest Rate	1.25%
Derivative, Notional Amount	$ 700
Tranche E \| Interest rate swap beginning June 30, 2020 [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	4.75%
Derivative, Notional Amount	$ 750
Derivative, Variable Interest Rate	2.50%
Derivative, Basis Spread on Variable Rate	2.25%
Tranche E \| Interest rate swap beginning June 29, 2018 [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	5.25%
Derivative, Notional Amount	$ 500
Derivative, Variable Interest Rate	3.00%
Derivative, Basis Spread on Variable Rate	2.25%
Tranche E \| Interest rate swap beginning June 30, 2022 [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	5.35%
Derivative, Notional Amount	$ 1,500
Derivative, Variable Interest Rate	3.10%
Derivative, Basis Spread on Variable Rate	2.25%
Tranche E \| Interest Rate Cap [Member]
Derivative [Line Items]
Derivative, Cap Interest Rate	2.50%
Derivative, Notional Amount	$ 750
Tranche G [Member] \| Interest rate swap beginning September 30, 2017 [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	4.15%
Derivative, Notional Amount	$ 400
Derivative, Variable Interest Rate	1.90%
Derivative, Basis Spread on Variable Rate	2.25%
Tranche G [Member] \| Interest rate swap beginning December 31, 2021 [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	5.35%
Derivative, Notional Amount	$ 900
Derivative, Variable Interest Rate	3.10%
Derivative, Basis Spread on Variable Rate	2.25%
Tranche G [Member] \| Interest rate swap beginning September 30, 2022 [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	5.25%
Derivative, Notional Amount	$ 400
Derivative, Variable Interest Rate	3.00%
Derivative, Basis Spread on Variable Rate	2.25%
Tranche G [Member] \| Interest rate swap beginning December 30, 2016
Derivative [Line Items]
Derivative, Fixed Interest Rate	4.15%
Derivative, Notional Amount	$ 500
Derivative, Variable Interest Rate	1.90%
Derivative, Basis Spread on Variable Rate	2.25%
Tranche G [Member] \| Interest rate cap beginning December 30, 2016
Derivative [Line Items]
Derivative, Cap Interest Rate	2.50%
Derivative, Notional Amount	$ 400

[1]	This component of accumulated other comprehensive loss is included in interest expense-net. Refer to Note 21, “Derivatives and Hedging Activities,” for additional information.

DERIVATIVES AND HEDGING ACTIV_4

DERIVATIVES AND HEDGING ACTIVITIES - Schedule of Interest Rate Derivatives (Details) - USD ($) $ in Millions		Sep. 30, 2021	Sep. 30, 2020
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]	$ 8	$ 0
Derivative Liability, Fair Value, Gross Liability	[1]	(280)	(384)
Interest Rate Cap
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset		8	0
Derivative Liability, Fair Value, Gross Liability		0	0
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset		0	0
Derivative Liability, Fair Value, Gross Liability		$ (280)	$ (384)
Tranche F \| Interest rate swap beginning June 30, 2021 [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate		5.25%
Derivative, Variable Interest Rate		3.00%
Derivative, Basis Spread on Variable Rate		2.25%
Tranche G [Member] \| Interest rate swap beginning September 30, 2017 [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate		4.15%
Derivative, Variable Interest Rate		1.90%
Derivative, Basis Spread on Variable Rate		2.25%
Tranche G [Member] \| Interest rate swap beginning December 31, 2021 [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate		5.35%
Derivative, Variable Interest Rate		3.10%
Derivative, Basis Spread on Variable Rate		2.25%
Tranche G [Member] \| Interest rate swap beginning September 30, 2022 [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate		5.25%
Derivative, Variable Interest Rate		3.00%
Derivative, Basis Spread on Variable Rate		2.25%
Tranche E \| Interest Rate Cap [Member]
Derivative [Line Items]
Derivative, Cap Interest Rate		2.50%
Tranche E \| Interest rate swap beginning June 30, 2020 [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate		4.75%
Derivative, Variable Interest Rate		2.50%
Derivative, Basis Spread on Variable Rate		2.25%
Tranche E \| Interest rate swap beginning June 30, 2022 [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate		5.35%
Derivative, Variable Interest Rate		3.10%
Derivative, Basis Spread on Variable Rate		2.25%
Tranche E \| Interest rate swap beginning June 29, 2018 [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate		5.25%
Derivative, Variable Interest Rate		3.00%
Derivative, Basis Spread on Variable Rate		2.25%

[1]	Refer to Note 20, "Fair Value Measurements," for the consolidated balance sheets classification of our interest rate swap agreements.

DERIVATIVES AND HEDGING ACTIV_5

DERIVATIVES AND HEDGING ACTIVITIES - Schedule of Notional Amounts (Details) $ in Millions	Sep. 30, 2021USD ($)
Tranche E \| Interest rate swap beginning June 29, 2018 [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 500
Tranche E \| Interest rate swap beginning June 30, 2020 [Member]
Derivative [Line Items]
Derivative, Notional Amount	750
Tranche E \| Interest rate swap beginning June 30, 2022 [Member]
Derivative [Line Items]
Derivative, Notional Amount	1,500
Tranche E \| Interest Rate Cap [Member]
Derivative [Line Items]
Derivative, Notional Amount	750
Tranche F \| Interest rate swap beginning June 30, 2021 [Member]
Derivative [Line Items]
Derivative, Notional Amount	1,400
Tranche G [Member] \| Interest rate swap beginning September 30, 2017 [Member]
Derivative [Line Items]
Derivative, Notional Amount	400
Tranche G [Member] \| Interest rate swap beginning December 31, 2021 [Member]
Derivative [Line Items]
Derivative, Notional Amount	900
Tranche G [Member] \| Interest rate swap beginning September 30, 2022 [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 400

ACCUMULATED OTHER COMPREHENSI_3

ACCUMULATED OTHER COMPREHENSIVE LOSS - Schedule of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions		12 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period		$ (401)	$ (379)
Other comprehensive loss before reclassification		148
Amounts reclassified from AOCI related to interest rate swap agreements		5
Other comprehensive income (loss), net of tax, attributable to TD Group		153	(22)	$ (383)
Balance at end of period		(248)	(401)	(379)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax		(8)	(1)	9
INCOME TAX PROVISION		34	87	222
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax		(23)	(36)	(70)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent		90	76	(115)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax, Parent		(73)	130	239
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent		(10)	32	(29)
Unrealized (loss) gain on derivatives designated and qualifying as cash flow hedges (2)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period	[1]	(302)	(172)
Other comprehensive loss before reclassification	[1]	68
Amounts reclassified from AOCI related to interest rate swap agreements	[1]	(5)
Balance at end of period	[1]	(229)	(302)	(172)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax, Parent	[1]	73	(130)
Unrealized (loss) gain on derivatives designated and qualifying as cash flow hedges (2) \| Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest Expense	[2]	2
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax, Portion Attributable to Parent	[3]	4
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax		(1)
Defined benefit pension plan activity (3)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period	[4]	(8)	(40)
Other comprehensive loss before reclassification	[4]	(10)
Amounts reclassified from AOCI related to interest rate swap agreements	[4]	0
Balance at end of period	[4]	(18)	(8)	(40)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent	[4]	(10)	32
Currency translation adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period		(91)	(167)
Balance at end of period		(1)	(91)	$ (167)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent		90	$ 76
Accounting Standards Update 2018-02 [Member] \| Currency translation adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Other comprehensive loss before reclassification		$ 90

[1]	Represents unrealized (losses) gains on derivatives designated and qualifying as cash flow hedges, net of tax (benefit) expense of $(23) million, $36 million and $70 million for the fiscal years ended September 30, 2021, 2020 and 2019, respectively.
[2]	This component of accumulated other comprehensive loss is included in interest expense-net. Refer to Note 21, “Derivatives and Hedging Activities,” for additional information.
[3]	This component of accumulated other comprehensive loss is included in net sales. Refer to Note 21, “Derivatives and Hedging Activities,” for additional information.
[4]	Defined benefit pension plan and other post-retirement plan activity represents pension liability adjustments, net of tax (benefit) expense of $(8) million, $(1) million and $9 million for the fiscal years ended September 30, 2021, 2020 and 2019, respectively. Amounts reclassified from AOCI related to defined benefit pension plan and other post-retirement plan activity were immaterial for the fiscal year ended September 30, 2021

DISCONTINUED OPERATIONS - Narra

DISCONTINUED OPERATIONS - Narrative (Details) - USD ($) $ in Millions	Dec. 20, 2019	Sep. 20, 2019	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash Provided by (Used in) Operating Activities, Discontinued Operations					$ 35
Cash Provided by (Used in) Investing Activities, Discontinued Operations					11
Revenues			$ 4,798	$ 5,103	5,223
Income from discontinued operations, net of tax			$ 0	47	51
Souriau Sunbank [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Businesses	$ 920
Revenues				79	199
Income from discontinued operations, before income taxes				11	(17)
Income from discontinued operations, net of tax				7
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax				40
Income from discontinued operations, net of tax				$ 47
Discontinued Operation, Tax Effect of Income (Loss) from Discontinued Operation During Phase-out Period					(14)
EIT [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Businesses		$ 190
Revenues					95
Income from discontinued operations, before income taxes					17
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax					38
Discontinued Operation, Tax Effect of Income (Loss) from Discontinued Operation During Phase-out Period					1
Souriau Sunbank and EIT
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues					294
Income from discontinued operations, before income taxes					0
Income from discontinued operations, net of tax					13
Income from discontinued operations, net of tax					$ 51

DISCONTINUED OPERATIONS - Sched

DISCONTINUED OPERATIONS - Schedule of Discontinued Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues	$ 4,798	$ 5,103	$ 5,223
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	$ 0	47	51
Souriau Sunbank [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues		79	199
Income from discontinued operations, before income taxes		11	(17)
Income tax provision (benefit)		4
Income from discontinued operations, net of tax		7
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax		40
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent		$ 47
EIT [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues			95
Income from discontinued operations, before income taxes			17
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			38
Souriau Sunbank and EIT
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues			294
Income from discontinued operations, before income taxes			0
Income tax provision (benefit)			(13)
Income from discontinued operations, net of tax			13
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent			$ 51

Valuation and Qualifying Acco_2

Valuation and Qualifying Accounts (Detail) - USD ($) $ in Millions		12 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Allowance for Doubtful Accounts
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		$ 37	$ 17	$ 5
Charged to Costs and Expenses		0	21	5
Acquisitions & Purchase Price Adjustments		0	(3)	(9)
Deductions from Reserve	[1]	(7)	(4)	(2)
Balance at End of Period		30	37	17
SEC Schedule 12-09, Inventory Reserve [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period			124
Balance at End of Period				124
Reserve for excess and obsolete inventory
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		178	124	99
Charged to Costs and Expenses		42	34	17
Acquisitions & Purchase Price Adjustments		(10)	(37)	(17)
Deductions from Reserve	[1]	(36)	(17)	(9)
Balance at End of Period		194	178	124
Valuation Allowance of Deferred Tax Assets
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		132	118	47
Charged to Costs and Expenses		(58)	15	40
Acquisitions & Purchase Price Adjustments		0	(1)	(31)
Deductions from Reserve	[1]	0	0	0
Balance at End of Period		$ 74	$ 132	$ 118

[1]	The amounts in this column represent the impact from divestitures, charge-offs net of recoveries and the impact of foreign currency translation adjustments.