The Travelers Companies, Inc. (TRV) 10-Q18 Oct 232023 Q3 Quarterly reportFinancial data

Company Profile

Cover Page

Cover Page - shares	9 Months Ended
Cover Page - shares	Sep. 30, 2023	Oct. 13, 2023
Cover [Abstract]
Document type	10-Q
Document quarterly report	true
Document period end date	Sep. 30, 2023
Document transition report	false
Entity file number	001-10898
Registrant name	Travelers Companies, Inc.
Entity incorporation, state	MN
Entity tax identification number	41-0518860
Entity address, address line one	485 Lexington Avenue
Entity address, city	New York
Entity address, state	NY
Entity address, postal zip code	10017
City area code	917
Local phone number	778-6000
Title of 12(b) security	Common stock, without par value
Trading symbol	TRV
Security exchange name	NYSE
Entity current reporting status	Yes
Entity interactive data current	Yes
Filer category	Large Accelerated Filer
Entity small business	false
Entity emerging growth company	false
Entity shell company	false
Common stock shares outstanding		228,399,446
Central index key	0000086312
Amendment flag	false
Current fiscal year end date	--12-31
Document fiscal year focus	2023
Document fiscal period focus	Q3

Consolidated Statement of Incom

Consolidated Statement of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenues
Premiums	$ 9,718	$ 8,615	$ 27,788	$ 24,946
Net investment income	769	593	2,144	1,937
Fee income	112	104	324	307
Net realized investment losses	(65)	(93)	(94)	(211)
Other revenues	101	84	275	269
Total revenues	10,635	9,303	30,437	27,248
Claims and expenses
Claims and claim adjustment expenses	7,149	6,088	20,335	16,930
Amortization of deferred acquisition costs	1,604	1,406	4,585	4,081
General and administrative expenses	1,312	1,193	3,887	3,607
Interest expense	98	88	278	263
Total claims and expenses	10,163	8,775	29,085	24,881
Income before income taxes	472	528	1,352	2,367
Income tax expense (benefit)	68	74	(13)	344
Net income	$ 404	$ 454	$ 1,365	$ 2,023
Net income per share
Basic (in dollars per share)	$ 1.75	$ 1.91	$ 5.89	$ 8.43
Diluted (in dollars per share)	$ 1.74	$ 1.89	$ 5.83	$ 8.34
Weighted average number of common shares outstanding
Basic (in shares)	228.8	235.4	230	238.3
Diluted (in shares)	231.1	237.9	232.5	240.9
Cash dividends declared per common share (in dollars per share)	$ 1	$ 0.93	$ 2.93	$ 2.74

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 404	$ 454	$ 1,365	$ 2,023
Other comprehensive income (loss):
Changes in net unrealized gains (losses) on investment securities having no credit losses recognized in the consolidated statement of income	(2,391)	(3,204)	(1,986)	(11,078)
Changes in net unrealized gains (losses) on investment securities having credit losses recognized in the consolidated statement of income	0	0	0	(3)
Net changes in benefit plan assets and obligations	(3)	12	(10)	34
Net changes in unrealized foreign currency translation	(118)	(251)	13	(423)
Other comprehensive loss before income taxes	(2,512)	(3,443)	(1,983)	(11,470)
Income tax benefit	(509)	(690)	(416)	(2,369)
Other comprehensive loss, net of taxes	(2,003)	(2,753)	(1,567)	(9,101)
Comprehensive loss	$ (1,599)	$ (2,299)	$ (202)	$ (7,078)

Consolidated Balance Sheet (Una

Consolidated Balance Sheet (Unaudited at September 30, 2023) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Assets
Fixed maturities, available for sale, at fair value (amortized cost $80,792 and $77,380; allowance for expected credit losses of $4 and $3)	$ 72,584	$ 71,160
Equity securities, at fair value (cost $546 and $747)	573	807
Real estate investments	960	952
Short-term securities	4,488	3,470
Other investments	4,351	4,065
Total investments	82,956	80,454
Cash	593	799
Investment income accrued	623	650
Premiums receivable (net of allowance for expected credit losses of $68 and $77)	10,345	8,922
Reinsurance recoverables (net of allowance for estimated uncollectible reinsurance of $121 and $132)	8,267	8,063
Ceded unearned premiums	1,389	1,024
Deferred acquisition costs	3,330	2,836
Deferred taxes	2,393	1,877
Contractholder receivables (net of allowance for expected credit losses of $20 and $17)	3,467	3,579
Goodwill	3,955	3,952
Other intangible assets	278	287
Other assets	3,788	3,274
Total assets	121,384	115,717
Liabilities
Claims and claim adjustment expense reserves	61,709	58,649
Unearned premium reserves	21,058	18,240
Contractholder payables	3,487	3,596
Payables for reinsurance premiums	807	419
Debt	8,031	7,292
Other liabilities	6,314	5,961
Total liabilities	101,406	94,157
Shareholders’ equity
Common stock (1,750.0 shares authorized; 228.4 and 232.1 shares issued and outstanding)	24,831	24,565
Retained earnings	44,198	43,516
Accumulated other comprehensive loss	(8,012)	(6,445)
Treasury stock, at cost (558.8 and 553.5 shares)	(41,039)	(40,076)
Total shareholders’ equity	19,978	21,560
Total liabilities and shareholders’ equity	$ 121,384	$ 115,717

Consolidated Balance Sheet Pare

Consolidated Balance Sheet Parentheticals (Unaudited at September 30, 2023) - USD ($) shares in Millions, $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Fixed maturities, available for sale, amortized cost	$ 80,792	$ 77,380
Fixed maturities, available for sale, allowance for expected credit losses	4	3
Equity securities, cost	546	747
Premiums receivable, allowance for expected credit losses	68	77
Reinsurance recoverables, allowance for estimated uncollectible reinsurance	121	132
Contractholder receivables, allowance for expected credit losses	$ 20	$ 17
Common stock, shares authorized (in shares)	1,750	1,750
Common stock, shares issued (in shares)	228.4	232.1
Common stock, shares outstanding (in shares)	228.4	232.1
Treasury stock, at cost (in shares)	558.8	553.5

Consolidated Statement of Chang

Consolidated Statement of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands, shares in Millions	Total	Common stock [Member]	Retained earnings [Member]	Accumulated other comprehensive income (loss), net of tax [Member]	Treasury stock, at cost [Member]	Common shares outstanding [Member]
Balance, beginning of period at Dec. 31, 2021		$ 24,154,000	$ 41,555,000	$ 1,193,000	$ (38,015,000)
Shareholders' Equity [Roll Forward]
Employee share-based compensation		176,000
Compensation amortization under share-based plans and other changes		142,000
Net income	$ 2,023,000		2,023,000
Dividends			(660,000)
Other			(1,000)
Other comprehensive loss	(9,101,000)			(9,101,000)
Treasury stock acquired — share repurchase authorizations					(1,500,000)
Net shares acquired related to employee share-based compensation plans					(60,000)
Balance, end of period at Sep. 30, 2022	19,906,000	24,472,000	42,917,000	(7,908,000)	(39,575,000)
Balance, beginning of period (in shares) at Dec. 31, 2021						241.2
Common shares outstanding
Treasury stock acquired - share repurchase authorizations (in shares)						(8.9)
Net shares issued under employee share-based compensation plans (in shares)						2
Balance, end of period (in shares) at Sep. 30, 2022						234.3
Balance, beginning of period at Jun. 30, 2022		24,419,000	42,684,000	(5,155,000)	(39,074,000)
Shareholders' Equity [Roll Forward]
Employee share-based compensation		11,000
Compensation amortization under share-based plans and other changes		42,000
Net income	454,000		454,000
Dividends			(221,000)
Other			0
Other comprehensive loss	(2,753,000)			(2,753,000)
Treasury stock acquired — share repurchase authorizations					(500,000)
Net shares acquired related to employee share-based compensation plans					(1,000)
Balance, end of period at Sep. 30, 2022	19,906,000	24,472,000	42,917,000	(7,908,000)	(39,575,000)
Balance, beginning of period (in shares) at Jun. 30, 2022						237.3
Common shares outstanding
Treasury stock acquired - share repurchase authorizations (in shares)						(3.1)
Net shares issued under employee share-based compensation plans (in shares)						0.1
Balance, end of period (in shares) at Sep. 30, 2022						234.3
Balance, beginning of period at Dec. 31, 2022	21,560,000	24,565,000	43,516,000	(6,445,000)	(40,076,000)
Shareholders' Equity [Roll Forward]
Employee share-based compensation		102,000
Compensation amortization under share-based plans and other changes		164,000
Net income	1,365,000		1,365,000
Dividends			(683,000)
Other			0
Other comprehensive loss	(1,567,000)			(1,567,000)
Treasury stock acquired — share repurchase authorizations	(900,000)				(900,000)
Net shares acquired related to employee share-based compensation plans	(63,000)				(63,000)
Balance, end of period at Sep. 30, 2023	$ 19,978,000	24,831,000	44,198,000	(8,012,000)	(41,039,000)
Balance, beginning of period (in shares) at Dec. 31, 2022	232.1					232.1
Common shares outstanding
Treasury stock acquired - share repurchase authorizations (in shares)	(5)					(5)
Net shares issued under employee share-based compensation plans (in shares)						1.3
Balance, end of period (in shares) at Sep. 30, 2023	228.4					228.4
Balance, beginning of period at Jun. 30, 2023		24,776,000	44,026,000	(6,009,000)	(40,938,000)
Shareholders' Equity [Roll Forward]
Employee share-based compensation		8,000
Compensation amortization under share-based plans and other changes		47,000
Net income	$ 404,000		404,000
Dividends			(232,000)
Other			0
Other comprehensive loss	(2,003,000)			(2,003,000)
Treasury stock acquired — share repurchase authorizations	(100,000)				(100,000)
Net shares acquired related to employee share-based compensation plans	(926)				(1,000)
Balance, end of period at Sep. 30, 2023	$ 19,978,000	$ 24,831,000	$ 44,198,000	$ (8,012,000)	$ (41,039,000)
Balance, beginning of period (in shares) at Jun. 30, 2023						228.9
Common shares outstanding
Treasury stock acquired - share repurchase authorizations (in shares)	(0.6)					(0.6)
Net shares issued under employee share-based compensation plans (in shares)						0.1
Balance, end of period (in shares) at Sep. 30, 2023	228.4					228.4

Consolidated Statement of Cash

Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Cash flows from operating activities
Net income	$ 1,365	$ 2,023
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized investment losses	94	211
Depreciation and amortization	552	639
Deferred federal income tax benefit	(107)	(130)
Amortization of deferred acquisition costs	4,585	4,081
Equity in income from other investments	(144)	(319)
Premiums receivable	(1,422)	(861)
Reinsurance recoverables	(204)	185
Deferred acquisition costs	(5,079)	(4,419)
Claims and claim adjustment expense reserves	3,053	1,694
Unearned premium reserves	2,817	2,033
Other operating activities	97	(12)
Net cash provided by operating activities	5,607	5,125
Cash flows from investing activities
Proceeds from maturities of fixed maturities	4,909	5,481
Proceeds from sales of investments:
Fixed maturities	4,619	3,951
Equity securities	117	104
Real estate investments	0	10
Other investments	166	242
Purchases of investments:
Fixed maturities	(13,054)	(12,100)
Equity securities	(80)	(112)
Real estate investments	(46)	(28)
Other investments	(375)	(414)
Net purchases of short-term securities	(1,018)	(107)
Securities transactions in the course of settlement	60	214
Acquisition, net of cash acquired	0	(4)
Other investing activities	(335)	(291)
Net cash used in investing activities	(5,037)	(3,054)
Cash flows from financing activities
Treasury stock acquired — share repurchase authorizations	(894)	(1,500)
Treasury stock acquired — net employee share-based compensation	(63)	(60)
Dividends paid to shareholders	(676)	(656)
Issuance of debt	738	0
Issuance of common stock — employee share options	117	205
Net cash used in financing activities	(778)	(2,011)
Effect of exchange rate changes on cash	2	(48)
Net increase (decrease) in cash	(206)	12
Cash at beginning of year	799	761
Cash at end of period	593	773
Supplemental disclosure of cash flow information
Income taxes paid	152	663
Interest paid	$ 234	$ 234

Basis of Presentation and Accou

Basis of Presentation and Accounting Policies	9 Months Ended
Basis of Presentation and Accounting Policies	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Accounting Policies	BASIS OF PRESENTATION AND ACCOUNTING POLICIES Basis of Presentation The interim consolidated financial statements include the accounts of The Travelers Companies, Inc. (together with its subsidiaries, the Company). These financial statements are prepared in conformity with U.S. generally accepted accounting principles (GAAP) and are unaudited. In the opinion of the Company’s management, all adjustments necessary for a fair presentation have been reflected. Certain financial information that is normally included in annual financial statements prepared in accordance with GAAP, but that is not required for interim reporting purposes, has been omitted. All material intercompany transactions and balances have been eliminated. The accompanying interim consolidated financial statements and related notes should be read in conjunction with the Company’s consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022 (the Company’s 2022 Annual Report). The preparation of the interim consolidated financial statements in conformity with 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 interim consolidated financial statements and the reported amounts of revenues and claims and expenses during the reporting period. Actual results could differ from those estimates. Adoption of Accounting Standards For information regarding accounting standards that the Company adopted during the periods presented, see note 1 of the notes to the consolidated financial statements in the Company’s 2022 Annual Report. Income Taxes The Company recognized a one-time tax benefit of $211 million in the first quarter of 2023 due to the expiration of the statute of limitations with respect to a tax item impacted by the repeal of Internal Revenue Code Section 847, which related to the discounting of property-casualty loss reserves.

Segment Information

Segment Information	9 Months Ended
Segment Information	Sep. 30, 2023
Segment Reporting [Abstract]
Segment Information	SEGMENT INFORMATION Nature of Operations The Company’s results are reported in the following three business segments — Business Insurance, Bond & Specialty Insurance and Personal Insurance. These segments reflect the manner in which the Company’s businesses are currently managed and represent an aggregation of products and services based on the type of customer, how the business is marketed and the manner in which risks are underwritten. For more information regarding the Company’s nature of operations, see the “Nature of Operations ” section of note 1 of the notes to the consolidated financial statements in the Company’s 2022 Annual Report. The following tables summarize the components of the Company’s revenues, income (loss) and total assets by reportable business segments: (For the three months ended September 30, in millions) Business Bond & Specialty Personal Total 2023 Premiums $ 4,956 $ 935 $ 3,827 $ 9,718 Net investment income 551 86 132 769 Fee income 102 — 10 112 Other revenues 71 6 24 101 Total segment revenues (1) $ 5,680 $ 1,027 $ 3,993 $ 10,700 Segment income (loss) (1) $ 468 $ 265 $ (193) $ 540 2022 Premiums $ 4,353 $ 877 $ 3,385 $ 8,615 Net investment income 426 65 102 593 Fee income 96 — 8 104 Other revenues 56 6 22 84 Total segment revenues (1) $ 4,931 $ 948 $ 3,517 $ 9,396 Segment income (loss) (1) $ 471 $ 242 $ (111) $ 602 ________________________________________________________ (1) Segment revenues for reportable business segments exclude net realized investment gains (losses) and revenues included in “interest expense and other.” Segment income (loss) for reportable business segments excludes the after-tax impact of net realized investment gains (losses) and income (loss) from “interest expense and other.” (For the nine months ended September 30, in millions) Business Bond & Specialty Personal Total 2023 Premiums $ 14,077 $ 2,721 $ 10,990 $ 27,788 Net investment income 1,533 237 374 2,144 Fee income 299 — 25 324 Other revenues 185 18 72 275 Total segment revenues (1) $ 16,094 $ 2,976 $ 11,461 $ 30,531 Segment income (loss) (1) $ 1,626 $ 702 $ (648) $ 1,680 2022 Premiums $ 12,642 $ 2,548 $ 9,756 $ 24,946 Net investment income 1,415 188 334 1,937 Fee income 285 — 22 307 Other revenues 194 14 61 269 Total segment revenues (1) $ 14,536 $ 2,750 $ 10,173 $ 27,459 Segment income (loss) (1) $ 1,806 $ 687 $ (79) $ 2,414 _______________________________________________________ (1) Segment revenues for reportable business segments exclude net realized investment gains (losses) and revenues included in “interest expense and other.” Segment income (loss) for reportable business segments excludes the after-tax impact of net realized investment gains (losses) and income (loss) from “interest expense and other.” Business Segment Reconciliations Three Months Ended Nine Months Ended (in millions) 2023 2022 2023 2022 Revenue reconciliation Earned premiums Business Insurance: Domestic: Workers’ compensation $ 876 $ 872 $ 2,584 $ 2,566 Commercial automobile 816 754 2,375 2,202 Commercial property 828 668 2,297 1,914 General liability 804 728 2,312 2,116 Commercial multi-peril 1,211 1,057 3,456 3,034 Other 21 19 55 52 Total Domestic 4,556 4,098 13,079 11,884 International 400 255 998 758 Total Business Insurance 4,956 4,353 14,077 12,642 Bond & Specialty Insurance: Domestic: Fidelity and surety 333 307 964 876 General liability 414 396 1,218 1,154 Other 57 57 168 166 Total Domestic 804 760 2,350 2,196 International 131 117 371 352 Total Bond & Specialty Insurance 935 877 2,721 2,548 Personal Insurance: Domestic: Automobile 1,772 1,575 5,084 4,544 Homeowners and Other 1,896 1,648 5,434 4,714 Total Domestic 3,668 3,223 10,518 9,258 International 159 162 472 498 Total Personal Insurance 3,827 3,385 10,990 9,756 Total earned premiums 9,718 8,615 27,788 24,946 Net investment income 769 593 2,144 1,937 Fee income 112 104 324 307 Other revenues 101 84 275 269 Total segment revenues 10,700 9,396 30,531 27,459 Net realized investment losses (65) (93) (94) (211) Total revenues $ 10,635 $ 9,303 $ 30,437 $ 27,248 Income reconciliation, net of tax Total segment income $ 540 $ 602 $ 1,680 $ 2,414 Interest Expense and Other (1) (86) (76) (241) (226) Core income 454 526 1,439 2,188 Net realized investment losses (50) (72) (74) (165) Net income $ 404 $ 454 $ 1,365 $ 2,023 _________________________________________________________ (1) The primary component of Interest Expense and Other was after-tax interest expense of $78 million and $70 million for the three months ended September 30, 2023 and 2022, respectively, and $220 million and $208 million for the nine months ended September 30, 2023 and 2022, respectively. (in millions) September 30, December 31, Asset reconciliation Business Insurance $ 89,980 $ 86,522 Bond & Specialty Insurance 11,088 10,119 Personal Insurance 19,454 18,275 Total assets by reportable segment 120,522 114,916 Other assets (1) 862 801 Total consolidated assets $ 121,384 $ 115,717 _________________________________________________________ (1) The primary components of other assets at both September 30, 2023 and December 31, 2022 were the over-funded benefit plan assets related to the Company’s qualified domestic pension plan and other intangible assets.

Investments

Investments	9 Months Ended
Investments	Sep. 30, 2023
Investments [Abstract]
Investments	INVESTMENTS Fixed Maturities The amortized cost and fair value of investments in fixed maturities classified as available for sale were as follows: Amortized Cost Allowance for Expected Credit Losses Gross Unrealized Fair Value (at September 30, 2023, in millions) Gains Losses U.S. Treasury securities and obligations of U.S. government and government agencies and authorities $ 6,575 $ — $ — $ 363 $ 6,212 Obligations of U.S. states, municipalities and political subdivisions: Local general obligation 18,358 — 1 2,675 15,684 Revenue 9,750 — 2 1,275 8,477 State general obligation 1,174 — — 137 1,037 Pre-refunded 1,048 — 1 9 1,040 Total obligations of U.S. states, municipalities and political subdivisions 30,330 — 4 4,096 26,238 Debt securities issued by foreign governments 1,037 — 1 56 982 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 6,927 — 7 411 6,523 Corporate and all other bonds 35,923 4 16 3,306 32,629 Total $ 80,792 $ 4 $ 28 $ 8,232 $ 72,584 Amortized Cost Allowance for Expected Credit Losses Gross Unrealized Fair Value (at December 31, 2022, in millions) Gains Losses U.S. Treasury securities and obligations of U.S. government and government agencies and authorities $ 5,798 $ — $ 3 $ 363 $ 5,438 Obligations of U.S. states, municipalities and political subdivisions: Local general obligation 19,615 — 33 1,825 17,823 Revenue 11,076 — 29 907 10,198 State general obligation 1,104 — 3 88 1,019 Pre-refunded 2,323 — 17 1 2,339 Total obligations of U.S. states, municipalities and political subdivisions 34,118 — 82 2,821 31,379 Debt securities issued by foreign governments 1,049 — — 55 994 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 2,178 — 13 200 1,991 Corporate and all other bonds 34,237 3 37 2,913 31,358 Total $ 77,380 $ 3 $ 135 $ 6,352 $ 71,160 Pre-refunded bonds of $1.04 billion and $2.34 billion at September 30, 2023 and December 31, 2022, respectively, were bonds for which U.S. states or municipalities have established irrevocable trusts that are almost exclusively comprised of U.S. Treasury securities and obligations of U.S. government and government agencies and authorities. These trusts were created to fund the payment of principal and interest due under the bonds. Proceeds from the sales of fixed maturities classified as available for sale were $4.62 billion and $3.95 billion during the nine months ended September 30, 2023 and 2022, respectively. Gross gains of $26 million and $17 million and gross losses of $93 million and $52 million were realized on those sales during the nine months ended September 30, 2023 and 2022, respectively. Equity Securities The cost and fair value of investments in equity securities were as follows: (at September 30, 2023, in millions) Cost Gross Gains Gross Losses Fair Value Common stock $ 502 $ 65 $ 40 $ 527 Non-redeemable preferred stock 44 2 — 46 Total $ 546 $ 67 $ 40 $ 573 (at December 31, 2022, in millions) Cost Gross Gains Gross Losses Fair Value Common stock $ 706 $ 89 $ 32 $ 763 Non-redeemable preferred stock 41 3 — 44 Total $ 747 $ 92 $ 32 $ 807 For the nine months ended September 30, 2023 and 2022, the Company recognized $11 million and $110 million of net losses on equity securities still held as of September 30, 2023 and 2022, respectively. Unrealized Investment Losses The following tables summarize, for all fixed maturities classified as available for sale in an unrealized loss position at September 30, 2023 and December 31, 2022, the aggregate fair value and gross unrealized loss by the length of time those securities have been continuously in an unrealized loss position. The fair value amounts reported in the tables are estimates that are prepared using the process described in note 4 herein and in note 4 of the notes to the consolidated financial statements in the Company’s 2022 Annual Report. The Company also relies upon estimates of several factors in its review and evaluation of individual investments, using the process described in note 1 of the notes to the consolidated financial statements in the Company’s 2022 Annual Report to determine whether a credit loss impairment exists. Less than 12 months 12 months or longer Total (at September 30, 2023, in millions) Fair Gross Fair Gross Fair Gross Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities $ 2,979 $ 32 $ 3,083 $ 331 $ 6,062 $ 363 Obligations of U.S. states, municipalities and political subdivisions 12,050 703 13,625 3,393 25,675 4,096 Debt securities issued by foreign governments 201 6 769 50 970 56 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 5,032 162 1,373 249 6,405 411 Corporate and all other bonds 5,680 167 26,034 3,139 31,714 3,306 Total $ 25,942 $ 1,070 $ 44,884 $ 7,162 $ 70,826 $ 8,232 Less than 12 months 12 months or longer Total (at December 31, 2022, in millions) Fair Gross Fair Gross Fair Gross Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities $ 2,835 $ 100 $ 1,679 $ 263 $ 4,514 $ 363 Obligations of U.S. states, municipalities and political subdivisions 19,251 1,975 3,134 846 22,385 2,821 Debt securities issued by foreign governments 604 22 367 33 971 55 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 1,414 128 316 72 1,730 200 Corporate and all other bonds 24,080 1,635 6,096 1,278 30,176 2,913 Total $ 48,184 $ 3,860 $ 11,592 $ 2,492 $ 59,776 $ 6,352 The following tables summarize, for all fixed maturities reported at fair value for which fair value was less than 80% of amortized cost at September 30, 2023 and December 31, 2022, the gross unrealized investment loss by length of time those securities have continuously been in an unrealized loss position of greater than 20% of amortized cost: Period For Which Fair Value is Less Than 80% of Amortized Cost (at September 30, 2023, in millions) 3 months or less Greater than 3 months, 6 months or less Greater than 6 months, 12 months or less Greater than 12 months Total Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities $ 17 $ — $ — $ — $ 17 Obligations of U.S. states, municipalities and political subdivisions 948 167 140 1,024 2,279 Debt securities issued by foreign governments — 1 — — 1 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 46 54 — — 100 Corporate and all other bonds 822 246 45 66 1,179 Total $ 1,833 $ 468 $ 185 $ 1,090 $ 3,576 Period For Which Fair Value is Less Than 80% of Amortized Cost (at December 31, 2022, in millions) 3 months or less Greater than 3 months, 6 months or less Greater than 6 months, 12 months or less Greater than 12 months Total Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities $ — $ — $ — $ — $ — Obligations of U.S. states, municipalities and political subdivisions 81 776 643 — 1,500 Debt securities issued by foreign governments 1 — — — 1 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 4 48 — — 52 Corporate and all other bonds 89 526 8 — 623 Total $ 175 $ 1,350 $ 651 $ — $ 2,176 Increases in interest rates resulted in the gross unrealized investment losses disclosed in the tables above; however, the net unrealized loss is considered temporary in nature as the decrease in value is not due to credit impairments and there is no impact on expected contractual cash flows from fixed maturities. Impairment Charges The following tables present changes in the allowance for expected credit losses on fixed maturities classified as available for sale for the category of Corporate and All Other Bonds (no other categories of fixed maturities currently have an allowance for expected credit losses): Fixed Maturities Corporate and All Other Bonds At and For the Three Months Ended (in millions) September 30, 2023 September 30, 2022 Balance, beginning of period $ 4 $ 4 Additions for expected credit losses on securities where no credit losses were previously recognized — — Additions for expected credit losses on securities where credit losses were previously recognized — — Reductions due to sales/defaults of credit-impaired securities — (1) Reductions for impairments of securities which the Company intends to sell or more likely than not will be required to sell — — Balance, end of period $ 4 $ 3 Fixed Maturities Corporate and All Other Bonds At and For the Nine Months Ended (in millions) September 30, 2023 September 30, 2022 Balance, beginning of period $ 3 $ 3 Additions for expected credit losses on securities where no credit losses were previously recognized — — Additions for expected credit losses on securities where credit losses were previously recognized 1 1 Reductions due to sales/defaults of credit-impaired securities — (1) Reductions for impairments of securities which the Company intends to sell or more likely than not will be required to sell — — Balance, end of period $ 4 $ 3 Total net impairment charges, including credit impairments, reported in net realized investment losses in the consolidated statement of income, were $1 million and $14 million for the three months ended September 30, 2023 and 2022, respectively, and $2 million and $35 million for the nine months ended September 30, 2023 and 2022, respectively. Credit losses related to the fixed maturity portfolio for both the three and nine months ended September 30, 2023 and 2022 represented less than 1% of the fixed maturity portfolio on a pre-tax basis and less than 1% of shareholders’ equity on an after-tax basis. Other Investments Included in other investments are private equity, hedge fund and real estate partnerships that are accounted for under the equity method of accounting and typically report their financial statement information to the Company one month to three months following the end of the reporting period. Accordingly, net investment income from these other investments is generally reflected in the Company’s financial statements on a quarter lag basis.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
Fair Value Measurements	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS The Company’s estimates of fair value for financial assets and financial liabilities are based on the framework established in the fair value accounting guidance. The framework is based on the inputs used in valuation, gives the highest priority to quoted prices in active markets and requires that observable inputs be used in the valuations when available. The disclosure of fair value estimates in the fair value accounting guidance hierarchy is based on whether the significant inputs into the valuation are observable. In determining the level of the hierarchy in which the estimate is disclosed, the highest priority is given to unadjusted quoted prices in active markets and the lowest priority to unobservable inputs that reflect the Company’s significant market assumptions. The level in the fair value hierarchy within which the fair value measurement is reported is based on the lowest level input that is significant to the measurement in its entirety. The three levels of the hierarchy are as follows: • Level 1 - Unadjusted quoted market prices for identical assets or liabilities in active markets that the Company has the ability to access. • Level 2 - Quoted prices for similar assets or liabilities in active markets; quoted prices for identical or similar assets or liabilities in inactive markets; or valuations based on models where the significant inputs are observable (e.g., interest rates, yield curves, prepayment speeds, default rates, loss severities, etc.) or can be corroborated by observable market data. • Level 3 - Valuations based on models where significant inputs are not observable. The unobservable inputs reflect the Company’s own assumptions about the inputs that market participants would use. Valuation of Investments Reported at Fair Value in Financial Statements The Company utilized a pricing service to estimate fair value measurements for approximately 99% of its fixed maturities at both September 30, 2023 and December 31, 2022. While the vast majority of the Company’s fixed maturities are included in Level 2, the Company holds a number of corporate bonds which are not valued by the pricing service and estimates the fair value of these bonds using either another internal pricing matrix, a present value income approach, or a broker quote (collectively, the other methodologies). The other methodologies include some unobservable inputs that are significant to the valuation. Due to the limited amount of observable market information available in the estimation of fair value, the Company includes the fair value estimates for bonds that are valued using the other methodologies in Level 3. For certain investments in non-public common and preferred equity securities, the fair value estimate is determined either internally or by an external fund manager based on the impact of recent observable transactions on the investment, recent filings, operating results, balance sheet stability, growth and other business and market sector fundamentals. Due to the significant unobservable inputs in these valuations, the Company included the fair value estimate of $36 million and $371 million for these investments at September 30, 2023 and December 31, 2022, respectively, in the amounts disclosed in Level 3. For more information regarding the valuation of the Company’s fixed maturities, equity securities and other investments, see note 4 of the notes to the consolidated financial statements in the Company’s 2022 Annual Report. Fair Value Hierarchy The following tables present the level within the fair value hierarchy at which the Company’s financial assets and financial liabilities are measured on a recurring basis. (at September 30, 2023, in millions) Total Level 1 Level 2 Level 3 Invested assets: Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities $ 6,212 $ 6,212 $ — $ — Obligations of U.S. states, municipalities and political subdivisions 26,238 — 26,238 — Debt securities issued by foreign governments 982 — 982 — Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 6,523 — 6,523 — Corporate and all other bonds 32,629 — 32,377 252 Total fixed maturities 72,584 6,212 66,120 252 Equity securities Common stock 527 520 — 7 Non-redeemable preferred stock 46 14 3 29 Total equity securities 573 534 3 36 Other investments 16 16 — — Total $ 73,173 $ 6,762 $ 66,123 $ 288 (at December 31, 2022, in millions) Total Level 1 Level 2 Level 3 Invested assets: Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities $ 5,438 $ 5,438 $ — $ — Obligations of U.S. states, municipalities and political subdivisions 31,379 — 31,379 — Debt securities issued by foreign governments 994 — 994 — Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 1,991 — 1,991 — Corporate and all other bonds 31,358 — 31,055 303 Total fixed maturities 71,160 5,438 65,419 303 Equity securities Common stock 763 418 — 345 Non-redeemable preferred stock 44 15 3 26 Total equity securities 807 433 3 371 Other investments 16 15 — 1 Total $ 71,983 $ 5,886 $ 65,422 $ 675 Other liabilities $ 2 $ — $ — $ 2 Transfers out of Level 3 during the nine months ended September 30, 2023 included $182 million of common stock that the Company exchanged during the first quarter of 2023 for shares in an investment that is reported using the equity method of accounting and $151 million of common stock in a company that had been privately held but became publicly traded during the second quarter of 2023, valued using an unadjusted quoted market price and disclosed in Level 1. There was no other significant activity in Level 3 of the hierarchy during the nine months ended September 30, 2023. Financial Instruments Disclosed, But Not Carried, At Fair Value The following tables present the carrying value and fair value of the Company’s financial assets and financial liabilities disclosed, but not carried, at fair value, and the level within the fair value hierarchy at which such assets and liabilities are categorized. (at September 30, 2023, in millions) Carrying Fair Level 1 Level 2 Level 3 Financial assets Short-term securities $ 4,488 $ 4,488 $ 971 $ 3,466 $ 51 Financial liabilities Debt $ 7,931 $ 6,900 $ — $ 6,900 $ — Commercial paper 100 100 — 100 — (at December 31, 2022, in millions) Carrying Fair Level 1 Level 2 Level 3 Financial assets Short-term securities $ 3,470 $ 3,470 $ 871 $ 2,546 $ 53 Financial liabilities Debt $ 7,192 $ 6,509 $ — $ 6,509 $ — Commercial paper 100 100 — 100 — The Company had no material assets or liabilities that were measured at fair value on a non-recurring basis during the nine months ended September 30, 2023 or the year ended December 31, 2022.

Allowance for Expected Credit L

Allowance for Expected Credit Losses	9 Months Ended
Allowance for Expected Credit Losses	Sep. 30, 2023
Credit Loss [Abstract]
Allowance for Expected Credit Losses	ALLOWANCE FOR EXPECTED CREDIT LOSSES Premiums Receivable The following tables present the balances of premiums receivable, net of the allowance for expected credit losses, at September 30, 2023 and 2022, and the changes in the allowance for expected credit losses for the three and nine months ended September 30, 2023 and 2022. At and For the Three Months Ended September 30, 2023 At and For the Three Months Ended September 30, 2022 (in millions) Premiums Receivable, Net of Allowance for Expected Credit Losses Allowance for Expected Credit Losses Premiums Receivable, Net of Allowance for Expected Credit Losses Allowance for Expected Credit Losses Balance, beginning of period $ 10,327 $ 72 $ 9,132 $ 89 Current period change for expected credit losses 11 14 Write-offs of uncollectible premiums receivable 15 17 Balance, end of period $ 10,345 $ 68 $ 8,886 $ 86 At and For the Nine Months Ended September 30, 2023 At and For the Nine Months Ended September 30, 2022 (in millions) Premiums Receivable, Net of Allowance for Expected Credit Losses Allowance for Expected Credit Losses Premiums Receivable, Net of Allowance for Expected Credit Losses Allowance for Expected Credit Losses Balance, beginning of period $ 8,922 $ 77 $ 8,085 $ 107 Current period change for expected credit losses 28 49 Write-offs of uncollectible premiums receivable 37 70 Balance, end of period $ 10,345 $ 68 $ 8,886 $ 86 Reinsurance Recoverables The following tables present the balances of reinsurance recoverables, net of the allowance for estimated uncollectible reinsurance, at September 30, 2023 and 2022, and the changes in the allowance for estimated uncollectible reinsurance for the three and nine months ended September 30, 2023 and 2022. At and For the Three Months Ended September 30, 2023 At and For the Three Months Ended September 30, 2022 (in millions) Reinsurance Recoverables, Net of Allowance for Estimated Uncollectible Reinsurance Allowance for Estimated Uncollectible Reinsurance Reinsurance Recoverables, Net of Allowance for Estimated Uncollectible Reinsurance Allowance for Estimated Uncollectible Reinsurance Balance, beginning of period $ 8,121 $ 121 $ 8,509 $ 132 Current period change for estimated uncollectible reinsurance — 1 Write-offs of uncollectible reinsurance recoverables — — Balance, end of period $ 8,267 $ 121 $ 8,202 $ 133 At and For the Nine Months Ended September 30, 2023 At and For the Nine Months Ended September 30, 2022 (in millions) Reinsurance Recoverables, Net of Allowance for Estimated Uncollectible Reinsurance Allowance for Estimated Uncollectible Reinsurance Reinsurance Recoverables, Net of Allowance for Estimated Uncollectible Reinsurance Allowance for Estimated Uncollectible Reinsurance Balance, beginning of period $ 8,063 $ 132 $ 8,452 $ 141 Current period change for estimated uncollectible reinsurance (11) (8) Write-offs of uncollectible reinsurance recoverables — — Balance, end of period $ 8,267 $ 121 $ 8,202 $ 133 Of the total reinsurance recoverables at September 30, 2023, $5.86 billion, or 87%, were rated by A.M. Best Company, after deducting mandatory pools and associations and before allowances for estimated uncollectible reinsurance. The Company utilizes updated A.M. Best credit ratings on a quarterly basis when determining the allowance. Of the total rated by A.M. Best Company, 94% were rated A- or better. The remaining 13% of reinsurance recoverables comprised the following: 6% related to captive insurance companies, 1% related to the Company’s participation in voluntary pools and 6% were balances from other companies not rated by A.M. Best Company. Certain of the Company’s reinsurance recoverables are collateralized by letters of credit, funds held or trust agreements. Contractholder Receivables The following tables present the balances of contractholder receivables, net of the allowance for expected credit losses, at September 30, 2023 and 2022, and the changes in the allowance for expected credit losses for the three and nine months ended September 30, 2023 and 2022. At and For the Three Months Ended September 30, 2023 At and For the Three Months Ended September 30, 2022 (in millions) Contractholder Receivables, Net of Allowance for Expected Credit Losses Allowance for Expected Credit Losses Contractholder Receivables, Net of Allowance for Expected Credit Losses Allowance for Expected Credit Losses Balance, beginning of period $ 3,449 $ 20 $ 3,735 $ 18 Current period change for expected credit losses — — Write-offs of uncollectible contractholder receivables — — Balance, end of period $ 3,467 $ 20 $ 3,749 $ 18 At and For the Nine Months Ended September 30, 2023 At and For the Nine Months Ended September 30, 2022 (in millions) Contractholder Receivables, Net of Allowance for Expected Credit Losses Allowance for Expected Credit Losses Contractholder Receivables, Net of Allowance for Expected Credit Losses Allowance for Expected Credit Losses Balance, beginning of period $ 3,579 $ 17 $ 3,890 $ 21 Current period change for expected credit losses 3 (2) Write-offs of uncollectible contractholder receivables — 1 Balance, end of period $ 3,467 $ 20 $ 3,749 $ 18

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	9 Months Ended
Goodwill and Other Intangible Assets	Sep. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	GOODWILL AND OTHER INTANGIBLE ASSETS Goodwill The following table presents the carrying amount of the Company’s goodwill by segment. Each reportable segment includes goodwill associated with the Company’s international business which is subject to the impact of changes in foreign currency exchange rates. (in millions) September 30, December 31, Business Insurance $ 2,568 $ 2,565 Bond & Specialty Insurance 550 550 Personal Insurance 811 811 Other 26 26 Total $ 3,955 $ 3,952 Other Intangible Assets The following tables present a summary of the Company’s other intangible assets by major asset class. (at September 30, 2023, in millions) Gross Accumulated Net Subject to amortization Customer-related $ 96 $ 55 $ 41 Contract-based (1) 204 193 11 Total subject to amortization 300 248 52 Not subject to amortization 226 — 226 Total $ 526 $ 248 $ 278 (at December 31, 2022, in millions) Gross Accumulated Net Subject to amortization Customer-related $ 96 $ 48 $ 48 Contract-based (1) 204 191 13 Total subject to amortization 300 239 61 Not subject to amortization 226 — 226 Total $ 526 $ 239 $ 287 _________________________________________________________ (1) Contract-based intangible assets subject to amortization are comprised of fair value adjustments on claims and claim adjustment expense reserves, reinsurance recoverables and other contract-related intangible assets. Fair value adjustments recorded in connection with insurance acquisitions were based on management’s estimate of nominal claims and claim adjustment expense reserves and reinsurance recoverables. The method used calculated a risk adjustment to a risk-free discounted reserve that would, if reserves ran off as expected, produce results that yielded the assumed cost-of-capital on the capital supporting the loss reserves. The fair value adjustments are reported as other intangible assets on the consolidated balance sheet, and the amounts measured in accordance with the acquirer’s accounting policies for insurance contracts have been reported as part of the claims and claim adjustment expense reserves and reinsurance recoverables. The intangible assets are being recognized into income over the expected payment pattern. Because the time value of money and the risk adjustment (cost of capital) components of the intangible assets run off at different rates, the amount recognized in income may be a net benefit in some periods and a net expense in other periods.

Insurance Claim Reserves

Insurance Claim Reserves	9 Months Ended
Insurance Claim Reserves	Sep. 30, 2023
Insurance Loss Reserves [Abstract]
Insurance Claim Reserves	INSURANCE CLAIM RESERVES Claims and claim adjustment expense reserves were as follows: (in millions) September 30, December 31, Property-casualty $ 61,703 $ 58,643 Accident and health 6 6 Total $ 61,709 $ 58,649 The following table presents a reconciliation of beginning and ending property casualty reserve balances for claims and claim adjustment expenses: Nine Months Ended September 30, (in millions) 2023 2022 Claims and claim adjustment expense reserves at beginning of year $ 58,643 $ 56,897 Less reinsurance recoverables on unpaid losses 7,790 8,209 Net reserves at beginning of year 50,853 48,688 Estimated claims and claim adjustment expenses for claims arising in the current year 20,205 17,257 Estimated increase (decrease) in claims and claim adjustment expenses for claims arising in prior years 62 (383) Total increases 20,267 16,874 Claims and claim adjustment expense payments for claims arising in: Current year 7,305 6,302 Prior years 10,031 8,638 Total payments 17,336 14,940 Unrealized foreign exchange gain (1) (391) Net reserves at end of period 53,783 50,231 Plus reinsurance recoverables on unpaid losses 7,920 7,900 Claims and claim adjustment expense reserves at end of period $ 61,703 $ 58,131 Gross claims and claim adjustment expense reserves at September 30, 2023 increased by $3.06 billion over December 31, 2022, primarily reflecting the impacts of (i) catastrophe losses in the first nine months of 2023, (ii) higher volumes of insured exposures and (iii) loss cost trends for the current accident year, partially offset by (iv) claim payments made during the first nine months of 2023 and (v) net favorable prior year reserve development. Reinsurance recoverables on unpaid losses at September 30, 2023 increased by $130 million over December 31, 2022. Prior Year Reserve Development The following disclosures regarding reserve development are on a “net of reinsurance” basis. For the nine months ended September 30, 2023 and 2022, estimated claims and claim adjustment expenses incurred included $(62) million and $383 million, respectively, of net favorable (unfavorable) development for claims arising in prior years, including $11 million and $464 million, respectively, of net favorable prior year reserve development, and $34 million and $35 million, respectively, of accretion of discount in each period that impacted the Company’s results of operations. Business Insurance. Net unfavorable prior year reserve development in the third quarter of 2023 totaled $263 million, primarily driven by (i) an addition to asbestos reserves of $284 million and higher than expected loss experience in the domestic operations’, (ii) general liability product line (excluding asbestos), including additions to reserves attributable to childhood sexual molestation and environmental claims in the Company’s run-off operations and (iii) commercial automobile product line for recent accident years, partially offset by (iv) better than expected loss experience in the workers’ compensation product line for multiple accident years. Net unfavorable prior year reserve development in the third quarter of 2022 totaled $61 million, primarily driven by an addition to asbestos reserves of $212 million, partially offset by better than expected loss experience in the domestic operations’ workers’ compensation product line for multiple accident years and in the commercial property product line for recent accident years. Net unfavorable prior year reserve development in the first nine months of 2023 totaled $345 million, primarily driven by (i) higher than expected loss experience in the domestic operations’ general liability product line (excluding asbestos) for multiple accident years, including additions to reserves attributable to childhood sexual molestation and environmental claims in the Company’s run-off operations, (ii) an addition to asbestos reserves of $284 million and (iii) higher than expected loss experience in the domestic operations’ commercial automobile product line for recent accident years, partially offset by (iv) better than expected loss experience in the domestic operations’ workers’ compensation product line for multiple accident years. Net favorable prior year reserve development in the first nine months of 2022 totaled $254 million, primarily driven by better than expected loss experience in the domestic operations’ (i) workers’ compensation product line for multiple accident years and (ii) commercial multi-peril and commercial property product lines for recent accident years, partially offset by (iii) an addition to asbestos reserves of $212 million and (iv) an addition to reserves in the domestic operations’ general liability product line (excluding asbestos and environmental) including for run-off operations. The first nine months of 2022 also included an increase to environmental reserves. Bond & Specialty Insurance. Net favorable prior year reserve development in the third quarter and first nine months of 2023 totaled $72 million and $249 million, respectively, primarily driven by better than expected loss experience in the domestic operations’ fidelity and surety product lines and in the general liability product line for management liability coverages for recent accident years. Net favorable prior year reserve development in the third quarter of 2022 totaled $63 million, primarily driven by better than expected loss experience in the domestic operations’ fidelity and surety product lines and in the general liability product line for management liability coverages for recent accident years. Net favorable prior year reserve development in the first nine months of 2022 totaled $171 million, primarily driven by better than expected loss experience in the domestic operations’ fidelity and surety product lines for recent accident years. Personal Insurance. Net favorable prior year reserve development in the third quarter and first nine months of 2023 totaled $37 million and $107 million, respectively, primarily driven by better than expected loss experience in the domestic operations’ homeowners and other product line for recent accident years. Net favorable prior year reserve development in the third quarter and first nine months of 2022 totaled $18 million and $39 million, respectively.

Other Comprehensive Income (Los

Other Comprehensive Income (Loss) and Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2023
Other Comprehensive Income And Accumulated Other Comprehensive Income Disclosure [Abstract]
Other Comprehensive Income (Loss) and Accumulated Other Comprehensive Income (Loss)	OTHER COMPREHENSIVE INCOME (LOSS) AND ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) The following tables present the changes in the Company’s accumulated other comprehensive income (loss) (AOCI) for the three and nine months ended September 30, 2023. Changes in Net Unrealized Gains (Losses) on Investment Securities (in millions) Having No Credit Losses Recognized in the Consolidated Statement of Income Having Credit Net Benefit Plan Assets and Obligations Recognized in Shareholders’ Equity Net Unrealized Foreign Currency Translation Total Accumulated Other Comprehensive Income (Loss) Balance, June 30, 2023 $ (4,755) $ 179 $ (548) $ (885) $ (6,009) Other comprehensive income (loss) (OCI) before reclassifications, net of tax (1,918) — 1 (111) (2,028) Amounts reclassified from AOCI, net of tax 28 — (3) — 25 Net OCI, current period (1,890) — (2) (111) (2,003) Balance, September 30, 2023 $ (6,645) $ 179 $ (550) $ (996) $ (8,012) Changes in Net Unrealized Gains (Losses) on Investment Securities (in millions) Having No Credit Having Credit Net Benefit Plan Assets and Net Unrealized Total Accumulated Balance, December 31, 2022 $ (5,077) $ 179 $ (542) $ (1,005) $ (6,445) Other comprehensive income (loss) (OCI) before reclassifications, net of tax (1,622) — — 9 (1,613) Amounts reclassified from AOCI, net of tax 54 — (8) — 46 Net OCI, current period (1,568) — (8) 9 (1,567) Balance, September 30, 2023 $ (6,645) $ 179 $ (550) $ (996) $ (8,012) The following table presents the pre-tax components of the Company’s other comprehensive loss and the related income tax expense (benefit). Three Months Ended Nine Months Ended (in millions) 2023 2022 2023 2022 Changes in net unrealized gains (losses) on investment securities: Having no credit losses recognized in the consolidated statement of income $ (2,391) $ (3,204) $ (1,986) $ (11,078) Income tax benefit (501) (678) (418) (2,348) Net of taxes (1,890) (2,526) (1,568) (8,730) Having credit losses recognized in the consolidated statement of income — — — (3) Income tax benefit — (1) — (1) Net of taxes — 1 — (2) Net changes in benefit plan assets and obligations (3) 12 (10) 34 Income tax expense (benefit) (1) 3 (2) 7 Net of taxes (2) 9 (8) 27 Net changes in unrealized foreign currency translation (118) (251) 13 (423) Income tax expense (benefit) (7) (14) 4 (27) Net of taxes (111) (237) 9 (396) Total other comprehensive loss (2,512) (3,443) (1,983) (11,470) Total income tax benefit (509) (690) (416) (2,369) Total other comprehensive loss, net of taxes $ (2,003) $ (2,753) $ (1,567) $ (9,101) The following table presents the pre-tax and related income tax (expense) benefit components of the amounts reclassified from the Company’s AOCI to the Company’s consolidated statement of income. Three Months Ended Nine Months Ended (in millions) 2023 2022 2023 2022 Reclassification adjustments related to unrealized gains (losses) on investment securities: Having no credit losses recognized in the consolidated statement of income (1) $ 35 $ 42 $ 68 $ 61 Income tax benefit (2) 7 9 14 13 Net of taxes 28 33 54 48 Having credit losses recognized in the consolidated statement of income (1) — — — — Income tax benefit (2) — — — — Net of taxes — — — — Reclassification adjustment related to benefit plan assets and obligations: Claims and claim adjustment expenses (benefit) (3) (2) 5 (4) 13 General and administrative expenses (benefit) (3) (2) 5 (6) 18 Total (4) 10 (10) 31 Income tax (expense) benefit (2) (1) 1 (2) 6 Net of taxes (3) 9 (8) 25 Reclassification adjustment related to foreign currency translation (1) — — — — Income tax benefit (2) — — — — Net of taxes — — — — Total reclassifications 31 52 58 92 Total income tax benefit 6 10 12 19 Total reclassifications, net of taxes $ 25 $ 42 $ 46 $ 73 _________________________________________________________ (1) (Increases) decreases net realized investment losses on the consolidated statement of income. (2) (Increases) decreases income tax expense (benefit) on the consolidated statement of income. (3) Increases (decreases) expenses on the consolidated statement of income.

Debt

Debt	9 Months Ended
Debt	Sep. 30, 2023
Debt Disclosure [Abstract]
Debt	DEBT Debt Issuance . On May 25, 2023, the Company issued $750 million aggregate principal amount of 5.45% senior notes that will mature on May 25, 2053. The net proceeds of the issuance, after the deduction of the underwriting discount and expenses payable by the Company, totaled approximately $738 million. Interest on the senior notes is payable semi-annually in arrears on May 25 and November 25. Prior to November 25, 2052, the senior notes may be redeemed, in whole or in part, at the Company’s option, at any time or from time to time, at a redemption price equal to the greater of (a) 100% of the principal amount of any senior notes to be redeemed or (b) the sum of the present values of the remaining scheduled payments of principal and interest to but excluding November 25, 2052 on any senior notes to be redeemed (exclusive of interest accrued to the date of redemption) discounted to the date of redemption on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the then current Treasury Rate (as defined in the senior notes), plus 25 basis points. On or after November 25, 2052, the senior notes may be redeemed, in whole or in part, at the Company’s option, at any time or from time to time, at a redemption price equal to 100% of the principal amount of any senior notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date.

Common Share Repurchases

Common Share Repurchases	9 Months Ended
Common Share Repurchases	Sep. 30, 2023
Treasury Stock Transactions, Excluding Value of Shares Reissued [Abstract]
Common Share Repurchases	COMMON SHARE REPURCHASES During the three and nine months ended September 30, 2023, the Company repurchased 0.6 million and 5.0 million common shares, respectively, under its share repurchase authorizations for total cost of $100 million and $900 million, respectively. The average cost per share repurchased was $164.46 and $179.59, respectively. In addition, the Company acquired 5,480 shares and 0.3 million common shares for a total cost of approximately $926,000 and $63 million during the three and nine months ended September 30, 2023, respectively, that were not part of its publicly announced share repurchase authorizations. These shares consisted of shares retained to cover payroll withholding taxes in connection with the vesting of restricted stock unit awards and performance share awards, and shares used by employees to cover the price of certain stock options that were exercised. On April 19, 2023, the Board of Directors approved a share repurchase authorization that added $5.0 billion of repurchase capacity. At September 30, 2023, the Company had $6.10 billion of capacity remaining under its share repurchase authorizations. Included in the cost of treasury stock acquired pursuant to common share repurchases is the 1% excise tax imposed as part of the Inflation Reduction Act.

Earnings per Share

Earnings per Share	9 Months Ended
Earnings per Share	Sep. 30, 2023
Earnings Per Share Reconciliation [Abstract]
Earnings per Share	EARNINGS PER SHARE The following is a reconciliation of the income and share data used in the basic and diluted earnings per share computations for the periods presented: Three Months Ended Nine Months Ended (in millions, except per share amounts) 2023 2022 2023 2022 Basic and Diluted Net income, as reported $ 404 $ 454 $ 1,365 $ 2,023 Participating share-based awards — allocated income (3) (4) (10) (15) Net income available to common shareholders — basic and diluted $ 401 $ 450 $ 1,355 $ 2,008 Common Shares Basic Weighted average shares outstanding 228.8 235.4 230.0 238.3 Diluted Weighted average shares outstanding 228.8 235.4 230.0 238.3 Weighted average effects of dilutive securities — stock options and performance shares 2.3 2.5 2.5 2.6 Total 231.1 237.9 232.5 240.9 Net Income per Common Share Basic $ 1.75 $ 1.91 $ 5.89 $ 8.43 Diluted $ 1.74 $ 1.89 $ 5.83 $ 8.34

Share-Based Incentive Compensat

Share-Based Incentive Compensation	9 Months Ended
Share-Based Incentive Compensation	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Share-Based Incentive Compensation	SHARE-BASED INCENTIVE COMPENSATION The following information relates to fully vested stock option awards at September 30, 2023: Stock Options Number Weighted Weighted Aggregate Vested at end of period (1) 7,420,703 $ 137.92 5.7 years $ 209 Exercisable at end of period 5,344,583 $ 128.37 4.7 years $ 187 _________________________________________________________ (1) Represents awards for which the requisite service has been rendered, including those that are retirement eligible. The total compensation cost for all share-based incentive compensation awards recognized in earnings was $46 million and $41 million for the three months ended September 30, 2023 and 2022, respectively, and $162 million and $141 million for the nine months ended September 30, 2023 and 2022, respectively. The related tax benefits recognized in the consolidated statement of income were $8 million and $7 million for the three months ended September 30, 2023 and 2022, respectively, and $27 million and $24 million for the nine months ended September 30, 2023 and 2022, respectively. The total unrecognized compensation cost related to all nonvested share-based incentive compensation awards at September 30, 2023 was $237 million, which is expected to be recognized over a weighted-average period of 1.8 years.

Pension Plans, Retirement Benef

Pension Plans, Retirement Benefits and Savings Plans	9 Months Ended
Pension Plans, Retirement Benefits and Savings Plans	Sep. 30, 2023
Retirement Benefits [Abstract]
Pension Plans, Retirement Benefits and Savings Plans	PENSION PLANS, RETIREMENT BENEFITS AND SAVINGS PLANS The following table summarizes the components of net periodic benefit cost (benefit) for the Company’s pension and postretirement benefit plans recognized in the consolidated statement of income for the three months ended September 30, 2023 and 2022. Pension Plans Postretirement Benefit Plans (for the three months ended September 30, in millions) 2023 2022 2023 2022 Net Periodic Benefit Cost (Benefit): Service cost $ 27 $ 36 $ — $ — Non-service cost (benefit): Interest cost on benefit obligation 44 25 2 — Expected return on plan assets (77) (74) — — Amortization of unrecognized: Prior service benefit (1) — (1) — Net actuarial (gain) loss — 12 (3) (1) Total non-service cost (benefit) (34) (37) (2) (1) Net periodic benefit cost (benefit) $ (7) $ (1) $ (2) $ (1) The following table indicates the line items in which the respective service cost and non-service cost (benefit) are presented in the consolidated statement of income for the three months ended September 30, 2023 and 2022. Pension Plans Postretirement Benefit Plans (for the three months ended September 30, in millions) 2023 2022 2023 2022 Service Cost: Claims and claim adjustment expenses $ 11 $ 14 $ — $ — General and administrative expenses 16 22 — — Total service cost 27 36 — — Non-Service Cost (Benefit): Claims and claim adjustment expenses (14) (15) (1) — General and administrative expenses (20) (22) (1) (1) Total non-service cost (benefit) (34) (37) (2) (1) Net periodic benefit cost (benefit) $ (7) $ (1) $ (2) $ (1) The following table summarizes the components of net periodic benefit cost (benefit) for the Company’s pension and postretirement benefit plans recognized in the consolidated statement of income for the nine months ended September 30, 2023 and 2022. Pension Plans Postretirement Benefit Plans (for the nine months ended September 30, in millions) 2023 2022 2023 2022 Net Periodic Benefit Cost (Benefit): Service cost $ 81 $ 109 $ — $ — Non-service cost (benefit): Interest cost on benefit obligation 132 76 4 2 Expected return on plan assets (233) (222) — — Amortization of unrecognized: Prior service benefit (1) — (3) (2) Net actuarial (gain) loss — 37 (7) (3) Total non-service cost (benefit) (102) (109) (6) (3) Net periodic benefit cost (benefit) $ (21) $ — $ (6) $ (3) The following table indicates the line items in which the respective service cost and non-service cost (benefit) are presented in the consolidated statement of income for the nine months ended September 30, 2023 and 2022. Pension Plans Postretirement Benefit Plans (for the nine months ended September 30, in millions) 2023 2022 2023 2022 Service Cost: Claims and claim adjustment expenses $ 33 $ 44 $ — $ — General and administrative expenses 48 65 — — Total service cost 81 109 — — Non-Service Cost (Benefit): Claims and claim adjustment expenses (41) (44) (3) (1) General and administrative expenses (61) (65) (3) (2) Total non-service cost (benefit) (102) (109) (6) (3) Net periodic benefit cost (benefit) $ (21) $ — $ (6) $ (3)

Leases

Leases	9 Months Ended
Leases	Sep. 30, 2023
Leases [Abstract]
Leases	LEASES The Company enters into lease agreements for real estate that is primarily used for office space in the ordinary course of business. These leases are accounted for as operating leases, whereby lease expense is recognized on a straight-line basis over the term of the lease, and a right-of-use asset and lease liability is recognized as part of other assets and other liabilities, respectively, in the consolidated balance sheet. Most leases include an option to extend or renew the lease term. The exercise of the renewal option is at the Company’s discretion. The operating lease liability includes lease payments related to options to extend or renew the lease term if the Company is reasonably certain of exercising those options. The Company, in determining the present value of lease payments, utilizes either the rate implicit in the lease, if that rate is readily determinable, or the Company’s incremental secured borrowing rate commensurate with the term of the underlying lease. Lease expense is included in general and administrative expenses in the consolidated statement of income. Additional information regarding the Company’s real estate operating leases is as follows: Three Months Ended Nine Months Ended (in millions) 2023 2022 2023 2022 Lease cost Operating leases $ 19 $ 19 $ 57 $ 61 Short-term leases (1) 1 1 2 2 Lease expense 20 20 59 63 Less: sublease income (2) — — — — Net lease cost $ 20 $ 20 $ 59 $ 63 Other information on operating leases Cash payments to settle a lease liability reported in cash flows $ 22 $ 23 $ 65 $ 71 Right-of-use assets obtained in exchange for new lease liabilities $ 12 $ 14 $ 25 $ 21 Weighted average discount rate 2.64 % 2.33 % 2.64 % 2.33 % Weighted average remaining lease term 4.2 years 4.5 years 4.2 years 4.5 years _________________________________________________________ (1) Leases with a term of twelve months or less are not recorded on the consolidated balance sheet.

Contingencies, Commitments and

Contingencies, Commitments and Guarantees	9 Months Ended
Contingencies, Commitments and Guarantees	Sep. 30, 2023
Contingencies, Commitments and Guarantees [Abstract]
Contingencies, Commitments and Guarantees	CONTINGENCIES, COMMITMENTS AND GUARANTEES Contingencies The major pending legal proceedings, other than ordinary routine litigation incidental to the business, to which the Company or any of its subsidiaries is a party or to which any of the Company’s properties is subject are described below. Asbestos and Environmental Claims and Litigation In the ordinary course of its insurance business, the Company has received and continues to receive claims for insurance arising under policies issued by the Company asserting alleged injuries and damages from asbestos- and environmental-related exposures that are the subject of related coverage litigation. The Company is defending asbestos- and environmental-related litigation vigorously and believes that it has meritorious defenses; however, the outcomes of these disputes are uncertain. In this regard, the Company employs dedicated specialists and comprehensive resolution strategies to manage asbestos and environmental loss exposure, including settling litigation under appropriate circumstances. Currently, it is not possible to predict legal outcomes and their impact on future loss development for claims and litigation relating to asbestos and environmental claims. Any such development could be affected by future court decisions and interpretations, as well as future changes, if any, in applicable legislation. Because of these uncertainties, additional liabilities may arise for amounts in excess of the Company’s current insurance reserves. In addition, the Company’s estimate of ultimate claims and claim adjustment expenses may change. These additional liabilities or changes in estimates, or a range of either, cannot now be reasonably estimated and could result in income statement charges that could be material to the Company’s results of operations in future periods. Other Proceedings Not Arising Under Insurance Contracts or Reinsurance Agreements The Company is involved in other lawsuits, including lawsuits alleging extra-contractual damages relating to insurance contracts or reinsurance agreements, that do not arise under insurance contracts or reinsurance agreements. The legal costs associated with such lawsuits are expensed in the period in which the costs are incurred. Based upon currently available information, the Company does not believe it is reasonably possible that any such lawsuit or related lawsuits would be material to the Company’s results of operations or would have a material adverse effect on the Company’s financial position or liquidity. Other Commitments and Guarantees Commitments Investment Commitments — The Company has unfunded commitments to private equity limited partnerships, real estate partnerships and others. These commitments totaled $1.66 billion and $1.80 billion at September 30, 2023 and December 31, 2022, respectively. Guarantees The maximum amount of the Company’s contingent obligation for indemnifications related to the sale of businesses that are quantifiable was $351 million at September 30, 2023. The maximum amount of the Company’s obligation related to the guarantee of certain insurance policy obligations of a former insurance subsidiary was $480 million at September 30, 2023, all of which is indemnified by a third party. For more information regarding the Company’s guarantees, see note 17 of the notes to the consolidated financial statements in the Company’s 2022 Annual Report.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Millions	3 Months Ended		9 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Millions	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Pay vs Performance Disclosure
Net income	$ 404	$ 454	$ 1,365	$ 2,023

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Sep. 30, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Basis of Presentation and Acc_2

Basis of Presentation and Accounting Policies (Policies)	9 Months Ended
Basis of Presentation and Accounting Policies (Policies)	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation [Policy Text Block]	Basis of Presentation The interim consolidated financial statements include the accounts of The Travelers Companies, Inc. (together with its subsidiaries, the Company). These financial statements are prepared in conformity with U.S. generally accepted accounting principles (GAAP) and are unaudited. In the opinion of the Company’s management, all adjustments necessary for a fair presentation have been reflected. Certain financial information that is normally included in annual financial statements prepared in accordance with GAAP, but that is not required for interim reporting purposes, has been omitted. All material intercompany transactions and balances have been eliminated. The accompanying interim consolidated financial statements and related notes should be read in conjunction with the Company’s consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022 (the Company’s 2022 Annual Report). The preparation of the interim consolidated financial statements in conformity with 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 interim consolidated financial statements and the reported amounts of revenues and claims and expenses during the reporting period. Actual results could differ from those estimates.
Adoption of Accounting Standards [Policy Text Block]	Adoption of Accounting Standards For information regarding accounting standards that the Company adopted during the periods presented, see note 1 of the notes to the consolidated financial statements in the Company’s 2022 Annual Report.

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
Segment Information (Tables)	Sep. 30, 2023
Segment Reporting [Abstract]
Company's revenues and income by segment [Table Text Block]	(For the three months ended September 30, in millions) Business Bond & Specialty Personal Total 2023 Premiums $ 4,956 $ 935 $ 3,827 $ 9,718 Net investment income 551 86 132 769 Fee income 102 — 10 112 Other revenues 71 6 24 101 Total segment revenues (1) $ 5,680 $ 1,027 $ 3,993 $ 10,700 Segment income (loss) (1) $ 468 $ 265 $ (193) $ 540 2022 Premiums $ 4,353 $ 877 $ 3,385 $ 8,615 Net investment income 426 65 102 593 Fee income 96 — 8 104 Other revenues 56 6 22 84 Total segment revenues (1) $ 4,931 $ 948 $ 3,517 $ 9,396 Segment income (loss) (1) $ 471 $ 242 $ (111) $ 602 ________________________________________________________ (1) Segment revenues for reportable business segments exclude net realized investment gains (losses) and revenues included in “interest expense and other.” Segment income (loss) for reportable business segments excludes the after-tax impact of net realized investment gains (losses) and income (loss) from “interest expense and other.” (For the nine months ended September 30, in millions) Business Bond & Specialty Personal Total 2023 Premiums $ 14,077 $ 2,721 $ 10,990 $ 27,788 Net investment income 1,533 237 374 2,144 Fee income 299 — 25 324 Other revenues 185 18 72 275 Total segment revenues (1) $ 16,094 $ 2,976 $ 11,461 $ 30,531 Segment income (loss) (1) $ 1,626 $ 702 $ (648) $ 1,680 2022 Premiums $ 12,642 $ 2,548 $ 9,756 $ 24,946 Net investment income 1,415 188 334 1,937 Fee income 285 — 22 307 Other revenues 194 14 61 269 Total segment revenues (1) $ 14,536 $ 2,750 $ 10,173 $ 27,459 Segment income (loss) (1) $ 1,806 $ 687 $ (79) $ 2,414 _______________________________________________________ (1) Segment revenues for reportable business segments exclude net realized investment gains (losses) and revenues included in “interest expense and other.” Segment income (loss) for reportable business segments excludes the after-tax impact of net realized investment gains (losses) and income (loss) from “interest expense and other.”
Business segment reconciliations of revenue and income, net of tax [Table Text Block]	Business Segment Reconciliations Three Months Ended Nine Months Ended (in millions) 2023 2022 2023 2022 Revenue reconciliation Earned premiums Business Insurance: Domestic: Workers’ compensation $ 876 $ 872 $ 2,584 $ 2,566 Commercial automobile 816 754 2,375 2,202 Commercial property 828 668 2,297 1,914 General liability 804 728 2,312 2,116 Commercial multi-peril 1,211 1,057 3,456 3,034 Other 21 19 55 52 Total Domestic 4,556 4,098 13,079 11,884 International 400 255 998 758 Total Business Insurance 4,956 4,353 14,077 12,642 Bond & Specialty Insurance: Domestic: Fidelity and surety 333 307 964 876 General liability 414 396 1,218 1,154 Other 57 57 168 166 Total Domestic 804 760 2,350 2,196 International 131 117 371 352 Total Bond & Specialty Insurance 935 877 2,721 2,548 Personal Insurance: Domestic: Automobile 1,772 1,575 5,084 4,544 Homeowners and Other 1,896 1,648 5,434 4,714 Total Domestic 3,668 3,223 10,518 9,258 International 159 162 472 498 Total Personal Insurance 3,827 3,385 10,990 9,756 Total earned premiums 9,718 8,615 27,788 24,946 Net investment income 769 593 2,144 1,937 Fee income 112 104 324 307 Other revenues 101 84 275 269 Total segment revenues 10,700 9,396 30,531 27,459 Net realized investment losses (65) (93) (94) (211) Total revenues $ 10,635 $ 9,303 $ 30,437 $ 27,248 Income reconciliation, net of tax Total segment income $ 540 $ 602 $ 1,680 $ 2,414 Interest Expense and Other (1) (86) (76) (241) (226) Core income 454 526 1,439 2,188 Net realized investment losses (50) (72) (74) (165) Net income $ 404 $ 454 $ 1,365 $ 2,023 _________________________________________________________ (1) The primary component of Interest Expense and Other was after-tax interest expense of $78 million and $70 million for the three months ended September 30, 2023 and 2022, respectively, and $220 million and $208 million for the nine months ended September 30, 2023 and 2022, respectively.
Asset reconciliation [Table Text Block]	(in millions) September 30, December 31, Asset reconciliation Business Insurance $ 89,980 $ 86,522 Bond & Specialty Insurance 11,088 10,119 Personal Insurance 19,454 18,275 Total assets by reportable segment 120,522 114,916 Other assets (1) 862 801 Total consolidated assets $ 121,384 $ 115,717 _________________________________________________________ (1) The primary components of other assets at both September 30, 2023 and December 31, 2022 were the over-funded benefit plan assets related to the Company’s qualified domestic pension plan and other intangible assets.

Investments (Tables)

Investments (Tables)	9 Months Ended
Investments (Tables)	Sep. 30, 2023
Investments [Abstract]
Amortized cost and fair value of investments in fixed maturities [Table Text Block]	The amortized cost and fair value of investments in fixed maturities classified as available for sale were as follows: Amortized Cost Allowance for Expected Credit Losses Gross Unrealized Fair Value (at September 30, 2023, in millions) Gains Losses U.S. Treasury securities and obligations of U.S. government and government agencies and authorities $ 6,575 $ — $ — $ 363 $ 6,212 Obligations of U.S. states, municipalities and political subdivisions: Local general obligation 18,358 — 1 2,675 15,684 Revenue 9,750 — 2 1,275 8,477 State general obligation 1,174 — — 137 1,037 Pre-refunded 1,048 — 1 9 1,040 Total obligations of U.S. states, municipalities and political subdivisions 30,330 — 4 4,096 26,238 Debt securities issued by foreign governments 1,037 — 1 56 982 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 6,927 — 7 411 6,523 Corporate and all other bonds 35,923 4 16 3,306 32,629 Total $ 80,792 $ 4 $ 28 $ 8,232 $ 72,584 Amortized Cost Allowance for Expected Credit Losses Gross Unrealized Fair Value (at December 31, 2022, in millions) Gains Losses U.S. Treasury securities and obligations of U.S. government and government agencies and authorities $ 5,798 $ — $ 3 $ 363 $ 5,438 Obligations of U.S. states, municipalities and political subdivisions: Local general obligation 19,615 — 33 1,825 17,823 Revenue 11,076 — 29 907 10,198 State general obligation 1,104 — 3 88 1,019 Pre-refunded 2,323 — 17 1 2,339 Total obligations of U.S. states, municipalities and political subdivisions 34,118 — 82 2,821 31,379 Debt securities issued by foreign governments 1,049 — — 55 994 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 2,178 — 13 200 1,991 Corporate and all other bonds 34,237 3 37 2,913 31,358 Total $ 77,380 $ 3 $ 135 $ 6,352 $ 71,160
Cost and fair value of investments in equity securities [Table Text Block]	The cost and fair value of investments in equity securities were as follows: (at September 30, 2023, in millions) Cost Gross Gains Gross Losses Fair Value Common stock $ 502 $ 65 $ 40 $ 527 Non-redeemable preferred stock 44 2 — 46 Total $ 546 $ 67 $ 40 $ 573 (at December 31, 2022, in millions) Cost Gross Gains Gross Losses Fair Value Common stock $ 706 $ 89 $ 32 $ 763 Non-redeemable preferred stock 41 3 — 44 Total $ 747 $ 92 $ 32 $ 807
Unrealized investment losses [Table Text Block]	The following tables summarize, for all fixed maturities classified as available for sale in an unrealized loss position at September 30, 2023 and December 31, 2022, the aggregate fair value and gross unrealized loss by the length of time those securities have been continuously in an unrealized loss position. The fair value amounts reported in the tables are estimates that are prepared using the process described in note 4 herein and in note 4 of the notes to the consolidated financial statements in the Company’s 2022 Annual Report. The Company also relies upon estimates of several factors in its review and evaluation of individual investments, using the process described in note 1 of the notes to the consolidated financial statements in the Company’s 2022 Annual Report to determine whether a credit loss impairment exists. Less than 12 months 12 months or longer Total (at September 30, 2023, in millions) Fair Gross Fair Gross Fair Gross Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities $ 2,979 $ 32 $ 3,083 $ 331 $ 6,062 $ 363 Obligations of U.S. states, municipalities and political subdivisions 12,050 703 13,625 3,393 25,675 4,096 Debt securities issued by foreign governments 201 6 769 50 970 56 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 5,032 162 1,373 249 6,405 411 Corporate and all other bonds 5,680 167 26,034 3,139 31,714 3,306 Total $ 25,942 $ 1,070 $ 44,884 $ 7,162 $ 70,826 $ 8,232 Less than 12 months 12 months or longer Total (at December 31, 2022, in millions) Fair Gross Fair Gross Fair Gross Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities $ 2,835 $ 100 $ 1,679 $ 263 $ 4,514 $ 363 Obligations of U.S. states, municipalities and political subdivisions 19,251 1,975 3,134 846 22,385 2,821 Debt securities issued by foreign governments 604 22 367 33 971 55 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 1,414 128 316 72 1,730 200 Corporate and all other bonds 24,080 1,635 6,096 1,278 30,176 2,913 Total $ 48,184 $ 3,860 $ 11,592 $ 2,492 $ 59,776 $ 6,352
Gross unrealized investment losses on securities continuously in an unrealized loss position of greater than 20% of amortized cost by length of time [Table Text Block]	The following tables summarize, for all fixed maturities reported at fair value for which fair value was less than 80% of amortized cost at September 30, 2023 and December 31, 2022, the gross unrealized investment loss by length of time those securities have continuously been in an unrealized loss position of greater than 20% of amortized cost: Period For Which Fair Value is Less Than 80% of Amortized Cost (at September 30, 2023, in millions) 3 months or less Greater than 3 months, 6 months or less Greater than 6 months, 12 months or less Greater than 12 months Total Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities $ 17 $ — $ — $ — $ 17 Obligations of U.S. states, municipalities and political subdivisions 948 167 140 1,024 2,279 Debt securities issued by foreign governments — 1 — — 1 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 46 54 — — 100 Corporate and all other bonds 822 246 45 66 1,179 Total $ 1,833 $ 468 $ 185 $ 1,090 $ 3,576 Period For Which Fair Value is Less Than 80% of Amortized Cost (at December 31, 2022, in millions) 3 months or less Greater than 3 months, 6 months or less Greater than 6 months, 12 months or less Greater than 12 months Total Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities $ — $ — $ — $ — $ — Obligations of U.S. states, municipalities and political subdivisions 81 776 643 — 1,500 Debt securities issued by foreign governments 1 — — — 1 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 4 48 — — 52 Corporate and all other bonds 89 526 8 — 623 Total $ 175 $ 1,350 $ 651 $ — $ 2,176
Changes in the allowance for expected credit losses on fixed maturities classified as available for sale [Table Text Block]	The following tables present changes in the allowance for expected credit losses on fixed maturities classified as available for sale for the category of Corporate and All Other Bonds (no other categories of fixed maturities currently have an allowance for expected credit losses): Fixed Maturities Corporate and All Other Bonds At and For the Three Months Ended (in millions) September 30, 2023 September 30, 2022 Balance, beginning of period $ 4 $ 4 Additions for expected credit losses on securities where no credit losses were previously recognized — — Additions for expected credit losses on securities where credit losses were previously recognized — — Reductions due to sales/defaults of credit-impaired securities — (1) Reductions for impairments of securities which the Company intends to sell or more likely than not will be required to sell — — Balance, end of period $ 4 $ 3 Fixed Maturities Corporate and All Other Bonds At and For the Nine Months Ended (in millions) September 30, 2023 September 30, 2022 Balance, beginning of period $ 3 $ 3 Additions for expected credit losses on securities where no credit losses were previously recognized — — Additions for expected credit losses on securities where credit losses were previously recognized 1 1 Reductions due to sales/defaults of credit-impaired securities — (1) Reductions for impairments of securities which the Company intends to sell or more likely than not will be required to sell — — Balance, end of period $ 4 $ 3

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
Fair Value Measurements (Tables)	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured on a recurring basis [Table Text Block]	The following tables present the level within the fair value hierarchy at which the Company’s financial assets and financial liabilities are measured on a recurring basis. (at September 30, 2023, in millions) Total Level 1 Level 2 Level 3 Invested assets: Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities $ 6,212 $ 6,212 $ — $ — Obligations of U.S. states, municipalities and political subdivisions 26,238 — 26,238 — Debt securities issued by foreign governments 982 — 982 — Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 6,523 — 6,523 — Corporate and all other bonds 32,629 — 32,377 252 Total fixed maturities 72,584 6,212 66,120 252 Equity securities Common stock 527 520 — 7 Non-redeemable preferred stock 46 14 3 29 Total equity securities 573 534 3 36 Other investments 16 16 — — Total $ 73,173 $ 6,762 $ 66,123 $ 288 (at December 31, 2022, in millions) Total Level 1 Level 2 Level 3 Invested assets: Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities $ 5,438 $ 5,438 $ — $ — Obligations of U.S. states, municipalities and political subdivisions 31,379 — 31,379 — Debt securities issued by foreign governments 994 — 994 — Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 1,991 — 1,991 — Corporate and all other bonds 31,358 — 31,055 303 Total fixed maturities 71,160 5,438 65,419 303 Equity securities Common stock 763 418 — 345 Non-redeemable preferred stock 44 15 3 26 Total equity securities 807 433 3 371 Other investments 16 15 — 1 Total $ 71,983 $ 5,886 $ 65,422 $ 675 Other liabilities $ 2 $ — $ — $ 2
Carrying value and fair value of the Company's financial assets and financial liabilities disclosed, but not carried, at fair value, and the level within the fair value hierarchy at which such assets and liabilities are categorized [Table Text Block]	The following tables present the carrying value and fair value of the Company’s financial assets and financial liabilities disclosed, but not carried, at fair value, and the level within the fair value hierarchy at which such assets and liabilities are categorized. (at September 30, 2023, in millions) Carrying Fair Level 1 Level 2 Level 3 Financial assets Short-term securities $ 4,488 $ 4,488 $ 971 $ 3,466 $ 51 Financial liabilities Debt $ 7,931 $ 6,900 $ — $ 6,900 $ — Commercial paper 100 100 — 100 — (at December 31, 2022, in millions) Carrying Fair Level 1 Level 2 Level 3 Financial assets Short-term securities $ 3,470 $ 3,470 $ 871 $ 2,546 $ 53 Financial liabilities Debt $ 7,192 $ 6,509 $ — $ 6,509 $ — Commercial paper 100 100 — 100 —

Allowance for Expected Credit_2

Allowance for Expected Credit Losses (Tables)	9 Months Ended
Allowance for Expected Credit Losses (Tables)	Sep. 30, 2023
Credit Loss [Abstract]
Changes in the allowance for expected credit losses on premiums receivable [Table Text Block]	The following tables present the balances of premiums receivable, net of the allowance for expected credit losses, at September 30, 2023 and 2022, and the changes in the allowance for expected credit losses for the three and nine months ended September 30, 2023 and 2022. At and For the Three Months Ended September 30, 2023 At and For the Three Months Ended September 30, 2022 (in millions) Premiums Receivable, Net of Allowance for Expected Credit Losses Allowance for Expected Credit Losses Premiums Receivable, Net of Allowance for Expected Credit Losses Allowance for Expected Credit Losses Balance, beginning of period $ 10,327 $ 72 $ 9,132 $ 89 Current period change for expected credit losses 11 14 Write-offs of uncollectible premiums receivable 15 17 Balance, end of period $ 10,345 $ 68 $ 8,886 $ 86 At and For the Nine Months Ended September 30, 2023 At and For the Nine Months Ended September 30, 2022 (in millions) Premiums Receivable, Net of Allowance for Expected Credit Losses Allowance for Expected Credit Losses Premiums Receivable, Net of Allowance for Expected Credit Losses Allowance for Expected Credit Losses Balance, beginning of period $ 8,922 $ 77 $ 8,085 $ 107 Current period change for expected credit losses 28 49 Write-offs of uncollectible premiums receivable 37 70 Balance, end of period $ 10,345 $ 68 $ 8,886 $ 86
Changes in the allowance for estimated uncollectible reinsurance [Table Text Block]	The following tables present the balances of reinsurance recoverables, net of the allowance for estimated uncollectible reinsurance, at September 30, 2023 and 2022, and the changes in the allowance for estimated uncollectible reinsurance for the three and nine months ended September 30, 2023 and 2022. At and For the Three Months Ended September 30, 2023 At and For the Three Months Ended September 30, 2022 (in millions) Reinsurance Recoverables, Net of Allowance for Estimated Uncollectible Reinsurance Allowance for Estimated Uncollectible Reinsurance Reinsurance Recoverables, Net of Allowance for Estimated Uncollectible Reinsurance Allowance for Estimated Uncollectible Reinsurance Balance, beginning of period $ 8,121 $ 121 $ 8,509 $ 132 Current period change for estimated uncollectible reinsurance — 1 Write-offs of uncollectible reinsurance recoverables — — Balance, end of period $ 8,267 $ 121 $ 8,202 $ 133 At and For the Nine Months Ended September 30, 2023 At and For the Nine Months Ended September 30, 2022 (in millions) Reinsurance Recoverables, Net of Allowance for Estimated Uncollectible Reinsurance Allowance for Estimated Uncollectible Reinsurance Reinsurance Recoverables, Net of Allowance for Estimated Uncollectible Reinsurance Allowance for Estimated Uncollectible Reinsurance Balance, beginning of period $ 8,063 $ 132 $ 8,452 $ 141 Current period change for estimated uncollectible reinsurance (11) (8) Write-offs of uncollectible reinsurance recoverables — — Balance, end of period $ 8,267 $ 121 $ 8,202 $ 133
Changes in the allowance for expected credit losses on contractholder receivables [Table Text Block]	The following tables present the balances of contractholder receivables, net of the allowance for expected credit losses, at September 30, 2023 and 2022, and the changes in the allowance for expected credit losses for the three and nine months ended September 30, 2023 and 2022. At and For the Three Months Ended September 30, 2023 At and For the Three Months Ended September 30, 2022 (in millions) Contractholder Receivables, Net of Allowance for Expected Credit Losses Allowance for Expected Credit Losses Contractholder Receivables, Net of Allowance for Expected Credit Losses Allowance for Expected Credit Losses Balance, beginning of period $ 3,449 $ 20 $ 3,735 $ 18 Current period change for expected credit losses — — Write-offs of uncollectible contractholder receivables — — Balance, end of period $ 3,467 $ 20 $ 3,749 $ 18 At and For the Nine Months Ended September 30, 2023 At and For the Nine Months Ended September 30, 2022 (in millions) Contractholder Receivables, Net of Allowance for Expected Credit Losses Allowance for Expected Credit Losses Contractholder Receivables, Net of Allowance for Expected Credit Losses Allowance for Expected Credit Losses Balance, beginning of period $ 3,579 $ 17 $ 3,890 $ 21 Current period change for expected credit losses 3 (2) Write-offs of uncollectible contractholder receivables — 1 Balance, end of period $ 3,467 $ 20 $ 3,749 $ 18

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	9 Months Ended
Goodwill and Other Intangible Assets (Tables)	Sep. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill by segment [Table Text Block]	The following table presents the carrying amount of the Company’s goodwill by segment. Each reportable segment includes goodwill associated with the Company’s international business which is subject to the impact of changes in foreign currency exchange rates. (in millions) September 30, December 31, Business Insurance $ 2,568 $ 2,565 Bond & Specialty Insurance 550 550 Personal Insurance 811 811 Other 26 26 Total $ 3,955 $ 3,952
Other intangible assets subject to amortization [Table Text Block]	The following tables present a summary of the Company’s other intangible assets by major asset class. (at September 30, 2023, in millions) Gross Accumulated Net Subject to amortization Customer-related $ 96 $ 55 $ 41 Contract-based (1) 204 193 11 Total subject to amortization 300 248 52 Not subject to amortization 226 — 226 Total $ 526 $ 248 $ 278 (at December 31, 2022, in millions) Gross Accumulated Net Subject to amortization Customer-related $ 96 $ 48 $ 48 Contract-based (1) 204 191 13 Total subject to amortization 300 239 61 Not subject to amortization 226 — 226 Total $ 526 $ 239 $ 287 _________________________________________________________ (1) Contract-based intangible assets subject to amortization are comprised of fair value adjustments on claims and claim adjustment expense reserves, reinsurance recoverables and other contract-related intangible assets. Fair value adjustments recorded in connection with insurance acquisitions were based on management’s estimate of nominal claims and claim adjustment expense reserves and reinsurance recoverables. The method used calculated a risk adjustment to a risk-free discounted reserve that would, if reserves ran off as expected, produce results that yielded the assumed cost-of-capital on the capital supporting the loss reserves. The fair value adjustments are reported as other intangible assets on the consolidated balance sheet, and the amounts measured in accordance with the acquirer’s accounting policies for insurance contracts have been reported as part of the claims and claim adjustment expense reserves and reinsurance recoverables. The intangible assets are being recognized into income over the expected payment pattern. Because the time value of money and the risk adjustment (cost of capital) components of the intangible assets run off at different rates, the amount recognized in income may be a net benefit in some periods and a net expense in other periods.
Other intangible assets not subject to amortization [Table Text Block]	The following tables present a summary of the Company’s other intangible assets by major asset class. (at September 30, 2023, in millions) Gross Accumulated Net Subject to amortization Customer-related $ 96 $ 55 $ 41 Contract-based (1) 204 193 11 Total subject to amortization 300 248 52 Not subject to amortization 226 — 226 Total $ 526 $ 248 $ 278 (at December 31, 2022, in millions) Gross Accumulated Net Subject to amortization Customer-related $ 96 $ 48 $ 48 Contract-based (1) 204 191 13 Total subject to amortization 300 239 61 Not subject to amortization 226 — 226 Total $ 526 $ 239 $ 287 _________________________________________________________ (1) Contract-based intangible assets subject to amortization are comprised of fair value adjustments on claims and claim adjustment expense reserves, reinsurance recoverables and other contract-related intangible assets. Fair value adjustments recorded in connection with insurance acquisitions were based on management’s estimate of nominal claims and claim adjustment expense reserves and reinsurance recoverables. The method used calculated a risk adjustment to a risk-free discounted reserve that would, if reserves ran off as expected, produce results that yielded the assumed cost-of-capital on the capital supporting the loss reserves. The fair value adjustments are reported as other intangible assets on the consolidated balance sheet, and the amounts measured in accordance with the acquirer’s accounting policies for insurance contracts have been reported as part of the claims and claim adjustment expense reserves and reinsurance recoverables. The intangible assets are being recognized into income over the expected payment pattern. Because the time value of money and the risk adjustment (cost of capital) components of the intangible assets run off at different rates, the amount recognized in income may be a net benefit in some periods and a net expense in other periods.

Insurance Claim Reserves (Table

Insurance Claim Reserves (Tables)	9 Months Ended
Insurance Claim Reserves (Tables)	Sep. 30, 2023
Insurance Loss Reserves [Abstract]
Claims and claim adjustment expense reserves [Table Text Block]	Claims and claim adjustment expense reserves were as follows: (in millions) September 30, December 31, Property-casualty $ 61,703 $ 58,643 Accident and health 6 6 Total $ 61,709 $ 58,649
Reconciliation of beginning and ending property casualty reserve balances for claims and claim adjustment expenses [Table Text Block]	The following table presents a reconciliation of beginning and ending property casualty reserve balances for claims and claim adjustment expenses: Nine Months Ended September 30, (in millions) 2023 2022 Claims and claim adjustment expense reserves at beginning of year $ 58,643 $ 56,897 Less reinsurance recoverables on unpaid losses 7,790 8,209 Net reserves at beginning of year 50,853 48,688 Estimated claims and claim adjustment expenses for claims arising in the current year 20,205 17,257 Estimated increase (decrease) in claims and claim adjustment expenses for claims arising in prior years 62 (383) Total increases 20,267 16,874 Claims and claim adjustment expense payments for claims arising in: Current year 7,305 6,302 Prior years 10,031 8,638 Total payments 17,336 14,940 Unrealized foreign exchange gain (1) (391) Net reserves at end of period 53,783 50,231 Plus reinsurance recoverables on unpaid losses 7,920 7,900 Claims and claim adjustment expense reserves at end of period $ 61,703 $ 58,131

Other Comprehensive Income (L_2

Other Comprehensive Income (Loss) and Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2023
Other Comprehensive Income And Accumulated Other Comprehensive Income Disclosure [Abstract]
Changes in accumulated other comprehensive income (loss) (AOCI) [Table Text Block]	The following tables present the changes in the Company’s accumulated other comprehensive income (loss) (AOCI) for the three and nine months ended September 30, 2023. Changes in Net Unrealized Gains (Losses) on Investment Securities (in millions) Having No Credit Losses Recognized in the Consolidated Statement of Income Having Credit Net Benefit Plan Assets and Obligations Recognized in Shareholders’ Equity Net Unrealized Foreign Currency Translation Total Accumulated Other Comprehensive Income (Loss) Balance, June 30, 2023 $ (4,755) $ 179 $ (548) $ (885) $ (6,009) Other comprehensive income (loss) (OCI) before reclassifications, net of tax (1,918) — 1 (111) (2,028) Amounts reclassified from AOCI, net of tax 28 — (3) — 25 Net OCI, current period (1,890) — (2) (111) (2,003) Balance, September 30, 2023 $ (6,645) $ 179 $ (550) $ (996) $ (8,012) Changes in Net Unrealized Gains (Losses) on Investment Securities (in millions) Having No Credit Having Credit Net Benefit Plan Assets and Net Unrealized Total Accumulated Balance, December 31, 2022 $ (5,077) $ 179 $ (542) $ (1,005) $ (6,445) Other comprehensive income (loss) (OCI) before reclassifications, net of tax (1,622) — — 9 (1,613) Amounts reclassified from AOCI, net of tax 54 — (8) — 46 Net OCI, current period (1,568) — (8) 9 (1,567) Balance, September 30, 2023 $ (6,645) $ 179 $ (550) $ (996) $ (8,012)
Pre-tax components of other comprehensive loss and the related income tax expense (benefit) for each component [Table Text Block]	The following table presents the pre-tax components of the Company’s other comprehensive loss and the related income tax expense (benefit). Three Months Ended Nine Months Ended (in millions) 2023 2022 2023 2022 Changes in net unrealized gains (losses) on investment securities: Having no credit losses recognized in the consolidated statement of income $ (2,391) $ (3,204) $ (1,986) $ (11,078) Income tax benefit (501) (678) (418) (2,348) Net of taxes (1,890) (2,526) (1,568) (8,730) Having credit losses recognized in the consolidated statement of income — — — (3) Income tax benefit — (1) — (1) Net of taxes — 1 — (2) Net changes in benefit plan assets and obligations (3) 12 (10) 34 Income tax expense (benefit) (1) 3 (2) 7 Net of taxes (2) 9 (8) 27 Net changes in unrealized foreign currency translation (118) (251) 13 (423) Income tax expense (benefit) (7) (14) 4 (27) Net of taxes (111) (237) 9 (396) Total other comprehensive loss (2,512) (3,443) (1,983) (11,470) Total income tax benefit (509) (690) (416) (2,369) Total other comprehensive loss, net of taxes $ (2,003) $ (2,753) $ (1,567) $ (9,101)
Pre-tax and related income tax (expense) benefit components of the amounts reclassified from AOCI to the consolidated statement of income [Table Text Block]	The following table presents the pre-tax and related income tax (expense) benefit components of the amounts reclassified from the Company’s AOCI to the Company’s consolidated statement of income. Three Months Ended Nine Months Ended (in millions) 2023 2022 2023 2022 Reclassification adjustments related to unrealized gains (losses) on investment securities: Having no credit losses recognized in the consolidated statement of income (1) $ 35 $ 42 $ 68 $ 61 Income tax benefit (2) 7 9 14 13 Net of taxes 28 33 54 48 Having credit losses recognized in the consolidated statement of income (1) — — — — Income tax benefit (2) — — — — Net of taxes — — — — Reclassification adjustment related to benefit plan assets and obligations: Claims and claim adjustment expenses (benefit) (3) (2) 5 (4) 13 General and administrative expenses (benefit) (3) (2) 5 (6) 18 Total (4) 10 (10) 31 Income tax (expense) benefit (2) (1) 1 (2) 6 Net of taxes (3) 9 (8) 25 Reclassification adjustment related to foreign currency translation (1) — — — — Income tax benefit (2) — — — — Net of taxes — — — — Total reclassifications 31 52 58 92 Total income tax benefit 6 10 12 19 Total reclassifications, net of taxes $ 25 $ 42 $ 46 $ 73 _________________________________________________________ (1) (Increases) decreases net realized investment losses on the consolidated statement of income. (2) (Increases) decreases income tax expense (benefit) on the consolidated statement of income. (3) Increases (decreases) expenses on the consolidated statement of income.

Earnings per Share (Table)

Earnings per Share (Table)	9 Months Ended
Earnings per Share (Table)	Sep. 30, 2023
Earnings Per Share Reconciliation [Abstract]
Earnings per share reconciliation [Table Text Block]	The following is a reconciliation of the income and share data used in the basic and diluted earnings per share computations for the periods presented: Three Months Ended Nine Months Ended (in millions, except per share amounts) 2023 2022 2023 2022 Basic and Diluted Net income, as reported $ 404 $ 454 $ 1,365 $ 2,023 Participating share-based awards — allocated income (3) (4) (10) (15) Net income available to common shareholders — basic and diluted $ 401 $ 450 $ 1,355 $ 2,008 Common Shares Basic Weighted average shares outstanding 228.8 235.4 230.0 238.3 Diluted Weighted average shares outstanding 228.8 235.4 230.0 238.3 Weighted average effects of dilutive securities — stock options and performance shares 2.3 2.5 2.5 2.6 Total 231.1 237.9 232.5 240.9 Net Income per Common Share Basic $ 1.75 $ 1.91 $ 5.89 $ 8.43 Diluted $ 1.74 $ 1.89 $ 5.83 $ 8.34

Share-Based Incentive Compens_2

Share-Based Incentive Compensation (Table)	9 Months Ended
Share-Based Incentive Compensation (Table)	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Information for fully vested stock option awards [Table Text Block]	The following information relates to fully vested stock option awards at September 30, 2023: Stock Options Number Weighted Weighted Aggregate Vested at end of period (1) 7,420,703 $ 137.92 5.7 years $ 209 Exercisable at end of period 5,344,583 $ 128.37 4.7 years $ 187 _________________________________________________________ (1) Represents awards for which the requisite service has been rendered, including those that are retirement eligible.

Pension Plans, Retirement Ben_2

Pension Plans, Retirement Benefits and Savings Plans (Tables)	9 Months Ended
	Sep. 30, 2023
Retirement Benefits [Abstract]
Summary of the components of net periodic benefit cost (benefit) for the Company's pension and postretirement benefit plans recognized in the consolidated statement of income [Table Text Block]	The following table summarizes the components of net periodic benefit cost (benefit) for the Company’s pension and postretirement benefit plans recognized in the consolidated statement of income for the three months ended September 30, 2023 and 2022. Pension Plans Postretirement Benefit Plans (for the three months ended September 30, in millions) 2023 2022 2023 2022 Net Periodic Benefit Cost (Benefit): Service cost $ 27 $ 36 $ — $ — Non-service cost (benefit): Interest cost on benefit obligation 44 25 2 — Expected return on plan assets (77) (74) — — Amortization of unrecognized: Prior service benefit (1) — (1) — Net actuarial (gain) loss — 12 (3) (1) Total non-service cost (benefit) (34) (37) (2) (1) Net periodic benefit cost (benefit) $ (7) $ (1) $ (2) $ (1) The following table summarizes the components of net periodic benefit cost (benefit) for the Company’s pension and postretirement benefit plans recognized in the consolidated statement of income for the nine months ended September 30, 2023 and 2022. Pension Plans Postretirement Benefit Plans (for the nine months ended September 30, in millions) 2023 2022 2023 2022 Net Periodic Benefit Cost (Benefit): Service cost $ 81 $ 109 $ — $ — Non-service cost (benefit): Interest cost on benefit obligation 132 76 4 2 Expected return on plan assets (233) (222) — — Amortization of unrecognized: Prior service benefit (1) — (3) (2) Net actuarial (gain) loss — 37 (7) (3) Total non-service cost (benefit) (102) (109) (6) (3) Net periodic benefit cost (benefit) $ (21) $ — $ (6) $ (3)
Consolidated statement of income line items impacted by service costs and non-service cost (benefit) [Table Text Block]	The following table indicates the line items in which the respective service cost and non-service cost (benefit) are presented in the consolidated statement of income for the three months ended September 30, 2023 and 2022. Pension Plans Postretirement Benefit Plans (for the three months ended September 30, in millions) 2023 2022 2023 2022 Service Cost: Claims and claim adjustment expenses $ 11 $ 14 $ — $ — General and administrative expenses 16 22 — — Total service cost 27 36 — — Non-Service Cost (Benefit): Claims and claim adjustment expenses (14) (15) (1) — General and administrative expenses (20) (22) (1) (1) Total non-service cost (benefit) (34) (37) (2) (1) Net periodic benefit cost (benefit) $ (7) $ (1) $ (2) $ (1) The following table indicates the line items in which the respective service cost and non-service cost (benefit) are presented in the consolidated statement of income for the nine months ended September 30, 2023 and 2022. Pension Plans Postretirement Benefit Plans (for the nine months ended September 30, in millions) 2023 2022 2023 2022 Service Cost: Claims and claim adjustment expenses $ 33 $ 44 $ — $ — General and administrative expenses 48 65 — — Total service cost 81 109 — — Non-Service Cost (Benefit): Claims and claim adjustment expenses (41) (44) (3) (1) General and administrative expenses (61) (65) (3) (2) Total non-service cost (benefit) (102) (109) (6) (3) Net periodic benefit cost (benefit) $ (21) $ — $ (6) $ (3)

Leases (Table)

Leases (Table)	9 Months Ended
Leases (Table)	Sep. 30, 2023
Leases [Abstract]
Additional information regarding real estate operating leases [Table Text Block]	Lease expense is included in general and administrative expenses in the consolidated statement of income. Additional information regarding the Company’s real estate operating leases is as follows: Three Months Ended Nine Months Ended (in millions) 2023 2022 2023 2022 Lease cost Operating leases $ 19 $ 19 $ 57 $ 61 Short-term leases (1) 1 1 2 2 Lease expense 20 20 59 63 Less: sublease income (2) — — — — Net lease cost $ 20 $ 20 $ 59 $ 63 Other information on operating leases Cash payments to settle a lease liability reported in cash flows $ 22 $ 23 $ 65 $ 71 Right-of-use assets obtained in exchange for new lease liabilities $ 12 $ 14 $ 25 $ 21 Weighted average discount rate 2.64 % 2.33 % 2.64 % 2.33 % Weighted average remaining lease term 4.2 years 4.5 years 4.2 years 4.5 years _________________________________________________________ (1) Leases with a term of twelve months or less are not recorded on the consolidated balance sheet.

Basis of Presentation and Acc_3

Basis of Presentation and Accounting Policies (Details) $ in Millions	3 Months Ended
	Mar. 31, 2023 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Tax benefit due to the expiration of the statute of limitations with respect to a tax item impacted by the repeal of Internal Revenue Code Section 847, which related to the discounting of property-casualty loss reserves	$ 211

Segment Information (Details)

Segment Information (Details) $ in Millions	3 Months Ended		9 Months Ended
Segment Information (Details) $ in Millions	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) segment	Sep. 30, 2022 USD ($)
Segment reporting information
Number of reportable business segments \| segment			3
Premiums	$ 9,718	$ 8,615	$ 27,788	$ 24,946
Net investment income	769	593	2,144	1,937
Fee income	112	104	324	307
Other revenues	101	84	275	269
Net realized investment losses	(65)	(93)	(94)	(211)
Total revenues	10,635	9,303	30,437	27,248
Core income (loss)	454	526	1,439	2,188
Net realized investment losses, net of tax	(50)	(72)	(74)	(165)
Net income	404	454	1,365	2,023
Reportable Segments [Member]
Segment reporting information
Premiums	9,718	8,615	27,788	24,946
Net investment income	769	593	2,144	1,937
Fee income	112	104	324	307
Other revenues	101	84	275	269
Total segment revenues	10,700	9,396	30,531	27,459
Core income (loss)	540	602	1,680	2,414
Reportable Segments [Member] \| Business Insurance [Member]
Segment reporting information
Premiums	4,956	4,353	14,077	12,642
Net investment income	551	426	1,533	1,415
Fee income	102	96	299	285
Other revenues	71	56	185	194
Total segment revenues	5,680	4,931	16,094	14,536
Core income (loss)	468	471	1,626	1,806
Reportable Segments [Member] \| Business Insurance [Member] \| Domestic [Member]
Segment reporting information
Premiums	4,556	4,098	13,079	11,884
Reportable Segments [Member] \| Business Insurance [Member] \| Domestic [Member] \| Workers' compensation [Member]
Segment reporting information
Premiums	876	872	2,584	2,566
Reportable Segments [Member] \| Business Insurance [Member] \| Domestic [Member] \| Automobile [Member]
Segment reporting information
Premiums	816	754	2,375	2,202
Reportable Segments [Member] \| Business Insurance [Member] \| Domestic [Member] \| Commercial property [Member]
Segment reporting information
Premiums	828	668	2,297	1,914
Reportable Segments [Member] \| Business Insurance [Member] \| Domestic [Member] \| General liability [Member]
Segment reporting information
Premiums	804	728	2,312	2,116
Reportable Segments [Member] \| Business Insurance [Member] \| Domestic [Member] \| Commercial multi-peril [Member]
Segment reporting information
Premiums	1,211	1,057	3,456	3,034
Reportable Segments [Member] \| Business Insurance [Member] \| Domestic [Member] \| Other [Member]
Segment reporting information
Premiums	21	19	55	52
Reportable Segments [Member] \| Business Insurance [Member] \| International [Member]
Segment reporting information
Premiums	400	255	998	758
Reportable Segments [Member] \| Bond & Specialty Insurance [Member]
Segment reporting information
Premiums	935	877	2,721	2,548
Net investment income	86	65	237	188
Fee income	0	0	0	0
Other revenues	6	6	18	14
Total segment revenues	1,027	948	2,976	2,750
Core income (loss)	265	242	702	687
Reportable Segments [Member] \| Bond & Specialty Insurance [Member] \| Domestic [Member]
Segment reporting information
Premiums	804	760	2,350	2,196
Reportable Segments [Member] \| Bond & Specialty Insurance [Member] \| Domestic [Member] \| General liability [Member]
Segment reporting information
Premiums	414	396	1,218	1,154
Reportable Segments [Member] \| Bond & Specialty Insurance [Member] \| Domestic [Member] \| Fidelity and surety [Member]
Segment reporting information
Premiums	333	307	964	876
Reportable Segments [Member] \| Bond & Specialty Insurance [Member] \| Domestic [Member] \| Other [Member]
Segment reporting information
Premiums	57	57	168	166
Reportable Segments [Member] \| Bond & Specialty Insurance [Member] \| International [Member]
Segment reporting information
Premiums	131	117	371	352
Reportable Segments [Member] \| Personal Insurance [Member]
Segment reporting information
Premiums	3,827	3,385	10,990	9,756
Net investment income	132	102	374	334
Fee income	10	8	25	22
Other revenues	24	22	72	61
Total segment revenues	3,993	3,517	11,461	10,173
Core income (loss)	(193)	(111)	(648)	(79)
Reportable Segments [Member] \| Personal Insurance [Member] \| Domestic [Member]
Segment reporting information
Premiums	3,668	3,223	10,518	9,258
Reportable Segments [Member] \| Personal Insurance [Member] \| Domestic [Member] \| Automobile [Member]
Segment reporting information
Premiums	1,772	1,575	5,084	4,544
Reportable Segments [Member] \| Personal Insurance [Member] \| Domestic [Member] \| Homeowners and Other [Member]
Segment reporting information
Premiums	1,896	1,648	5,434	4,714
Reportable Segments [Member] \| Personal Insurance [Member] \| International [Member]
Segment reporting information
Premiums	159	162	472	498
Other [Member]
Segment reporting information
Core income (loss)	(86)	(76)	(241)	(226)
After-tax interest expense	$ 78	$ 70	$ 220	$ 208

Segment Information (Details) -

Segment Information (Details) - Assets by Segment - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Assets by segment
Total assets	$ 121,384	$ 115,717
Reportable Segments [Member]
Assets by segment
Total assets	120,522	114,916
Reportable Segments [Member] \| Business Insurance [Member]
Assets by segment
Total assets	89,980	86,522
Reportable Segments [Member] \| Bond & Specialty Insurance [Member]
Assets by segment
Total assets	11,088	10,119
Reportable Segments [Member] \| Personal Insurance [Member]
Assets by segment
Total assets	19,454	18,275
Other assets [Member]
Assets by segment
Total assets	$ 862	$ 801

Investments (Details) - Investm

Investments (Details) - Investment Information, Debt Securities - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2021
Investment disclosure details
Fixed maturities, amortized cost	$ 80,792			$ 77,380
Allowance for expected credit losses	4			3
Gross unrealized gains	28			135
Gross unrealized losses	8,232			6,352
Fixed maturities, at fair value	72,584			71,160
Proceeds from sales of fixed maturities classified as available for sale	4,619	$ 3,951
Gross realized gains	26	17
Gross realized losses	93	52
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities [Member]
Investment disclosure details
Fixed maturities, amortized cost	6,575			5,798
Allowance for expected credit losses	0			0
Gross unrealized gains	0			3
Gross unrealized losses	363			363
Fixed maturities, at fair value	6,212			5,438
Obligations of U.S. states, municipalities and political subdivisions [Member]
Investment disclosure details
Fixed maturities, amortized cost	30,330			34,118
Allowance for expected credit losses	0			0
Gross unrealized gains	4			82
Gross unrealized losses	4,096			2,821
Fixed maturities, at fair value	26,238			31,379
Obligations of U.S. states, municipalities and political subdivisions, local general obligation [Member]
Investment disclosure details
Fixed maturities, amortized cost	18,358			19,615
Allowance for expected credit losses	0			0
Gross unrealized gains	1			33
Gross unrealized losses	2,675			1,825
Fixed maturities, at fair value	15,684			17,823
Obligations of U.S. states, municipalities and political subdivisions, revenue [Member]
Investment disclosure details
Fixed maturities, amortized cost	9,750			11,076
Allowance for expected credit losses	0			0
Gross unrealized gains	2			29
Gross unrealized losses	1,275			907
Fixed maturities, at fair value	8,477			10,198
Obligations of U.S. states, municipalities and political subdivisions, state general obligation [Member]
Investment disclosure details
Fixed maturities, amortized cost	1,174			1,104
Allowance for expected credit losses	0			0
Gross unrealized gains	0			3
Gross unrealized losses	137			88
Fixed maturities, at fair value	1,037			1,019
Obligations of U.S. states, municipalities and political subdivisions, pre-refunded [Member]
Investment disclosure details
Fixed maturities, amortized cost	1,048			2,323
Allowance for expected credit losses	0			0
Gross unrealized gains	1			17
Gross unrealized losses	9			1
Fixed maturities, at fair value	1,040			2,339
Debt securities issued by foreign governments [Member]
Investment disclosure details
Fixed maturities, amortized cost	1,037			1,049
Allowance for expected credit losses	0			0
Gross unrealized gains	1			0
Gross unrealized losses	56			55
Fixed maturities, at fair value	982			994
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities [Member]
Investment disclosure details
Fixed maturities, amortized cost	6,927			2,178
Allowance for expected credit losses	0			0
Gross unrealized gains	7			13
Gross unrealized losses	411			200
Fixed maturities, at fair value	6,523			1,991
Corporate and all other bonds [Member]
Investment disclosure details
Fixed maturities, amortized cost	35,923			34,237
Allowance for expected credit losses	4	$ 3	$ 4	3	$ 4	$ 3
Gross unrealized gains	16			37
Gross unrealized losses	3,306			2,913
Fixed maturities, at fair value	$ 32,629			$ 31,358

Investments (Details) - Inves_2

Investments (Details) - Investment Information, Equity Securities - USD ($) $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Investment disclosure details
Equity securities, cost	$ 546		$ 747
Gross gains	67		92
Gross losses	40		32
Equity securities, at fair value	573		807
Net recognized losses on equity securities still held	11	$ 110
Common stock [Member]
Investment disclosure details
Equity securities, cost	502		706
Gross gains	65		89
Gross losses	40		32
Equity securities, at fair value	527		763
Non-redeemable preferred stock [Member]
Investment disclosure details
Equity securities, cost	44		41
Gross gains	2		3
Gross losses	0		0
Equity securities, at fair value	$ 46		$ 44

Investments (Details) - Inves_3

Investments (Details) - Investment Information, Losses - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Investment disclosure details
Continuous unrealized loss position, less than 12 months, fair value	$ 25,942	$ 48,184
Continuous unrealized loss position, less than 12 months, gross unrealized losses	1,070	3,860
Continuous unrealized loss position, 12 months or longer, fair value	44,884	11,592
Continuous unrealized loss position, 12 months or longer, gross unrealized losses	7,162	2,492
Continuous unrealized loss position, total, fair value	70,826	59,776
Continuous unrealized loss position, total, gross unrealized losses	8,232	6,352
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, 3 months or less	1,833	175
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost greater than 3 months, 6 months or less	468	1,350
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 6 months, 12 months or less	185	651
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 12 months	1,090	0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, total	3,576	2,176
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities [Member]
Investment disclosure details
Continuous unrealized loss position, less than 12 months, fair value	2,979	2,835
Continuous unrealized loss position, less than 12 months, gross unrealized losses	32	100
Continuous unrealized loss position, 12 months or longer, fair value	3,083	1,679
Continuous unrealized loss position, 12 months or longer, gross unrealized losses	331	263
Continuous unrealized loss position, total, fair value	6,062	4,514
Continuous unrealized loss position, total, gross unrealized losses	363	363
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, 3 months or less	17	0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost greater than 3 months, 6 months or less	0	0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 6 months, 12 months or less	0	0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 12 months	0	0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, total	17	0
Obligations of U.S. states, municipalities and political subdivisions [Member]
Investment disclosure details
Continuous unrealized loss position, less than 12 months, fair value	12,050	19,251
Continuous unrealized loss position, less than 12 months, gross unrealized losses	703	1,975
Continuous unrealized loss position, 12 months or longer, fair value	13,625	3,134
Continuous unrealized loss position, 12 months or longer, gross unrealized losses	3,393	846
Continuous unrealized loss position, total, fair value	25,675	22,385
Continuous unrealized loss position, total, gross unrealized losses	4,096	2,821
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, 3 months or less	948	81
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost greater than 3 months, 6 months or less	167	776
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 6 months, 12 months or less	140	643
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 12 months	1,024	0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, total	2,279	1,500
Debt securities issued by foreign governments [Member]
Investment disclosure details
Continuous unrealized loss position, less than 12 months, fair value	201	604
Continuous unrealized loss position, less than 12 months, gross unrealized losses	6	22
Continuous unrealized loss position, 12 months or longer, fair value	769	367
Continuous unrealized loss position, 12 months or longer, gross unrealized losses	50	33
Continuous unrealized loss position, total, fair value	970	971
Continuous unrealized loss position, total, gross unrealized losses	56	55
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, 3 months or less	0	1
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost greater than 3 months, 6 months or less	1	0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 6 months, 12 months or less	0	0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 12 months	0	0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, total	1	1
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities [Member]
Investment disclosure details
Continuous unrealized loss position, less than 12 months, fair value	5,032	1,414
Continuous unrealized loss position, less than 12 months, gross unrealized losses	162	128
Continuous unrealized loss position, 12 months or longer, fair value	1,373	316
Continuous unrealized loss position, 12 months or longer, gross unrealized losses	249	72
Continuous unrealized loss position, total, fair value	6,405	1,730
Continuous unrealized loss position, total, gross unrealized losses	411	200
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, 3 months or less	46	4
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost greater than 3 months, 6 months or less	54	48
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 6 months, 12 months or less	0	0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 12 months	0	0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, total	100	52
Corporate and all other bonds [Member]
Investment disclosure details
Continuous unrealized loss position, less than 12 months, fair value	5,680	24,080
Continuous unrealized loss position, less than 12 months, gross unrealized losses	167	1,635
Continuous unrealized loss position, 12 months or longer, fair value	26,034	6,096
Continuous unrealized loss position, 12 months or longer, gross unrealized losses	3,139	1,278
Continuous unrealized loss position, total, fair value	31,714	30,176
Continuous unrealized loss position, total, gross unrealized losses	3,306	2,913
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, 3 months or less	822	89
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost greater than 3 months, 6 months or less	246	526
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 6 months, 12 months or less	45	8
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 12 months	66	0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, total	$ 1,179	$ 623

Investments (Details) - Allowan

Investments (Details) - Allowance for Expected Credit Losses - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Allowance for expected credit losses [Roll Forward]
Allowance for expected credit losses on fixed maturities classified as available-for-sale, balance, beginning of period			$ 3
Allowance for expected credit losses on fixed maturities classified as available-for-sale, balance, end of period	$ 4		4
Total net impairment charges, including credit impairments, reported in net realized investment losses in the consolidated statement of income	$ 1	$ 14	$ 2	$ 35
Credit losses on fixed maturities recognized in the consolidated statement of income, as a percentage of the fixed maturity portfolio on a pre-tax basis (less than)	1%	1%	1%	1%
Credit losses on fixed maturities recognized in the consolidated statement of income, as a percentage of shareholders' equity on an after-tax basis (less than)	1%	1%	1%	1%
Corporate and all other bonds [Member]
Allowance for expected credit losses [Roll Forward]
Allowance for expected credit losses on fixed maturities classified as available-for-sale, balance, beginning of period	$ 4	$ 4	$ 3	$ 3
Additions for expected credit losses on securities where no credit losses were previously recognized	0	0	0	0
Additions for expected credit losses on securities where credit losses were previously recognized	0	0	1	1
Reductions due to sales/defaults of credit-impaired securities	0	(1)	0	(1)
Reductions for impairments of securities which the Company intends to sell or more likely than not will be required to sell	0	0	0	0
Allowance for expected credit losses on fixed maturities classified as available-for-sale, balance, end of period	$ 4	$ 3	$ 4	$ 3

Investments (Details) - Other I

Investments (Details) - Other Investments	9 Months Ended
Investments (Details) - Other Investments	Sep. 30, 2023
Investments [Abstract]
Availability of financial information provided by hedge funds following the date of the reporting	1 month
Availability of financial information provided by private equity and real estate partnerships following the date of the reporting, maximum	3 months

Fair Value Measurements (Detail

Fair Value Measurements (Details)	Sep. 30, 2023	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Percent of fixed maturities for which a pricing service estimates fair value	99%	99%

Fair Value Measurements (Deta_2

Fair Value Measurements (Details) - Fair Value Hierarchy - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Common stock [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Transfers out of Level 3	$ 151	$ 182
Recurring basis [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			$ 73,173	$ 71,983
Other liabilities measured on a recurring basis				2
Recurring basis [Member] \| Fixed maturities [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			72,584	71,160
Recurring basis [Member] \| U.S. Treasury securities and obligations of U.S. government and government agencies and authorities [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			6,212	5,438
Recurring basis [Member] \| Obligations of U.S. states, municipalities and political subdivisions [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			26,238	31,379
Recurring basis [Member] \| Debt securities issued by foreign governments [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			982	994
Recurring basis [Member] \| Mortgage-backed securities, collateralized mortgage obligations and pass-through securities [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			6,523	1,991
Recurring basis [Member] \| Corporate and all other bonds [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			32,629	31,358
Recurring basis [Member] \| Equity securities [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			573	807
Recurring basis [Member] \| Common stock [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			527	763
Recurring basis [Member] \| Non-redeemable preferred stock [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			46	44
Recurring basis [Member] \| Other Investments [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			16	16
Recurring basis [Member] \| Level 1 [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			6,762	5,886
Other liabilities measured on a recurring basis				0
Recurring basis [Member] \| Level 1 [Member] \| Fixed maturities [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			6,212	5,438
Recurring basis [Member] \| Level 1 [Member] \| U.S. Treasury securities and obligations of U.S. government and government agencies and authorities [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			6,212	5,438
Recurring basis [Member] \| Level 1 [Member] \| Obligations of U.S. states, municipalities and political subdivisions [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			0	0
Recurring basis [Member] \| Level 1 [Member] \| Debt securities issued by foreign governments [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			0	0
Recurring basis [Member] \| Level 1 [Member] \| Mortgage-backed securities, collateralized mortgage obligations and pass-through securities [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			0	0
Recurring basis [Member] \| Level 1 [Member] \| Corporate and all other bonds [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			0	0
Recurring basis [Member] \| Level 1 [Member] \| Equity securities [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			534	433
Recurring basis [Member] \| Level 1 [Member] \| Common stock [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			520	418
Recurring basis [Member] \| Level 1 [Member] \| Non-redeemable preferred stock [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			14	15
Recurring basis [Member] \| Level 1 [Member] \| Other Investments [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			16	15
Recurring basis [Member] \| Level 2 [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			66,123	65,422
Other liabilities measured on a recurring basis				0
Recurring basis [Member] \| Level 2 [Member] \| Fixed maturities [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			66,120	65,419
Recurring basis [Member] \| Level 2 [Member] \| U.S. Treasury securities and obligations of U.S. government and government agencies and authorities [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			0	0
Recurring basis [Member] \| Level 2 [Member] \| Obligations of U.S. states, municipalities and political subdivisions [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			26,238	31,379
Recurring basis [Member] \| Level 2 [Member] \| Debt securities issued by foreign governments [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			982	994
Recurring basis [Member] \| Level 2 [Member] \| Mortgage-backed securities, collateralized mortgage obligations and pass-through securities [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			6,523	1,991
Recurring basis [Member] \| Level 2 [Member] \| Corporate and all other bonds [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			32,377	31,055
Recurring basis [Member] \| Level 2 [Member] \| Equity securities [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			3	3
Recurring basis [Member] \| Level 2 [Member] \| Common stock [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			0	0
Recurring basis [Member] \| Level 2 [Member] \| Non-redeemable preferred stock [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			3	3
Recurring basis [Member] \| Level 2 [Member] \| Other Investments [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			0	0
Recurring basis [Member] \| Level 3 [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			288	675
Other liabilities measured on a recurring basis				2
Recurring basis [Member] \| Level 3 [Member] \| Fixed maturities [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			252	303
Recurring basis [Member] \| Level 3 [Member] \| U.S. Treasury securities and obligations of U.S. government and government agencies and authorities [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			0	0
Recurring basis [Member] \| Level 3 [Member] \| Obligations of U.S. states, municipalities and political subdivisions [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			0	0
Recurring basis [Member] \| Level 3 [Member] \| Debt securities issued by foreign governments [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			0	0
Recurring basis [Member] \| Level 3 [Member] \| Mortgage-backed securities, collateralized mortgage obligations and pass-through securities [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			0	0
Recurring basis [Member] \| Level 3 [Member] \| Corporate and all other bonds [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			252	303
Recurring basis [Member] \| Level 3 [Member] \| Equity securities [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			36	371
Recurring basis [Member] \| Level 3 [Member] \| Common stock [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			7	345
Recurring basis [Member] \| Level 3 [Member] \| Non-redeemable preferred stock [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			29	26
Recurring basis [Member] \| Level 3 [Member] \| Investment in non-public common and preferred equity securities where the fair value estimate is determined either internally or by an external fund manager [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			36	371
Recurring basis [Member] \| Level 3 [Member] \| Other Investments [Member]
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured
Total invested assets measured on a recurring basis			$ 0	$ 1

Fair Value Measurements (Deta_3

Fair Value Measurements (Details) - Financial Instruments - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Financial Instruments
Short-term securities	$ 4,488	$ 3,470
Carrying Value [Member]
Financial Instruments
Short-term securities	4,488	3,470
Debt	7,931	7,192
Commercial paper	100	100
Fair Value [Member]
Financial Instruments
Short-term securities	4,488	3,470
Debt	6,900	6,509
Commercial paper	100	100
Fair Value [Member] \| Level 1 [Member]
Financial Instruments
Short-term securities	971	871
Debt	0	0
Commercial paper	0	0
Fair Value [Member] \| Level 2 [Member]
Financial Instruments
Short-term securities	3,466	2,546
Debt	6,900	6,509
Commercial paper	100	100
Fair Value [Member] \| Level 3 [Member]
Financial Instruments
Short-term securities	51	53
Debt	0	0
Commercial paper	$ 0	$ 0

Allowance for Expected Credit_3

Allowance for Expected Credit Losses (Details) - Changes in the Allowance for Expected Credit Losses on Premiums Receivable - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Credit Loss [Abstract]
Premiums receivable (net of allowance for expected credit losses), balance, beginning of period	$ 10,327	$ 9,132	$ 8,922	$ 8,085
Premiums receivable (net of allowance for expected credit losses), balance, end of period	10,345	8,886	10,345	8,886
Premiums receivable, allowance for expected credit losses [Roll Forward]
Premiums receivable, allowance for expected credit losses, beginning balance	72	89	77	107
Current period change for expected credit losses	11	14	28	49
Write-offs of uncollectible premiums receivable	15	17	37	70
Premiums receivable, allowance for expected credit losses, ending balance	$ 68	$ 86	$ 68	$ 86

Allowance for Expected Credit_4

Allowance for Expected Credit Losses (Details) - Changes in the Allowance for Estimated Uncollectible Reinsurance - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Credit Loss [Abstract]
Reinsurance recoverables (net of allowance for estimated uncollectible reinsurance), balance, beginning of period	$ 8,121	$ 8,509	$ 8,063	$ 8,452
Reinsurance recoverables (net of allowance for estimated uncollectible reinsurance), balance, end of period	8,267	8,202	8,267	8,202
Reinsurance recoverables, allowance for uncollectible reinsurance [Roll Forward]
Reinsurance recoverables, allowance for uncollectible reinsurance, beginning balance	121	132	132	141
Current period change for estimated uncollectible reinsurance	0	1	(11)	(8)
Write-offs of uncollectible reinsurance recoverables	0	0	0	0
Reinsurance recoverables, allowance for uncollectible reinsurance, ending balance	$ 121	$ 133	$ 121	$ 133

Allowance for Expected Credit_5

Allowance for Expected Credit Losses (Details) - Narrative - Reinsurer Concentration Risk [Member] $ in Millions	9 Months Ended
	Sep. 30, 2023 USD ($)
Reinsurance Recoverables [Member] \| Reinsurer Group Rated by A.M. Best [Member] \| A.M. Best, Rating Provided [Member]
Reinsurance recoverables, credit quality indicator
Reinsurance recoverables, after deducting mandatory pools and associations and before allowances for expected credit losses	$ 5,860
Concentration risk percentage	87%
Reinsurance Recoverables [Member] \| Reinsurer Group Not Rated by A.M. Best [Member]
Reinsurance recoverables, credit quality indicator
Concentration risk percentage	13%
Reinsurance Recoverables [Member] \| Captive Insurance Companies [Member]
Reinsurance recoverables, credit quality indicator
Concentration risk percentage	6%
Reinsurance Recoverables [Member] \| Voluntary Pools [Member]
Reinsurance recoverables, credit quality indicator
Concentration risk percentage	1%
Reinsurance Recoverables [Member] \| Other Companies [Member]
Reinsurance recoverables, credit quality indicator
Concentration risk percentage	6%
Reinsurance Recoverables Rated by A.M. Best [Member] \| Reinsurer Group Rated by A.M. Best [Member] \| A.M. Best, A- Rating Or Better [Member]
Reinsurance recoverables, credit quality indicator
Concentration risk percentage	94%

Allowance for Expected Credit_6

Allowance for Expected Credit Losses (Details) - Changes in the Allowance for Expected Credit Losses on Contractholder Receivables (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Credit Loss [Abstract]
Contractholder receivables (net of the allowance for expected credit losses), balance, beginning of period	$ 3,449	$ 3,735	$ 3,579	$ 3,890
Contractholder receivables (net of the allowance for expected credit losses), balance, end of period	3,467	3,749	3,467	3,749
Contractholder receivables, allowance for expected credit losses [Roll Forward]
Contractholder receivables, allowance for expected credit losses, beginning balance	20	18	17	21
Current period change for expected credit losses	0	0	3	(2)
Write-offs of uncollectible contractholder receivables	0	0	0	1
Contractholder receivables, allowance for expected credit losses, ending balance	$ 20	$ 18	$ 20	$ 18

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Goodwill by segment
Goodwill	$ 3,955	$ 3,952
Reportable Segments [Member] \| Business Insurance [Member]
Goodwill by segment
Goodwill	2,568	2,565
Reportable Segments [Member] \| Bond & Specialty Insurance [Member]
Goodwill by segment
Goodwill	550	550
Reportable Segments [Member] \| Personal Insurance [Member]
Goodwill by segment
Goodwill	811	811
Other [Member]
Goodwill by segment
Goodwill	$ 26	$ 26

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets (Details) - Other Intangible Assets - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount	$ 300	$ 300
Intangible assets subject to amortization, accumulated amortization	248	239
Intangible assets subject to amortization, net	52	61
Intangible assets not subject to amortization	226	226
Total other intangible assets, gross carrying amount	526	526
Total other intangible assets, net	278	287
Customer-related [Member]
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount	96	96
Intangible assets subject to amortization, accumulated amortization	55	48
Intangible assets subject to amortization, net	41	48
Contract-based [Member]
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount	204	204
Intangible assets subject to amortization, accumulated amortization	193	191
Intangible assets subject to amortization, net	$ 11	$ 13

Insurance Claim Reserves (Detai

Insurance Claim Reserves (Details) - Reserve Detail for Claims and Claim Adjustment Expenses - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Reconciliation of beginning and ending reserve balances for claims and claim adjustment expenses [Roll Forward]
Claims and claim adjustment expense reserves at beginning of year	$ 58,649
Claims and claim adjustment expense reserves at end of period	61,709
Property-casualty [Member]
Reconciliation of beginning and ending reserve balances for claims and claim adjustment expenses [Roll Forward]
Claims and claim adjustment expense reserves at beginning of year	58,643	$ 56,897
Reinsurance recoverables on unpaid losses	7,790	8,209
Net reserves at beginning of year	50,853	48,688
Estimated claims and claim adjustment expenses for claims arising in the current year	20,205	17,257
Estimated increase (decrease) in claims and claim adjustment expenses for claims arising in prior years	62	(383)
Total increases	20,267	16,874
Claims and claim adjustment expense payments for claims arising in current year	7,305	6,302
Claims and claim adjustment expense payments for claims arising in prior years	10,031	8,638
Total payments	17,336	14,940
Unrealized foreign exchange gain	(1)	(391)
Net reserves at end of period	53,783	50,231
Reinsurance recoverables on unpaid losses	7,920	7,900
Claims and claim adjustment expense reserves at end of period	61,703	$ 58,131
Amount of increase in gross claims and claim adjustment expense reserves	3,060
Amount of increase in reinsurance recoverables on unpaid losses	130
Accident and health [Member]
Reconciliation of beginning and ending reserve balances for claims and claim adjustment expenses [Roll Forward]
Claims and claim adjustment expense reserves at beginning of year	6
Claims and claim adjustment expense reserves at end of period	$ 6

Insurance Claim Reserves (Det_2

Insurance Claim Reserves (Details) - Prior Year Reserve Development - Property-casualty [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Liability for claims and claim adjustment expense
Net favorable (unfavorable) prior year reserve development included in estimated claims and claim adjustment expenses incurred for claims arising in prior years			$ (62)	$ 383
Net favorable (unfavorable) prior year reserve development impacting the Company's results of operations			11	464
Accretion expense			34	35
Business Insurance [Member]
Liability for claims and claim adjustment expense
Net favorable (unfavorable) prior year reserve development impacting the Company's results of operations	$ (263)	$ (61)	(345)	254
Business Insurance [Member] \| Asbestos reserves [Member]
Liability for claims and claim adjustment expense
Increase to reserves	284	212	284	212
Bond & Specialty Insurance [Member]
Liability for claims and claim adjustment expense
Net favorable (unfavorable) prior year reserve development impacting the Company's results of operations	72	63	249	171
Personal Insurance [Member]
Liability for claims and claim adjustment expense
Net favorable (unfavorable) prior year reserve development impacting the Company's results of operations	$ 37	$ 18	$ 107	$ 39

Other Comprehensive Income (L_3

Other Comprehensive Income (Loss) and Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Accumulated other comprehensive income (loss) [Roll Forward]
Balance, beginning of period			$ 21,560
Other comprehensive loss, net of taxes	$ (2,003)	$ (2,753)	(1,567)	$ (9,101)
Balance, end of period	19,978	19,906	19,978	19,906
Pre-tax components of other comprehensive income (loss) and the related income tax expense (benefit)
Other comprehensive income (loss), before taxes	(2,512)	(3,443)	(1,983)	(11,470)
Income tax expense (benefit)	(509)	(690)	(416)	(2,369)
Other comprehensive loss, net of taxes	(2,003)	(2,753)	(1,567)	(9,101)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated other comprehensive income (loss) [Roll Forward]
Balance, beginning of period	(6,009)	(5,155)	(6,445)	1,193
Other comprehensive income (loss) before reclassifications	(2,028)		(1,613)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	25		46
Other comprehensive loss, net of taxes	(2,003)	(2,753)	(1,567)	(9,101)
Balance, end of period	(8,012)	(7,908)	(8,012)	(7,908)
Pre-tax components of other comprehensive income (loss) and the related income tax expense (benefit)
Other comprehensive income (loss), before taxes	(2,512)	(3,443)	(1,983)	(11,470)
Income tax expense (benefit)	(509)	(690)	(416)	(2,369)
Other comprehensive loss, net of taxes	(2,003)	(2,753)	(1,567)	(9,101)
Changes in Net Unrealized Gains (Losses) on Investment Securities Having No Credit Losses Recognized in the Consolidated Statement of Income [Member]
Accumulated other comprehensive income (loss) [Roll Forward]
Balance, beginning of period	(4,755)		(5,077)
Other comprehensive income (loss) before reclassifications	(1,918)		(1,622)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	28		54
Other comprehensive loss, net of taxes	(1,890)	(2,526)	(1,568)	(8,730)
Balance, end of period	(6,645)		(6,645)
Pre-tax components of other comprehensive income (loss) and the related income tax expense (benefit)
Other comprehensive income (loss), before taxes	(2,391)	(3,204)	(1,986)	(11,078)
Income tax expense (benefit)	(501)	(678)	(418)	(2,348)
Other comprehensive loss, net of taxes	(1,890)	(2,526)	(1,568)	(8,730)
Changes in Net Unrealized Gains (Losses) on Investment Securities Having Credit Losses Recognized in the Consolidated Statement of Income [Member]
Accumulated other comprehensive income (loss) [Roll Forward]
Balance, beginning of period	179		179
Other comprehensive income (loss) before reclassifications	0		0
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	0		0
Other comprehensive loss, net of taxes	0	1	0	(2)
Balance, end of period	179		179
Pre-tax components of other comprehensive income (loss) and the related income tax expense (benefit)
Other comprehensive income (loss), before taxes	0	0	0	(3)
Income tax expense (benefit)	0	(1)	0	(1)
Other comprehensive loss, net of taxes	0	1	0	(2)
Net Benefit Plan Assets and Obligations Recognized in Shareholders' Equity [Member]
Accumulated other comprehensive income (loss) [Roll Forward]
Balance, beginning of period	(548)		(542)
Other comprehensive income (loss) before reclassifications	1		0
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(3)		(8)
Other comprehensive loss, net of taxes	(2)	9	(8)	27
Balance, end of period	(550)		(550)
Pre-tax components of other comprehensive income (loss) and the related income tax expense (benefit)
Other comprehensive income (loss), before taxes	(3)	12	(10)	34
Income tax expense (benefit)	(1)	3	(2)	7
Other comprehensive loss, net of taxes	(2)	9	(8)	27
Net Unrealized Foreign Currency Translation [Member]
Accumulated other comprehensive income (loss) [Roll Forward]
Balance, beginning of period	(885)		(1,005)
Other comprehensive income (loss) before reclassifications	(111)		9
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	0		0
Other comprehensive loss, net of taxes	(111)	(237)	9	(396)
Balance, end of period	(996)		(996)
Pre-tax components of other comprehensive income (loss) and the related income tax expense (benefit)
Other comprehensive income (loss), before taxes	(118)	(251)	13	(423)
Income tax expense (benefit)	(7)	(14)	4	(27)
Other comprehensive loss, net of taxes	$ (111)	$ (237)	$ 9	$ (396)

Other Comprehensive Income (L_4

Other Comprehensive Income (Loss) and Accumulated Other Comprehensive Income (Loss) (Details) - Reclassifications - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Reclassification adjustment impacting net realized investment losses on the consolidated statement of income	$ 65	$ 93	$ 94	$ 211
Reclassification adjustment impacting claims and claim adjustment expenses (benefit) on the consolidated statement of income	7,149	6,088	20,335	16,930
Reclassification adjustment impacting general and administrative expenses (benefit) on the consolidated statement of income	1,312	1,193	3,887	3,607
Total reclassifications	(472)	(528)	(1,352)	(2,367)
Income tax (expense) benefit	(68)	(74)	13	(344)
Amounts reclassified from accumulated other comprehensive income (loss), net of taxes	(404)	(454)	(1,365)	(2,023)
Accumulated Other Comprehensive Income (Loss) [Member] \| Reclassification out of Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Total reclassifications	31	52	58	92
Income tax (expense) benefit	6	10	12	19
Amounts reclassified from accumulated other comprehensive income (loss), net of taxes	25	42	46	73
Changes in Net Unrealized Gains (Losses) on Investment Securities Having No Credit Losses Recognized in the Consolidated Statement of Income [Member] \| Reclassification out of Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Reclassification adjustment impacting net realized investment losses on the consolidated statement of income	35	42	68	61
Income tax (expense) benefit	7	9	14	13
Amounts reclassified from accumulated other comprehensive income (loss), net of taxes	28	33	54	48
Changes in Net Unrealized Gains (Losses) on Investment Securities Having Credit Losses Recognized in the Consolidated Statement of Income [Member] \| Reclassification out of Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Reclassification adjustment impacting net realized investment losses on the consolidated statement of income	0	0	0	0
Income tax (expense) benefit	0	0	0	0
Amounts reclassified from accumulated other comprehensive income (loss), net of taxes	0	0	0	0
Net Benefit Plan Assets and Obligations Recognized in Shareholders' Equity [Member] \| Reclassification out of Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Reclassification adjustment impacting claims and claim adjustment expenses (benefit) on the consolidated statement of income	(2)	5	(4)	13
Reclassification adjustment impacting general and administrative expenses (benefit) on the consolidated statement of income	(2)	5	(6)	18
Total reclassifications	(4)	10	(10)	31
Income tax (expense) benefit	(1)	1	(2)	6
Amounts reclassified from accumulated other comprehensive income (loss), net of taxes	(3)	9	(8)	25
Net Unrealized Foreign Currency Translation [Member] \| Reclassification out of Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Reclassification adjustment impacting net realized investment losses on the consolidated statement of income	0	0	0	0
Income tax (expense) benefit	0	0	0	0
Amounts reclassified from accumulated other comprehensive income (loss), net of taxes	$ 0	$ 0	$ 0	$ 0

Debt (Details)

Debt (Details) - USD ($) $ in Millions		9 Months Ended
Debt (Details) - USD ($) $ in Millions	May 25, 2023	Sep. 30, 2023	Sep. 30, 2022
Debt Instrument
Net proceeds of issuance, after the deduction of the underwriting discount and expenses		$ 738	$ 0
Senior Notes [Member] \| 5.45% Senior notes due May 25, 2053 [Member]
Debt Instrument
Debt, principal amount	$ 750
Interest rate (percent)	5.45%
Net proceeds of issuance, after the deduction of the underwriting discount and expenses	$ 738
Percentage of principal amount at which redemption price may be set	100%
Basis points added to current Treasury rate used in calculation of alternative redemption price	0.25%

Common Share Repurchases (Detai

Common Share Repurchases (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2023	Apr. 19, 2023
Treasury Stock Transactions, Excluding Value of Shares Reissued [Abstract]
Number of shares repurchased under share repurchase authorization (in shares)	600,000	5,000,000
Cost of shares repurchased under share repurchase authorization	$ 100,000	$ 900,000
Average cost per share repurchased under share repurchase authorization (in dollars per share)	$ 164.46	$ 179.59
Number of shares acquired to cover tax withholding costs and exercise costs (in shares)	5,480	300,000
Cost of shares acquired to cover tax withholding costs and exercise costs	$ 926	$ 63,000
Share repurchase authorization			$ 5,000,000
Remaining capacity under share repurchase authorization	$ 6,100,000	$ 6,100,000

Earnings per Share (Details)

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
Earnings Per Share Reconciliation [Abstract]
Net income	$ 404	$ 454	$ 1,365	$ 2,023
Participating share-based awards — allocated income	(3)	(4)	(10)	(15)
Net income available to common shareholders -- basic	401	450	1,355	2,008
Net income available to common shareholders -- diluted	$ 401	$ 450	$ 1,355	$ 2,008
Weighted average shares outstanding, basic (in shares)	228.8	235.4	230	238.3
Weighted average effects of dilutive securities - stock options and performance shares (in shares)	2.3	2.5	2.5	2.6
Weighted average shares outstanding, diluted (in shares)	231.1	237.9	232.5	240.9
Net income per common share, basic (in dollars per share)	$ 1.75	$ 1.91	$ 5.89	$ 8.43
Net income per common share, diluted (in dollars per share)	$ 1.74	$ 1.89	$ 5.83	$ 8.34

Share-Based Incentive Compens_3

Share-Based Incentive Compensation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Stock options vested at end of period, number (in shares)	7,420,703		7,420,703
Stock options vested at end of period, weighted average exercise price (in dollars per share)	$ 137.92		$ 137.92
Stock options vested at end of period, weighted average contractual life remaining (in years)			5 years 8 months 12 days
Stock options vested at end of period, aggregate intrinsic value	$ 209		$ 209
Stock options exercisable at end of period, number (in shares)	5,344,583		5,344,583
Stock options exercisable at end of period, weighted average exercise price (in dollars per share)	$ 128.37		$ 128.37
Stock options exercisable at end of period, weighted average contractual life remaining (in years)			4 years 8 months 12 days
Stock options exercisable at end of period, aggregate intrinsic value	$ 187		$ 187
Total compensation cost recognized in earnings for all share-based incentive compensation awards	46	$ 41	162	$ 141
Tax benefit recognized in the consolidated statement of income related to compensation costs	8	$ 7	27	$ 24
Total unrecognized compensation cost related to all nonvested share-based incentive compensation awards	$ 237		$ 237
Weighted-average period of recognition for unrecognized compensation cost (in years)			1 year 9 months 18 days

Pension Plans, Retirement Ben_3

Pension Plans, Retirement Benefits and Savings Plans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Pension Plans [Member]
Defined benefit plan disclosure
Service cost	$ 27	$ 36	$ 81	$ 109
Interest cost on benefit obligation	44	25	132	76
Expected return on plan assets	(77)	(74)	(233)	(222)
Net periodic benefit cost (benefit), amortization of unrecognized prior service benefit	(1)	0	(1)	0
Net periodic benefit cost (benefit), amortization of unrecognized net actuarial (gain) loss	0	12	0	37
Total non-service cost (benefit)	(34)	(37)	(102)	(109)
Net periodic benefit cost (benefit)	(7)	(1)	(21)	0
Pension Plans [Member] \| Claims and claim adjustment expenses [Member]
Defined benefit plan disclosure
Service cost	11	14	33	44
Total non-service cost (benefit)	(14)	(15)	(41)	(44)
Pension Plans [Member] \| General and administrative expenses [Member]
Defined benefit plan disclosure
Service cost	16	22	48	65
Total non-service cost (benefit)	(20)	(22)	(61)	(65)
Postretirement Benefit Plans [Member]
Defined benefit plan disclosure
Service cost	0	0	0	0
Interest cost on benefit obligation	2	0	4	2
Expected return on plan assets	0	0	0	0
Net periodic benefit cost (benefit), amortization of unrecognized prior service benefit	(1)	0	(3)	(2)
Net periodic benefit cost (benefit), amortization of unrecognized net actuarial (gain) loss	(3)	(1)	(7)	(3)
Total non-service cost (benefit)	(2)	(1)	(6)	(3)
Net periodic benefit cost (benefit)	(2)	(1)	(6)	(3)
Postretirement Benefit Plans [Member] \| Claims and claim adjustment expenses [Member]
Defined benefit plan disclosure
Service cost	0	0	0	0
Total non-service cost (benefit)	(1)	0	(3)	(1)
Postretirement Benefit Plans [Member] \| General and administrative expenses [Member]
Defined benefit plan disclosure
Service cost	0	0	0	0
Total non-service cost (benefit)	$ (1)	$ (1)	$ (3)	$ (2)

Leases (Details)

Leases (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
Leases (Details) - USD ($) $ in Millions	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Leases [Abstract]
Operating leases	$ 19	$ 19	$ 57	$ 61
Short-term leases	1	1	2	2
Lease expense	20	20	59	63
Less: sublease income	0	0	0	0
Net lease cost	20	20	59	63
Cash payments to settle a lease liability reported in cash flows	22	23	65	71
Right-of-use assets obtained in exchange for new lease liabilities	$ 12	$ 14	$ 25	$ 21
Weighted average discount rate (percent)	2.64%	2.33%	2.64%	2.33%
Weighted average remaining lease term (in years)	4 years 2 months 12 days	4 years 6 months	4 years 2 months 12 days	4 years 6 months

Contingencies, Commitments an_2

Contingencies, Commitments and Guarantees (Details) - Commitments - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Contingencies, Commitments and Guarantees [Abstract]
Unfunded commitments to private equity limited partnerships, real estate partnerships and others	$ 1,660	$ 1,800

Contingencies, Commitments an_3

Contingencies, Commitments and Guarantees (Details) - Guarantees $ in Millions	Sep. 30, 2023 USD ($)
Indemnifications related to the sale of businesses [Member]
Guarantor obligations
Maximum amount of contingent obligation	$ 351
Guarantees of certain insurance policy obligations [Member]
Guarantor obligations
Maximum amount of contingent obligation	480
Amount indemnified by a third party	$ 480