Janus Henderson (JHG) 10-Q1 Nov 232023 Q3 Quarterly reportFinancial data

Company Profile

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
Document And Entity Information - shares	Sep. 30, 2023	Oct. 30, 2023
Document Information [Line Items]
Entity Central Index Key	0001274173
Entity Registrant Name	JANUS HENDERSON GROUP PLC
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2023
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2023
Document Transition Report	false
Entity File Number	001-38103
Entity Incorporation, State or Country Code	Y9
Entity Tax Identification Number	98-1376360
Entity Address, Address Line One	201 Bishopsgate
Entity Address, City or Town	London
Entity Address, Country	GB
Entity Address, Postal Zip Code	EC2M3AE
City Area Code	0
Local Phone Number	20 7818 1818
Title of 12(b) Security	Common Stock, $1.50 Per Share Par Value
Trading Symbol	JHG
Security Exchange Name	NYSE
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
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		165,657,905

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 1,121.2	$ 1,162.3
Investments	293.1	261.6
Fees and other receivables	232.8	252.9
OEIC and unit trust receivables	137.5	65.7
Other current assets	151.9	120.3
Total current assets	2,288.1	2,214.8
Non-current assets:
Property, equipment and software, net	45.3	51.8
Intangible assets, net	2,415.9	2,414.7
Goodwill	1,259.8	1,253.1
Retirement benefit asset, net	100.7	97.9
Other non-current assets	189.9	205.5
Total assets	6,299.7	6,237.8
Current liabilities:
Accounts payable and accrued liabilities	205	232.6
Current portion of accrued compensation, benefits and staff costs	232.3	300.8
OEIC and unit trust payables	144.1	72.8
Total current liabilities	595.6	610.5
Non-current liabilities:
Accrued compensation, benefits and staff costs	35.9	46.9
Long-term debt	305.3	307.5
Deferred tax liabilities, net	568.7	574.6
Retirement benefit obligations, net	2.9	3
Other non-current liabilities	86.7	98.8
Total liabilities	1,595.1	1,641.3
Commitments and contingencies (See Note 15)
REDEEMABLE NONCONTROLLING INTERESTS	245.9	233.9
EQUITY
Common stock, $1.50 par value; 480,000,000 shares authorized, and 165,657,905 and 165,657,905 shares issued and outstanding as of September 30, 2023, and December 31, 2022, respectively	248.5	248.5
Additional paid-in capital	3,704.4	3,706.6
Treasury shares, 42,132 and 312,469 shares held at September 30, 2023, and December 31, 2022, respectively	(1.1)	(8.3)
Accumulated other comprehensive loss, net of tax	(633.3)	(647.7)
Retained earnings	1,137.4	1,060.7
Total shareholders’ equity	4,455.9	4,359.8
Nonredeemable noncontrolling interests	2.8	2.8
Total equity	4,458.7	4,362.6
Total liabilities, redeemable noncontrolling interests and equity	6,299.7	6,237.8
Variable Interest Entity, Primary Beneficiary [Member]
Current assets:
Cash and cash equivalents	19.1	14.1
Investments	315.1	334.3
Other current assets	17.4	3.6
Current liabilities:
Accounts payable and accrued liabilities	$ 14.2	$ 4.3

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parentheticals) - $ / shares	Sep. 30, 2023	Dec. 31, 2022
Common stock, par value (in dollars per share)	$ 1.50	$ 1.50
Common stock, shares authorized (in shares)	480,000,000	480,000,000
Common stock, shares issued (in shares)	165,657,905	165,657,905
Common stock, shares outstanding (in shares)	165,657,905	165,657,905
Treasury shares (in shares)	42,132	312,469

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Total revenue	$ 521	$ 512.9	$ 1,533.3	$ 1,688.4
Operating expenses:
Employee compensation and benefits	149.2	142.5	437.2	452.1
Long-term incentive plans	32.6	41.1	125.7	133.2
Distribution expenses	116	118.7	342.6	388.3
Investment administration	12.4	12.5	35.1	37.6
Marketing	9.6	5.6	27.7	20.8
General, administrative and occupancy	73.7	64.7	207	210.1
Depreciation and amortization	5.8	7.1	18	24.3
Total operating expenses	399.3	392.2	1,193.3	1,266.4
Operating income:	121.7	120.7	340	422
Interest expense	(3.2)	(3.1)	(9.5)	(9.5)
Investment gains (losses), net	(5.9)	11	18.6	(130.6)
Other non-operating income (expense), net	(13.4)	13.9	0.7	6.7
Income before taxes	99.2	142.5	349.8	288.6
Income tax provision	(13.2)	(27.9)	(67.4)	(95.3)
Net income	86	114.6	282.4	193.3
Net loss (income) attributable to noncontrolling interests	7.5	(7)	(11.7)	114.1
Net income attributable to JHG	$ 93.5	$ 107.6	$ 270.7	$ 307.4
Earnings per share attributable to JHG common shareholders:
Basic (in dollars per share)	$ 0.56	$ 0.65	$ 1.64	$ 1.84
Diluted (in dollars per share)	$ 0.56	$ 0.65	$ 1.64	$ 1.84
Other comprehensive income (loss), net of tax:
Foreign currency translation gains (losses)	$ (70.7)	$ (139.2)	$ 14.3	$ (364)
Actuarial gains	0.5	0.1	0.7	0.3
Other comprehensive income (loss), net of tax	(70.2)	(139.1)	15	(363.7)
Other comprehensive loss (income) attributable to noncontrolling interests	1	(20.2)	(0.6)	3.2
Other comprehensive income (loss) attributable to JHG	(69.2)	(159.3)	14.4	(360.5)
Total comprehensive income (loss)	15.8	(24.5)	297.4	(170.4)
Total comprehensive loss (income) attributable to noncontrolling interests	8.5	(27.2)	(12.3)	117.3
Total comprehensive income (loss) attributable to JHG	24.3	(51.7)	285.1	(53.1)
Investment Advice [Member]
Total revenue	434.9	426.2	1,273	1,393.8
Investment Performance [Member]
Total revenue	(15.8)	(13.2)	(36.6)	(25)
Shareholder Service [Member]
Total revenue	54.9	54	159.7	172.7
Product and Service, Other [Member]
Total revenue	$ 47	$ 45.9	$ 137.2	$ 146.9

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Operating activities:
Net income	$ 282.4	$ 193.3
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	18	24.3
Deferred income taxes	(5.2)	9.2
Stock-based compensation plan expense	59.8	68
Loss on sale of Intech	0	9.1
Provision for credit losses and contingent consideration adjustments	25.3	0
Investment losses (gains), net	(18.6)	130.6
Contributions to pension plans in excess of costs recognized	(1.3)	0.3
Other, net	(4)	(8.3)
Changes in operating assets and liabilities:
OEIC and unit trust receivables and payables	(0.5)	(1.8)
Other assets	49.6	114.7
Other accruals and liabilities	(125.4)	(212.1)
Net operating activities	280.1	327.3
Investing activities:
Investments, net	(48.5)	34.8
Property, equipment and software	(8.4)	(10.3)
Investments by consolidated seeded investment products, net	(169.8)	21.7
Cash received (paid) on settled seed capital hedges, net	(15.3)	62.6
Dividends received from equity method investments	0.7	0.5
Long-term note with Intech	(1)	(13.2)
Proceeds from sale of Intech	0	14.9
Receipt of contingent consideration payments from sale of subsidiaries	0.2	0
Net investing activities	(242.1)	111
Financing activities:
Proceeds from stock-based compensation plans	2.5	3.3
Purchase of common stock for stock-based compensation plans	(57.3)	(106.7)
Purchase of common stock for share buyback program	0	(98.9)
Dividends paid to shareholders	(194)	(194.5)
Revolving credit facility issuance costs	(1.1)	0
Distributions to noncontrolling interests	0	(1)
Third-party sales (purchases) in consolidated seeded investment products, net	174.5	(16.2)
Principal payments under capital lease obligations	(0.4)	(1.2)
Net financing activities	(75.8)	(415.2)
Cash and cash equivalents:
Effect of foreign exchange rate changes	1.7	(106)
Net change	(36.1)	(82.9)
At beginning of period	1,176.4	1,118.6
At end of period	1,140.3	1,035.7
Supplemental cash flow information:
Cash paid for interest	14.6	14.6
Cash paid for income taxes, net of refunds	79.1	122.1
Reconciliation of cash and cash equivalents:
Total cash and cash equivalents	1,140.3	1,035.7
Consolidated Entity, Excluding VIE [Member]
Reconciliation of cash and cash equivalents:
Total cash and cash equivalents	1,121.2	1,022.9
Variable Interest Entity, Primary Beneficiary [Member]
Reconciliation of cash and cash equivalents:
Total cash and cash equivalents	$ 19.1	$ 12.8

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Changes In Equity (Unaudited) - USD ($) shares in Millions, $ in Millions	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock, Common [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Noncontrolling Interest [Member]	Total
Balance (in shares) at Dec. 31, 2021	169
Balance at Dec. 31, 2021	$ 253.6	$ 3,771.8	$ (55.1)	$ (387)	$ 1,040.2	$ 15.4	$ 4,638.9
Net income	0	0	0	0	307.4	0	307.4
Other comprehensive loss	0	0	0	(360.5)	0	0	(360.5)
Dividends paid to shareholders	0		0	0	(194.6)	0	(194.5)
Dividends paid to shareholders	0		0	0	(194.6)	0	(194.5)
Purchase of common stock for stock-based compensation plans	0	(105.8)	(0.9)	0	0	0	(106.7)
Vesting of stock-based compensation plans	0	(52.6)	52.6	0	0	0	0
Stock-based compensation plan expense	0	68	0	0	0	0	68
Proceeds from stock-based compensation plans	0	3.3	0	0	0	0	3.3
Other comprehensive income (loss)	$ 0	0	0	(360.5)	0	0	(360.5)
Dividends paid to shareholders		0.1
Dividends paid to shareholders		0.1
Purchase of common stock from share buyback program (in shares)	(3.3)
Purchase of common stock from share buyback program	$ (5.1)	0	0	0	(93.8)	0	(98.9)
Distributions to noncontrolling interests	0	0	0	0	0	(1)	(1)
Sale of Intech	0	0	0	0	0	(11.6)	(11.6)
Fair value adjustments to redeemable noncontrolling interests	$ 0	0	0	0	1.4	0	1.4
Balance (in shares) at Sep. 30, 2022	165.7
Balance at Sep. 30, 2022	$ 248.5	3,684.8	(3.4)	(747.5)	1,060.6	2.8	4,245.8
Balance (in shares) at Jun. 30, 2022	165.7
Balance at Jun. 30, 2022	$ 248.5	3,673.6	(5.9)	(588.2)	1,017.8	2.8	4,348.6
Net income	0	0	0	0	107.6	0	107.6
Other comprehensive loss	0	0	0	(159.3)	0	0	(159.3)
Dividends paid to shareholders	0		0	0	(64.8)	0	(64.7)
Dividends paid to shareholders	0		0	0	(64.8)	0	(64.7)
Purchase of common stock for stock-based compensation plans	0	(9.4)	(0.3)	0	0	0	(9.7)
Vesting of stock-based compensation plans	0	(2.8)	2.8	0	0	0	0
Stock-based compensation plan expense	0	22.2	0	0	0	0	22.2
Proceeds from stock-based compensation plans	0	1.1	0	0	0	0	1.1
Other comprehensive income (loss)	$ 0	0	0	(159.3)	0	0	(159.3)
Dividends paid to shareholders		0.1
Dividends paid to shareholders		0.1
Balance (in shares) at Sep. 30, 2022	165.7
Balance at Sep. 30, 2022	$ 248.5	3,684.8	(3.4)	(747.5)	1,060.6	2.8	4,245.8
Balance (in shares) at Dec. 31, 2022	165.7
Balance at Dec. 31, 2022	$ 248.5	3,706.6	(8.3)	(647.7)	1,060.7	2.8	4,362.6
Net income	0	0	0	0	270.7	0	270.7
Other comprehensive loss	0	0	0	14.4	0	0	14.4
Dividends paid to shareholders	0		0	0	(194)	0	(194)
Dividends paid to shareholders	0		0	0	(194)	0	(194)
Purchase of common stock for stock-based compensation plans	0	(56.5)	(0.8)	0	0	0	(57.3)
Vesting of stock-based compensation plans	0	(8)	8	0	0	0	0
Stock-based compensation plan expense	0	59.8	0	0	0	0	59.8
Proceeds from stock-based compensation plans	0	2.5	0	0	0	0	2.5
Other comprehensive income (loss)	$ 0	0	0	14.4	0	0	14.4
Dividends paid to shareholders		0
Dividends paid to shareholders		0
Balance (in shares) at Sep. 30, 2023	165.7
Balance at Sep. 30, 2023	$ 248.5	3,704.4	(1.1)	(633.3)	1,137.4	2.8	4,458.7
Balance (in shares) at Jun. 30, 2023	165.7
Balance at Jun. 30, 2023	$ 248.5	3,687.1	(1.1)	(564.1)	1,108.6	2.8	4,481.8
Net income	0	0	0	0	93.5	0	93.5
Other comprehensive loss	0	0	0	(69.2)	0	0	(69.2)
Dividends paid to shareholders	0	0	0	0	(64.7)	0	(64.7)
Dividends paid to shareholders	0	0	0	0	(64.7)	0	(64.7)
Purchase of common stock for stock-based compensation plans	0		(0.3)	0	0	0
Purchase of common stock for stock-based compensation plans		0.5					0.2
Vesting of stock-based compensation plans	0	(0.3)	0.3	0	0	0	0
Stock-based compensation plan expense	0	16.9	0	0	0	0	16.9
Proceeds from stock-based compensation plans	0	0.2	0	0	0	0	0.2
Other comprehensive income (loss)	$ 0	0	0	(69.2)	0	0	(69.2)
Balance (in shares) at Sep. 30, 2023	165.7
Balance at Sep. 30, 2023	$ 248.5	$ 3,704.4	$ (1.1)	$ (633.3)	$ 1,137.4	$ 2.8	$ 4,458.7

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Changes In Equity (Unaudited) (Parentheticals) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Dividends paid (in dollars per share)	$ 0.39	$ 0.39	$ 1.17	$ 1.16

Note 1 - Basis of Presentation

Note 1 - Basis of Presentation	9 Months Ended
Note 1 - Basis of Presentation	Sep. 30, 2023
Notes to Financial Statements
Basis of Presentation and Significant Accounting Policies [Text Block]	Note 1 Basis of Presentation Basis of Presentation In the opinion of management of Janus Henderson Group plc (“JHG,” “the Company,” “we,” “us,” “our” and similar terms), the accompanying unaudited condensed consolidated financial statements contain all normal recurring adjustments necessary to fairly state our financial position, results of operations and cash flows in accordance with accounting principles generally accepted in the United States of America (“GAAP”). Such financial statements have been prepared in accordance with the instructions to Form 10 not 10 December 31, 2022

Note 2 - Dispositions

Note 2 - Dispositions	9 Months Ended
Note 2 - Dispositions	Sep. 30, 2023
Notes to Financial Statements
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	Note 2 Dispositions On February 3, 2022, March 31, 2022, seventh The terms of the transaction also included a $20.0 million seven first second September 30, 2023 second not September 30, 2023 first second As of September 30, 2023, nil.

Note 3 - Consolidation

Note 3 - Consolidation	9 Months Ended
Note 3 - Consolidation	Sep. 30, 2023
Notes to Financial Statements
Variable Interest Entities Voting Rights Entities Consolidation Disclosure [Text Block]	Note 3 Consolidation Variable Interest Entities Consolidated Variable Interest Entities Our consolidated variable interest entities (“VIEs”) as of September 30, 2023 December 31, 2022 not may not, third no Unconsolidated Variable Interest Entities The following table presents the carrying value of investment securities included in our Condensed Consolidated Balance Sheets pertaining to unconsolidated VIEs (in millions): September 30, December 31, 2023 2022 Unconsolidated VIEs $ 15.3 $ 1.5 Our total exposure to unconsolidated VIEs represents the value of our economic ownership interest in the investments. Voting Rights Entities Consolidated Voting Rights Entities The following table presents the balances related to consolidated voting rights entities (“VREs”) that were recorded in our Condensed Consolidated Balance Sheets, including our net interest in these products (in millions): September 30, December 31, 2023 2022 Investments $ 209.1 $ 206.0 Cash and cash equivalents 5.5 5.8 Other current assets 22.0 1.8 Accounts payable and accrued liabilities (2.9 ) (1.0 ) Total $ 233.7 $ 212.6 Redeemable noncontrolling interests in consolidated VREs (81.0 ) (35.1 ) JHG's net interest in consolidated VREs $ 152.7 $ 177.5 Third-party assets held in consolidated VREs are not may not, third no Our total exposure to consolidated VREs represents the value of our economic ownership interest in these seeded investment products. Unconsolidated Voting Rights Entities The following table presents the carrying value of investment securities included in our Condensed Consolidated Balance Sheets pertaining to unconsolidated VREs (in millions): September 30, December 31, 2023 2022 Unconsolidated VREs $ 9.2 $ 3.4 Our total exposure to unconsolidated VREs represents the value of our economic ownership interest in the investments.

Note 4 - Investments

Note 4 - Investments	9 Months Ended
Note 4 - Investments	Sep. 30, 2023
Notes to Financial Statements
Investment [Text Block]	Note 4 Investments Our investments as of September 30, 2023 December 31, 2022 September 30, December 31, 2023 2022 Current investments: Seeded investment products: Consolidated VIEs $ 315.1 $ 334.3 Consolidated VREs 209.1 206.0 Unconsolidated VIEs and VREs 24.5 4.9 Separately managed accounts 40.0 29.7 Total seeded investment products 588.7 574.9 Investments related to deferred compensation plans 11.1 10.7 Other investments 8.4 10.3 Total current investments $ 608.2 $ 595.9 Non-current investments: Equity method investments 30.7 18.7 Total investments $ 638.9 $ 614.6 Net unrealized gains (losses) on investments held as of September 30, 2023 and 2022, gross of noncontrolling interests, for the three and nine months ended September 30, 2023 and 2022, are summarized as follows (in millions): Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Unrealized gains (losses) on investments held at period end $ (6.5 ) $ 10.0 $ 1.1 $ (44.6 ) Investment Gains (Losses), Net Investment gains (losses), net in our Condensed Consolidated Statements of Comprehensive Income included the following for the three nine September 30, 2023 2022 Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Seeded investment products and hedges, net $ 2.5 $ 3.3 $ 17.5 $ (14.9 ) Third-party ownership interests in seeded investment products (7.5 ) 7.0 11.7 (114.1 ) Equity method investments (0.8 ) 0.2 (12.3 ) 1.9 Other (0.1 ) 0.5 1.7 (3.5 ) Investment gains (losses), net $ (5.9 ) $ 11.0 $ 18.6 $ (130.6 ) Investment gains (losses), net for the nine September 30, 2023, Gains and losses attributable to third not Equity Method Investments On June 1, 2023, Cash Flows Cash flows related to our investments for the nine September 30, 2023 2022 Nine months ended September 30, 2023 2022 Purchases Sales, Purchases Sales, and settlements and Net and settlements and Net settlements maturities cash flow settlements maturities cash flow Investments by consolidated seeded investment products $ (179.9 ) $ 10.1 $ (169.8 ) $ (18.8 ) $ 40.5 $ 21.7 Investments (150.1 ) 101.6 (48.5 ) (109.6 ) 144.4 34.8

Note 5 - Derivative Instruments

Note 5 - Derivative Instruments	9 Months Ended
Note 5 - Derivative Instruments	Sep. 30, 2023
Notes to Financial Statements
Derivative Instruments and Hedging Activities Disclosure [Text Block]	Note 5 Derivative Instruments Derivative Instruments Used to Hedge Seeded Investment Products We maintain an economic hedge program that uses derivative instruments to mitigate against market exposure of certain seeded investments by using index and commodity futures (“futures”), total return swaps and credit default swaps. Certain foreign currency exposures associated with our seeded investment products are also hedged by using foreign currency forward contracts and swaps. We were party to the following derivative instruments as of September 30, 2023 December 31, 2022 Notional value September 30, 2023 December 31, 2022 Futures $ 1,095.7 $ 196.8 Credit default swaps 106.7 115.1 Total return swaps 40.9 37.2 Foreign currency forward contracts and swaps 173.8 131.7 The derivative instruments are not three nine September 30, 2023 2022 Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Futures $ 9.1 $ 8.7 $ 6.0 $ 45.7 Credit default swaps 0.8 0.2 (1.7 ) 5.8 Total return swaps 5.2 3.1 (6.5 ) 39.3 Foreign currency forward contracts and swaps (2.5 ) (3.8 ) 6.3 (13.3 ) Total gains (losses) from derivative instruments $ 12.6 $ 8.2 $ 4.1 $ 77.5 Derivative assets and liabilities are generally recognized on a gross basis and included in other current assets or in accounts payable and accrued liabilities in our Condensed Consolidated Balance Sheets. The derivative assets and liabilities as of September 30, 2023 December 31, 2022 Fair value September 30, 2023 December 31, 2022 Derivative assets $ 10.6 $ 5.3 Derivative liabilities 5.4 4.0 In addition to using derivative instruments to mitigate against market exposure of certain seeded investments, we also engage in short sales of securities to hedge seed investments. As of September 30, 2023 December 31, 2022 not Derivative Instruments Used in Consolidated Seeded Investment Products Certain of our consolidated seeded investment products use derivative instruments to contribute to the achievement of defined investment objectives. These derivative instruments are classified within other current assets or in accounts payable and accrued liabilities in our Condensed Consolidated Balance Sheets. Gains and losses on these derivative instruments are classified within investment gains (losses), net in our Condensed Consolidated Statements of Comprehensive Income. Our consolidated seeded investment products were party to the following derivative instruments as of September 30, 2023 December 31, 2022 Notional value September 30, 2023 December 31, 2022 Futures $ 1,751.3 $ 141.3 Credit default swaps 11.0 2.2 Total return swaps 0.2 10.4 Interest rate swaps 2.1 — Options — 0.1 Foreign currency forward contracts and swaps 9.7 18.3 As of September 30, 2023 December 31, 2022 Derivative Instruments Foreign Currency Hedging Program We maintain a foreign currency hedging program to take reasonable measures to minimize the income statement effects of foreign currency remeasurement of monetary balance sheet accounts. The program uses foreign currency forward contracts and swaps to achieve its objectives, and it is considered an economic hedge for accounting purposes. The notional value of the foreign currency forward contracts and swaps as of September 30, 2023 December 31, 2022 Notional value September 30, 2023 December 31, 2022 Foreign currency forward contracts and swaps $ 89.1 $ 74.7 The derivative assets and liabilities are generally recognized on a gross basis and included in other current assets or in accounts payable and accrued liabilities in our Condensed Consolidated Balance Sheets. As of September 30, 2023 December 31, 2022 Changes in fair value of the derivatives are recognized in other non-operating income (expense), net in our Condensed Consolidated Statements of Comprehensive Income. Foreign currency remeasurement is also recognized in other non-operating income (expense), net in our Condensed Consolidated Statements of Comprehensive Income. For the three nine September 30, 2023 2022

Note 6 - Fair Value Measurement

Note 6 - Fair Value Measurements	9 Months Ended
Note 6 - Fair Value Measurements	Sep. 30, 2023
Notes to Financial Statements
Fair Value Disclosures [Text Block]	Note 6 Fair Value Measurements The following table presents assets and liabilities reflected in the financial statements or disclosed in the notes to the financial statements at fair value on a recurring basis as of September 30, 2023 Fair value measurements using: Quoted prices in Significant active markets for other Significant identical assets observable unobservable and liabilities inputs inputs (Level 1) (Level 2) (Level 3) Total Assets: Cash equivalents $ 825.2 $ — $ — $ 825.2 Investments: Consolidated VIEs 144.1 170.9 0.1 315.1 Other investments 227.4 65.6 0.1 293.1 Total investments 371.5 236.5 0.2 608.2 Seed hedge derivatives — 10.6 — 10.6 Derivatives used in consolidated seeded investment products — 1.2 — 1.2 Derivatives used in foreign currency hedging program — 0.6 — 0.6 Total assets $ 1,196.7 $ 248.9 $ 0.2 $ 1,445.8 Liabilities: Derivatives used in consolidated seeded investment products $ — $ 2.0 $ — $ 2.0 Derivatives used in foreign currency hedging program — 0.8 — 0.8 Securities sold, not yet purchased 1.5 — — 1.5 Seed hedge derivatives — 5.4 — 5.4 Long-term debt (1) — 293.7 — 293.7 Deferred bonuses — — 92.1 92.1 Total liabilities $ 1.5 $ 301.9 $ 92.1 $ 395.5 ( 1 Carried at amortized cost and disclosed at fair value. The following table presents assets and liabilities reflected in the financial statements or disclosed in the notes to the financial statements at fair value on a recurring basis as of December 31, 2022 Fair value measurements using: Quoted prices in Significant active markets for other Significant identical assets observable unobservable and liabilities inputs inputs (Level 1) (Level 2) (Level 3) Total Assets: Cash equivalents $ 688.4 $ — $ — $ 688.4 Investments: Consolidated VIEs 275.4 54.0 4.9 334.3 Other investments 171.9 89.4 0.3 261.6 Total investments 447.3 143.4 5.2 595.9 Seed hedge derivatives — 5.3 — 5.3 Derivatives used in consolidated seeded investment products — 0.1 — 0.1 Derivatives used in foreign currency hedging program — 0.4 — 0.4 Option agreement — — 0.8 0.8 Contingent consideration from sale of subsidiaries — — 12.3 12.3 Total assets $ 1,135.7 $ 149.2 $ 18.3 $ 1,303.2 Liabilities: Derivatives used in consolidated seeded investment products $ — $ 0.6 $ — $ 0.6 Derivatives used in foreign currency hedging program — 1.1 — 1.1 Securities sold, not yet purchased 0.5 — — 0.5 Seed hedge derivatives — 4.0 — 4.0 Long-term debt (1) — 295.4 — 295.4 Deferred bonuses — — 46.5 46.5 Total liabilities $ 0.5 $ 301.1 $ 46.5 $ 348.1 ( 1 Carried at amortized cost and disclosed at fair value. Level 1 Our Level 1 not Level 2 Our Level 2 2 Level 3 Investments As of September 30, 2023 December 31, 2022 3 Deferred Bonuses Deferred bonuses represent liabilities to employees over the vesting period that will be settled by investments in our products or cash. Upon vesting, employees receive the value of the investment product selected by the participant, adjusted for gains or losses attributable to the product. The significant unobservable inputs used to value the liabilities are investment designations and vesting periods. Changes in Fair Value Changes in fair value of our Level 3 three nine September 30, 2023 2022 Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Beginning of period fair value $ 16.6 $ 21.1 $ 18.3 $ 8.8 Option agreement — (1.8 ) — 1.3 Contingent consideration from sale of subsidiaries — (0.2 ) — 12.1 Settlement of contingent consideration — — (0.2 ) — Fair value adjustments (11.7 ) — (13.1 ) (1.8 ) Transfers from Level 1 — — 0.2 0.5 Transfers to Level 1 (4.8 ) — (4.8 ) (2.1 ) Purchases of securities — (0.1 ) — 0.9 Sales of securities 0.1 — (0.2 ) (0.3 ) Foreign currency translation — (0.2 ) — (0.6 ) End of period fair value $ 0.2 $ 18.8 $ 0.2 $ 18.8 Changes in fair value of our Level 3 three nine September 30, 2023 2022 Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Beginning of period fair value $ 78.2 $ 27.6 $ 46.5 $ 50.5 Fair value adjustments (0.7 ) (1.2 ) 1.9 (3.8 ) Vesting of deferred bonuses (0.2 ) (0.5 ) (34.5) (36.5 ) Amortization of deferred bonuses 15.9 9.6 41.8 28.8 Foreign currency translation (1.1 ) (2.6 ) 0.6 (6.1 ) Additions — — 35.8 — End of period fair value $ 92.1 $ 32.9 $ 92.1 $ 32.9 Nonrecurring Fair Value Measurements Nonrecurring Level 3 3.

Note 7 - Goodwill and Intangibl

Note 7 - Goodwill and Intangible Assets	9 Months Ended
Note 7 - Goodwill and Intangible Assets	Sep. 30, 2023
Notes to Financial Statements
Goodwill and Intangible Assets Disclosure [Text Block]	Note 7 Goodwill and Intangible Assets The following tables present movements in our intangible assets and goodwill during the nine September 30, 2023 2022 Foreign December 31, currency September 30, 2022 Amortization Disposal translation 2023 Indefinite-lived intangible assets: Investment management agreements $ 2,046.5 $ — $ — $ 3.1 $ 2,049.6 Trademarks 360.0 — — — 360.0 Definite-lived intangible assets: Client relationships 68.9 — — (0.7 ) 68.2 Accumulated amortization (60.7 ) (1.5 ) — 0.3 (61.9 ) Net intangible assets $ 2,414.7 $ (1.5 ) $ — $ 2.7 $ 2,415.9 Goodwill $ 1,253.1 $ — $ — $ 6.7 $ 1,259.8 Foreign December 31, currency September 30, 2021 Amortization Disposal translation 2022 Indefinite-lived intangible assets: Investment management agreements $ 2,114.8 $ — $ — $ (67.1 ) $ 2,047.7 Trademarks 366.7 — (4.7 ) — 362.0 Definite-lived intangible assets: Client relationships 168.4 — (84.8 ) (11.0 ) 72.6 Accumulated amortization (107.2 ) (3.2 ) 44.7 8.9 (56.8 ) Net intangible assets $ 2,542.7 $ (3.2 ) $ (44.8 ) $ (69.2 ) $ 2,425.5 Goodwill $ 1,341.5 $ — $ (7.0 ) $ (128.5 ) $ 1,206.0 Management Buyout of Intech As detailed in Note 2 March 31, 2022, Future Amortization Expected future amortization expense related to client relationships is summarized below (in millions): Future amortization Amount 2023 (remainder of year) $ 0.2 2024 0.4 2025 0.4 2026 0.4 2027 0.4 Thereafter 4.5 Total $ 6.3

Note 8 - Debt

Note 8 - Debt	9 Months Ended
Note 8 - Debt	Sep. 30, 2023
Notes to Financial Statements
Debt Disclosure [Text Block]	Note 8 Debt Our debt as of September 30, 2023 December 31, 2022 September 30, 2023 December 31, 2022 Carrying Fair Carrying Fair value value value value 4.875% Senior Notes due 2025 $ 305.3 $ 293.7 $ 307.5 $ 295.4 4.875% 2025 The 4.875% Senior Notes due 2025 “2025 February 1 August 1 August 1, 2025. 2025 September 30, 2023 2025 Credit Facility On June 30, 2023, June 30, 2028, two one first second may 3.00x September 30, 2023

Note 9 - Income Taxes

Note 9 - Income Taxes	9 Months Ended
Note 9 - Income Taxes	Sep. 30, 2023
Notes to Financial Statements
Income Tax Disclosure [Text Block]	Note 9 Income Taxes Our effective tax rates for the three nine September 30, 2023 2022 Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Effective tax rate 13.2 % 19.6 % 19.3 % 33.0 % The effective tax rates for the three nine September 30, 2023 2022, nine September 30, 2023 As of September 30, 2023 12

Note 10 - Noncontrolling Intere

Note 10 - Noncontrolling Interests	9 Months Ended
Note 10 - Noncontrolling Interests	Sep. 30, 2023
Notes to Financial Statements
Noncontrolling Interest Disclosure [Text Block]	Note 10 Noncontrolling Interests Redeemable Noncontrolling Interests Redeemable noncontrolling interests as of September 30, 2023 December 31, 2022 September 30, December 31, 2023 2022 Consolidated seeded investment products $ 245.9 $ 233.9 Consolidated Seeded Investment Products Noncontrolling interests in consolidated seeded investment products are classified as redeemable noncontrolling interests when there is an obligation to repurchase units at the investor’s request. Redeemable noncontrolling interests in consolidated seeded investment products may third The following table presents the movement in redeemable noncontrolling interests in consolidated seeded investment products for the three nine September 30, 2023 2022 Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Opening balance $ 389.8 $ 921.1 $ 233.9 $ 148.5 Changes in market value (7.5 ) 7.0 11.7 (114.1 ) Changes in ownership (135.4 ) (795.3 ) 0.8 121.9 Foreign currency translation (1.0 ) 20.3 (0.5 ) (3.2 ) Closing balance $ 245.9 $ 153.1 $ 245.9 $ 153.1

Note 11 - Long-Term Incentive a

Note 11 - Long-Term Incentive and Employee Compensation	9 Months Ended
Note 11 - Long-Term Incentive and Employee Compensation	Sep. 30, 2023
Notes to Financial Statements
Share-Based Payment Arrangement [Text Block]	Note 11 Long-Term Incentive and Employee Compensation The following table presents restricted stock and mutual fund awards granted during the three nine September 30, 2023 Three months ended Nine months ended September 30, September 30, 2023 2023 Restricted stock $ 3.7 $ 66.1 Mutual fund awards 0.1 54.1 Total $ 3.8 $ 120.2 Restricted stock and mutual fund awards generally vest and will be recognized using a graded vesting method over a three

Note 12 - Retirement Benefit Pl

Note 12 - Retirement Benefit Plans	9 Months Ended
Note 12 - Retirement Benefit Plans	Sep. 30, 2023
Notes to Financial Statements
Retirement Benefits [Text Block]	Note 12 Retirement Benefit Plans We operate defined contribution retirement benefit plans and defined benefit pension plans. Our primary defined benefit pension plan is the defined benefit section of the Janus Henderson Group UK Pension Scheme (“JHGPS”). Net Periodic Benefit Cost The components of net periodic benefit cost in respect of defined benefit plans for the three nine September 30, 2023 2022 Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Interest cost $ (7.0 ) $ (3.9 ) $ (20.7 ) $ (12.5 ) Amortization of prior service cost (0.1 ) (0.1 ) (0.3 ) (0.3 ) Amortization of net loss (0.4 ) — (0.4 ) — Expected return on plan assets 6.9 3.3 20.3 10.5 Net periodic benefit cost $ (0.6 ) $ (0.7 ) $ (1.1 ) $ (2.3 )

Note 13 - Accumulated Other Com

Note 13 - Accumulated Other Comprehensive Loss	9 Months Ended
Note 13 - Accumulated Other Comprehensive Loss	Sep. 30, 2023
Notes to Financial Statements
Comprehensive Income (Loss) Note [Text Block]	Note 13 Accumulated Other Comprehensive Loss Changes in accumulated other comprehensive loss, net of tax for the three nine September 30, 2023 2022 Three months ended September 30, 2023 2022 Retirement Retirement Foreign benefit Foreign benefit currency asset, net Total currency asset, net Total Beginning balance $ (493.9 ) $ (70.2 ) $ (564.1 ) $ (555.6 ) $ (32.6 ) $ (588.2 ) Other comprehensive loss (67.9 ) — (67.9 ) (129.4 ) — (129.4 ) Reclassifications to net income (2.8 ) 0.5 (2.3 ) (9.8 ) 0.1 (9.7 ) Total other comprehensive income (loss) (70.7 ) 0.5 (70.2 ) (139.2 ) 0.1 (139.1 ) Less: other comprehensive loss (income) attributable to noncontrolling interests 1.0 — 1.0 (20.2 ) — (20.2 ) Ending balance $ (563.6 ) $ (69.7 ) $ (633.3 ) $ (715.0 ) $ (32.5 ) $ (747.5 ) Nine months ended September 30, 2023 2022 Retirement Retirement Foreign benefit Foreign benefit currency asset, net Total currency asset, net Total Beginning balance $ (577.3 ) $ (70.4 ) $ (647.7 ) $ (354.2 ) $ (32.8 ) $ (387.0 ) Other comprehensive income (loss) 15.0 — 15.0 (359.9 ) — (359.9 ) Reclassifications to net income (0.7 ) 0.7 — (4.1 ) 0.3 (3.8 ) Total other comprehensive income (loss) 14.3 0.7 15.0 (364.0 ) 0.3 (363.7 ) Less: other comprehensive loss (income) attributable to noncontrolling interests (0.6 ) — (0.6 ) 3.2 — 3.2 Ending balance $ (563.6 ) $ (69.7 ) $ (633.3 ) $ (715.0 ) $ (32.5 ) $ (747.5 ) The components of other comprehensive income (loss), net of tax for the three nine September 30, 2023 2022 Three months ended September 30, 2023 2022 Pre-tax Tax Net Pre-tax Tax Net amount impact amount amount impact amount Foreign currency translation adjustments $ (68.8 ) $ 0.9 $ (67.9 ) $ (130.8 ) $ 1.4 $ (129.4 ) Reclassifications to net income (2.3 ) — (2.3 ) (9.7 ) — (9.7 ) Total other comprehensive income (loss) $ (71.1 ) $ 0.9 $ (70.2 ) $ (140.5 ) $ 1.4 $ (139.1 ) Nine months ended September 30, 2023 2022 Pre-tax Tax Net Pre-tax Tax Net amount impact amount amount impact amount Foreign currency translation adjustments $ 11.5 $ 3.5 $ 15.0 $ (364.5 ) $ 4.6 $ (359.9 ) Reclassifications to net income — — — (3.8 ) — (3.8 ) Total other comprehensive income (loss) $ 11.5 $ 3.5 $ 15.0 $ (368.3 ) $ 4.6 $ (363.7 )

Note 14 - Earnings and Dividend

Note 14 - Earnings and Dividends Per Share	9 Months Ended
Note 14 - Earnings and Dividends Per Share	Sep. 30, 2023
Notes to Financial Statements
Earnings and Dividends Per Share [Text Block]	Note 14 Earnings and Dividends Per Share Earnings Per Share The following is a summary of the earnings per share calculation for the three nine September 30, 2023 2022 Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Net income attributable to JHG $ 93.5 $ 107.6 $ 270.7 $ 307.4 Allocation of earnings to participating stock-based awards (2.8 ) (3.5 ) (7.8 ) (9.0 ) Net income attributable to JHG common shareholders $ 90.7 $ 104.1 $ 262.9 $ 298.4 Weighted-average common shares outstanding — basic 160.8 160.5 160.5 162.2 Dilutive effect of nonparticipating stock-based awards 0.1 0.4 0.2 0.4 Weighted-average common shares outstanding — diluted 160.9 160.9 160.7 162.6 Earnings per share: Basic $ 0.56 $ 0.65 $ 1.64 $ 1.84 Diluted $ 0.56 $ 0.65 $ 1.64 $ 1.84 Dividends Per Share The payment of cash dividends is within the discretion of our Board of Directors and depends on many factors, including, but not The following is a summary of cash dividends declared and paid during the nine September 30, 2023 Dividend Date Dividends paid Date per share declared (in US$ millions) paid $ 0.39 February 1, 2023 $ 64.7 February 28, 2023 $ 0.39 May 2, 2023 $ 64.6 May 31, 2023 $ 0.39 August 1, 2023 $ 64.7 August 30, 2023 On October 31, 2023 third 2023 November 30, 2023 November 13, 2023

Note 15 - Commitments and Conti

Note 15 - Commitments and Contingencies	9 Months Ended
Note 15 - Commitments and Contingencies	Sep. 30, 2023
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	Note 15 Commitments and Contingencies Commitments and contingencies may Litigation and Other Regulatory Matters We are periodically involved in various legal proceedings and other regulatory matters. Sandra Schissler v Janus Henderson US (Holdings) Inc., Janus Henderson Advisory Committee, and John and Jane Does 1 30 On September 9, 2022, Schissler v. Janus Henderson US (Holdings) Inc., et al. 401 September 9, 2016. January 10, 2023, November 23, 2022, two September 9, 2016, September 9, 2022, February 9, 2023, March 13, 2023, March 28, 2023. September 7, 2023, September 21, 2023, October 12, 2023.

Item 5 - Other Information

Item 5 - Other Information	9 Months Ended
Item 5 - Other Information	Sep. 30, 2023
Notes to Financial Statements
Issuer Rule 10b5-1, Material Terms [Text Block]	5. Other Information Trading Plans of Directors and Officers During the quarter ended September 30, 2023 no 16 10b5–1 10b5–1 408

Note 3 - Consolidation (Tables)

Note 3 - Consolidation (Tables)	9 Months Ended
Note 3 - Consolidation (Tables)	Sep. 30, 2023
Notes Tables
Schedule of Variable Interest Entities [Table Text Block]	September 30, December 31, 2023 2022 Unconsolidated VIEs $ 15.3 $ 1.5
Consolidated Voting Right Entities VRE [Table Text Block]	September 30, December 31, 2023 2022 Investments $ 209.1 $ 206.0 Cash and cash equivalents 5.5 5.8 Other current assets 22.0 1.8 Accounts payable and accrued liabilities (2.9 ) (1.0 ) Total $ 233.7 $ 212.6 Redeemable noncontrolling interests in consolidated VREs (81.0 ) (35.1 ) JHG's net interest in consolidated VREs $ 152.7 $ 177.5
Unconsolidated Voting Right Entities VRE [Table Text Block]	September 30, December 31, 2023 2022 Unconsolidated VREs $ 9.2 $ 3.4

Note 4 - Investments (Tables)

Note 4 - Investments (Tables)	9 Months Ended
Note 4 - Investments (Tables)	Sep. 30, 2023
Notes Tables
Investment [Table Text Block]	September 30, December 31, 2023 2022 Current investments: Seeded investment products: Consolidated VIEs $ 315.1 $ 334.3 Consolidated VREs 209.1 206.0 Unconsolidated VIEs and VREs 24.5 4.9 Separately managed accounts 40.0 29.7 Total seeded investment products 588.7 574.9 Investments related to deferred compensation plans 11.1 10.7 Other investments 8.4 10.3 Total current investments $ 608.2 $ 595.9 Non-current investments: Equity method investments 30.7 18.7 Total investments $ 638.9 $ 614.6 Net unrealized gains (losses) on investments held as of September 30, 2023 and 2022, gross of noncontrolling interests, for the three and nine months ended September 30, 2023 and 2022, are summarized as follows (in millions):
Unrealized Gain (Loss) on Investments [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Unrealized gains (losses) on investments held at period end $ (6.5 ) $ 10.0 $ 1.1 $ (44.6 )
Gain (Loss) on Securities [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Seeded investment products and hedges, net $ 2.5 $ 3.3 $ 17.5 $ (14.9 ) Third-party ownership interests in seeded investment products (7.5 ) 7.0 11.7 (114.1 ) Equity method investments (0.8 ) 0.2 (12.3 ) 1.9 Other (0.1 ) 0.5 1.7 (3.5 ) Investment gains (losses), net $ (5.9 ) $ 11.0 $ 18.6 $ (130.6 )
Cash Flows Related to Investment Securities and Other Assets [Table Text Block]	Nine months ended September 30, 2023 2022 Purchases Sales, Purchases Sales, and settlements and Net and settlements and Net settlements maturities cash flow settlements maturities cash flow Investments by consolidated seeded investment products $ (179.9 ) $ 10.1 $ (169.8 ) $ (18.8 ) $ 40.5 $ 21.7 Investments (150.1 ) 101.6 (48.5 ) (109.6 ) 144.4 34.8

Note 5 - Derivative Instrumen_2

Note 5 - Derivative Instruments (Tables)	9 Months Ended
Note 5 - Derivative Instruments (Tables)	Sep. 30, 2023
Notes Tables
Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]	Notional value September 30, 2023 December 31, 2022 Futures $ 1,095.7 $ 196.8 Credit default swaps 106.7 115.1 Total return swaps 40.9 37.2 Foreign currency forward contracts and swaps 173.8 131.7 Notional value September 30, 2023 December 31, 2022 Futures $ 1,751.3 $ 141.3 Credit default swaps 11.0 2.2 Total return swaps 0.2 10.4 Interest rate swaps 2.1 — Options — 0.1 Foreign currency forward contracts and swaps 9.7 18.3 Notional value September 30, 2023 December 31, 2022 Foreign currency forward contracts and swaps $ 89.1 $ 74.7
Derivative Instruments, Gain (Loss) [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Futures $ 9.1 $ 8.7 $ 6.0 $ 45.7 Credit default swaps 0.8 0.2 (1.7 ) 5.8 Total return swaps 5.2 3.1 (6.5 ) 39.3 Foreign currency forward contracts and swaps (2.5 ) (3.8 ) 6.3 (13.3 ) Total gains (losses) from derivative instruments $ 12.6 $ 8.2 $ 4.1 $ 77.5
Schedule of Derivative Instruments [Table Text Block]	Fair value September 30, 2023 December 31, 2022 Derivative assets $ 10.6 $ 5.3 Derivative liabilities 5.4 4.0

Note 6 - Fair Value Measureme_2

Note 6 - Fair Value Measurements (Tables)	9 Months Ended
Note 6 - Fair Value Measurements (Tables)	Sep. 30, 2023
Notes Tables
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	Fair value measurements using: Quoted prices in Significant active markets for other Significant identical assets observable unobservable and liabilities inputs inputs (Level 1) (Level 2) (Level 3) Total Assets: Cash equivalents $ 825.2 $ — $ — $ 825.2 Investments: Consolidated VIEs 144.1 170.9 0.1 315.1 Other investments 227.4 65.6 0.1 293.1 Total investments 371.5 236.5 0.2 608.2 Seed hedge derivatives — 10.6 — 10.6 Derivatives used in consolidated seeded investment products — 1.2 — 1.2 Derivatives used in foreign currency hedging program — 0.6 — 0.6 Total assets $ 1,196.7 $ 248.9 $ 0.2 $ 1,445.8 Liabilities: Derivatives used in consolidated seeded investment products $ — $ 2.0 $ — $ 2.0 Derivatives used in foreign currency hedging program — 0.8 — 0.8 Securities sold, not yet purchased 1.5 — — 1.5 Seed hedge derivatives — 5.4 — 5.4 Long-term debt (1) — 293.7 — 293.7 Deferred bonuses — — 92.1 92.1 Total liabilities $ 1.5 $ 301.9 $ 92.1 $ 395.5 Fair value measurements using: Quoted prices in Significant active markets for other Significant identical assets observable unobservable and liabilities inputs inputs (Level 1) (Level 2) (Level 3) Total Assets: Cash equivalents $ 688.4 $ — $ — $ 688.4 Investments: Consolidated VIEs 275.4 54.0 4.9 334.3 Other investments 171.9 89.4 0.3 261.6 Total investments 447.3 143.4 5.2 595.9 Seed hedge derivatives — 5.3 — 5.3 Derivatives used in consolidated seeded investment products — 0.1 — 0.1 Derivatives used in foreign currency hedging program — 0.4 — 0.4 Option agreement — — 0.8 0.8 Contingent consideration from sale of subsidiaries — — 12.3 12.3 Total assets $ 1,135.7 $ 149.2 $ 18.3 $ 1,303.2 Liabilities: Derivatives used in consolidated seeded investment products $ — $ 0.6 $ — $ 0.6 Derivatives used in foreign currency hedging program — 1.1 — 1.1 Securities sold, not yet purchased 0.5 — — 0.5 Seed hedge derivatives — 4.0 — 4.0 Long-term debt (1) — 295.4 — 295.4 Deferred bonuses — — 46.5 46.5 Total liabilities $ 0.5 $ 301.1 $ 46.5 $ 348.1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Beginning of period fair value $ 16.6 $ 21.1 $ 18.3 $ 8.8 Option agreement — (1.8 ) — 1.3 Contingent consideration from sale of subsidiaries — (0.2 ) — 12.1 Settlement of contingent consideration — — (0.2 ) — Fair value adjustments (11.7 ) — (13.1 ) (1.8 ) Transfers from Level 1 — — 0.2 0.5 Transfers to Level 1 (4.8 ) — (4.8 ) (2.1 ) Purchases of securities — (0.1 ) — 0.9 Sales of securities 0.1 — (0.2 ) (0.3 ) Foreign currency translation — (0.2 ) — (0.6 ) End of period fair value $ 0.2 $ 18.8 $ 0.2 $ 18.8
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Beginning of period fair value $ 78.2 $ 27.6 $ 46.5 $ 50.5 Fair value adjustments (0.7 ) (1.2 ) 1.9 (3.8 ) Vesting of deferred bonuses (0.2 ) (0.5 ) (34.5) (36.5 ) Amortization of deferred bonuses 15.9 9.6 41.8 28.8 Foreign currency translation (1.1 ) (2.6 ) 0.6 (6.1 ) Additions — — 35.8 — End of period fair value $ 92.1 $ 32.9 $ 92.1 $ 32.9

Note 7 - Goodwill and Intangi_2

Note 7 - Goodwill and Intangible Assets (Tables)	9 Months Ended
Note 7 - Goodwill and Intangible Assets (Tables)	Sep. 30, 2023
Notes Tables
Schedule of Intangible Assets and Goodwill [Table Text Block]	Foreign December 31, currency September 30, 2022 Amortization Disposal translation 2023 Indefinite-lived intangible assets: Investment management agreements $ 2,046.5 $ — $ — $ 3.1 $ 2,049.6 Trademarks 360.0 — — — 360.0 Definite-lived intangible assets: Client relationships 68.9 — — (0.7 ) 68.2 Accumulated amortization (60.7 ) (1.5 ) — 0.3 (61.9 ) Net intangible assets $ 2,414.7 $ (1.5 ) $ — $ 2.7 $ 2,415.9 Goodwill $ 1,253.1 $ — $ — $ 6.7 $ 1,259.8 Foreign December 31, currency September 30, 2021 Amortization Disposal translation 2022 Indefinite-lived intangible assets: Investment management agreements $ 2,114.8 $ — $ — $ (67.1 ) $ 2,047.7 Trademarks 366.7 — (4.7 ) — 362.0 Definite-lived intangible assets: Client relationships 168.4 — (84.8 ) (11.0 ) 72.6 Accumulated amortization (107.2 ) (3.2 ) 44.7 8.9 (56.8 ) Net intangible assets $ 2,542.7 $ (3.2 ) $ (44.8 ) $ (69.2 ) $ 2,425.5 Goodwill $ 1,341.5 $ — $ (7.0 ) $ (128.5 ) $ 1,206.0
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	Future amortization Amount 2023 (remainder of year) $ 0.2 2024 0.4 2025 0.4 2026 0.4 2027 0.4 Thereafter 4.5 Total $ 6.3

Note 8 - Debt (Tables)

Note 8 - Debt (Tables)	9 Months Ended
Note 8 - Debt (Tables)	Sep. 30, 2023
Notes Tables
Schedule of Long-Term Debt Instruments [Table Text Block]	September 30, 2023 December 31, 2022 Carrying Fair Carrying Fair value value value value 4.875% Senior Notes due 2025 $ 305.3 $ 293.7 $ 307.5 $ 295.4

Note 9 - Income Taxes (Tables)

Note 9 - Income Taxes (Tables)	9 Months Ended
Note 9 - Income Taxes (Tables)	Sep. 30, 2023
Notes Tables
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Effective tax rate 13.2 % 19.6 % 19.3 % 33.0 %

Note 10 - Noncontrolling Inte_2

Note 10 - Noncontrolling Interests (Tables)	9 Months Ended
Note 10 - Noncontrolling Interests (Tables)	Sep. 30, 2023
Notes Tables
Redeemable Noncontrolling Interest [Table Text Block]	September 30, December 31, 2023 2022 Consolidated seeded investment products $ 245.9 $ 233.9
Noncontrolling Interest Increase (Decrease) [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Opening balance $ 389.8 $ 921.1 $ 233.9 $ 148.5 Changes in market value (7.5 ) 7.0 11.7 (114.1 ) Changes in ownership (135.4 ) (795.3 ) 0.8 121.9 Foreign currency translation (1.0 ) 20.3 (0.5 ) (3.2 ) Closing balance $ 245.9 $ 153.1 $ 245.9 $ 153.1

Note 11 - Long-Term Incentive_2

Note 11 - Long-Term Incentive and Employee Compensation (Tables)	9 Months Ended
	Sep. 30, 2023
Notes Tables
Share-Based Payment Arrangement, Activity [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2023 2023 Restricted stock $ 3.7 $ 66.1 Mutual fund awards 0.1 54.1 Total $ 3.8 $ 120.2

Note 12 - Retirement Benefit _2

Note 12 - Retirement Benefit Plans (Tables)	9 Months Ended
Note 12 - Retirement Benefit Plans (Tables)	Sep. 30, 2023
Notes Tables
Schedule of Net Benefit Costs [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Interest cost $ (7.0 ) $ (3.9 ) $ (20.7 ) $ (12.5 ) Amortization of prior service cost (0.1 ) (0.1 ) (0.3 ) (0.3 ) Amortization of net loss (0.4 ) — (0.4 ) — Expected return on plan assets 6.9 3.3 20.3 10.5 Net periodic benefit cost $ (0.6 ) $ (0.7 ) $ (1.1 ) $ (2.3 )

Note 13 - Accumulated Other C_2

Note 13 - Accumulated Other Comprehensive Loss (Tables)	9 Months Ended
Note 13 - Accumulated Other Comprehensive Loss (Tables)	Sep. 30, 2023
Notes Tables
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	Three months ended September 30, 2023 2022 Retirement Retirement Foreign benefit Foreign benefit currency asset, net Total currency asset, net Total Beginning balance $ (493.9 ) $ (70.2 ) $ (564.1 ) $ (555.6 ) $ (32.6 ) $ (588.2 ) Other comprehensive loss (67.9 ) — (67.9 ) (129.4 ) — (129.4 ) Reclassifications to net income (2.8 ) 0.5 (2.3 ) (9.8 ) 0.1 (9.7 ) Total other comprehensive income (loss) (70.7 ) 0.5 (70.2 ) (139.2 ) 0.1 (139.1 ) Less: other comprehensive loss (income) attributable to noncontrolling interests 1.0 — 1.0 (20.2 ) — (20.2 ) Ending balance $ (563.6 ) $ (69.7 ) $ (633.3 ) $ (715.0 ) $ (32.5 ) $ (747.5 ) Nine months ended September 30, 2023 2022 Retirement Retirement Foreign benefit Foreign benefit currency asset, net Total currency asset, net Total Beginning balance $ (577.3 ) $ (70.4 ) $ (647.7 ) $ (354.2 ) $ (32.8 ) $ (387.0 ) Other comprehensive income (loss) 15.0 — 15.0 (359.9 ) — (359.9 ) Reclassifications to net income (0.7 ) 0.7 — (4.1 ) 0.3 (3.8 ) Total other comprehensive income (loss) 14.3 0.7 15.0 (364.0 ) 0.3 (363.7 ) Less: other comprehensive loss (income) attributable to noncontrolling interests (0.6 ) — (0.6 ) 3.2 — 3.2 Ending balance $ (563.6 ) $ (69.7 ) $ (633.3 ) $ (715.0 ) $ (32.5 ) $ (747.5 )
Comprehensive Income (Loss) [Table Text Block]	Three months ended September 30, 2023 2022 Pre-tax Tax Net Pre-tax Tax Net amount impact amount amount impact amount Foreign currency translation adjustments $ (68.8 ) $ 0.9 $ (67.9 ) $ (130.8 ) $ 1.4 $ (129.4 ) Reclassifications to net income (2.3 ) — (2.3 ) (9.7 ) — (9.7 ) Total other comprehensive income (loss) $ (71.1 ) $ 0.9 $ (70.2 ) $ (140.5 ) $ 1.4 $ (139.1 ) Nine months ended September 30, 2023 2022 Pre-tax Tax Net Pre-tax Tax Net amount impact amount amount impact amount Foreign currency translation adjustments $ 11.5 $ 3.5 $ 15.0 $ (364.5 ) $ 4.6 $ (359.9 ) Reclassifications to net income — — — (3.8 ) — (3.8 ) Total other comprehensive income (loss) $ 11.5 $ 3.5 $ 15.0 $ (368.3 ) $ 4.6 $ (363.7 )

Note 14 - Earnings and Divide_2

Note 14 - Earnings and Dividends Per Share (Tables)	9 Months Ended
Note 14 - Earnings and Dividends Per Share (Tables)	Sep. 30, 2023
Notes Tables
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Net income attributable to JHG $ 93.5 $ 107.6 $ 270.7 $ 307.4 Allocation of earnings to participating stock-based awards (2.8 ) (3.5 ) (7.8 ) (9.0 ) Net income attributable to JHG common shareholders $ 90.7 $ 104.1 $ 262.9 $ 298.4 Weighted-average common shares outstanding — basic 160.8 160.5 160.5 162.2 Dilutive effect of nonparticipating stock-based awards 0.1 0.4 0.2 0.4 Weighted-average common shares outstanding — diluted 160.9 160.9 160.7 162.6 Earnings per share: Basic $ 0.56 $ 0.65 $ 1.64 $ 1.84 Diluted $ 0.56 $ 0.65 $ 1.64 $ 1.84
Dividends Declared [Table Text Block]	Dividend Date Dividends paid Date per share declared (in US$ millions) paid $ 0.39 February 1, 2023 $ 64.7 February 28, 2023 $ 0.39 May 2, 2023 $ 64.6 May 31, 2023 $ 0.39 August 1, 2023 $ 64.7 August 30, 2023

Note 2 - Dispositions (Details

Note 2 - Dispositions (Details Textual) $ in Thousands		9 Months Ended
Note 2 - Dispositions (Details Textual) $ in Thousands	Mar. 31, 2022 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Feb. 03, 2022
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal		$ 0	$ (9,100)
Proceeds from Divestiture of Businesses		0	$ 14,900
Intech Investment Management LLC [Member] \| Term Note [Member]
Financing Receivable, before Allowance for Credit Loss	$ 20,000	15,900
Financing Receivable Term (Year)	7 years
Number Of Tranches	2
Interest Receivable		900
Intech Investment Management LLC [Member] \| Term Note, Tranche One [Member]
Financing Receivable, before Allowance for Credit Loss	$ 10,000
Investment Interest Rate	5.50%
Intech Investment Management LLC [Member] \| Term Note, Tranche Two [Member]
Investment Interest Rate	6%
Financing Receivable, Allowance for Credit Loss		$ 0
Intech Investment Management LLC [Member]
Percentage Of Ownership Sold				97%
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal	$ 9,100
Proceeds from Divestiture of Businesses	14,900
Disposal Group Including Discontinued Operation Contingent Consideration	$ 17,500

Note 3 - Consolidation - VIEs (

Note 3 - Consolidation - VIEs (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Variable Interest Entity, Primary Beneficiary [Member]
Unconsolidated VIEs	$ 15.3	$ 1.5

Note 3 - Consolidation - VREs (

Note 3 - Consolidation - VREs (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Investments	$ 293.1	$ 261.6
Cash and cash equivalents	1,121.2	1,162.3
Other current assets	151.9	120.3
Accounts payable and accrued liabilities	(205)	(232.6)
Variable Rights Entity, Primary Beneficiary, Aggregated Disclosure [Member]
Investments	209.1	206
Cash and cash equivalents	5.5	5.8
Other current assets	22	1.8
Accounts payable and accrued liabilities	(2.9)	(1)
Total	233.7	212.6
Redeemable noncontrolling interests in consolidated VREs	(81)	(35.1)
JHG's net interest in consolidated VREs	$ 152.7	$ 177.5

Note 3 - Consolidation - Uncons

Note 3 - Consolidation - Unconsolidated VREs (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Unconsolidated VREs [Member]
JHG's net interest in consolidated VREs	$ 9.2	$ 3.4

Note 4 - Investments (Details T

Note 4 - Investments (Details Textual) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	Jun. 01, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Gain (Loss) on Investments		$ (5.9)	$ 11	$ 18.6	$ (130.6)
Privacore [Member]
Payments to Acquire Equity Method Investments	$ 25
Equity Method Investment, Ownership Percentage		49%		49%
Long Tail Alpha Investment [Member]
Equity Method Investment, Ownership Percentage		20%		20%
Reclassification of Earnings from an Equity Method Investment [Member]
Gain (Loss) on Investments				$ 12.5

Note 4 - Investment - General D

Note 4 - Investment - General Disclosure (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Seeded investment products	$ 588.7	$ 574.9
Estimated Fair Value	638.9	614.6
Equity method investments	30.7	18.7
Unconsolidated VIEs and VREs [Member]
Seeded investment products	24.5	4.9
Separately Managed Accounts [Member]
Seeded investment products	40	29.7
Investments Related to Deferred Compensation Plans [Member]
Estimated Fair Value	11.1	10.7
Other Security Investments [Member]
Estimated Fair Value	8.4	10.3
Current Investments [Member]
Estimated Fair Value	608.2	595.9
Variable Interest Entity, Primary Beneficiary [Member]
Seeded investment products	315.1	334.3
Voting Rights Entity, Primary Beneficiary Aggregated Disclosure [Member]
Seeded investment products	$ 209.1	$ 206

Note 4 - Investment Securities

Note 4 - Investment Securities - Net Unrealized Gains (Losses) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Unrealized gains (losses) on investments held at period end	$ (6.5)	$ 10	$ 1.1	$ (44.6)

Note 4 - Investment Securitie_2

Note 4 - Investment Securities - Investment Gains (Losses), Net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Investment gains (losses), net	$ (5.9)	$ 11	$ 18.6	$ (130.6)
Seeded Investment Products and Hedges, Net [Member]
Investment gains (losses), net	2.5	3.3	17.5	(14.9)
Third-party Ownership Interests in Seeded Investment Products [Member]
Investment gains (losses), net	(7.5)	7	11.7	(114.1)
Equity Method Investments [Member]
Investment gains (losses), net	(0.8)	0.2	(12.3)	1.9
Other Security Investments [Member]
Investment gains (losses), net	$ (0.1)	$ 0.5	$ 1.7	$ (3.5)

Note 4 - Investment Securitie_3

Note 4 - Investment Securities - Cash Flows (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Investments, net	$ (48.5)	$ 34.8
Seeded Investment Products [Member]
Purchases and settlements	(179.9)	(18.8)
Sales, settlements and maturities	10.1	40.5
Investments, net	(169.8)	21.7
Securities Investment [Member]
Purchases and settlements	(150.1)	(109.6)
Sales, settlements and maturities	101.6	144.4
Investments, net	$ (48.5)	$ 34.8

Note 5 - Derivative Instrumen_3

Note 5 - Derivative Instruments (Details Textual) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Financial Instruments Sold, Not yet Purchased, Derivatives and Other Contracts	$ 1.5	$ 0.5

Note 5 - Derivative Instrumen_4

Note 5 - Derivative Instruments - Derivative Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Futures [Member]
Notional value of derivative	$ 1,095.7	$ 196.8
Futures [Member] \| Seeded Investment Products [Member]
Notional value of derivative	1,751.3	141.3
Foreign Currency, Forward Contracts and Swaps [Member]
Notional value of derivative	173.8	131.7
Foreign Currency, Forward Contracts and Swaps [Member] \| Not Designated as Hedging Instrument, Economic Hedge [Member]
Notional value of derivative	89.1	74.7
Foreign Currency, Forward Contracts and Swaps [Member] \| Seeded Investment Products [Member]
Notional value of derivative	9.7	18.3
Credit Default Swaps [Member]
Notional value of derivative	106.7	115.1
Credit Default Swaps [Member] \| Seeded Investment Products [Member]
Notional value of derivative	11	2.2
Total Return Swaps [Member]
Notional value of derivative	40.9	37.2
Total Return Swaps [Member] \| Seeded Investment Products [Member]
Notional value of derivative	0.2	10.4
Interest Rate Swap [Member] \| Seeded Investment Products [Member]
Notional value of derivative	2.1	0
Options [Member] \| Seeded Investment Products [Member]
Notional value of derivative	$ 0	$ 0.1

Note 5 - Derivative Instrumen_5

Note 5 - Derivative Instruments - Change in Fair Value of Derivatives (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Gain (losses) from derivative instruments	$ 12.6	$ 8.2	$ 4.1	$ 77.5
Futures [Member]
Gain (losses) from derivative instruments	9.1	8.7	6	45.7
Credit Default Swaps [Member]
Gain (losses) from derivative instruments	0.8	0.2	(1.7)	5.8
Total Return Swaps [Member]
Gain (losses) from derivative instruments	5.2	3.1	(6.5)	39.3
Foreign Currency, Forward Contracts and Swaps [Member]
Gain (losses) from derivative instruments	$ (2.5)	$ (3.8)	$ 6.3	$ (13.3)

Note 5 - Derivative Instrumen_6

Note 5 - Derivative Instruments - Derivative Assets and Liabilities (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Derivative assets	$ 10.6	$ 5.3
Derivative liabilities	$ 5.4	$ 4

Note 6 - Fair Value Measureme_3

Note 6 - Fair Value Measurements - Level of Fair Value (Details) - USD ($) $ in Millions	Sep. 30, 2023		Dec. 31, 2022
Total investment securities	$ 293.1		$ 261.6
Securities sold, not yet purchased	1.5		0.5
Variable Interest Entity, Primary Beneficiary [Member]
Total investment securities	315.1		334.3
Fair Value, Recurring [Member]
Cash equivalents	825.2		688.4
Total investment securities	608.2		595.9
Total assets	1,445.8		1,303.2
Securities sold, not yet purchased	1.5		0.5
Long-term debt	293.7		295.4
Total liabilities	395.5		348.1
Contingent consideration from sale of subsidiaries			12.3
Fair Value, Recurring [Member] \| Seed Hedge Derivatives [Member]
Derivative assets	10.6		5.3
Derivative liabilities	5.4		4
Fair Value, Recurring [Member] \| Derivatives Used in Consolidated Seeded Investment Products [Member]
Derivative assets	1.2		0.1
Derivative liabilities	2		0.6
Fair Value, Recurring [Member] \| Foreign Currency, Forward Contracts and Swaps [Member]
Derivative assets	0.6		0.4
Derivative liabilities	0.8		1.1
Fair Value, Recurring [Member] \| Options [Member]
Derivative assets			0.8
Fair Value, Recurring [Member] \| Deferred Bonuses Hedge [Member]
Derivative liabilities	92.1		46.5
Fair Value, Recurring [Member] \| Other Investment Securities [Member]
Total investment securities	293.1		261.6
Fair Value, Recurring [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Total investment securities	315.1		334.3
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Cash equivalents	825.2		688.4
Total investment securities	371.5		447.3
Total assets	1,196.7		1,135.7
Securities sold, not yet purchased	1.5		0.5
Long-term debt	0		0	[1]
Total liabilities	1.5		0.5
Contingent consideration from sale of subsidiaries			0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Seed Hedge Derivatives [Member]
Derivative assets	0		0
Derivative liabilities	0		0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Derivatives Used in Consolidated Seeded Investment Products [Member]
Derivative assets	0		0
Derivative liabilities	0		0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Foreign Currency, Forward Contracts and Swaps [Member]
Derivative assets	0		0
Derivative liabilities	0		0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Options [Member]
Derivative assets			0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Deferred Bonuses Hedge [Member]
Derivative liabilities	0		0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Other Investment Securities [Member]
Total investment securities	227.4		171.9
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Total investment securities	144.1		275.4
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Cash equivalents	0		0
Total investment securities	236.5		143.4
Total assets	248.9		149.2
Securities sold, not yet purchased	0		0
Long-term debt	293.7	[1]	295.4
Total liabilities	301.9		301.1
Contingent consideration from sale of subsidiaries			0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Seed Hedge Derivatives [Member]
Derivative assets	10.6		5.3
Derivative liabilities	5.4		4
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Derivatives Used in Consolidated Seeded Investment Products [Member]
Derivative assets	1.2		0.1
Derivative liabilities	2		0.6
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Foreign Currency, Forward Contracts and Swaps [Member]
Derivative assets	0.6		0.4
Derivative liabilities	0.8		1.1
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Options [Member]
Derivative assets			0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Deferred Bonuses Hedge [Member]
Derivative liabilities	0		0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Other Investment Securities [Member]
Total investment securities	65.6		89.4
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Total investment securities	170.9		54
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Cash equivalents	0		0
Total investment securities	0.2		5.2
Total assets	0.2		18.3
Securities sold, not yet purchased	0		0
Long-term debt	0		0
Total liabilities	92.1		46.5
Contingent consideration from sale of subsidiaries			12.3
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Seed Hedge Derivatives [Member]
Derivative assets	0		0
Derivative liabilities	0		0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Derivatives Used in Consolidated Seeded Investment Products [Member]
Derivative assets	0		0
Derivative liabilities	0		0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Foreign Currency, Forward Contracts and Swaps [Member]
Derivative assets	0		0
Derivative liabilities	0		0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Options [Member]
Derivative assets			0.8
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Deferred Bonuses Hedge [Member]
Derivative liabilities	92.1		46.5
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Other Investment Securities [Member]
Total investment securities	0.1		0.3
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Total investment securities	$ 0.1		$ 4.9

[1]Carried at amortized cost and disclosed at fair value.

Note 6 - Fair Value Measureme_4

Note 6 - Fair Value Measurements - Changes in Level 3 Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Beginning of period fair value	$ 16.6	$ 21.1	$ 18.3	$ 8.8
Option agreement	0	(1.8)	0	1.3
Contingent consideration from sale of subsidiaries	0	(0.2)	0	12.1
Settlement of contingent consideration	0	0	(0.2)	0
Fair value adjustments	(11.7)	0	(13.1)	(1.8)
Transfers from Level 1	0	0	0.2	0.5
Transfers to Level 1	(4.8)	0	(4.8)	(2.1)
Purchases of securities	0	(0.1)	0	0.9
Sales of securities	0.1	0	(0.2)	(0.3)
Foreign currency translation	0	(0.2)	0	(0.6)
End of period fair value	$ 0.2	$ 18.8	$ 0.2	$ 18.8

Note 6 - Fair Value Measureme_5

Note 6 - Fair Value Measurements - Changes in Level 3 Liabilities (Details) - Deferred Bonuses [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Beginning of period fair value	$ 78.2	$ 27.6	$ 46.5	$ 50.5
Fair value adjustments	(0.7)	(1.2)	1.9	(3.8)
Vesting of deferred bonuses	(0.2)	(0.5)	(34.5)	(36.5)
Amortization of deferred bonuses	15.9	9.6	41.8	28.8
Foreign currency translation	(1.1)	(2.6)	0.6	(6.1)
Additions	0	0	35.8	0
End of period fair value	$ 92.1	$ 32.9	$ 92.1	$ 32.9

Note 7 - Goodwill and Intangi_3

Note 7 - Goodwill and Intangible Assets (Details Textual) - USD ($) $ in Millions	Sep. 30, 2023	Sep. 30, 2022	Mar. 31, 2022
Disposal Group, Including Discontinued Operation, Goodwill	$ 0
Intech Investment Management LLC [Member]
Disposal Group, Including Discontinued Operation, Goodwill			$ 7
Trademarks [Member] \| Intech Investment Management LLC [Member]
Disposal Group, Including Discontinued Operation, Intangible Assets			4.7
Client Relationships [Member]
Disposal Group, Including Discontinued Operation, Intangible Assets	$ 0	$ 84.8
Client Relationships [Member] \| Intech Investment Management LLC [Member]
Disposal Group, Including Discontinued Operation, Intangible Assets			$ 40.1

Note 7 - Goodwill and Intangi_4

Note 7 - Goodwill and Intangible Assets - Intangible Assets and Goodwill (Details) - USD ($) $ in Millions	6 Months Ended	9 Months Ended
	Jun. 30, 2023	Sep. 30, 2023	Sep. 30, 2022
Intangible assets, amortization		$ (1.5)	$ (3.2)
Accumulated amortization, balance	$ (60.7)	(60.7)	(107.2)
Accumulated amortization, disposals		0
Foreign currency translation		0.3	8.9
Accumulated amortization, balance		(61.9)	(56.8)
Net intangible assets, balance	2,414.7	2,414.7	2,542.7
Net intangible assets, disposals		0
Net intangible assets		2.7	(69.2)
Net intangible assets, balance		2,415.9	2,425.5
Goodwill, balance	1,253.1	1,253.1	1,341.5
Goodwill, disposals		0
Goodwill, foreign currency translation		6.7	(128.5)
Goodwill, balance		1,259.8	1,206
Intangible assets, impairment			(44.8)
Goodwill impairment			(7)
Client Relationships [Member]
Intangible assets, disposals		0	(84.8)
Foreign currency translation	(0.7)		(11)
Balance	68.9	68.9	168.4
Intangible assets, amortization		0	0
Client relationships	(0.7)		(11)
Balance		68.2	72.6
Investment Management Agreements [Member]
Balance	2,046.5	2,046.5	2,114.8
Intangible assets, disposals		0
Foreign currency translation		3.1	(67.1)
Balance		2,049.6	2,047.7
Client relationships		3.1	(67.1)
Intangible assets, impairment			0
Trademarks [Member]
Balance	360	360	366.7
Intangible assets, disposals		0
Foreign currency translation		0	0
Balance	$ 360		362
Client relationships		$ 0	0
Intangible assets, impairment			$ (4.7)

Note 7 - Goodwill and Intangi_5

Note 7 - Goodwill and Intangible Assets - Schedule of Future Amortization (Details) $ in Millions	Sep. 30, 2023 USD ($)
2023 (remainder of year)	$ 0.2
2024	0.4
2025	0.4
2026	0.4
2027	0.4
Thereafter	4.5
Total	$ 6.3

Note 8 - Debt (Details Textual)

Note 8 - Debt (Details Textual) $ in Thousands	9 Months Ended
Note 8 - Debt (Details Textual) $ in Thousands	Sep. 30, 2023 USD ($)
Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 200,000
Line of Credit Facility, Option for Additional Capacity, Additional Borrowing Capacity	$ 50,000
Line of Credit Facility, Covenant Terms Financing Leverage Ratio, Upper Range Limit	3
Long-Term Line of Credit, Total	$ 0
Senior Notes, 4.876 Percent, Due 2025 [Member]
Debt Instrument, Interest Rate, Stated Percentage	4.875%
Debt Instrument, Face Amount	$ 300,000
Debt Instrument, Unamortized Premium	$ 5,300

Note 8 - Debt - Schedule of Deb

Note 8 - Debt - Schedule of Debt (Details) - Senior Notes, 4.876 Percent, Due 2025 [Member] - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Long-term debt	$ 305.3	$ 307.5
Long-term debt, fair value	$ 293.7	$ 295.4

Note 9 - Income Taxes (Details

Note 9 - Income Taxes (Details Textual) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent	23.90%	23.50%	23.90%	23.50%
Non Cash Deferred Tax Expense (Benefit)			$ (8.8)
Unrecognized Tax Benefits	$ 23.6		23.6
Maximum [Member]
Decrease in Unrecognized Tax Benefits is Reasonably Possible	$ 6.7		$ 6.7

Note 9 - Income Taxes - Schedul

Note 9 - Income Taxes - Schedule of Effective Income Tax Rate (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Effective tax rate	13.20%	19.60%	19.30%	33%

Note 10 - Noncontrolling Inte_3

Note 10 - Noncontrolling Interests - Redeemable Noncontrolling Interest (Details) - USD ($) $ in Millions	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Total redeemable noncontrolling interests	$ 245.9	$ 389.8	$ 233.9	$ 153.1	$ 921.1	$ 148.5
Consolidated Entity, Excluding VIE [Member]
Total redeemable noncontrolling interests	$ 245.9		$ 233.9

Note 10 - Noncontrolling Inte_4

Note 10 - Noncontrolling Interests - Schedule of Changes in Noncontrolling Interests (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Opening balance	$ 389.8	$ 921.1	$ 233.9	$ 148.5
Changes in market value	(7.5)	7	11.7	(114.1)
Changes in ownership	(135.4)	(795.3)	0.8	121.9
Foreign currency translation	(1)	20.3	(0.5)	(3.2)
Closing balance	$ 245.9	$ 153.1	$ 245.9	$ 153.1

Note 11 - Long-Term Incentive_3

Note 11 - Long-Term Incentive and Employee Compensation - Award Activity (Details) - shares shares in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2023
Awards granted (in shares)	3.8	120.2
Restricted Stock [Member]
Awards granted (in shares)	3.7	66.1
Mutual Fund Awards [Member]
Awards granted (in shares)	0.1	54.1

Note 12 - Retirement Benefit _3

Note 12 - Retirement Benefit Plans - Actuarial Gains (Losses), Benefit Cost, Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Interest cost	$ (7)	$ (3.9)	$ (20.7)	$ (12.5)
Amortization of prior service cost	(0.1)	(0.1)	(0.3)	(0.3)
Amortization of net loss	(0.4)	0	(0.4)	0
Expected return on plan assets	6.9	3.3	20.3	10.5
Net periodic benefit cost	$ (0.6)	$ (0.7)	$ (1.1)	$ (2.3)

Note 13 - Accumulated Other C_3

Note 13 - Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Beginning balance			$ 4,359.8
Total other comprehensive income (loss)	$ (70.2)	$ (139.1)	15	$ (363.7)
Less: other comprehensive loss (income) attributable to noncontrolling interests	(1)	20.2	0.6	(3.2)
Ending balance	4,455.9		4,455.9
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Beginning balance	(493.9)	(555.6)	(577.3)	(354.2)
Other comprehensive loss	(67.9)	(129.4)	15	(359.9)
Reclassifications to net income	(2.8)	(9.8)	(0.7)	(4.1)
Total other comprehensive income (loss)	(70.7)	(139.2)	14.3	(364)
Less: other comprehensive loss (income) attributable to noncontrolling interests	1	(20.2)	(0.6)	3.2
Ending balance	(563.6)	(715)	(563.6)	(715)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Beginning balance	(70.2)	(32.6)	(70.4)	(32.8)
Other comprehensive loss	0	0	0	0
Reclassifications to net income	0.5	0.1	0.7	0.3
Total other comprehensive income (loss)	0.5	0.1	0.7	0.3
Less: other comprehensive loss (income) attributable to noncontrolling interests	0	0	0	0
Ending balance	(69.7)	(32.5)	(69.7)	(32.5)
AOCI Attributable to Parent [Member]
Beginning balance	(564.1)	(588.2)	(647.7)	(387)
Other comprehensive loss	(67.9)	(129.4)	15	(359.9)
Reclassifications to net income	(2.3)	(9.7)	0	(3.8)
Total other comprehensive income (loss)	(70.2)	(139.1)	15	(363.7)
Less: other comprehensive loss (income) attributable to noncontrolling interests	1	(20.2)	(0.6)	3.2
Ending balance	$ (633.3)	$ (747.5)	$ (633.3)	$ (747.5)

Note 13 - Accumulated Other C_4

Note 13 - Accumulated Other Comprehensive Loss - Schedule of Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Total other comprehensive loss, pre tax	$ (71.1)	$ (140.5)	$ 11.5	$ (368.3)
Total other comprehensive loss, tax	0.9	1.4	3.5	4.6
Total other comprehensive loss, net	(70.2)	(139.1)	15	(363.7)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Total other comprehensive loss, pre tax	(68.8)	(130.8)	11.5	(364.5)
Total other comprehensive loss, tax	0.9	1.4	3.5	4.6
Total other comprehensive loss, net	(67.9)	(129.4)	15	(359.9)
Reclassification to Net Income [Member]
Total other comprehensive loss, pre tax	(2.3)	(9.7)	0	(3.8)
Total other comprehensive loss, tax	0	0	0	0
Total other comprehensive loss, net	$ (2.3)	$ (9.7)	$ 0	$ (3.8)

Note 14 - Earnings and Divide_3

Note 14 - Earnings and Dividends Per Share (Details Textual) - $ / shares	Oct. 31, 2023	Aug. 01, 2023	May 02, 2023	Feb. 28, 2023
Common Stock, Dividends, Per Share, Declared (in dollars per share)		$ 0.39	$ 0.39	$ 0.39
Subsequent Event [Member]
Common Stock, Dividends, Per Share, Declared (in dollars per share)	$ 0.39

Note 14 - Earnings and Divide_4

Note 14 - Earnings and Dividends Per Share - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Net income attributable to JHG	$ 93.5	$ 107.6	$ 270.7	$ 307.4
Allocation of earnings to participating stock-based awards	(2.8)	(3.5)	(7.8)	(9)
Net income attributable to JHG common shareholders	$ 90.7	$ 104.1	$ 262.9	$ 298.4
Weighted-average common shares outstanding — basic (in shares)	160.8	160.5	160.5	162.2
Dilutive effect of nonparticipating stock-based awards (in shares)	0.1	0.4	0.2	0.4
Weighted-average common shares outstanding — diluted (in shares)	160.9	160.9	160.7	162.6
Basic (in dollars per share)	$ 0.56	$ 0.65	$ 1.64	$ 1.84
Diluted (in dollars per share)	$ 0.56	$ 0.65	$ 1.64	$ 1.84

Note 14 - Earnings and Divide_5

Note 14 - Earnings and Dividends Per Share - Dividends Declared (Details) - USD ($) $ / shares in Units, $ in Millions				9 Months Ended
	Aug. 01, 2023	May 02, 2023	Feb. 28, 2023	Sep. 30, 2023	Sep. 30, 2022
Dividend per share (in dollars per share)	$ 0.39	$ 0.39	$ 0.39
Dividends paid	$ 64.7	$ 64.6	$ 64.7	$ 194	$ 194.5