Arch Capital (ACGL) 10-Q 7 Nov 24 2024 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2024	Nov. 01, 2024
Document and Entity Information [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Document Transition Report	false
Entity File Number	001-16209
Entity Registrant Name	ARCH CAPITAL GROUP LTD.
Entity Incorporation, State or Country Code	D0
Entity Tax Identification Number	98-0374481
Entity Address, Address Line One	Waterloo House, Ground Floor
Entity Address, Address Line Two	100 Pitts Bay Road,
Entity Address, City or Town	Pembroke
Entity Address, Postal Zip Code	HM 08,
Entity Address, Country	BM
City Area Code	(441)
Local Phone Number	278-9250
Entity Listings [Line Items]
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		376,241,879
Document Fiscal Period Focus	Q2
Document Fiscal Year Focus	2024
Current Fiscal Year End Date	--12-31
Entity Central Index Key	0000947484
Amendment Flag	false
Common shares
Entity Listings [Line Items]
Title of 12(b) Security	Common shares, $0.0011 par value per share
Trading Symbol	ACGL
Security Exchange Name	NASDAQ
Series F Depositary Share Equivalent
Entity Listings [Line Items]
Title of 12(b) Security	Depositary shares, each representing a 1/1000th interest in a 5.45% Series F preferred share
Trading Symbol	ACGLO
Security Exchange Name	NASDAQ
Series G Depositary Share Equivalent
Entity Listings [Line Items]
Title of 12(b) Security	Depositary shares, each representing a 1/1000th interest in a 4.55% Series G preferred share
Trading Symbol	ACGLN
Security Exchange Name	NASDAQ

Unaudited Consolidated Balance

Unaudited Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Investments:
Debt securities available for sale, at fair value	$ 31,775	$ 25,616
Equity securities, at fair value	1,623	1,186
Other investments, at fair value	3,261	2,488
Investments accounted for using the equity method	5,244	4,566
Total investments	41,903	33,856
Cash	1,025	917
Accrued investment income	292	236
Investment in operating affiliates	1,236	1,119
Premiums receivable (net of allowance for credit losses: $52 and $34)	6,364	4,644
Reinsurance recoverable on unpaid and paid losses and loss adjustment expenses (net of allowance for credit losses: $17 and $21)	7,948	7,064
Contractholder receivables (net of allowance for credit losses: $4 and $3)	2,078	1,814
Ceded unearned premiums	2,935	2,170
Deferred acquisition costs	1,744	1,531
Receivable for securities sold	790	63
Goodwill and intangible assets	1,486	731
Other assets	5,855	4,761
Total assets	73,656	58,906
Liabilities
Reserve for losses and loss adjustment expenses	28,679	22,752
Unearned premiums	11,238	8,808
Reinsurance balances payable	2,586	2,000
Contractholder payables	2,082	1,817
Collateral held for insured obligations	268	259
Senior notes	2,727	2,726
Payable for securities purchased	967	247
Other liabilities	2,835	1,942
Total liabilities	51,382	40,551
Commitments and contingencies (refer to Note 11)
Redeemable noncontrolling interests	0	2
Shareholders' Equity
Non-cumulative preferred shares	830	830
Common shares ($0.0011 par, shares issued: 595.2 and 591.9)	1	1
Additional paid-in capital	2,465	2,327
Retained earnings	23,642	20,295
Accumulated other comprehensive income (loss), net of deferred income tax	(200)	(676)
Common shares held in treasury, at cost (shares: 219.0 and 218.5)	(4,464)	(4,424)
Total shareholders' equity available to Arch	22,274	18,353
Total liabilities, noncontrolling interests and shareholders' equity	73,656	58,906
Fixed maturities available for sale, at fair value (amortized cost: $28,466 and $24,131; net of allowance for credit losses: $19 and $28)
Investments:
Debt securities available for sale, at fair value	28,434	23,553
Short-term investments available for sale, at fair value (amortized cost: $3,337 and $2,064; net of allowance for credit losses: $0 and $0)
Investments:
Debt securities available for sale, at fair value	$ 3,341	$ 2,063

Unaudited Consolidated Balanc_2

Unaudited Consolidated Balance Sheets (Parentheticals) - USD ($) shares in Millions, $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Available for sale securities, amortized cost	$ 31,803	$ 26,195
Allowance for credit losses on investments	19	28
Allowance for credit losses on premiums receivable	52	34
Allowance for credit losses on reinsurance recoverable	17	21
Allowance for credit losses on contractholder receivable	$ 4	$ 3
Common shares, par value per share	$ 0.0011	$ 0.0011
Common shares issued (shares)	595.2	591.9
Common shares held in treasury (shares)	219	218.5
Fixed maturities
Available for sale securities, amortized cost	$ 28,466	$ 24,131
Allowance for credit losses on investments	19	28
Short-term investments
Available for sale securities, amortized cost	3,337	2,064
Allowance for credit losses on investments	$ 0	$ 0

Unaudited Consolidated Statemen

Unaudited Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenues
Net premiums earned	$ 3,970	$ 3,248	$ 10,957	$ 9,096
Net investment income	399	269	1,090	710
Net realized gains (losses)	169	(248)	358	(354)
Other underwriting income	5	5	20	21
Equity in net income (loss) of investment funds accounted for using the equity method	171	59	437	176
Other income (loss)	8	(4)	30	10
Total revenues	4,722	3,329	12,892	9,659
Expenses
Losses and loss adjustment expenses	2,403	1,647	5,958	4,609
Acquisition expenses	681	575	1,921	1,669
Other operating expenses	353	310	1,062	942
Corporate expenses	49	20	143	71
Amortization of intangible assets	88	24	136	71
Interest expense	35	34	104	99
Net foreign exchange (gains) losses	63	(22)	31	1
Total expenses	3,672	2,588	9,355	7,462
Income (loss) before income taxes and income (loss) from operating affiliates	1,050	741	3,537	2,197
Income tax (expense) benefit	(98)	(72)	(296)	(203)
Income (loss) from operating affiliates	36	54	136	115
Net income (loss) available to Arch	988	723	3,377	2,109
Preferred dividends	(10)	(10)	(30)	(30)
Net income (loss) available to Arch common shareholders	$ 978	$ 713	$ 3,347	$ 2,079
Net income per common share and common share equivalent
Basic (per share)	$ 2.62	$ 1.93	$ 8.99	$ 5.64
Diluted (per share)	$ 2.56	$ 1.88	$ 8.78	$ 5.50
Weighted average common shares and common share equivalents outstanding
Basic (shares)	373.2	369.2	372.3	368.4
Diluted (shares)	382.3	379.4	381.3	378.3

Unaudited Consolidated Statem_2

Unaudited Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Comprehensive Income
Net income (loss)	$ 988	$ 723	$ 3,377	$ 2,109
Unrealized appreciation (decline) in value of available-for-sale investments:
Unrealized holding gains (losses) arising during period	645	(190)	478	(118)
Portion of other-than-temporary impairment losses recognized in other comprehensive income	0	0	0	0
Reclassification of net realized (gains) losses, included in net income (loss)	(60)	96	22	344
Foreign currency translation adjustments	25	(40)	(24)	(33)
Comprehensive income (loss) available to Arch	$ 1,598	$ 589	$ 3,853	$ 2,302

Unaudited Consolidated Statem_3

Unaudited Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Millions	Total	Non-cumulative preferred shares	Common shares	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss), net of deferred income tax	Unrealized appreciation (decline) in value of available-for-sale securities, net of deferred income tax	Foreign currency translation adjustments, net of deferred income tax	Common shares held in treasury, at cost
Balance at beginning of period at Dec. 31, 2022		$ 830	$ 1	$ 2,211	$ 15,892	$ (1,646)	$ (1,512)	$ (134)	$ (4,378)
Amortization of share-based compensation				73
Other changes				13
Net income (loss)	$ 2,109				2,109
Preferred share dividends	(30)				(30)
Unrealized holding gains (losses) during period, net of reclassification adjustment							226
Foreign currency translation adjustments	(33)							(33)
Shares repurchased for treasury									(29)
Balance at end of period at Sep. 30, 2023	15,239	830	1	2,297	17,971	(1,453)	(1,286)	(167)	(4,407)
Balance at beginning of period at Jun. 30, 2023		830	1	2,278	17,258	(1,319)	(1,192)	(127)	(4,407)
Amortization of share-based compensation				15
Other changes				4
Net income (loss)	723				723
Preferred share dividends	(10)				(10)
Unrealized holding gains (losses) during period, net of reclassification adjustment							(94)
Foreign currency translation adjustments	(40)							(40)
Shares repurchased for treasury									0
Balance at end of period at Sep. 30, 2023	15,239	830	1	2,297	17,971	(1,453)	(1,286)	(167)	(4,407)
Balance at beginning of period at Dec. 31, 2023	18,353	830	1	2,327	20,295	(676)	(565)	(111)	(4,424)
Amortization of share-based compensation				100
Other changes				38
Net income (loss)	3,377				3,377
Preferred share dividends	(30)				(30)
Unrealized holding gains (losses) during period, net of reclassification adjustment							500
Foreign currency translation adjustments	(24)							(24)
Shares repurchased for treasury									(40)
Balance at end of period at Sep. 30, 2024	22,274	830	1	2,465	23,642	(200)	(65)	(135)	(4,464)
Balance at beginning of period at Jun. 30, 2024		830	1	2,443	22,664	(810)	(650)	(160)	(4,463)
Amortization of share-based compensation				16
Other changes				6
Net income (loss)	988				988
Preferred share dividends	(10)				(10)
Unrealized holding gains (losses) during period, net of reclassification adjustment							585
Foreign currency translation adjustments	25							25
Shares repurchased for treasury									(1)
Balance at end of period at Sep. 30, 2024	$ 22,274	$ 830	$ 1	$ 2,465	$ 23,642	$ (200)	$ (65)	$ (135)	$ (4,464)

Unaudited Consolidated Statem_4

Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Operating Activities
Net income (loss)	$ 3,377	$ 2,109
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Net realized (gains) losses	(361)	367
Equity in net (income) or loss of investment funds accounted for using the equity method and other income or loss	(336)	(104)
Amortization of intangible assets	136	71
Share-based compensation	100	73
Changes in:
Reserve for losses and loss adjustment expenses, net of unpaid losses and loss adjustment expenses recoverable	2,447	1,604
Unearned premiums, net of ceded unearned premiums	956	1,111
Premiums receivable	(1,504)	(1,333)
Deferred acquisition costs	(166)	(190)
Reinsurance balances payable	589	692
Deferred income tax assets, net	61	40
Other items, net	(199)	(356)
Net cash provided by operating activities	5,100	4,084
Investing Activities
Purchases of fixed maturity investments	(21,559)	(13,024)
Purchases of equity securities	(932)	(176)
Purchases of other investments	(1,898)	(1,112)
Proceeds from sales of fixed maturity investments	16,447	9,655
Proceeds from sales of equity securities	673	216
Proceeds from sales, redemptions and maturities of other investments	1,024	345
Proceeds from redemptions and maturities of fixed maturity investments	1,270	589
Net settlements of derivative instruments	127	(69)
Net (purchases) sales of short-term investments	(818)	(323)
Acquisitions, net of cash	852	0
Purchases of fixed assets	(38)	(37)
Other	(29)	0
Net cash used for investing activities	(4,881)	(3,936)
Financing Activities
Proceeds from common shares issued, net	(2)	5
Change in third party investment in redeemable noncontrolling interests	0	(22)
Other	(3)	(5)
Preferred dividends paid	(30)	(30)
Net cash used for financing activities	(35)	(52)
Effects of exchange rate changes on foreign currency cash and restricted cash	30	(14)
Increase (decrease) in cash and restricted cash	214	82
Cash and restricted cash, beginning of year	1,498	1,273
Cash and restricted cash, end of period	1,712	1,355
Income taxes paid (received)	221	127
Interest paid	$ 63	$ 63

Basis of Presentation and Recen

Basis of Presentation and Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Recent Accounting Pronouncements	General Arch Capital Group Ltd. (“Arch Capital”) is a publicly listed Bermuda exempted company which provides insurance, reinsurance and mortgage insurance on a worldwide basis through its wholly-owned subsidiaries. As used herein, the “Company” means Arch Capital and its subsidiaries. Basis of Presentation The interim consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). All significant intercompany transactions and balances have been eliminated in consolidation. The preparation of 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 financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ materially from those estimates and assumptions. In the opinion of management, the accompanying unaudited interim consolidated financial statements reflect all adjustments (consisting of normally recurring accruals) necessary for a fair statement of results on an interim basis. The results of any interim period are not necessarily indicative of the results for a full year or any future periods. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted; however, management believes that the disclosures are adequate to make the information presented not misleading. This report should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2023 (“2023 Form 10-K”), including the Company’s audited consolidated financial statements and related notes. The Company has reclassified the presentation of certain prior year information to conform to the current presentation. Such reclassifications had no effect on the Company’s net income, comprehensive income, shareholders’ equity or cash flows. All amounts are in millions, except per share amounts, unless otherwise noted. Recent Accounting Pronouncements For information regarding additional accounting standards that the Company has not yet adopted, see note 3(t), “Significant Accounting Policies—Recent Accounting Pronouncements,” of the notes to consolidated financial statements in the Company’s 2023 Form 10-K.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2024
Business Combinations [Abstract]
Business Acquired	On August 1, 2024, the Company completed the acquisition of Allianz’s U.S Middle Market Property & Casualty Insurance and U.S. Entertainment Property and Casualty Insurance Business. This business is written by Fireman’s Fund Insurance Company, an affiliate of Allianz (“MCE”), and its subsidiaries (together with MCE, collectively, the “Business Entities”), in each case, relating to relevant policies with accident years 2016 and onwards (collectively, the “Business”), as well as certain assets of Allianz and its affiliates related to the Business. In connection with the acquisition of the Business, the Company also entered into certain reinsurance agreements relating to the Business and the Business Entities and other agreements providing for administration and other services for the Business Entities by the Company for the applicable policies being reinsured following the closing. The acquisition of the Business is an important part of the Company’s growth strategy, and provides a ballast to our existing insurance business. It further enhances the Company’s capabilities in the U.S. middle markets and represents an attractive way to enter a new niche entertainment insurance market. Aggregate cash consideration for the transaction was $450 million. Direct costs related to the acquisition are immaterial, and were expensed as incurred. These include one-time costs that are directly attributable to third party consulting fees and other professional and legal fees related to the acquisition. Such costs are included within ‘corporate expenses’ in the consolidated statement of income. The Business acquired is included within the Company’s insurance segment beginning from the acquisition date, August 1, 2024. The following table summarizes the Company’s allocation of the purchase price to the acquired assets and liabilities assumed based on estimated fair values on August 1, 2024. The fair value of the assets and liabilities are preliminary and may change with offsetting adjustments to goodwill. The Company may make further adjustments to its purchase price allocation through the end of the permissible one-year measurement period. Total Useful Life Purchase price Cash paid (a) $ 450 Assets Acquired Cash and investments, at fair value $ 2,332 Premiums receivable 290 Intangible asset -- distribution relationships 220 10 years Intangible asset -- value of business acquired 163 1-2 years Intangible asset -- other (1) 178 5-7 years Other assets acquired 158 Total assets acquired $ 3,341 Liabilities Acquired Reserves for losses and loss adjustment expenses $ 2,404 Unearned premiums 632 Other liabilities acquired 121 Total liabilities acquired 3,157 Identifiable net assets acquired (b) $ 184 Goodwill (a) - (b) $ 266 (1) Includes $128 million related to the net fair value adjustment to reserves for loss and loss adjustment expenses on August 1, 2024. The Company recognized goodwill of $266 million that is primarily attributed to the expanded presence and long-term growth opportunities in the insurance market provided by this strategic acquisition. Approximately $568 million of the acquired goodwill and intangibles is expected to be deductible for income tax purposes. At the date of the acquisition, the Company established a net deferred tax asset of $23 million related to the estimated fair value of reserves for losses and loss adjustment expenses and unearned premiums. Intangible assets resulting from the acquisition are amortized as part of ‘amortization of intangible assets’ in the Company’s consolidated statements of income. The significant fair value adjustments and related future amortization are as follows: Value of business acquired (“VOBA”)— which represents the present value of the expected underwriting profit within the unearned premium liability, less costs to service the related policies and a risk premium. The fair value of VOBA was determined after taking into consideration certain key assumptions, including the estimated cost of capital, investment yield, loss ratio and related expenses; Reserves for losses and loss adjustment expenses— to reflect a decrease related to the present value of the reserve for losses and loss adjustment expenses based on the estimated payout patterns, partially offset by an increase in losses and loss adjustment expenses related to the estimated market based risk margin. The risk margin represents the estimated costs of capital required by a market participant to assume the losses and loss adjustment expenses. The fair value of the reserve for losses and loss adjustment expenses was determined after taking into consideration certain key assumptions, including the estimated cost of capital, and investment yield. Distribution relationships— the value of the distribution relationships was determined after taking into consideration certain key assumptions, including the estimated cost of capital, investment yield, retention rates, loss ratios, related expenses and effective tax rates that would impact the expected cash flows from Business policies written on a go forward basis. The results of the acquired Business Entities have been included in the Company’s consolidated financial statements beginning as of their acquisition date. It is impracticable to provide historical supplemental pro forma financial information along with revenue and earnings subsequent to the acquisition due to a variety of factors, including access to historical information and the operations of acquirees being integrated within the Company shortly after closing and not operating as discrete operations within the Company’s organizational structure.

Share Transactions

Share Transactions	9 Months Ended
	Sep. 30, 2024
Stockholders' Equity Note [Abstract]
Share transactions	Share Repurchases The Board of Directors of Arch Capital has authorized the investment in Arch Capital’s common shares through a share repurchase program. At September 30, 2024, $1.0 billion of share repurchases were available under the program. Repurchases under the program may be effected from time to time in open market or privately negotiated transactions through December 31, 2024. The timing and amount of the repurchase transactions under this program will depend on a variety of factors, including market conditions and corporate and regulatory considerations.

Earnings Per Common Share

Earnings Per Common Share	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Earnings Per Common Share	The following table sets forth the computation of basic and diluted earnings per common share: Three Months Ended Nine Months Ended September 30, September 30, 2024 2023 2024 2023 Numerator: Net income (loss) available to Arch $ 988 $ 723 $ 3,377 $ 2,109 Preferred dividends (10) (10) (30) (30) Net income (loss) available to Arch common shareholders $ 978 $ 713 $ 3,347 $ 2,079 Denominator: Weighted average common shares and common share equivalents outstanding — basic 373.2 369.2 372.3 368.4 Effect of dilutive common share equivalents: Nonvested restricted shares 2.0 2.6 1.8 2.4 Stock options (1) 7.1 7.6 7.2 7.5 Weighted average common shares and common share equivalents outstanding — diluted 382.3 379.4 381.3 378.3 Earnings per common share: Basic $ 2.62 $ 1.93 $ 8.99 $ 5.64 Diluted $ 2.56 $ 1.88 $ 8.78 $ 5.50

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2024
Segment Reporting [Abstract]
Segment Information	The Company’s insurance, reinsurance and mortgage segments each have managers who are responsible for the overall profitability of their respective segments and who are directly accountable to the Company’s chief operating decision makers. The Chief Executive Officer and the Chief Financial Officer and Treasurer are the Company’s chief operating decision makers. The Company’s chief operating decision makers do not assess performance, measure return on equity or make resource allocation decisions on a line of business basis. Management measures segment performance for its three reportable segments based on underwriting income or loss. The Company does not manage its assets by segment, with the exception of goodwill and intangible assets, and accordingly, investment income is not allocated to each segment. The Company determined its segments using the management approach described in accounting guidance regarding disclosures about segments of an enterprise and related information. The accounting policies of the segments are the same as those used for the preparation of the Company’s consolidated financial statements. Intersegment business is allocated to the segment accountable for the underwriting results. The Company’s insurance segment primarily consists of commercial insurance lines of business, with a focus on specialty insurance products. These products are mainly offered in North America, Bermuda, the United Kingdom, continental Europe and Australia. Products offered in North America include: commercial automobile; commercial multi‐peril; other liability—claims made, which includes financial and professional lines; other liability—occurrence, which includes admitted and excess and surplus casualty lines; property and short-tail specialty; workers compensation; and other. Products offered across the Company’s International units include: property and short-tail specialty; and casualty and other. The Company’s reinsurance segment offers reinsurance products on a worldwide basis. Product lines of business include: casualty; marine and aviation; other specialty; property catastrophe; property excluding property catastrophe; and other . The Company’s mortgage segment consists of U.S. primary mortgage insurance business written predominantly on loans sold to the Federal National Mortgage Association (“Fannie Mae”) and the Federal Home Loan Mortgage Corporation (“Freddie Mac”), each a government sponsored entity ("GSE") and also through non GSE approved entities (combined “Arch MI U.S.”); reinsurance and underwriting services related to U.S. credit-risk transfer (“CRT”) business which are predominately with the GSEs and other U.S. mortgage reinsurance transactions; and international mortgage insurance and reinsurance business covering loans primarily in Australia and Europe. The Company’s results also include net investment income, net realized gains or losses (which includes realized and unrealized changes in the fair value of equity securities and assets accounted for using the fair value option, realized and unrealized gains or losses on derivative instruments, changes in the allowance for credit losses on financial assets and gains or losses realized from the acquisition or disposition of subsidiaries), equity in net income or loss of investment funds accounted for using the equity method, other income (loss), corporate expenses, transaction costs and other, amortization of intangible assets, interest expense, net foreign exchange gains or losses, income tax items, income or loss from operating affiliates and items related to the Company’s non-cumulative preferred shares. The following tables summarize the Company’s underwriting income or loss by segment, together with a reconciliation of underwriting income or loss to net income available to Arch common shareholders: Three Months Ended September 30, 2024 Insurance Reinsurance Mortgage Total Gross premiums written (1) $ 2,341 $ 2,763 $ 339 $ 5,440 Premiums ceded (1) (521) (818) (57) (1,393) Net premiums written 1,820 1,945 282 4,047 Change in unearned premiums (55) (53) 31 (77) Net premiums earned 1,765 1,892 313 3,970 Other underwriting income (loss) — 2 3 5 Losses and loss adjustment expenses (1,087) (1,317) 1 (2,403) Acquisition expenses (308) (374) 1 (681) Other operating expenses (250) (54) (49) (353) Underwriting income (loss) $ 120 $ 149 $ 269 538 Net investment income 399 Net realized gains (losses) 169 Equity in net income (loss) of investment funds accounted for using the equity method 171 Other income (loss) 8 Corporate expenses (2) (19) Transaction costs and other (2) (30) Amortization of intangible assets (88) Interest expense (35) Net foreign exchange gains (losses) (63) Income (loss) before income taxes and income (loss) from operating affiliates 1,050 Income tax (expense) benefit (98) Income (loss) from operating affiliates 36 Net income (loss) available to Arch 988 Preferred dividends (10) Net income (loss) available to Arch common shareholders $ 978 Underwriting Ratios Loss ratio 61.6 % 69.6 % (0.4) % 60.5 % Acquisition expense ratio 17.4 % 19.8 % (0.4) % 17.2 % Other operating expense ratio 14.1 % 2.9 % 15.6 % 8.9 % Combined ratio 93.1 % 92.3 % 14.8 % 86.6 % Goodwill and intangible assets $ 1,025 $ 113 $ 348 $ 1,486 (1) Certain assumed and ceded amounts related to intersegment transactions are included in individual segment results. Accordingly, the sum of such transactions for each segment does not agree to the total due to eliminations. (2) Certain expenses have been excluded from ‘corporate expenses’ and reflected in ‘transaction costs and other.’ Three Months Ended September 30, 2023 Insurance Reinsurance Mortgage Total Gross premiums written (1) $ 2,043 $ 2,138 $ 347 $ 4,527 Premiums ceded (1) (521) (576) (76) (1,172) Net premiums written 1,522 1,562 271 3,355 Change in unearned premiums (110) (19) 22 (107) Net premiums earned 1,412 1,543 293 3,248 Other underwriting income (loss) — 2 3 5 Losses and loss adjustment expenses (812) (870) 35 (1,647) Acquisition expenses (269) (304) (2) (575) Other operating expenses (202) (61) (47) (310) Underwriting income (loss) $ 129 $ 310 $ 282 721 Net investment income 269 Net realized gains (losses) (248) Equity in net income (loss) of investment funds accounted for using the equity method 59 Other income (loss) (4) Corporate expenses (2) (20) Transaction costs and other (2) — Amortization of intangible assets (24) Interest expense (34) Net foreign exchange gains (losses) 22 Income (loss) before income taxes and income (loss) from operating affiliates 741 Income tax (expense) benefit (72) Income (loss) from operating affiliates 54 Net income (loss) available to Arch 723 Preferred dividends (10) Net income (loss) available to Arch common shareholders $ 713 Underwriting Ratios Loss ratio 57.5 % 56.4 % (12.1) % 50.7 % Acquisition expense ratio 19.1 % 19.7 % 0.6 % 17.7 % Other operating expense ratio 14.3 % 3.9 % 16.2 % 9.5 % Combined ratio 90.9 % 80.0 % 4.7 % 77.9 % Goodwill and intangible assets $ 220 $ 132 $ 387 $ 739 (1) Certain assumed and ceded amounts related to intersegment transactions are included in individual segment results. Accordingly, the sum of such transactions for each segment does not agree to the total due to eliminations. (2) Certain expenses have been excluded from ‘corporate expenses’ and reflected in ‘transaction costs and other.’ Nine Months Ended September 30, 2024 Insurance Reinsurance Mortgage Total Gross premiums written (1) $ 6,569 $ 9,171 $ 1,020 $ 16,755 Premiums ceded (1) (1,649) (3,013) (185) (4,842) Net premiums written 4,920 6,158 835 11,913 Change in unearned premiums (226) (820) 90 (956) Net premiums earned 4,694 5,338 925 10,957 Other underwriting income (loss) — 5 15 20 Losses and loss adjustment expenses (2,789) (3,206) 37 (5,958) Acquisition expenses (872) (1,050) 1 (1,921) Other operating expenses (718) (193) (151) (1,062) Underwriting income (loss) $ 315 $ 894 $ 827 2,036 Net investment income 1,090 Net realized gains (losses) 358 Equity in net income (loss) of investment funds accounted for using the equity method 437 Other income (loss) 30 Corporate expenses (2) (88) Transaction costs and other (2) (55) Amortization of intangible assets (136) Interest expense (104) Net foreign exchange gains (losses) (31) Income (loss) before income taxes and income (loss) from operating affiliates 3,537 Income tax (expense) benefit (296) Income (loss) from operating affiliates 136 Net income (loss) available to Arch 3,377 Preferred dividends (30) Net income (loss) available to Arch common shareholders $ 3,347 Underwriting Ratios Loss ratio 59.4 % 60.1 % (4.0) % 54.4 % Acquisition expense ratio 18.6 % 19.7 % (0.1) % 17.5 % Other operating expense ratio 15.3 % 3.6 % 16.3 % 9.7 % Combined ratio 93.3 % 83.4 % 12.2 % 81.6 % (1) Certain assumed and ceded amounts related to intersegment transactions are included in individual segment results. Accordingly, the sum of such transactions for each segment does not agree to the total due to eliminations. (2) Certain expenses have been excluded from ‘corporate expenses’ and reflected in ‘transaction costs and other.’ Nine Months Ended September 30, 2023 Insurance Reinsurance Mortgage Total Gross premiums written (1) $ 5,977 $ 7,142 $ 1,037 $ 14,152 Premiums ceded (1) (1,564) (2,145) (240) (3,945) Net premiums written 4,413 4,997 797 10,207 Change in unearned premiums (416) (781) 86 (1,111) Net premiums earned 3,997 4,216 883 9,096 Other underwriting income (loss) — 9 12 21 Losses and loss adjustment expenses (2,276) (2,379) 46 (4,609) Acquisition expenses (778) (875) (16) (1,669) Other operating expenses (592) (203) (147) (942) Underwriting income (loss) $ 351 $ 768 $ 778 1,897 Net investment income 710 Net realized gains (losses) (354) Equity in net income (loss) of investment funds accounted for using the equity method 176 Other income (loss) 10 Corporate expenses (2) (69) Transaction costs and other (2) (2) Amortization of intangible assets (71) Interest expense (99) Net foreign exchange gains (losses) (1) Income (loss) before income taxes and income (loss) from operating affiliates 2,197 Income tax (expense) benefit (203) Income (loss) from operating affiliates 115 Net income (loss) available to Arch 2,109 Preferred dividends (30) Net income (loss) available to Arch common shareholders $ 2,079 Underwriting Ratios Loss ratio 57.0 % 56.4 % (5.3) % 50.7 % Acquisition expense ratio 19.5 % 20.7 % 1.8 % 18.3 % Other operating expense ratio 14.8 % 4.8 % 16.7 % 10.4 % Combined ratio 91.3 % 81.9 % 13.2 % 79.4 % (1) Certain assumed and ceded amounts related to intersegment transactions are included in individual segment results. Accordingly, the sum of such transactions for each segment does not agree to the total due to eliminations.

Reserve for Losses and Loss Adj

Reserve for Losses and Loss Adjustment Expenses	9 Months Ended
	Sep. 30, 2024
Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense [Abstract]
Reserve for losses and loss adjustment expenses	The following table represents an analysis of losses and loss adjustment expenses and a reconciliation of the beginning and ending reserve for losses and loss adjustment expenses: Three Months Ended Nine Months Ended September 30, September 30, 2024 2023 2024 2023 Reserve for losses and loss adjustment expenses at beginning of period $ 24,466 $ 21,268 $ 22,752 $ 20,032 Unpaid losses and loss adjustment expenses recoverable 7,083 6,394 6,690 6,280 Net reserve for losses and loss adjustment expenses at beginning of period 17,383 14,874 16,062 13,752 Net incurred losses and loss adjustment expenses relating to losses occurring in: Current year 2,524 1,793 6,324 5,012 Prior years (121) (146) (366) (403) Total net incurred losses and loss adjustment expenses 2,403 1,647 5,958 4,609 Net losses and loss adjustment expense reserves of acquired businesses (1) 2,413 — 2,463 — Net foreign exchange (gains) losses and other 246 (123) 152 (24) Net paid losses and loss adjustment expenses relating to losses occurring in: Current year (362) (345) (647) (700) Prior years (967) (713) (2,872) (2,297) Total net paid losses and loss adjustment expenses (1,329) (1,058) (3,519) (2,997) Net reserve for losses and loss adjustment expenses at end of period 21,116 15,340 21,116 15,340 Unpaid losses and loss adjustment expenses recoverable 7,563 6,496 7,563 6,496 Reserve for losses and loss adjustment expenses at end of period $ 28,679 $ 21,836 $ 28,679 $ 21,836 (1) Activity for the 2024 third quarter related to the acquisition of MCE (see note 2 ) and Watford Insurance Company (see note 16 ), while activity for the nine months ended September 30, 2024 also reflects the Company’s acquisition of RMIC Companies, Inc. and its wholly-owned subsidiaries (“RMIC”) that, together, comprise the run-off mortgage insurance business of Old Republic International Corporation. Prior year development (“PYD”) arises from changes in loss estimates during the current period related to events occurring in prior calendar years. Long-tailed lines include lines of business that typically take many years for claims to settle such as third-party liability; short-tailed lines are those that settle more quickly such as property. The table below summarizes (favorable) and adverse net PYD by segment and tail length: Three Months Ended Nine Months Ended (Favorable) Adverse September 30, September 30, 2024 Short-tailed Long-tailed Total Short-tailed Long-tailed Total Insurance $ (31) $ 15 $ (16) $ (61) $ 30 $ (31) Reinsurance (68) 27 (41) (158) 43 (115) Mortgage (64) — (64) (220) — (220) Total $ (163) $ 42 $ (121) $ (439) $ 73 $ (366) 2023 Insurance $ (29) $ 19 $ (10) $ (74) $ 40 $ (34) Reinsurance (65) 21 (44) (168) 42 (126) Mortgage (92) — (92) (243) — (243) Total $ (186) $ 40 $ (146) $ (485) $ 82 $ (403) 2024 Third Quarter The insurance segment’s short-tailed lines included $15 million of favorable development in property and marine, primarily from the 2012 and 2023 accident years ( i.e. , the year in which a loss occurred), and $11 million of favorable development in travel and accident, primarily from the 2023 accident year. Long tailed lines primarily included adverse development in programs, mainly from the 2023 accident year. The reinsurance segment’s short-tailed lines included $35 million of favorable development from other specialty lines, primarily from the 2012 and subsequent underwriting years ( i.e. , all premiums and losses attributable to contracts having an inception or renewal date within the given 12 month period), and $20 million of favorable development from property other than property catastrophe, primarily from the 2022 and 2023 underwriting years. Long-tailed lines included $27 million of adverse development in casualty, primarily from the 2020 and 2022 underwriting years. The mortgage segment’s favorable development was driven by reductions on reserves for delinquent loans associated with the U.S. first lien portfolio from the 2023 accident year. The Company’s credit risk transfer and international businesses also contributed to the favorable development. 2023 Third Quarter The insurance segment’s short-tailed lines included $16 million of favorable development in property and marine, primarily from the 2021 and 2022 accident years. Long-tailed lines included $25 million of adverse development in professional liability, primarily from 2019 and 2020 accident years. The reinsurance segment’s short-tailed lines included $29 million of favorable development in property other than property catastrophe, primarily from the 2020 to 2022 underwriting years, $22 million of favorable development in property catastrophe, primarily from the 2021 and 2022 underwriting years, and $19 million of favorable development in other specialty lines, primarily from the 2021 and prior underwriting years. Long-tailed lines included $21 million of adverse development in casualty, primarily from the 2016 to 2020 underwriting years. The mortgage segment’s favorable development was driven by reserve releases associated with the U.S. first lien portfolio from the 2020 through 2022 accident years, with the credit risk transfer and international businesses also contributing. Nine Months Ended September 30, 2024 The insurance segment’s short-tailed lines included $31 million of favorable development in surety, primarily from the 2007 and 2022 accident years, and $29 million of favorable development in travel and accident, primarily from the 2023 accident year. Net adverse development in long-tailed lines primarily included adverse development in programs, mainly from the 2023 accident year. The reinsurance segment’s short-tailed lines included $72 million of favorable development from other specialty lines, primarily from the 2015 and subsequent underwriting years and $71 million of favorable development from property other than property catastrophe, primarily from the 2022 and 2023 underwriting years. Long-tailed lines included $43 million of adverse development in casualty, primarily from the 2017 and 2020 underwriting years. The mortgage segment’s favorable development was driven by reserve releases associated with the U.S. first lien portfolio from the 2022 and 2023 accident years. The Company’s credit risk transfer and international businesses also contributed to the favorable development. Nine Months Ended September 30, 2023 The insurance segment’s short-tailed lines included $44 million of favorable development in property and marine, primarily from the 2021 and 2022 accident years and $20 million of favorable development in warranty and lenders solutions, primarily from the 2022 accident year. Long-tailed lines included $48 million of adverse development in professional liability, primarily from the 2017 to 2020 accident years, partially offset by $24 million of favorable development in executive assurance, primarily from the 2019 and 2021 accident years. The reinsurance segment’s short-tailed lines included $75 million of favorable development in property other than property catastrophe, primarily from the 2021 and 2022 underwriting years, $46 million in other specialty lines, primarily from the 2021 underwriting year, and $29 million of favorable development in property catastrophe, primarily from the 2019 and 2022 underwriting years. Long-tailed lines primarily included $39 million of adverse development in casualty, primarily from the 2014 to 2020 underwriting years. The mortgage segment’s favorable development was driven by reserve releases associated with the U.S. first lien portfolio from the 2020 to 2022 accident years, with the credit risk transfer and international businesses also contributing.

Allowance for Expected Credit L

Allowance for Expected Credit Losses	9 Months Ended
	Sep. 30, 2024
Credit Loss [Abstract]
Allowance for expected credit losses	Premiums Receivable The following table provides a roll forward of the allowance for expected credit losses of the Company’s premium receivables: Premium Receivables, Net of Allowance Allowance for Expected Credit Losses Three Months Ended September 30, 2024 Balance at beginning of period $ 6,268 $ 36 Provision on business acquired (1) 16 Change for provision of expected credit losses (2) — Balance at end of period $ 6,364 $ 52 Three Months Ended September 30, 2023 Balance at beginning of period $ 5,296 $ 34 Change for provision of expected credit losses (2) — Balance at end of period $ 4,937 $ 34 Nine Months Ended September 30, 2024 Balance at beginning of year $ 4,644 $ 34 Provision on business acquired (1) 16 Change for provision of expected credit losses (2) 2 Balance at end of period $ 6,364 $ 52 Nine Months Ended September 30, 2023 Balance at beginning of year $ 3,625 $ 35 Change for provision of expected credit losses (2) (1) Balance at end of period $ 4,937 $ 34 (1) Represents MCE’s provision for current expected credit losses on premiums receivable. See note 2 . (2) Amounts deemed uncollectible are written-off in operating expenses. For the 2024 third quarter and 2023 third quarter, amounts written off were $1 million and nil, respectively. For the nine months ended September 30, 2024 and 2023 period, amounts written off were $1 million and $2 million, respectively. Reinsurance Recoverables The following table provides a roll forward of the allowance for expected credit losses of the Company’s reinsurance recoverables: Reinsurance Recoverables, Net of Allowance Allowance for Expected Credit Losses Three Months Ended September 30, 2024 Balance at beginning of period $ 7,473 $ 20 Change for provision of expected credit losses (3) Balance at end of period $ 7,948 $ 17 Three Months Ended September 30, 2023 Balance at beginning of period $ 6,717 $ 22 Change for provision of expected credit losses 1 Balance at end of period $ 6,821 $ 23 Nine Months Ended September 30, 2024 Balance at beginning of year $ 7,064 $ 21 Change for provision of expected credit losses (4) Balance at end of period $ 7,948 $ 17 Nine Months Ended September 30, 2023 Balance at beginning of year $ 6,564 $ 22 Change for provision of expected credit losses 1 Balance at end of period $ 6,821 $ 23 The following table summarizes the Company’s reinsurance recoverables on paid and unpaid losses (not including ceded unearned premiums): September 30, December 31, 2024 2023 Reinsurance recoverable on unpaid and paid losses and loss adjustment expenses $ 7,948 $ 7,064 % due from carriers with A.M. Best rating of “A-” or better 65.3 % 66.8 % % due from all other rated carriers 0.0 % 0.1 % % due from all other carriers with no A.M. Best rating (1) 34.7 % 33.1 % Largest balance due from any one carrier as % of total shareholders’ equity 7.1 % 7.2 % (1) At September 30, 2024 and December 31, 2023 over 95% of such amount were collateralized through reinsurance trusts, funds withheld arrangements, letters of credit or other. Contractholder Receivables The following table provides a roll forward of the allowance for expected credit losses of the Company’s contractholder receivables: Contract-holder Receivables, Net of Allowance Allowance for Expected Credit Losses Three Months Ended September 30, 2024 Balance at beginning of period $ 2,016 $ 4 Change for provision of expected credit losses — Balance at end of period $ 2,078 $ 4 Three Months Ended September 30, 2023 Balance at beginning of period $ 1,761 $ 3 Change for provision of expected credit losses — Balance at end of period 1,805 $ 3 Nine Months Ended September 30, 2024 Balance at beginning of year $ 1,814 $ 3 Change for provision of expected credit losses 1 Balance at end of period $ 2,078 $ 4 Nine Months Ended September 30, 2023 Balance at beginning of year $ 1,731 $ 3 Change for provision of expected credit losses — Balance at end of period 1,805 $ 3

Investment Information

Investment Information	9 Months Ended
	Sep. 30, 2024
Disclosure Investment Information [Abstract]
Investment	Available For Sale Investments The following table summarizes the fair value and cost or amortized cost of the Company’s securities classified as available for sale: Estimated Gross Gross Allowance for Expected Credit Losses Cost or September 30, 2024 Fixed maturities: Corporate bonds $ 13,996 $ 339 $ (294) $ (12) $ 13,963 U.S. government and government agencies 5,863 53 (48) — 5,858 Asset backed securities 2,989 27 (27) (5) 2,994 Non-U.S. government securities 2,853 75 (84) (1) 2,863 Commercial mortgage backed securities 1,146 8 (17) (1) 1,156 Residential mortgage backed securities 1,313 14 (50) — 1,349 Municipal bonds 274 2 (11) — 283 Total 28,434 518 (531) (19) 28,466 Short-term investments 3,341 6 (2) — 3,337 Total $ 31,775 $ 524 $ (533) $ (19) $ 31,803 December 31, 2023 Fixed maturities: Corporate bonds $ 10,855 $ 157 $ (464) $ (20) $ 11,182 U.S. government and government agencies 5,814 63 (86) — 5,837 Asset backed securities 2,250 11 (55) (5) 2,299 Non-U.S. government securities 2,062 33 (100) (1) 2,130 Commercial mortgage backed securities 1,213 3 (34) (2) 1,246 Residential mortgage backed securities 1,103 7 (66) — 1,162 Municipal bonds 256 1 (20) — 275 Total 23,553 275 (825) (28) 24,131 Short-term investments 2,063 1 (2) — 2,064 Total $ 25,616 $ 276 $ (827) $ (28) $ 26,195 The following table summarizes, for all available for sale securities in an unrealized loss position, the fair value and gross unrealized loss by length of time the security has been in a continual unrealized loss position: Less than 12 Months 12 Months or More Total Estimated Gross Estimated Gross Estimated Gross September 30, 2024 Fixed maturities: Corporate bonds $ 1,903 $ (76) $ 3,316 $ (218) $ 5,219 $ (294) U.S. government and government agencies 1,815 (10) 571 (38) 2,386 (48) Non-U.S. government securities 614 (8) 743 (76) 1,357 (84) Residential mortgage backed securities 213 (2) 485 (48) 698 (50) Asset backed securities 199 (3) 442 (24) 641 (27) Commercial mortgage backed securities 176 (1) 644 (16) 820 (17) Municipal bonds 1 — 185 (11) 186 (11) Total 4,921 (100) 6,386 (431) 11,307 (531) Short-term investments 362 (2) — — 362 (2) Total $ 5,283 $ (102) $ 6,386 $ (431) $ 11,669 $ (533) December 31, 2023 Fixed maturities: Corporate bonds $ 1,559 $ (45) $ 4,959 $ (419) $ 6,518 $ (464) U.S. government and government agencies 1,066 (10) 941 (76) 2,007 (86) Non-U.S. government securities 365 (4) 897 (96) 1,262 (100) Residential mortgage backed securities 221 (3) 522 (63) 743 (66) Asset backed securities 234 (1) 1,112 (54) 1,346 (55) Commercial mortgage backed securities 100 (1) 909 (33) 1,009 (34) Municipal bonds 20 (1) 215 (19) 235 (20) Total 3,565 (65) 9,555 (760) 13,120 (825) Short-term investments 302 (2) — — 302 (2) Total $ 3,867 $ (67) $ 9,555 $ (760) $ 13,422 $ (827) At September 30, 2024, on a lot level basis, approximately 6,710 security lots out of a total of approximately 19,840 security lots were in an unrealized loss position and the largest single unrealized loss from a single lot in the Company’s fixed maturity portfolio was $4 million. At December 31, 2023, on a lot level basis, approximately 7,100 security lots out of a total of approximately 15,720 security lots were in an unrealized loss position and the largest single unrealized loss from a single lot in the Company’s fixed maturity portfolio was $6 million. The contractual maturities of the Company’s fixed maturities are shown in the following table. Expected maturities, which are management’s best estimates, will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. September 30, 2024 December 31, 2023 Maturity Estimated Amortized Estimated Amortized Due in one year or less $ 430 $ 445 $ 480 $ 499 Due after one year through five years 15,533 15,457 12,924 13,101 Due after five years through 10 years 6,572 6,595 5,249 5,450 Due after 10 years 451 470 334 374 22,986 22,967 18,987 19,424 Residential mortgage backed securities 1,313 1,349 1,103 1,162 Commercial mortgage backed securities 1,146 1,156 1,213 1,246 Asset backed securities 2,989 2,994 2,250 2,299 Total $ 28,434 $ 28,466 $ 23,553 $ 24,131 Equity Securities, at Fair Value At September 30, 2024, the Company held $1.6 billion of equity securities, at fair value, compared to $1.2 billion at December 31, 2023. Such holdings include publicly traded common stocks, primarily in the consumer cyclical and non-cyclical, technology, communication and financial sectors, and exchange-traded funds in fixed income, equity and other sectors. Other Investments, at Fair Value The following table summarizes the Company’s other investments: September 30, December 31, Other investments $ 2,096 $ 1,777 Fixed maturities 1,097 683 Short term investments 61 21 Equity securities 7 7 Total $ 3,261 $ 2,488 The following table summarizes the Company’s other investments, as detailed in the previous table, by strategy: September 30, December 31, Investment grade fixed income $ 957 $ 754 Term loan investments 499 272 Lending 299 427 Private equity 212 182 Credit related funds 111 124 Energy 18 18 Total $ 2,096 $ 1,777 Net Investment Income The components of net investment income were derived from the following sources: September 30, 2024 2023 Three Months Ended Fixed maturities $ 340 $ 243 Short term investments 38 19 Equity securities 9 5 Other (1) 35 22 Gross investment income 422 289 Investment expenses (23) (20) Net investment income $ 399 $ 269 Nine Months Ended Fixed maturities $ 926 $ 645 Short term investments 102 48 Equity securities 27 15 Other (1) 103 60 Gross investment income 1,158 768 Investment expenses (68) (58) Net investment income $ 1,090 $ 710 (1) Amounts include dividends and other distributions on investment funds, term loan investments, funds held balances, cash balances and other items. Net Realized Gains (Losses) Net realized gains (losses), which include changes in the allowance for credit losses on financial assets and net impairment losses recognized in earnings were as follows: September 30, 2024 2023 Three Months Ended Available for sale securities: Gross gains on investment sales $ 104 $ 12 Gross losses on investment sales (50) (116) Change in fair value of assets and liabilities accounted for using the fair value option: Fixed maturities 25 (16) Other investments (120) 3 Equity securities, at fair value: Net realized gains (losses) on sales during the period 15 14 Net unrealized gains (losses) on equity securities still held at reporting date 58 (46) Allowance for credit losses: Investments related 6 — Underwriting related 2 (1) Derivative instruments (1) 125 (102) Other 4 4 Net realized gains (losses) $ 169 $ (248) Nine Months Ended Available for sale securities: Gross gains on investment sales $ 167 $ 51 Gross losses on investment sales (205) (396) Change in fair value of assets and liabilities accounted for using the fair value option: Fixed maturities 23 (12) Other investments (150) 17 Equity securities — 1 Equity securities, at fair value: Net realized gains (losses) on sales during the period 31 50 Net unrealized gains (losses) on equity securities still held at reporting date 147 17 Allowance for credit losses: Investments related 4 (23) Underwriting related — (2) Derivative instruments (1) 116 (61) Other (2) 225 4 Net realized gains (losses) $ 358 $ (354) (1) See note 10 for information on the Company’s derivative instruments. (2) Amounts include benefits from the sale of Castel Underwriting Agencies Limited and the acquisition of RMIC. Investments Accounted For Using the Equity Method The following table summarizes the Company’s investments accounted for using the equity method, by strategy: September 30, December 31, Private equity $ 1,737 $ 1,175 Credit related funds 1,366 1,258 Real estate 721 666 Lending 474 597 Fixed income 377 277 Infrastructure 323 320 Equities 177 178 Energy 69 95 Total $ 5,244 $ 4,566 Certain of the Company’s other investments are in investment funds for which the Company has the option to redeem at agreed upon values as described in each investment fund’s subscription agreement. Depending on the terms of the various subscription agreements, investments in investment funds may be redeemed daily, monthly, quarterly or on other terms. Two common redemption restrictions which may impact the Company’s ability to redeem these investment funds are gates and lockups. A gate is a suspension of redemptions which may be implemented by the general partner or investment manager of the fund in order to defer, in whole or in part, the redemption request in the event the aggregate amount of redemption requests exceeds a predetermined percentage of the investment fund’s net assets which may otherwise hinder the general partner or investment manager’s ability to liquidate holdings in an orderly fashion in order to generate the cash necessary to fund extraordinarily large redemption payouts. A lockup period is the initial amount of time an investor is contractually required to hold the security before having the ability to redeem. If the investment funds are eligible to be redeemed, the time to redeem such fund can take weeks or months following the notification. Limited Partnership Interests In the normal course of its activities, the Company invests in limited partnerships as part of its overall investment strategy. Such amounts are included in ‘investments accounted for using the equity method’ and ‘investments accounted for using the fair value option.’ The Company has determined that it is not required to consolidate these investments because it is not the primary beneficiary of the funds. The Company’s maximum exposure to loss with respect to these investments is limited to the investment carrying amounts reported in the Company’s consolidated balance sheet and any unfunded commitment. The following table summarizes investments in limited partnership interests where the Company has a variable interest by balance sheet line item: September 30, December 31, Investments accounted for using the equity method (1) $ 5,244 $ 4,566 Investments accounted for using the fair value option (2) 83 114 Total $ 5,327 $ 4,680 (1) Aggregate unfunded commitments were $4.3 billion at September 30, 2024, compared with $3.4 billion at December 31, 2023. (2) Aggregate unfunded commitments were $21 million at September 30, 2024, compared to $32 million at December 31, 2023. Equity in Net Income (Loss) of Investment Funds Accounted for Using the Equity Method Income from investment funds accounted for using the equity method for the 2024 third quarter was $171 million, compared to $59 million for the 2023 third quarter and an income of $437 million for the nine months ended September 30, 2024, compared to income of $176 million for the nine months ended September 30, 2023. In applying the equity method, investments are initially recorded at cost and are subsequently adjusted based on the Company’s proportionate share of the net income or loss of the funds (which include changes in the market value of the underlying securities in the funds). Such investments are generally recorded on a one Investments in Operating Affiliates Investments in which the Company has significant influence over the operating and financial policies are classified as ‘investments in operating affiliates’ on the Company’s balance sheets and are accounted for under the equity method. Such investments primarily include the Company’s investment in Coface SA (“Coface”), Greysbridge Holdings Ltd., (“Greysbridge”) and Premia Holdings Ltd. Investments in Coface and Premia Holdings Ltd. are generally recorded on a three month lag, while the Company’s investment in Greysbridge is not recorded on a lag. As of September 30, 2024, the Company owned approximately 29.9% of the issued shares of Coface, or 30% excluding treasury shares, with a carrying value of $596 million, compared to $570 million at December 31, 2023. As of September 30, 2024, the Company owned 40% of Greysbridge with a carrying value of $521 million, compared to $430 million at December 31, 2023. Income from operating affiliates for the 2024 third quarter was $36 million, compared to $54 million for the 2023 third quarter and income of $136 million for the nine months ended September 30, 2024, compared to income of $115 million for nine months ended September 30, 2023 See note 1 6 for information on Company’s transactions with related parties. Allowance for Expected Credit Losses The following table provides a roll forward of the allowance for expected credit losses of the Company’s securities classified as available for sale: Structured Securities (1) Corporate Non-U.S. Total Three Months Ended September 30, 2024 Balance at beginning of period $ 10 $ 16 $ 1 $ 27 Additions (reductions) for previously recognized expected credit losses (3) (3) — (6) Reductions due to disposals (1) (1) — (2) Balance at end of period $ 6 $ 12 $ 1 $ 19 Three Months Ended September 30, 2023 Balance at beginning of period $ 8 $ 50 $ 3 $ 61 Additions for current-period provision for expected credit losses 2 4 — 6 Additions (reductions) for previously recognized expected credit losses — (3) — (3) Reductions due to disposals (2) (4) (1) (7) Balance at end of period $ 8 $ 47 $ 2 $ 57 Nine Months Ended September 30, 2024 Balance at beginning of year $ 7 $ 20 $ 1 $ 28 Additions (reductions) for previously recognized expected credit losses — (4) — (4) Reductions due to disposals (1) (4) — (5) Balance at end of period $ 6 $ 12 $ 1 $ 19 Nine Months Ended September 30, 2023 Balance at beginning of year $ 9 $ 30 $ 2 $ 41 Additions for current-period provision for expected credit losses 2 5 — 7 Additions (reductions) for previously recognized expected credit losses (1) 18 1 18 Reductions due to disposals (2) (6) (1) (9) Balance at end of period $ 8 $ 47 $ 2 $ 57 (1) Includes asset backed securities, residential mortgage backed securities and commercial mortgage backed securities. Restricted Assets The Company is required to maintain assets on deposit, which primarily consist of fixed maturities, with various regulatory authorities to support its underwriting operations. The Company’s subsidiaries maintain assets in trust accounts as collateral for transactions with affiliated companies and also have investments in segregated portfolios primarily to provide collateral or guarantees for letters of credit to third parties. See note 18, “Commitments and Contingencies,” of the notes to consolidated financial statements in the Company’s 2023 Form 10-K. The following table details the value of the Company’s restricted assets: September 30, December 31, Assets used for collateral or guarantees: Affiliated transactions $ 5,306 $ 4,854 Third party agreements (1) 5,679 2,869 Deposits with U.S. regulatory authorities 883 833 Other (2) 1,453 1,376 Total restricted assets $ 13,321 $ 9,932 (1) 2024 period includes amounts related to the MCE Acquisition. (2) Primarily includes Funds at Lloyds, deposits with non-U.S. regulatory authorities and other restricted assets. Reconciliation of Cash and Restricted Cash The following table details reconciliation of cash and restricted cash within the Consolidated Balance Sheets: September 30, December 31, Cash $ 1,025 $ 917 Restricted cash (included in ‘other assets’) 687 581 Cash and restricted cash $ 1,712 $ 1,498

Fair Value

Fair Value	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Fair Value	Accounting guidance regarding fair value measurements addresses how companies should measure fair value when they are required to use a fair value measure for recognition or disclosure purposes under GAAP and provides a common definition of fair value to be used throughout GAAP. It defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly fashion between market participants at the measurement date. In addition, it establishes a three-level valuation hierarchy for the disclosure of fair value measurements. The valuation hierarchy is based upon the transparency of inputs to the valuation of an asset or liability as of the measurement date. The level in the hierarchy within which a given fair value measurement falls is determined based on the lowest level input that is significant to the measurement (Level 1 being the highest priority and Level 3 being the lowest priority). The levels in the hierarchy are defined as follows: Level 1: Inputs to the valuation methodology are observable inputs that reflect quoted prices (unadjusted) for identical assets or liabilities in active markets Level 2: Inputs to the valuation methodology include quoted prices for similar assets and liabilities in active markets, and inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument Level 3: Inputs to the valuation methodology are unobservable and significant to the fair value measurement Following is a description of the valuation methodologies used for securities measured at fair value, as well as the general classification of such securities pursuant to the valuation hierarchy. The Company reviews its securities measured at fair value and discusses the proper classification of such investments with investment advisers and others. The Company determines the existence of an active market based on its judgment as to whether transactions for the financial instrument occur in such market with sufficient frequency and volume to provide reliable pricing information. The independent pricing sources obtain market quotations and actual transaction prices for securities that have quoted prices in active markets. The Company uses quoted values and other data provided by nationally recognized independent pricing sources as inputs into its process for determining fair values of its fixed maturity investments. To validate the techniques or models used by pricing sources, the Company's review process includes, but is not limited to: (i) quantitative analysis ( e.g., comparing the quarterly return for each managed portfolio to its target benchmark, with significant differences identified and investigated); (ii) a review of the average number of prices obtained in the pricing process and the range of resulting fair values; (iii) initial and ongoing evaluation of methodologies used by outside parties to calculate fair value; (iv) a comparison of the fair value estimates to the Company’s knowledge of the current market; (v) a comparison of the pricing services' fair values to other pricing services' fair values for the same investments; and (vi) periodic back-testing, which includes randomly selecting purchased or sold securities and comparing the executed prices to the fair value estimates from the pricing service. A price source hierarchy was maintained in order to determine which price source would be used (i.e. , a price obtained from a pricing service with more seniority in the hierarchy will be used over a less senior one in all cases). The hierarchy prioritizes pricing services based on availability and reliability and assigns the highest priority to index providers. Based on the above review, the Company will challenge any prices for a security or portfolio which are considered not to be representative of fair value. The Company did not adjust any of the prices obtained from the independent pricing sources at September 30, 2024. In certain circumstances, when fair values are unavailable from these independent pricing sources, quotes are obtained directly from broker-dealers who are active in the corresponding markets. Such quotes are subject to the validation procedures noted above. Where quotes are unavailable, fair value is determined by the Investment Manager using quantitative and qualitative assessments such as internally modeled values. Of the $36.9 billion of financial assets and liabilities measured at fair value at September 30, 2024, approximately $146 million, or 0.4%, were priced using non-binding broker-dealer quotes or modeled valuations. Of the $29.6 billion of financial assets and liabilities measured at fair value at December 31, 2023, approximately $14 million, or 0.0%, were priced using non-binding broker-dealer quotes or modeled valuations. Fixed maturities The Company uses the market approach valuation technique to estimate the fair value of its fixed maturity securities, when possible. The market approach includes obtaining prices from independent pricing services, such as index providers and pricing vendors, as well as to a lesser extent quotes from broker-dealers. The independent pricing sources obtain market quotations and actual transaction prices for securities that have quoted prices in active markets. Each source has its own proprietary method for determining the fair value of securities that are not actively traded. In general, these methods involve the use of “matrix pricing” in which the independent pricing source uses observable market inputs including, but not limited to, investment yields, credit risks and spreads, benchmarking of like securities, broker-dealer quotes, reported trades and sector groupings to determine a reasonable fair value. The following describes the significant inputs generally used to determine the fair value of the Company’s fixed maturity securities by asset class: U.S. government and government agencies – valuations provided by independent pricing services, with all prices provided through index providers and pricing vendors. The Company determined that all U.S. Treasuries would be classified as Level 1 securities due to observed levels of trading activity, the high number of strongly correlated pricing quotes received on U.S. Treasuries and other factors. The fair values of U.S. government agency securities are generally determined using the spread above the risk-free yield curve. As the yields for the risk-free yield curve and the spreads for these securities are observable market inputs, the fair values of U.S. government agency securities are classified within Level 2. Corporate bonds – valuations provided by independent pricing services, substantially all through index providers and pricing vendors with a small amount through broker-dealers. The fair values of these securities are generally determined using the spread above the risk-free yield curve. These spreads are generally obtained from the new issue market, secondary trading and from broker-dealers who trade in the relevant security market. As the significant inputs used in the pricing process for corporate bonds are observable market inputs, the fair value of these securities are classified within Level 2. A small number of securities are included in Level 3 due to a low level of transparency on the inputs used in the pricing process. Municipal bonds – valuations provided by independent pricing services, with all prices provided through index providers and pricing vendors. The fair values of these securities are generally determined using spreads obtained from broker-dealers who trade in the relevant security market, trade prices and the new issue market. As the significant inputs used in the pricing process for municipal bonds are observable market inputs, the fair value of these securities are classified within Level 2. Residential mortgage-backed securities – valuations provided by independent pricing services, substantially all through pricing vendors and index providers with a small amount through broker-dealers. The fair values of these securities are generally determined through the use of pricing models (including Option Adjusted Spread) which use spreads to determine the expected average life of the securities. These spreads are generally obtained from the new issue market, secondary trading and from broker-dealers who trade in the relevant security market. The pricing services also review prepayment speeds and other indicators, when applicable. As the significant inputs used in the pricing process for mortgage-backed securities are observable market inputs, the fair value of these securities are classified within Level 2. A small number of securities are included in Level 3 due to a low level of transparency on the inputs used in the pricing process. Commercial mortgage-backed securities – valuations provided by independent pricing services, substantially all through index providers and pricing vendors with a small amount through broker-dealers. The fair values of these securities are generally determined through the use of pricing models which use spreads to determine the appropriate average life of the securities. These spreads are generally obtained from the new issue market, secondary trading and from broker-dealers who trade in the relevant security market. The pricing services also review prepayment speeds and other indicators, when applicable. As the significant inputs used in the pricing process for commercial mortgage-backed securities are observable market inputs, the fair value of these securities are classified within Level 2. Non-U.S. government securities – valuations provided by independent pricing services, with all prices provided through index providers and pricing vendors. The fair values of these securities are generally based on international indices or valuation models which include daily observed yield curves, cross-currency basis index spreads and country credit spreads. As the significant inputs used in the pricing process for non-U.S. government securities are observable market inputs, the fair value of these securities are classified within Level 2. Asset-backed securities – valuations provided by independent pricing services, substantially all through index providers and pricing vendors with a small amount through broker-dealers. The fair values of these securities are generally determined through the use of pricing models (including Option Adjusted Spread) which use spreads to determine the appropriate average life of the securities. These spreads are generally obtained from the new issue market, secondary trading and from broker-dealers who trade in the relevant security market. The pricing services also review prepayment speeds and other indicators, when applicable. As the significant inputs used in the pricing process for asset-backed securities are observable market inputs, the fair value of these securities are classified within Level 2. Equity securities The Company determined that exchange-traded equity securities would be included in Level 1 as their fair values are based on quoted market prices in active markets. Certain equity securities are included in Level 2 of the valuation hierarchy as the significant inputs used in the pricing process for such securities are observable market inputs. Other equity securities are included in Level 3 due to the lack of an available independent price source for such securities. As the significant inputs used to price these securities are unobservable, the fair value of such securities are classified as Level 3. Other investments The Company’s other investments include term loan investments for which fair values are estimated by using quoted prices of term loan investments with similar characteristics, pricing models or matrix pricing. Such investments are generally classified within Level 2. The fair values for certain of the Company’s other investments are determined using net asset values as advised by external fund managers. The net asset value is based on the fund manager’s valuation of the underlying holdings in accordance with the fund’s governing documents. In accordance with applicable accounting guidance, certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. A small number of securities are included in Level 3 due to the lack of an available independent price source for such securities. Derivative instruments The Company’s futures contracts, foreign currency forward contracts, interest rate swaps and other derivatives trade in the over-the-counter derivative market. The Company uses the market approach valuation technique to estimate the fair value for these derivatives based on significant observable market inputs from third party pricing vendors, non-binding broker-dealer quotes and/or recent trading activity. As the significant inputs used in the pricing process for these derivative instruments are observable market inputs, the fair value of these securities are classified within Level 2. Short-term investments The Company determined that certain of its short-term investments held in highly liquid money market-type funds, Treasury bills and commercial paper would be included in Level 1 as their fair values are based on quoted market prices in active markets. The fair values of certain short-term investments are generally determined using the spread above the risk-free yield curve and are classified within Level 2. Other short-term investments are included in Level 3 due to the lack of an available independent price source for such securities. As the significant inputs used to price these short-term securities are unobservable, the fair value of such securities are classified as Level 3. Residential mortgage loans The Company’s residential mortgage loans (included in ‘other assets’ in the consolidated balance sheets) include amounts related to the Company’s whole mortgage loan purchase and sell program. Fair values of residential mortgage loans are generally determined based on market prices. As significant inputs used in pricing process for these residential mortgage loans are observable market inputs, the fair value of these securities are classified within Level 2. Other liabilities The Company’s other liabilities include contingent and deferred consideration liabilities related to the Company’s acquisitions. Contingent consideration liabilities are remeasured at fair value at each balance sheet date with changes in fair value recognized in ‘net realized gains (losses’). To determine the fair value of contingent consideration liabilities, the Company estimates the future payments using an income approach based on modeled inputs which include a weighted average cost of capital. Deferred consideration liabilities are measured at fair value on the transaction date. The Company determined that contingent and deferred consideration liabilities would be included within Level 3. The following table presents the Company’s financial assets and liabilities measured at fair value by level at September 30, 2024: Estimated Fair Value Measurements Using: Estimated Quoted Prices in Significant Significant Assets measured at fair value: Available for sale securities: Fixed maturities: Corporate bonds $ 13,996 $ 2 $ 13,853 $ 141 U.S. government and government agencies 5,863 5,850 13 — Asset backed securities 2,989 — 2,989 — Non-U.S. government securities 2,853 — 2,853 — Commercial mortgage backed securities 1,146 — 1,146 — Residential mortgage backed securities 1,313 — 1,313 — Municipal bonds 274 — 274 — Total 28,434 5,852 22,441 141 Short-term investments 3,341 3,081 163 97 Equity securities, at fair value 1,623 1,590 27 6 Derivative instruments (2) 147 — 147 — Residential mortgage loans 13 — 13 — Fair value option: Corporate bonds 1,085 — 1,085 — Non-U.S. government bonds 8 — 8 — U.S. government and government agencies 4 4 — — Short-term investments 61 3 43 15 Equity securities 7 3 — 4 Other investments 703 — 413 290 Other investments measured at net asset value (1) 1,393 Total 3,261 10 1,549 309 Total assets measured at fair value $ 36,819 $ 10,533 $ 24,340 $ 553 Liabilities measured at fair value: Other liabilities $ (43) $ — $ — $ (43) Derivative instruments (2) (81) — (81) — Total liabilities measured at fair value $ (124) $ — $ (81) $ (43) (1) In accordance with applicable accounting guidance, certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the consolidated balance sheets. (2) See note 10 . The following table presents the Company’s financial assets and liabilities measured at fair value by level at December 31, 2023: Estimated Fair Value Measurements Using: Estimated Quoted Prices in Significant Significant Assets measured at fair value: Available for sale securities: Fixed maturities: Corporate bonds $ 10,855 $ — $ 10,708 $ 147 U.S. government and government agencies 5,814 5,792 22 — Asset backed securities 2,250 — 2,250 — Non-U.S. government securities 2,062 — 2,062 — Commercial mortgage backed securities 1,213 — 1,213 — Residential mortgage backed securities 1,103 — 1,103 — Municipal bonds 256 — 256 — Total 23,553 5,792 17,614 147 Short-term investments 2,063 1,786 193 84 Equity securities, at fair value 1,186 1,151 30 5 Derivative instruments (2) 197 — 197 — Residential mortgage loans 2 — 2 — Fair value option: Corporate bonds 662 — 662 — Non-U.S. government bonds 6 — 6 — Asset backed securities 2 — 2 — U.S. government and government agencies 13 13 — — Short-term investments 21 — 11 10 Equity securities 7 3 — 4 Other investments 316 — 210 106 Other investments measured at net asset value (1) 1,461 Total 2,488 16 891 120 Total assets measured at fair value $ 29,489 $ 8,745 $ 18,927 $ 356 Liabilities measured at fair value: Other liabilities $ (22) $ — $ — $ (22) Derivative instruments (2) (119) — (119) — Total liabilities measured at fair value $ (141) $ — $ (119) $ (22) (1) In accordance with applicable accounting guidance, certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the consolidated balance sheets. (2) See note 10 . The following table presents a reconciliation of the beginning and ending balances for all financial assets and liabilities measured at fair value on a recurring basis using Level 3 inputs: Assets Liabilities s Available For Sale Fair Value Option Fair Value Corporate Short-term Other Short-term Equity Equity Other Liabilities Three Months Ended September 30, 2024 Balance at beginning of period $ 160 $ 97 $ 144 $ 14 $ 4 $ 6 $ (35) Total gains or (losses) (realized/unrealized) Included in earnings (1) — — — — — — (1) Included in other comprehensive income — — — — — — — Purchases, issuances, sales and settlements Purchases — — 39 5 — — — Issuances (2) — — — — — — (9) Sales — — (2) — — — — Settlements (19) — (14) (4) — — 2 Transfers in and/or out of Level 3 — — 123 — — — — Balance at end of period $ 141 $ 97 $ 290 $ 15 $ 4 $ 6 $ (43) Three Months Ended September 30, 2023 Balance at beginning of period $ 100 $ — $ 86 $ — $ 4 $ 5 $ (19) Total gains or (losses) (realized/unrealized) Included in earnings (1) — — — — — — — Included in other comprehensive income (1) — — — — — — Purchases, issuances, sales and settlements Purchases 25 — 29 4 — — — Issuances — — — — — — (4) Sales — — (6) — — — — Settlements — — (9) — — — 2 Transfers in and/or out of Level 3 — — — — — — — Balance at end of period $ 124 $ — $ 100 $ 4 $ 4 $ 5 $ (21) Nine Months Ended September 30, 2024 Balance at beginning of year $ 147 $ 84 $ 106 $ 10 $ 4 $ 5 $ (22) Total gains or (losses) (realized/unrealized) Included in earnings (1) — — (4) — — — (1) Included in other comprehensive income 2 1 — — — — — Purchases, issuances, sales and settlements Purchases 98 12 99 15 — 1 — Issuances (2) — — — — — — (22) Sales — — (4) — — — — Settlements (106) — (30) (10) — — 2 Transfers in and/or out of Level 3 — — 123 — — — — Balance at end of period $ 141 $ 97 $ 290 $ 15 $ 4 $ 6 $ (43) Nine Months Ended September 30, 2023 Balance at beginning of year $ 121 $ — $ 33 $ — $ 4 $ 4 $ (14) Total gains or (losses) (realized/unrealized) Included in earnings (1) 1 — (1) — — — — Included in other comprehensive income (1) — — — — — — Purchases, issuances, sales and settlements Purchases 68 — 87 4 — 1 — Issuances — — — — — — (9) Sales — — (10) — — — — Settlements (65) — (9) — — — 2 Transfers in and/or out of Level 3 — — — — — — — Balance at end of period $ 124 $ — $ 100 $ 4 $ 4 $ 5 $ (21) (1) Gains or losses were included in net realized gains (losses). Financial Instruments Disclosed, But Not Carried, At Fair Value The Company uses various financial instruments in the normal course of its business. The carrying values of cash, accrued investment income, receivable for securities sold, certain other assets, payable for securities purchased and certain other liabilities approximated their fair values at September 30, 2024, due to their respective short maturities. As these financial instruments are not actively traded, their respective fair values are classified within Level 2.

Derivative Instruments

Derivative Instruments	9 Months Ended
	Sep. 30, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	The Company’s investment strategy allows for the use of derivative instruments. The Company’s derivative instruments are recorded on its consolidated balance sheets at fair value. The Company utilizes exchange traded U.S. Treasury note, Eurodollar and other futures contracts and commodity futures to manage portfolio duration or replicate investment positions in its portfolios and the Company routinely utilizes foreign currency forward contracts, currency options, index futures contracts and other derivatives as part of its total return objective. In addition, certain of the Company’s investments are managed in portfolios which incorporate the use of foreign currency forward contracts which are intended to provide an economic hedge against foreign currency movements. From time to time, the Company purchases to-be-announced mortgage backed securities (“TBAs”) as part of its investment strategy. TBAs represent commitments to purchase a future issuance of agency mortgage backed securities. For the period between purchase of a TBA and issuance of the underlying security, the Company’s position is accounted for as a derivative. The Company purchases TBAs in both long and short positions to enhance investment performance and as part of its overall investment strategy. The following table summarizes information on the fair values and notional values of the Company’s derivative instruments: Estimated Fair Value Asset Derivatives (1) Liability Derivatives (1) Notional September 30, 2024 Futures contracts $ 70 $ (6) $ 3,030 Foreign currency forward contracts 33 (38) 1,400 Other (3) 44 (37) 423 Total $ 147 $ (81) December 31, 2023 Futures contracts $ 139 $ (61) $ 3,746 Foreign currency forward contracts 27 (32) 1,224 Other (3) 31 (26) 512 Total $ 197 $ (119) (1) The fair value of asset derivatives are included in ‘ other assets other liabilities (2) Represents the absolute notional value of all outstanding contracts, consisting of long and short positions. (3) Includes swaps, options and other derivatives contracts. The Company did not hold any derivatives which were designated as hedging instruments at September 30, 2024 or December 31, 2023. The Company’s derivative instruments can be traded under master netting agreements, which establish terms that apply to all derivative transactions with a counterparty. In the event of a bankruptcy or other stipulated event of default, such agreements provide that the non-defaulting party may elect to terminate all outstanding derivative transactions, in which case all individual derivative positions (loss or gain) with a counterparty are closed out and netted and replaced with a single amount, usually referred to as the termination amount, which is expressed in a single currency. The resulting single net amount, where positive, is payable to the party “in-the-money” regardless of whether or not it is the defaulting party, unless the parties have agreed that only the non-defaulting party is entitled to receive a termination payment where the net amount is positive and is in its favor. Contractual close-out netting reduces derivatives credit exposure from gross to net exposure. At September 30, 2024, asset derivatives and liability derivatives of $147 million and $81 million, respectively, were subject to a master netting agreement, compared to $197 million and $119 million, respectively, at December 31, 2023. Realized and unrealized contract gains or losses on the Company’s derivative instruments are reflected in ‘net realized gains (losses)’ in the consolidated statements of income, as summarized in the following table: Derivatives not designated as September 30, hedging instruments: 2024 2023 Three Months Ended Net realized gains (losses): Futures contracts $ 86 $ (87) Foreign currency forward contracts 31 (20) Other (1) 8 5 Total $ 125 $ (102) Nine Months Ended Net realized gains (losses): Futures contracts $ 69 $ (73) Foreign currency forward contracts 32 4 Other (1) 15 8 Total $ 116 $ (61) (1) Includes realized gains or losses on swaps, options and other derivatives contracts.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Investment Commitments The Company’s investment commitments, which are primarily related to agreements entered into by the Company to invest in funds and separately managed accounts when called upon, were approximately $4.5 billion at September 30, 2024, compared to $3.6 billion at December 31, 2023. Interest Paid Interest paid on the Company’s senior notes and other borrowings was $63 million for the nine months ended September 30, 2024, consistent with $63 million for the 2023 period.

Variable Interest Entities

Variable Interest Entities	9 Months Ended
	Sep. 30, 2024
Variable Interest Entity, Not Primary Beneficiary, Disclosures [Abstract]
Variable Interest Entity Disclosure	Bellemeade Re The Company has entered into aggregate excess of loss mortgage reinsurance agreements with various special purpose reinsurance companies domiciled in Bermuda (the “Bellemeade Agreements”). At the time the Bellemeade Agreements were entered into, the applicability of the accounting guidance that addresses VIEs was evaluated. As a result of the evaluation of the Bellemeade Agreements, the Company concluded that these entities are VIEs. However, given that the ceding insurers do not have the unilateral power to direct those activities that are significant to their economic performance, the Company does not consolidate such entities in its consolidated financial statements. The reinsurance premium paid in regard to the Bellemeade Agreements is calculated by multiplying the outstanding reinsurance coverage amount at the beginning of the period by the coupon rate, which is the SOFR plus a contractual risk margin, less the actual investment income collected during the preceding month on the assets included in the underlying reinsurance trusts. In the event the assets included in the underlying reinsurance trusts became severely impaired or worthless and the special purpose reinsurance companies were unable to meet their future obligations, the Company’s mortgage insurance subsidiaries would be liable to fulfill claim payments to policyholders. The Company’s maximum exposure to loss associated with these VIEs is determined as the amount of mortgage insurance claim payments on the insured policies, net of aggregate reinsurance payments previously received, up to the full aggregate excess of loss reinsurance coverage amounts. The following table summarizes the total assets of the Bellemeade entities: September 30, December 31, 2023 Bellemeade Entities Total VIE Assets Coverage Remaining from Reinsurers (1) Total VIE 2019-1 Ltd. (Mar-19) $ — $ — $ 71 2019-3 Ltd. (Jul-19) — — 99 2021-3 Ltd. (Sep-21) 378 101 429 2022-1 Ltd. (Jan-22) 216 17 256 2022-2 Ltd. (Sep-22) 190 120 201 2023-1 Ltd. (Oct-23) 186 47 186 2024-1 Ltd. (Aug-24) 163 41 — Total $ 1,133 $ 326 $ 1,242 (1) Coverage from a separate panel of reinsurers remaining at September 30, 2024.

Other Comprehensive Income (Los

Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2024
Comprehensive Income Note Disclosure [Abstract]
Other Comprehensive Income (Loss)	The following tables present details about amounts reclassified from accumulated other comprehensive income and the tax effects allocated to each component of other comprehensive income (loss): Amounts Reclassified from AOCI Consolidated Statement of Income Three Months Ended Nine Months Ended Details About Line Item That Includes September 30, September 30, AOCI Components Reclassification 2024 2023 2024 2023 Unrealized appreciation (decline) on available-for-sale investments Net realized gains (losses) $ 54 $ (104) $ (38) $ (345) Provision for credit losses 6 — 4 (23) Total before tax 60 (104) (34) (368) Income tax (expense) benefit — 8 12 24 Net of tax $ 60 $ (96) $ (22) $ (344) Before Tax Amount Tax Expense (Benefit) Net of Tax Amount Three Months Ended September 30, 2024 Unrealized appreciation (decline) in value of investments: Unrealized holding gains (losses) arising during period $ 736 $ 91 $ 645 Less reclassification of net realized gains (losses) included in net income 60 — 60 Foreign currency translation adjustments 25 — 25 Other comprehensive income (loss) $ 701 $ 91 $ 610 Three Months Ended September 30, 2023 Unrealized appreciation (decline) in value of investments: Unrealized holding gains (losses) arising during period $ (208) $ (18) $ (190) Less reclassification of net realized gains (losses) included in net income (104) (8) (96) Foreign currency translation adjustments (40) — (40) Other comprehensive income (loss) $ (144) $ (10) $ (134) Nine Months Ended September 30, 2024 Unrealized appreciation (decline) in value of investments: Unrealized holding gains (losses) arising during period $ 549 $ 71 $ 478 Less reclassification of net realized gains (losses) included in net income (34) (12) (22) Foreign currency translation adjustments (24) — (24) Other comprehensive income (loss) $ 559 $ 83 $ 476 Nine Months Ended September 30, 2023 Unrealized appreciation (decline) in value of investments: Unrealized holding gains (losses) arising during period $ (131) $ (13) $ (118) Less reclassification of net realized gains (losses) included in net income (368) (24) (344) Foreign currency translation adjustments (33) — (33) Other comprehensive income (loss) $ 204 $ 11 $ 193

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2024
Income Tax Disclosure [Abstract]
Income Taxes	The Company’s income tax provision on income before income taxes, including income (loss) from operating affiliates, resulted in an effective tax rate of 8.1% for the nine months ended September 30, 2024, compared to 8.8% for the nine months ended September 30, 2023. The Company’s effective tax rate, which is based upon the expected annual effective tax rate, may fluctuate from period to period based on the relative mix of income or loss reported by jurisdiction and the varying tax rates in each jurisdiction.

Legal Proceedings

Legal Proceedings	9 Months Ended
	Sep. 30, 2024
Disclosure Legal Proceedings [Abstract]
Legal Proceedings	The Company, in common with the insurance industry in general, is subject to litigation and arbitration in the normal course of its business. As of September 30, 2024, the Company was not a party to any litigation or arbitration which is expected by management to have a material adverse effect on the Company’s results of operations and financial condition and liquidity.

Transactions With Related Parti

Transactions With Related Parties	9 Months Ended
	Sep. 30, 2024
Related Party Transactions [Abstract]
Transactions with related parties	Premia Reinsurance Ltd. is a multi-line Bermuda reinsurance company (and its affiliates together with Premia Holdings Ltd., “Premia”). The Company has entered into certain reinsurance transactions with Premia. For the nine months ended September 30, 2024, the Company recorded an immaterial amount of net premiums written and earned, compared to $80 million for the nine months ended September 30, 2023. At September 30, 2024, the Company recorded a funds held asset from Premia of $137 million, compared to $158 million at December 31, 2023. Somers Group Holdings Ltd. and its wholly owned subsidiaries (collectively, “Somers”) are wholly owned by Greysbridge. The Company has entered into certain reinsurance transactions with Somers. For the nine months ended September 30, 2024, the Company’s net premiums written was reduced by $581 million, compared to $457 million for the nine months ended September 30, 2023. In addition, Somers paid certain acquisition costs and administrative fees to the Company. At September 30, 2024, the Company recorded a reinsurance recoverable on unpaid and paid losses from Somers of $1.6 billion and a reinsurance balance payable to Somers of $546 million, compared to $1.3 billion and $475 million, respectively, at December 31, 2023. Under the terms of the Greysbridge equity financing, beginning January 1, 2024, the Company has a call right (but not the obligation) and Warburg Pincus LLC (“Warburg”) and Kelso & Company (“Kelso”) each have a put right (but not the obligation) to buy/sell one third of their initial shares annually at the current year end tangible book value per share of Greysbridge. During the 2024 third quarter, Warburg and Kelso both delivered a put option notice to sell one third of their initial shares. The transaction is expected to occur in the first half of the 2025 calendar year, subject to any required regulatory approvals. In association with the put/call notice at September 30, 2024, the Company’s balance sheet reflected $261 million in both other assets and other liabilities. During the third quarter, the Company completed the acquisition of Watford Insurance Company from Somers for a total consideration paid of $35 million.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2024
Subsequent Events [Abstract]
Subsequent Event	Hurricane Milton The Company estimates that its 2024 fourth quarter results will be negatively impacted by Hurricane Milton, which occurred in October 2024. The Company currently estimates that the losses will be in a range of $275 million to $375 million, net of reinsurance and reinstatement premiums. This pre-tax preliminary loss estimate is based on industry insured losses ranging from $25 billion to $35 billion. The Company’s preliminary estimate for Hurricane Milton is based on currently available information derived from modeling techniques, industry assessments of exposure, preliminary claims information obtained from the Company’s clients and brokers to date and a review of in-force contracts. The Company’s actual losses from this event may vary materially from the estimates due to the inherent uncertainties in making such determinations. Letter of Credit Facility Agreement On October 30, 2024, Arch Reinsurance Ltd. (“Arch Re Bermuda”), a wholly-owned subsidiary of Arch Capital, entered into Amendment No. 4 to Letter of Credit Facility Agreement (“Amendment No. 4”), as the borrower with Lloyds Bank Corporate Markets plc, as Administrative Agent and L/C Agent, which amends the Letter of Credit Facility Agreement, dated as of November 3, 2020, as amended by Amendment No. 1 to Letter of Credit Facility Agreement dated as of October 29, 2021, as further amended by Amendment No. 2 and Joinder to Letter of Credit Facility Agreement dated as of October 27, 2022, and as further amended by Amendment No. 3 and Joinder to Letter of Credit Facility Agreement dated as of October 25, 2023 (the “Existing L/C Agreement”). The Existing L/C Agreement, as amended by Amendment No. 4, provides for a $700 million facility for letters of credit, the size of which was increased by $170 million, from $530 million. As of October 31, 2024 $700 million face amount of letters of credit had been issued under the facility. Special Cash Dividend

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net income available to Arch	$ 988	$ 723	$ 3,377	$ 2,109

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2024
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 Rec_2

Basis of Presentation and Recent Accounting Pronouncements (Policies)	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of accounting	The interim consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). All significant intercompany transactions and balances have been eliminated in consolidation.
Use of estimates	The preparation of 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 financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ materially from those estimates and assumptions. In the opinion of management, the accompanying unaudited interim consolidated financial statements reflect all adjustments (consisting of normally recurring accruals) necessary for a fair statement of results on an interim basis. The results of any interim period are not necessarily indicative of the results for a full year or any future periods.
Reclassification of prior periods	The Company has reclassified the presentation of certain prior year information to conform to the current presentation. Such reclassifications had no effect on the Company’s net income, comprehensive income, shareholders’ equity or cash flows.
Recent accounting pronouncements	For information regarding additional accounting standards that the Company has not yet adopted, see note 3(t), “Significant Accounting Policies—Recent Accounting Pronouncements,” of the notes to consolidated financial statements in the Company’s 2023 Form 10-K

Acquisitions (Tables)

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2024
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition	The following table summarizes the Company’s allocation of the purchase price to the acquired assets and liabilities assumed based on estimated fair values on August 1, 2024. The fair value of the assets and liabilities are preliminary and may change with offsetting adjustments to goodwill. The Company may make further adjustments to its purchase price allocation through the end of the permissible one-year measurement period. Total Useful Life Purchase price Cash paid (a) $ 450 Assets Acquired Cash and investments, at fair value $ 2,332 Premiums receivable 290 Intangible asset -- distribution relationships 220 10 years Intangible asset -- value of business acquired 163 1-2 years Intangible asset -- other (1) 178 5-7 years Other assets acquired 158 Total assets acquired $ 3,341 Liabilities Acquired Reserves for losses and loss adjustment expenses $ 2,404 Unearned premiums 632 Other liabilities acquired 121 Total liabilities acquired 3,157 Identifiable net assets acquired (b) $ 184 Goodwill (a) - (b) $ 266 (1) Includes $128 million related to the net fair value adjustment to reserves for loss and loss adjustment expenses on August 1, 2024.

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Schedule of computation of basic and diluted earnings per common share	The following table sets forth the computation of basic and diluted earnings per common share: Three Months Ended Nine Months Ended September 30, September 30, 2024 2023 2024 2023 Numerator: Net income (loss) available to Arch $ 988 $ 723 $ 3,377 $ 2,109 Preferred dividends (10) (10) (30) (30) Net income (loss) available to Arch common shareholders $ 978 $ 713 $ 3,347 $ 2,079 Denominator: Weighted average common shares and common share equivalents outstanding — basic 373.2 369.2 372.3 368.4 Effect of dilutive common share equivalents: Nonvested restricted shares 2.0 2.6 1.8 2.4 Stock options (1) 7.1 7.6 7.2 7.5 Weighted average common shares and common share equivalents outstanding — diluted 382.3 379.4 381.3 378.3 Earnings per common share: Basic $ 2.62 $ 1.93 $ 8.99 $ 5.64 Diluted $ 2.56 $ 1.88 $ 8.78 $ 5.50

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2024
Segment Reporting [Abstract]
Analysis of underwriting income or loss by segment and reconciliation to net income available to common shareholders	The following tables summarize the Company’s underwriting income or loss by segment, together with a reconciliation of underwriting income or loss to net income available to Arch common shareholders: Three Months Ended September 30, 2024 Insurance Reinsurance Mortgage Total Gross premiums written (1) $ 2,341 $ 2,763 $ 339 $ 5,440 Premiums ceded (1) (521) (818) (57) (1,393) Net premiums written 1,820 1,945 282 4,047 Change in unearned premiums (55) (53) 31 (77) Net premiums earned 1,765 1,892 313 3,970 Other underwriting income (loss) — 2 3 5 Losses and loss adjustment expenses (1,087) (1,317) 1 (2,403) Acquisition expenses (308) (374) 1 (681) Other operating expenses (250) (54) (49) (353) Underwriting income (loss) $ 120 $ 149 $ 269 538 Net investment income 399 Net realized gains (losses) 169 Equity in net income (loss) of investment funds accounted for using the equity method 171 Other income (loss) 8 Corporate expenses (2) (19) Transaction costs and other (2) (30) Amortization of intangible assets (88) Interest expense (35) Net foreign exchange gains (losses) (63) Income (loss) before income taxes and income (loss) from operating affiliates 1,050 Income tax (expense) benefit (98) Income (loss) from operating affiliates 36 Net income (loss) available to Arch 988 Preferred dividends (10) Net income (loss) available to Arch common shareholders $ 978 Underwriting Ratios Loss ratio 61.6 % 69.6 % (0.4) % 60.5 % Acquisition expense ratio 17.4 % 19.8 % (0.4) % 17.2 % Other operating expense ratio 14.1 % 2.9 % 15.6 % 8.9 % Combined ratio 93.1 % 92.3 % 14.8 % 86.6 % Goodwill and intangible assets $ 1,025 $ 113 $ 348 $ 1,486 (1) Certain assumed and ceded amounts related to intersegment transactions are included in individual segment results. Accordingly, the sum of such transactions for each segment does not agree to the total due to eliminations. (2) Certain expenses have been excluded from ‘corporate expenses’ and reflected in ‘transaction costs and other.’ Three Months Ended September 30, 2023 Insurance Reinsurance Mortgage Total Gross premiums written (1) $ 2,043 $ 2,138 $ 347 $ 4,527 Premiums ceded (1) (521) (576) (76) (1,172) Net premiums written 1,522 1,562 271 3,355 Change in unearned premiums (110) (19) 22 (107) Net premiums earned 1,412 1,543 293 3,248 Other underwriting income (loss) — 2 3 5 Losses and loss adjustment expenses (812) (870) 35 (1,647) Acquisition expenses (269) (304) (2) (575) Other operating expenses (202) (61) (47) (310) Underwriting income (loss) $ 129 $ 310 $ 282 721 Net investment income 269 Net realized gains (losses) (248) Equity in net income (loss) of investment funds accounted for using the equity method 59 Other income (loss) (4) Corporate expenses (2) (20) Transaction costs and other (2) — Amortization of intangible assets (24) Interest expense (34) Net foreign exchange gains (losses) 22 Income (loss) before income taxes and income (loss) from operating affiliates 741 Income tax (expense) benefit (72) Income (loss) from operating affiliates 54 Net income (loss) available to Arch 723 Preferred dividends (10) Net income (loss) available to Arch common shareholders $ 713 Underwriting Ratios Loss ratio 57.5 % 56.4 % (12.1) % 50.7 % Acquisition expense ratio 19.1 % 19.7 % 0.6 % 17.7 % Other operating expense ratio 14.3 % 3.9 % 16.2 % 9.5 % Combined ratio 90.9 % 80.0 % 4.7 % 77.9 % Goodwill and intangible assets $ 220 $ 132 $ 387 $ 739 (1) Certain assumed and ceded amounts related to intersegment transactions are included in individual segment results. Accordingly, the sum of such transactions for each segment does not agree to the total due to eliminations. (2) Certain expenses have been excluded from ‘corporate expenses’ and reflected in ‘transaction costs and other.’ Nine Months Ended September 30, 2024 Insurance Reinsurance Mortgage Total Gross premiums written (1) $ 6,569 $ 9,171 $ 1,020 $ 16,755 Premiums ceded (1) (1,649) (3,013) (185) (4,842) Net premiums written 4,920 6,158 835 11,913 Change in unearned premiums (226) (820) 90 (956) Net premiums earned 4,694 5,338 925 10,957 Other underwriting income (loss) — 5 15 20 Losses and loss adjustment expenses (2,789) (3,206) 37 (5,958) Acquisition expenses (872) (1,050) 1 (1,921) Other operating expenses (718) (193) (151) (1,062) Underwriting income (loss) $ 315 $ 894 $ 827 2,036 Net investment income 1,090 Net realized gains (losses) 358 Equity in net income (loss) of investment funds accounted for using the equity method 437 Other income (loss) 30 Corporate expenses (2) (88) Transaction costs and other (2) (55) Amortization of intangible assets (136) Interest expense (104) Net foreign exchange gains (losses) (31) Income (loss) before income taxes and income (loss) from operating affiliates 3,537 Income tax (expense) benefit (296) Income (loss) from operating affiliates 136 Net income (loss) available to Arch 3,377 Preferred dividends (30) Net income (loss) available to Arch common shareholders $ 3,347 Underwriting Ratios Loss ratio 59.4 % 60.1 % (4.0) % 54.4 % Acquisition expense ratio 18.6 % 19.7 % (0.1) % 17.5 % Other operating expense ratio 15.3 % 3.6 % 16.3 % 9.7 % Combined ratio 93.3 % 83.4 % 12.2 % 81.6 % (1) Certain assumed and ceded amounts related to intersegment transactions are included in individual segment results. Accordingly, the sum of such transactions for each segment does not agree to the total due to eliminations. (2) Certain expenses have been excluded from ‘corporate expenses’ and reflected in ‘transaction costs and other.’ Nine Months Ended September 30, 2023 Insurance Reinsurance Mortgage Total Gross premiums written (1) $ 5,977 $ 7,142 $ 1,037 $ 14,152 Premiums ceded (1) (1,564) (2,145) (240) (3,945) Net premiums written 4,413 4,997 797 10,207 Change in unearned premiums (416) (781) 86 (1,111) Net premiums earned 3,997 4,216 883 9,096 Other underwriting income (loss) — 9 12 21 Losses and loss adjustment expenses (2,276) (2,379) 46 (4,609) Acquisition expenses (778) (875) (16) (1,669) Other operating expenses (592) (203) (147) (942) Underwriting income (loss) $ 351 $ 768 $ 778 1,897 Net investment income 710 Net realized gains (losses) (354) Equity in net income (loss) of investment funds accounted for using the equity method 176 Other income (loss) 10 Corporate expenses (2) (69) Transaction costs and other (2) (2) Amortization of intangible assets (71) Interest expense (99) Net foreign exchange gains (losses) (1) Income (loss) before income taxes and income (loss) from operating affiliates 2,197 Income tax (expense) benefit (203) Income (loss) from operating affiliates 115 Net income (loss) available to Arch 2,109 Preferred dividends (30) Net income (loss) available to Arch common shareholders $ 2,079 Underwriting Ratios Loss ratio 57.0 % 56.4 % (5.3) % 50.7 % Acquisition expense ratio 19.5 % 20.7 % 1.8 % 18.3 % Other operating expense ratio 14.8 % 4.8 % 16.7 % 10.4 % Combined ratio 91.3 % 81.9 % 13.2 % 79.4 % (1) Certain assumed and ceded amounts related to intersegment transactions are included in individual segment results. Accordingly, the sum of such transactions for each segment does not agree to the total due to eliminations.

Reserve for Losses and Loss A_2

Reserve for Losses and Loss Adjustment Expenses (Tables)	9 Months Ended
	Sep. 30, 2024
Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense [Abstract]
Analysis of losses and loss adjustment expenses and reconciliation of beginning and ending reserve balances	The following table represents an analysis of losses and loss adjustment expenses and a reconciliation of the beginning and ending reserve for losses and loss adjustment expenses: Three Months Ended Nine Months Ended September 30, September 30, 2024 2023 2024 2023 Reserve for losses and loss adjustment expenses at beginning of period $ 24,466 $ 21,268 $ 22,752 $ 20,032 Unpaid losses and loss adjustment expenses recoverable 7,083 6,394 6,690 6,280 Net reserve for losses and loss adjustment expenses at beginning of period 17,383 14,874 16,062 13,752 Net incurred losses and loss adjustment expenses relating to losses occurring in: Current year 2,524 1,793 6,324 5,012 Prior years (121) (146) (366) (403) Total net incurred losses and loss adjustment expenses 2,403 1,647 5,958 4,609 Net losses and loss adjustment expense reserves of acquired businesses (1) 2,413 — 2,463 — Net foreign exchange (gains) losses and other 246 (123) 152 (24) Net paid losses and loss adjustment expenses relating to losses occurring in: Current year (362) (345) (647) (700) Prior years (967) (713) (2,872) (2,297) Total net paid losses and loss adjustment expenses (1,329) (1,058) (3,519) (2,997) Net reserve for losses and loss adjustment expenses at end of period 21,116 15,340 21,116 15,340 Unpaid losses and loss adjustment expenses recoverable 7,563 6,496 7,563 6,496 Reserve for losses and loss adjustment expenses at end of period $ 28,679 $ 21,836 $ 28,679 $ 21,836 (1) Activity for the 2024 third quarter related to the acquisition of MCE (see note 2 ) and Watford Insurance Company (see note 16 ), while activity for the nine months ended September 30, 2024 also reflects the Company’s acquisition of RMIC Companies, Inc. and its wholly-owned subsidiaries (“RMIC”) that, together, comprise the run-off mortgage insurance business of Old Republic International Corporation.
Schedule of Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense	Three Months Ended Nine Months Ended (Favorable) Adverse September 30, September 30, 2024 Short-tailed Long-tailed Total Short-tailed Long-tailed Total Insurance $ (31) $ 15 $ (16) $ (61) $ 30 $ (31) Reinsurance (68) 27 (41) (158) 43 (115) Mortgage (64) — (64) (220) — (220) Total $ (163) $ 42 $ (121) $ (439) $ 73 $ (366) 2023 Insurance $ (29) $ 19 $ (10) $ (74) $ 40 $ (34) Reinsurance (65) 21 (44) (168) 42 (126) Mortgage (92) — (92) (243) — (243) Total $ (186) $ 40 $ (146) $ (485) $ 82 $ (403)

Allowance for Expected Credit_2

Allowance for Expected Credit Losses (Tables)	9 Months Ended
	Sep. 30, 2024
Credit Loss [Abstract]
Premiums receivable	The following table provides a roll forward of the allowance for expected credit losses of the Company’s premium receivables: Premium Receivables, Net of Allowance Allowance for Expected Credit Losses Three Months Ended September 30, 2024 Balance at beginning of period $ 6,268 $ 36 Provision on business acquired (1) 16 Change for provision of expected credit losses (2) — Balance at end of period $ 6,364 $ 52 Three Months Ended September 30, 2023 Balance at beginning of period $ 5,296 $ 34 Change for provision of expected credit losses (2) — Balance at end of period $ 4,937 $ 34 Nine Months Ended September 30, 2024 Balance at beginning of year $ 4,644 $ 34 Provision on business acquired (1) 16 Change for provision of expected credit losses (2) 2 Balance at end of period $ 6,364 $ 52 Nine Months Ended September 30, 2023 Balance at beginning of year $ 3,625 $ 35 Change for provision of expected credit losses (2) (1) Balance at end of period $ 4,937 $ 34 (1) Represents MCE’s provision for current expected credit losses on premiums receivable. See note 2 . (2) Amounts deemed uncollectible are written-off in operating expenses. For the 2024 third quarter and 2023 third quarter, amounts written off were $1 million and nil, respectively. For the nine months ended September 30, 2024 and 2023 period, amounts written off were $1 million and $2 million, respectively.
Reinsurance recoverables	The following table provides a roll forward of the allowance for expected credit losses of the Company’s reinsurance recoverables: Reinsurance Recoverables, Net of Allowance Allowance for Expected Credit Losses Three Months Ended September 30, 2024 Balance at beginning of period $ 7,473 $ 20 Change for provision of expected credit losses (3) Balance at end of period $ 7,948 $ 17 Three Months Ended September 30, 2023 Balance at beginning of period $ 6,717 $ 22 Change for provision of expected credit losses 1 Balance at end of period $ 6,821 $ 23 Nine Months Ended September 30, 2024 Balance at beginning of year $ 7,064 $ 21 Change for provision of expected credit losses (4) Balance at end of period $ 7,948 $ 17 Nine Months Ended September 30, 2023 Balance at beginning of year $ 6,564 $ 22 Change for provision of expected credit losses 1 Balance at end of period $ 6,821 $ 23
Ceded credit risk	The following table summarizes the Company’s reinsurance recoverables on paid and unpaid losses (not including ceded unearned premiums): September 30, December 31, 2024 2023 Reinsurance recoverable on unpaid and paid losses and loss adjustment expenses $ 7,948 $ 7,064 % due from carriers with A.M. Best rating of “A-” or better 65.3 % 66.8 % % due from all other rated carriers 0.0 % 0.1 % % due from all other carriers with no A.M. Best rating (1) 34.7 % 33.1 % Largest balance due from any one carrier as % of total shareholders’ equity 7.1 % 7.2 % (1) At September 30, 2024 and December 31, 2023 over 95% of such amount were collateralized through reinsurance trusts, funds withheld arrangements, letters of credit or other.
Contractholder receivables	The following table provides a roll forward of the allowance for expected credit losses of the Company’s contractholder receivables: Contract-holder Receivables, Net of Allowance Allowance for Expected Credit Losses Three Months Ended September 30, 2024 Balance at beginning of period $ 2,016 $ 4 Change for provision of expected credit losses — Balance at end of period $ 2,078 $ 4 Three Months Ended September 30, 2023 Balance at beginning of period $ 1,761 $ 3 Change for provision of expected credit losses — Balance at end of period 1,805 $ 3 Nine Months Ended September 30, 2024 Balance at beginning of year $ 1,814 $ 3 Change for provision of expected credit losses 1 Balance at end of period $ 2,078 $ 4 Nine Months Ended September 30, 2023 Balance at beginning of year $ 1,731 $ 3 Change for provision of expected credit losses — Balance at end of period 1,805 $ 3

Investment Information (Tables)

Investment Information (Tables)	9 Months Ended
	Sep. 30, 2024
Disclosure Investment Information [Abstract]
Summary of fair value and cost or amortized cost of available for sale securities	The following table summarizes the fair value and cost or amortized cost of the Company’s securities classified as available for sale: Estimated Gross Gross Allowance for Expected Credit Losses Cost or September 30, 2024 Fixed maturities: Corporate bonds $ 13,996 $ 339 $ (294) $ (12) $ 13,963 U.S. government and government agencies 5,863 53 (48) — 5,858 Asset backed securities 2,989 27 (27) (5) 2,994 Non-U.S. government securities 2,853 75 (84) (1) 2,863 Commercial mortgage backed securities 1,146 8 (17) (1) 1,156 Residential mortgage backed securities 1,313 14 (50) — 1,349 Municipal bonds 274 2 (11) — 283 Total 28,434 518 (531) (19) 28,466 Short-term investments 3,341 6 (2) — 3,337 Total $ 31,775 $ 524 $ (533) $ (19) $ 31,803 December 31, 2023 Fixed maturities: Corporate bonds $ 10,855 $ 157 $ (464) $ (20) $ 11,182 U.S. government and government agencies 5,814 63 (86) — 5,837 Asset backed securities 2,250 11 (55) (5) 2,299 Non-U.S. government securities 2,062 33 (100) (1) 2,130 Commercial mortgage backed securities 1,213 3 (34) (2) 1,246 Residential mortgage backed securities 1,103 7 (66) — 1,162 Municipal bonds 256 1 (20) — 275 Total 23,553 275 (825) (28) 24,131 Short-term investments 2,063 1 (2) — 2,064 Total $ 25,616 $ 276 $ (827) $ (28) $ 26,195
Summary of available for sale securities in a continual unrealized loss position	The following table summarizes, for all available for sale securities in an unrealized loss position, the fair value and gross unrealized loss by length of time the security has been in a continual unrealized loss position: Less than 12 Months 12 Months or More Total Estimated Gross Estimated Gross Estimated Gross September 30, 2024 Fixed maturities: Corporate bonds $ 1,903 $ (76) $ 3,316 $ (218) $ 5,219 $ (294) U.S. government and government agencies 1,815 (10) 571 (38) 2,386 (48) Non-U.S. government securities 614 (8) 743 (76) 1,357 (84) Residential mortgage backed securities 213 (2) 485 (48) 698 (50) Asset backed securities 199 (3) 442 (24) 641 (27) Commercial mortgage backed securities 176 (1) 644 (16) 820 (17) Municipal bonds 1 — 185 (11) 186 (11) Total 4,921 (100) 6,386 (431) 11,307 (531) Short-term investments 362 (2) — — 362 (2) Total $ 5,283 $ (102) $ 6,386 $ (431) $ 11,669 $ (533) December 31, 2023 Fixed maturities: Corporate bonds $ 1,559 $ (45) $ 4,959 $ (419) $ 6,518 $ (464) U.S. government and government agencies 1,066 (10) 941 (76) 2,007 (86) Non-U.S. government securities 365 (4) 897 (96) 1,262 (100) Residential mortgage backed securities 221 (3) 522 (63) 743 (66) Asset backed securities 234 (1) 1,112 (54) 1,346 (55) Commercial mortgage backed securities 100 (1) 909 (33) 1,009 (34) Municipal bonds 20 (1) 215 (19) 235 (20) Total 3,565 (65) 9,555 (760) 13,120 (825) Short-term investments 302 (2) — — 302 (2) Total $ 3,867 $ (67) $ 9,555 $ (760) $ 13,422 $ (827)
Contractual maturities of the Company's fixed maturities	The contractual maturities of the Company’s fixed maturities are shown in the following table. Expected maturities, which are management’s best estimates, will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. September 30, 2024 December 31, 2023 Maturity Estimated Amortized Estimated Amortized Due in one year or less $ 430 $ 445 $ 480 $ 499 Due after one year through five years 15,533 15,457 12,924 13,101 Due after five years through 10 years 6,572 6,595 5,249 5,450 Due after 10 years 451 470 334 374 22,986 22,967 18,987 19,424 Residential mortgage backed securities 1,313 1,349 1,103 1,162 Commercial mortgage backed securities 1,146 1,156 1,213 1,246 Asset backed securities 2,989 2,994 2,250 2,299 Total $ 28,434 $ 28,466 $ 23,553 $ 24,131
Summary of other investments, at fair value	The following table summarizes the Company’s other investments: September 30, December 31, Other investments $ 2,096 $ 1,777 Fixed maturities 1,097 683 Short term investments 61 21 Equity securities 7 7 Total $ 3,261 $ 2,488 The following table summarizes the Company’s other investments, as detailed in the previous table, by strategy: September 30, December 31, Investment grade fixed income $ 957 $ 754 Term loan investments 499 272 Lending 299 427 Private equity 212 182 Credit related funds 111 124 Energy 18 18 Total $ 2,096 $ 1,777
Components of net investment income	The components of net investment income were derived from the following sources: September 30, 2024 2023 Three Months Ended Fixed maturities $ 340 $ 243 Short term investments 38 19 Equity securities 9 5 Other (1) 35 22 Gross investment income 422 289 Investment expenses (23) (20) Net investment income $ 399 $ 269 Nine Months Ended Fixed maturities $ 926 $ 645 Short term investments 102 48 Equity securities 27 15 Other (1) 103 60 Gross investment income 1,158 768 Investment expenses (68) (58) Net investment income $ 1,090 $ 710
Summary of net realized gains (losses), including change in allowance for credit losses on financial assets and net impairment losses recognized in earnings	Net realized gains (losses), which include changes in the allowance for credit losses on financial assets and net impairment losses recognized in earnings were as follows: September 30, 2024 2023 Three Months Ended Available for sale securities: Gross gains on investment sales $ 104 $ 12 Gross losses on investment sales (50) (116) Change in fair value of assets and liabilities accounted for using the fair value option: Fixed maturities 25 (16) Other investments (120) 3 Equity securities, at fair value: Net realized gains (losses) on sales during the period 15 14 Net unrealized gains (losses) on equity securities still held at reporting date 58 (46) Allowance for credit losses: Investments related 6 — Underwriting related 2 (1) Derivative instruments (1) 125 (102) Other 4 4 Net realized gains (losses) $ 169 $ (248) Nine Months Ended Available for sale securities: Gross gains on investment sales $ 167 $ 51 Gross losses on investment sales (205) (396) Change in fair value of assets and liabilities accounted for using the fair value option: Fixed maturities 23 (12) Other investments (150) 17 Equity securities — 1 Equity securities, at fair value: Net realized gains (losses) on sales during the period 31 50 Net unrealized gains (losses) on equity securities still held at reporting date 147 17 Allowance for credit losses: Investments related 4 (23) Underwriting related — (2) Derivative instruments (1) 116 (61) Other (2) 225 4 Net realized gains (losses) $ 358 $ (354) (1) See note 10 for information on the Company’s derivative instruments. (2) Amounts include benefits from the sale of Castel Underwriting Agencies Limited and the acquisition of RMIC.
Summary of investments accounted for using equity method	The following table summarizes the Company’s investments accounted for using the equity method, by strategy: September 30, December 31, Private equity $ 1,737 $ 1,175 Credit related funds 1,366 1,258 Real estate 721 666 Lending 474 597 Fixed income 377 277 Infrastructure 323 320 Equities 177 178 Energy 69 95 Total $ 5,244 $ 4,566
Summary of investments in limited partnership interests where the Company has a variable interest	The following table summarizes investments in limited partnership interests where the Company has a variable interest by balance sheet line item: September 30, December 31, Investments accounted for using the equity method (1) $ 5,244 $ 4,566 Investments accounted for using the fair value option (2) 83 114 Total $ 5,327 $ 4,680 (1) Aggregate unfunded commitments were $4.3 billion at September 30, 2024, compared with $3.4 billion at December 31, 2023. (2) Aggregate unfunded commitments were $21 million at September 30, 2024, compared to $32 million at December 31, 2023.
Rollforward of the allowance for expected credit losses of securities classified as available for sale	The following table provides a roll forward of the allowance for expected credit losses of the Company’s securities classified as available for sale: Structured Securities (1) Corporate Non-U.S. Total Three Months Ended September 30, 2024 Balance at beginning of period $ 10 $ 16 $ 1 $ 27 Additions (reductions) for previously recognized expected credit losses (3) (3) — (6) Reductions due to disposals (1) (1) — (2) Balance at end of period $ 6 $ 12 $ 1 $ 19 Three Months Ended September 30, 2023 Balance at beginning of period $ 8 $ 50 $ 3 $ 61 Additions for current-period provision for expected credit losses 2 4 — 6 Additions (reductions) for previously recognized expected credit losses — (3) — (3) Reductions due to disposals (2) (4) (1) (7) Balance at end of period $ 8 $ 47 $ 2 $ 57 Nine Months Ended September 30, 2024 Balance at beginning of year $ 7 $ 20 $ 1 $ 28 Additions (reductions) for previously recognized expected credit losses — (4) — (4) Reductions due to disposals (1) (4) — (5) Balance at end of period $ 6 $ 12 $ 1 $ 19 Nine Months Ended September 30, 2023 Balance at beginning of year $ 9 $ 30 $ 2 $ 41 Additions for current-period provision for expected credit losses 2 5 — 7 Additions (reductions) for previously recognized expected credit losses (1) 18 1 18 Reductions due to disposals (2) (6) (1) (9) Balance at end of period $ 8 $ 47 $ 2 $ 57 (1) Includes asset backed securities, residential mortgage backed securities and commercial mortgage backed securities.
Summary of restricted assets	The following table details the value of the Company’s restricted assets: September 30, December 31, Assets used for collateral or guarantees: Affiliated transactions $ 5,306 $ 4,854 Third party agreements (1) 5,679 2,869 Deposits with U.S. regulatory authorities 883 833 Other (2) 1,453 1,376 Total restricted assets $ 13,321 $ 9,932 (1) 2024 period includes amounts related to the MCE Acquisition. (2) Primarily includes Funds at Lloyds, deposits with non-U.S. regulatory authorities and other restricted assets.
Reconciliation of cash and restricted cash	The following table details reconciliation of cash and restricted cash within the Consolidated Balance Sheets: September 30, December 31, Cash $ 1,025 $ 917 Restricted cash (included in ‘other assets’) 687 581 Cash and restricted cash $ 1,712 $ 1,498

Fair Value (Tables)

Fair Value (Tables)	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Fair value hierarchy	The following table presents the Company’s financial assets and liabilities measured at fair value by level at September 30, 2024: Estimated Fair Value Measurements Using: Estimated Quoted Prices in Significant Significant Assets measured at fair value: Available for sale securities: Fixed maturities: Corporate bonds $ 13,996 $ 2 $ 13,853 $ 141 U.S. government and government agencies 5,863 5,850 13 — Asset backed securities 2,989 — 2,989 — Non-U.S. government securities 2,853 — 2,853 — Commercial mortgage backed securities 1,146 — 1,146 — Residential mortgage backed securities 1,313 — 1,313 — Municipal bonds 274 — 274 — Total 28,434 5,852 22,441 141 Short-term investments 3,341 3,081 163 97 Equity securities, at fair value 1,623 1,590 27 6 Derivative instruments (2) 147 — 147 — Residential mortgage loans 13 — 13 — Fair value option: Corporate bonds 1,085 — 1,085 — Non-U.S. government bonds 8 — 8 — U.S. government and government agencies 4 4 — — Short-term investments 61 3 43 15 Equity securities 7 3 — 4 Other investments 703 — 413 290 Other investments measured at net asset value (1) 1,393 Total 3,261 10 1,549 309 Total assets measured at fair value $ 36,819 $ 10,533 $ 24,340 $ 553 Liabilities measured at fair value: Other liabilities $ (43) $ — $ — $ (43) Derivative instruments (2) (81) — (81) — Total liabilities measured at fair value $ (124) $ — $ (81) $ (43) (1) In accordance with applicable accounting guidance, certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the consolidated balance sheets. (2) See note 10 . The following table presents the Company’s financial assets and liabilities measured at fair value by level at December 31, 2023: Estimated Fair Value Measurements Using: Estimated Quoted Prices in Significant Significant Assets measured at fair value: Available for sale securities: Fixed maturities: Corporate bonds $ 10,855 $ — $ 10,708 $ 147 U.S. government and government agencies 5,814 5,792 22 — Asset backed securities 2,250 — 2,250 — Non-U.S. government securities 2,062 — 2,062 — Commercial mortgage backed securities 1,213 — 1,213 — Residential mortgage backed securities 1,103 — 1,103 — Municipal bonds 256 — 256 — Total 23,553 5,792 17,614 147 Short-term investments 2,063 1,786 193 84 Equity securities, at fair value 1,186 1,151 30 5 Derivative instruments (2) 197 — 197 — Residential mortgage loans 2 — 2 — Fair value option: Corporate bonds 662 — 662 — Non-U.S. government bonds 6 — 6 — Asset backed securities 2 — 2 — U.S. government and government agencies 13 13 — — Short-term investments 21 — 11 10 Equity securities 7 3 — 4 Other investments 316 — 210 106 Other investments measured at net asset value (1) 1,461 Total 2,488 16 891 120 Total assets measured at fair value $ 29,489 $ 8,745 $ 18,927 $ 356 Liabilities measured at fair value: Other liabilities $ (22) $ — $ — $ (22) Derivative instruments (2) (119) — (119) — Total liabilities measured at fair value $ (141) $ — $ (119) $ (22) (1) In accordance with applicable accounting guidance, certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the consolidated balance sheets. (2) See note 10 .
Rollforward of Level 3 investments	The following table presents a reconciliation of the beginning and ending balances for all financial assets and liabilities measured at fair value on a recurring basis using Level 3 inputs: Assets Liabilities s Available For Sale Fair Value Option Fair Value Corporate Short-term Other Short-term Equity Equity Other Liabilities Three Months Ended September 30, 2024 Balance at beginning of period $ 160 $ 97 $ 144 $ 14 $ 4 $ 6 $ (35) Total gains or (losses) (realized/unrealized) Included in earnings (1) — — — — — — (1) Included in other comprehensive income — — — — — — — Purchases, issuances, sales and settlements Purchases — — 39 5 — — — Issuances (2) — — — — — — (9) Sales — — (2) — — — — Settlements (19) — (14) (4) — — 2 Transfers in and/or out of Level 3 — — 123 — — — — Balance at end of period $ 141 $ 97 $ 290 $ 15 $ 4 $ 6 $ (43) Three Months Ended September 30, 2023 Balance at beginning of period $ 100 $ — $ 86 $ — $ 4 $ 5 $ (19) Total gains or (losses) (realized/unrealized) Included in earnings (1) — — — — — — — Included in other comprehensive income (1) — — — — — — Purchases, issuances, sales and settlements Purchases 25 — 29 4 — — — Issuances — — — — — — (4) Sales — — (6) — — — — Settlements — — (9) — — — 2 Transfers in and/or out of Level 3 — — — — — — — Balance at end of period $ 124 $ — $ 100 $ 4 $ 4 $ 5 $ (21) Nine Months Ended September 30, 2024 Balance at beginning of year $ 147 $ 84 $ 106 $ 10 $ 4 $ 5 $ (22) Total gains or (losses) (realized/unrealized) Included in earnings (1) — — (4) — — — (1) Included in other comprehensive income 2 1 — — — — — Purchases, issuances, sales and settlements Purchases 98 12 99 15 — 1 — Issuances (2) — — — — — — (22) Sales — — (4) — — — — Settlements (106) — (30) (10) — — 2 Transfers in and/or out of Level 3 — — 123 — — — — Balance at end of period $ 141 $ 97 $ 290 $ 15 $ 4 $ 6 $ (43) Nine Months Ended September 30, 2023 Balance at beginning of year $ 121 $ — $ 33 $ — $ 4 $ 4 $ (14) Total gains or (losses) (realized/unrealized) Included in earnings (1) 1 — (1) — — — — Included in other comprehensive income (1) — — — — — — Purchases, issuances, sales and settlements Purchases 68 — 87 4 — 1 — Issuances — — — — — — (9) Sales — — (10) — — — — Settlements (65) — (9) — — — 2 Transfers in and/or out of Level 3 — — — — — — — Balance at end of period $ 124 $ — $ 100 $ 4 $ 4 $ 5 $ (21)

Derivative Instruments (Tables)

Derivative Instruments (Tables)	9 Months Ended
	Sep. 30, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair value and notional amount of derivatives	The following table summarizes information on the fair values and notional values of the Company’s derivative instruments: Estimated Fair Value Asset Derivatives (1) Liability Derivatives (1) Notional September 30, 2024 Futures contracts $ 70 $ (6) $ 3,030 Foreign currency forward contracts 33 (38) 1,400 Other (3) 44 (37) 423 Total $ 147 $ (81) December 31, 2023 Futures contracts $ 139 $ (61) $ 3,746 Foreign currency forward contracts 27 (32) 1,224 Other (3) 31 (26) 512 Total $ 197 $ (119) (1) The fair value of asset derivatives are included in ‘ other assets other liabilities (2) Represents the absolute notional value of all outstanding contracts, consisting of long and short positions. (3) Includes swaps, options and other derivatives contracts.
Summary of net realized gains (losses) recorded in the consolidated statements of income	Realized and unrealized contract gains or losses on the Company’s derivative instruments are reflected in ‘net realized gains (losses)’ in the consolidated statements of income, as summarized in the following table: Derivatives not designated as September 30, hedging instruments: 2024 2023 Three Months Ended Net realized gains (losses): Futures contracts $ 86 $ (87) Foreign currency forward contracts 31 (20) Other (1) 8 5 Total $ 125 $ (102) Nine Months Ended Net realized gains (losses): Futures contracts $ 69 $ (73) Foreign currency forward contracts 32 4 Other (1) 15 8 Total $ 116 $ (61) (1) Includes realized gains or losses on swaps, options and other derivatives contracts.

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	9 Months Ended
	Sep. 30, 2024
Variable Interest Entity, Not Primary Beneficiary, Disclosures [Abstract]
Total assets and maximum exposure to loss associated with VIEs	The following table summarizes the total assets of the Bellemeade entities: September 30, December 31, 2023 Bellemeade Entities Total VIE Assets Coverage Remaining from Reinsurers (1) Total VIE 2019-1 Ltd. (Mar-19) $ — $ — $ 71 2019-3 Ltd. (Jul-19) — — 99 2021-3 Ltd. (Sep-21) 378 101 429 2022-1 Ltd. (Jan-22) 216 17 256 2022-2 Ltd. (Sep-22) 190 120 201 2023-1 Ltd. (Oct-23) 186 47 186 2024-1 Ltd. (Aug-24) 163 41 — Total $ 1,133 $ 326 $ 1,242 (1) Coverage from a separate panel of reinsurers remaining at September 30, 2024.

Other Comprehensive Income (L_2

Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2024
Comprehensive Income Note Disclosure [Abstract]
Details about amounts reclassified from AOCI	The following tables present details about amounts reclassified from accumulated other comprehensive income and the tax effects allocated to each component of other comprehensive income (loss): Amounts Reclassified from AOCI Consolidated Statement of Income Three Months Ended Nine Months Ended Details About Line Item That Includes September 30, September 30, AOCI Components Reclassification 2024 2023 2024 2023 Unrealized appreciation (decline) on available-for-sale investments Net realized gains (losses) $ 54 $ (104) $ (38) $ (345) Provision for credit losses 6 — 4 (23) Total before tax 60 (104) (34) (368) Income tax (expense) benefit — 8 12 24 Net of tax $ 60 $ (96) $ (22) $ (344)
Schedule of comprehensive income (loss)	Before Tax Amount Tax Expense (Benefit) Net of Tax Amount Three Months Ended September 30, 2024 Unrealized appreciation (decline) in value of investments: Unrealized holding gains (losses) arising during period $ 736 $ 91 $ 645 Less reclassification of net realized gains (losses) included in net income 60 — 60 Foreign currency translation adjustments 25 — 25 Other comprehensive income (loss) $ 701 $ 91 $ 610 Three Months Ended September 30, 2023 Unrealized appreciation (decline) in value of investments: Unrealized holding gains (losses) arising during period $ (208) $ (18) $ (190) Less reclassification of net realized gains (losses) included in net income (104) (8) (96) Foreign currency translation adjustments (40) — (40) Other comprehensive income (loss) $ (144) $ (10) $ (134) Nine Months Ended September 30, 2024 Unrealized appreciation (decline) in value of investments: Unrealized holding gains (losses) arising during period $ 549 $ 71 $ 478 Less reclassification of net realized gains (losses) included in net income (34) (12) (22) Foreign currency translation adjustments (24) — (24) Other comprehensive income (loss) $ 559 $ 83 $ 476 Nine Months Ended September 30, 2023 Unrealized appreciation (decline) in value of investments: Unrealized holding gains (losses) arising during period $ (131) $ (13) $ (118) Less reclassification of net realized gains (losses) included in net income (368) (24) (344) Foreign currency translation adjustments (33) — (33) Other comprehensive income (loss) $ 204 $ 11 $ 193

Acquisitions - Summary of alloc

Acquisitions - Summary of allocation of purchase price (Details) - US MidCorp and Entertainment $ in Millions	Aug. 01, 2024 USD ($)
Purchase price
Business acquisition, cash paid	$ 450
Assets Acquired
Cash and investments, at fair value	2,332
Premiums receivable	290
Other assets acquired	158
Total assets acquired	3,341
Liabilities Acquired
Reserves for losses and loss adjustment expenses	2,404
Unearned premiums	632
Other liabilities acquired	121
Total liabilities acquired	3,157
Net assets acquired	184
Goodwill	266
Deferred tax asset, goodwill and intangibles	568
Net deferred tax asset, loss reserves and unearned premium	23
Reserves For Losses And Loss Adjustment Expenses
Liabilities Acquired
Loss reserves, fair value adjustment	128
Distribution relationships
Assets Acquired
Intangible assets	$ 220
Useful life	10 years
Value of business acquired
Assets Acquired
Intangible assets	$ 163
Other intangible assets
Assets Acquired
Intangible assets	$ 178	[1]
Minimum | Value of business acquired
Assets Acquired
Useful life	1 year
Minimum | Other intangible assets
Assets Acquired
Useful life	5 years
Maximum | Value of business acquired
Assets Acquired
Useful life	2 years
Maximum | Other intangible assets
Assets Acquired
Useful life	7 years
[1]Includes $128 million related to the net fair value adjustment to reserves for loss and loss adjustment expenses on August 1, 2024.

Share Transactions - Share repu

Share Transactions - Share repurchases (Details) $ in Billions	Sep. 30, 2024 USD ($)
Common shares
Class of Stock [Line Items]
Remaining authorized repurchase amount	$ 1

Earnings Per Common Share (Deta

Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Numerator:
Net income available to Arch		$ 988	$ 723	$ 3,377	$ 2,109
Preferred dividends		(10)	(10)	(30)	(30)
Net income (loss) available to Arch common shareholders		$ 978	$ 713	$ 3,347	$ 2,079
Denominator:
Weighted average common shares outstanding — basic		373.2	369.2	372.3	368.4
Effect of dilutive common share equivalents:
Nonvested restricted shares		2	2.6	1.8	2.4
Stock options	[1]	7.1	7.6	7.2	7.5
Weighted average common shares and common share equivalents outstanding — diluted		382.3	379.4	381.3	378.3
Earnings per common share:
Basic (per share)		$ 2.62	$ 1.93	$ 8.99	$ 5.64
Diluted (per share)		$ 2.56	$ 1.88	$ 8.78	$ 5.50
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per common share (shares)		0.2	0.3	0.4	0.5
[1]Certain stock options were not included in the computation of diluted earnings per share where the exercise price of the stock options exceeded the average market price and would have been anti-dilutive or where, when applying the treasury stock method to in-the-money options, the sum of the proceeds, including unrecognized compensation, exceeded the average market price and would have been anti-dilutive. For the 2024 third quarter and 2023 third quarter, the number of stock options excluded were 0.2 million and 0.3 million, respectively. For the nine months ended September 30, 2024 and 2023, the number of stock options excluded were 0.4 million and 0.5 million, respectively.

Segment Information - Summary o

Segment Information - Summary of underwriting income or loss by segment (Details) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) segment	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)
Segment Reporting Information [Line Items]
Number of segments | segment				3
Gross premiums written		$ 5,440	$ 4,527	$ 16,755	$ 14,152
Premiums ceded		(1,393)	(1,172)	(4,842)	(3,945)
Net premiums written		4,047	3,355	11,913	10,207
Change in unearned premiums		(77)	(107)	(956)	(1,111)
Net premiums earned		3,970	3,248	10,957	9,096
Other underwriting income		5	5	20	21
Losses and loss adjustment expenses		(2,403)	(1,647)	(5,958)	(4,609)
Acquisition expenses		(681)	(575)	(1,921)	(1,669)
Other operating expenses		(353)	(310)	(1,062)	(942)
Underwriting income (loss)		538	721	2,036	1,897
Net investment income		399	269	1,090	710
Net realized gains (losses)		169	(248)	358	(354)
Equity in net income (loss) of investment funds accounted for using the equity method		171	59	437	176
Other income (loss)		8	(4)	30	10
Corporate expenses	[1]	(19)	(20)	(88)	(69)
Transaction costs and other	[1]	(30)	0	(55)	(2)
Amortization of intangible assets		(88)	(24)	(136)	(71)
Interest expense		(35)	(34)	(104)	(99)
Net foreign exchange gains (losses)		(63)	22	(31)	(1)
Income (loss) before income taxes and income (loss) from operating affiliates		1,050	741	3,537	2,197
Income tax expense (benefit)		(98)	(72)	(296)	(203)
Income (loss) from operating affiliates		36	54	136	115
Net income available to Arch		988	723	3,377	2,109
Preferred dividends		(10)	(10)	(30)	(30)
Net income (loss) available to Arch common shareholders		$ 978	$ 713	$ 3,347	$ 2,079
Underwriting Ratios
Loss ratio		60.50%	50.70%	54.40%	50.70%
Acquisition expense ratio		17.20%	17.70%	17.50%	18.30%
Other operating expense ratio		8.90%	9.50%	9.70%	10.40%
Combined ratio		86.60%	77.90%	81.60%	79.40%
Goodwill and intangible assets		$ 1,486	$ 739	$ 1,486	$ 739	$ 731
Operating segments | Insurance
Segment Reporting Information [Line Items]
Gross premiums written	[2]	2,341	2,043	6,569	5,977
Premiums ceded	[2]	(521)	(521)	(1,649)	(1,564)
Net premiums written		1,820	1,522	4,920	4,413
Change in unearned premiums		(55)	(110)	(226)	(416)
Net premiums earned		1,765	1,412	4,694	3,997
Other underwriting income		0	0	0	0
Losses and loss adjustment expenses		(1,087)	(812)	(2,789)	(2,276)
Acquisition expenses		(308)	(269)	(872)	(778)
Other operating expenses		(250)	(202)	(718)	(592)
Underwriting income (loss)		$ 120	$ 129	$ 315	$ 351
Underwriting Ratios
Loss ratio		61.60%	57.50%	59.40%	57%
Acquisition expense ratio		17.40%	19.10%	18.60%	19.50%
Other operating expense ratio		14.10%	14.30%	15.30%	14.80%
Combined ratio		93.10%	90.90%	93.30%	91.30%
Goodwill and intangible assets		$ 1,025	$ 220	$ 1,025	$ 220
Operating segments | Reinsurance
Segment Reporting Information [Line Items]
Gross premiums written	[2]	2,763	2,138	9,171	7,142
Premiums ceded	[2]	(818)	(576)	(3,013)	(2,145)
Net premiums written		1,945	1,562	6,158	4,997
Change in unearned premiums		(53)	(19)	(820)	(781)
Net premiums earned		1,892	1,543	5,338	4,216
Other underwriting income		2	2	5	9
Losses and loss adjustment expenses		(1,317)	(870)	(3,206)	(2,379)
Acquisition expenses		(374)	(304)	(1,050)	(875)
Other operating expenses		(54)	(61)	(193)	(203)
Underwriting income (loss)		$ 149	$ 310	$ 894	$ 768
Underwriting Ratios
Loss ratio		69.60%	56.40%	60.10%	56.40%
Acquisition expense ratio		19.80%	19.70%	19.70%	20.70%
Other operating expense ratio		2.90%	3.90%	3.60%	4.80%
Combined ratio		92.30%	80%	83.40%	81.90%
Goodwill and intangible assets		$ 113	$ 132	$ 113	$ 132
Operating segments | Mortgage
Segment Reporting Information [Line Items]
Gross premiums written	[2]	339	347	1,020	1,037
Premiums ceded	[2]	(57)	(76)	(185)	(240)
Net premiums written		282	271	835	797
Change in unearned premiums		31	22	90	86
Net premiums earned		313	293	925	883
Other underwriting income		3	3	15	12
Losses and loss adjustment expenses		1	35	37	46
Acquisition expenses		1	(2)	1	(16)
Other operating expenses		(49)	(47)	(151)	(147)
Underwriting income (loss)		$ 269	$ 282	$ 827	$ 778
Underwriting Ratios
Loss ratio		(0.40%)	(12.10%)	(4.00%)	(5.30%)
Acquisition expense ratio		(0.40%)	0.60%	(0.10%)	1.80%
Other operating expense ratio		15.60%	16.20%	16.30%	16.70%
Combined ratio		14.80%	4.70%	12.20%	13.20%
Goodwill and intangible assets		$ 348	$ 387	$ 348	$ 387
[1]Certain expenses have been excluded from ‘corporate expenses’ and reflected in ‘transaction costs and other.’[2]Certain assumed and ceded amounts related to intersegment transactions are included in individual segment results. Accordingly, the sum of such transactions for each segment does not agree to the total due to eliminations.

Reserve for Losses and Loss A_3

Reserve for Losses and Loss Adjustment Expenses - Reconciliation of beginning and ending balances of losses and loss adjustment reserves (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense [Abstract]
Reserve for losses and loss adjustment expenses at beginning of period		$ 24,466	$ 21,268	$ 22,752	$ 20,032
Unpaid losses and loss adjustment expenses recoverable		7,083	6,394	6,690	6,280
Net reserve for losses and loss adjustment expenses at beginning of period		17,383	14,874	16,062	13,752
Net incurred losses and loss adjustment expenses relating to losses occurring in:
Current year		2,524	1,793	6,324	5,012
Prior years		(121)	(146)	(366)	(403)
Total net incurred losses and loss adjustment expenses		2,403	1,647	5,958	4,609
Net losses and loss adjustment expense reserves of acquired business	[1]	2,413	0	2,463	0
Net foreign exchange (gains) losses and other		246	(123)	152	(24)
Net paid losses and loss adjustment expenses relating to losses occurring in:
Current year		(362)	(345)	(647)	(700)
Prior years		(967)	(713)	(2,872)	(2,297)
Total net paid losses and loss adjustment expenses		(1,329)	(1,058)	(3,519)	(2,997)
Net reserve for losses and loss adjustment expenses at end of period		21,116	15,340	21,116	15,340
Unpaid losses and loss adjustment expenses recoverable		7,563	6,496	7,563	6,496
Reserve for losses and loss adjustment expenses at end of period		$ 28,679	$ 21,836	$ 28,679	$ 21,836
[1]Activity for the 2024 third quarter related to the acquisition of MCE (see note 2 ) and Watford Insurance Company (see note 16

Reserve for Losses and Loss A_4

Reserve for Losses and Loss Adjustment Expenses - Prior year development (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse	$ (121)	$ (146)	$ (366)	$ (403)
Operating segments
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse	(121)	(146)	(366)	(403)
Operating segments | Short tailed lines
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse	(163)	(186)	(439)	(485)
Operating segments | Long tailed lines
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse	42	40	73	82
Operating segments | Insurance
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse	(16)	(10)	(31)	(34)
Operating segments | Insurance | Short tailed lines
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse	(31)	(29)	(61)	(74)
Operating segments | Insurance | Short tailed lines | Property And Marine Product Line
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse	(15)	(16)		(44)
Operating segments | Insurance | Short tailed lines | Travel and accident
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse	(11)		(29)
Operating segments | Insurance | Short tailed lines | Warranty and lenders solutions
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse				(20)
Operating segments | Insurance | Short tailed lines | Surety Product Line
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse			(31)
Operating segments | Insurance | Long tailed lines
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse	15	19	30	40
Operating segments | Insurance | Long tailed lines | Professional liability
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse		25		48
Operating segments | Insurance | Long tailed lines | Executive assurance
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse				(24)
Operating segments | Reinsurance
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse	(41)	(44)	(115)	(126)
Operating segments | Reinsurance | Short tailed lines
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse	(68)	(65)	(158)	(168)
Operating segments | Reinsurance | Short tailed lines | Property other than property catastrophe
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse	(20)	(29)	(71)	(75)
Operating segments | Reinsurance | Short tailed lines | Property catastrophe
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse		(22)		(29)
Operating segments | Reinsurance | Short tailed lines | Other specialty lines
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse	(35)	(19)	(72)	(46)
Operating segments | Reinsurance | Long tailed lines
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse	27	21	43	42
Operating segments | Reinsurance | Long tailed lines | Casualty
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse	27	21	43	39
Operating segments | Mortgage
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse	(64)	(92)	(220)	(243)
Operating segments | Mortgage | Short tailed lines
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse	(64)	(92)	(220)	(243)
Operating segments | Mortgage | Long tailed lines
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior year development (favorable) adverse	$ 0	$ 0	$ 0	$ 0

Allowance for Expected Credit_3

Allowance for Expected Credit Losses - Premiums receivable (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Credit Loss [Abstract]
Balance at beginning of period		$ 6,268	$ 5,296	$ 4,644	$ 3,625
Balance at end of period		6,364	4,937	6,364	4,937
Allowance for Expected Credit Losses
Balance at beginning of period		36	34	34	35
Provision on business acquired	[1]	16		16
Change for provision of expected credit losses	[2]	0	0	2	(1)
Balance at end of period		52	34	52	34
Premium receivable, write-offs during the period		$ 1	$ 0	$ 1	$ 2
[1]Represents MCE’s provision for current expected credit losses on premiums receivable[2] Amounts deemed uncollectible are written-off in operating expenses. For the 2024 third quarter and 2023 third quarter, amounts written off were $1 million and nil, respectively. For the nine months ended September 30, 2024 and 2023 period, amounts written off were $1 million and $2 million, respectively.

Allowance for Expected Credit_4

Allowance for Expected Credit Losses - Reinsurance recoverables (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Credit Loss [Abstract]
Balance at beginning of period	$ 7,473	$ 6,717	$ 7,064	$ 6,564
Balance at end of period	7,948	6,821	7,948	6,821
Allowance for Expected Credit Losses
Balance at beginning of period	20	22	21	22
Change for provision of expected credit losses	(3)	1	(4)	1
Balance at end of period	$ 17	$ 23	$ 17	$ 23

Allowance for Expected Credit_5

Allowance for Expected Credit Losses - Ceded credit risk (Details) - USD ($) $ in Millions		9 Months Ended	12 Months Ended
		Sep. 30, 2024	Dec. 31, 2023	Jun. 30, 2024	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Ceded Credit Risk [Line Items]
Reinsurance recoverable on unpaid and paid losses and loss adjustment expenses		$ 7,948	$ 7,064	$ 7,473	$ 6,821	$ 6,717	$ 6,564
Reinsurance recoverable | Reinsurer concentration risk | AM Best A minus Or Better Rating
Ceded Credit Risk [Line Items]
Concentration risk percentage		65.30%	66.80%
Reinsurance recoverable | Reinsurer concentration risk | AM Best Rating Below A Minus | All Other Carriers
Ceded Credit Risk [Line Items]
Concentration risk percentage		0%	0.10%
Reinsurance recoverable | Reinsurer concentration risk | Not Rated | All Other Carriers
Ceded Credit Risk [Line Items]
Concentration risk percentage	[1]	34.70%	33.10%
Reinsurance recoverable | Reinsurer concentration risk | Not Rated | Ceded credit risk, secured
Ceded Credit Risk [Line Items]
Concentration risk percentage		95%	95%
Stockholders' equity | Reinsurer concentration risk | Largest Balance Due From Any One Carrier
Ceded Credit Risk [Line Items]
Concentration risk percentage		7.10%	7.20%
[1]At September 30, 2024 and December 31, 2023 over 95% of such amount were collateralized through reinsurance trusts, funds withheld arrangements, letters of credit or other

Allowance for Expected Credit_6

Allowance for Expected Credit Losses - Contractholder receivables (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Credit Loss [Abstract]
Balance at beginning of period	$ 2,016	$ 1,761	$ 1,814	$ 1,731
Balance at end of period	2,078	1,805	2,078	1,805
Allowance for Expected Credit Losses
Balance at beginning of period	4	3	3	3
Change for provision of expected credit losses	0	0	1	0
Balance at end of period	$ 4	$ 3	$ 4	$ 3

Investment Information - Summar

Investment Information - Summary of available for sale securities (Details) - USD ($) $ in Millions	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	$ 31,775		$ 25,616
Gross Unrealized Gains	524		276
Gross Unrealized Losses	(533)		(827)
Allowance for Expected Credit Losses	(19)		(28)
Cost or Amortized Cost	31,803		26,195
Fixed maturities
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	28,434		23,553
Gross Unrealized Gains	518		275
Gross Unrealized Losses	(531)		(825)
Allowance for Expected Credit Losses	(19)	$ (27)	(28)	$ (57)	$ (61)	$ (41)
Cost or Amortized Cost	28,466		24,131
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	13,996		10,855
Gross Unrealized Gains	339		157
Gross Unrealized Losses	(294)		(464)
Allowance for Expected Credit Losses	(12)	(16)	(20)	(47)	(50)	(30)
Cost or Amortized Cost	13,963		11,182
U.S. government and government agencies
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	5,863		5,814
Gross Unrealized Gains	53		63
Gross Unrealized Losses	(48)		(86)
Allowance for Expected Credit Losses	0		0
Cost or Amortized Cost	5,858		5,837
Asset backed securities
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	2,989		2,250
Gross Unrealized Gains	27		11
Gross Unrealized Losses	(27)		(55)
Allowance for Expected Credit Losses	(5)		(5)
Cost or Amortized Cost	2,994		2,299
Non-U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	2,853		2,062
Gross Unrealized Gains	75		33
Gross Unrealized Losses	(84)		(100)
Allowance for Expected Credit Losses	(1)	$ (1)	(1)	$ (2)	$ (3)	$ (2)
Cost or Amortized Cost	2,863		2,130
Commercial mortgage backed securities
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	1,146		1,213
Gross Unrealized Gains	8		3
Gross Unrealized Losses	(17)		(34)
Allowance for Expected Credit Losses	(1)		(2)
Cost or Amortized Cost	1,156		1,246
Residential mortgage backed securities
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	1,313		1,103
Gross Unrealized Gains	14		7
Gross Unrealized Losses	(50)		(66)
Allowance for Expected Credit Losses	0		0
Cost or Amortized Cost	1,349		1,162
Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	274		256
Gross Unrealized Gains	2		1
Gross Unrealized Losses	(11)		(20)
Allowance for Expected Credit Losses	0		0
Cost or Amortized Cost	283		275
Short-term investments
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	3,341		2,063
Gross Unrealized Gains	6		1
Gross Unrealized Losses	(2)		(2)
Allowance for Expected Credit Losses	0		0
Cost or Amortized Cost	$ 3,337		$ 2,064

Investment Information - Aging

Investment Information - Aging of available for sale securities in an unrealized loss position (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale, Unrealized Loss Position, Estimated Fair Value [Abstract]
Estimated Fair Value - Less than 12 Months	$ 5,283	$ 3,867
Estimated Fair Value - 12 Months or More	6,386	9,555
Estimated Fair Value	11,669	13,422
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Gross Unrealized Losses - Less than 12 Months	(102)	(67)
Gross Unrealized Losses - 12 Months or More	(431)	(760)
Gross Unrealized Losses	(533)	(827)
Fixed maturities
Debt Securities, Available-for-sale, Unrealized Loss Position, Estimated Fair Value [Abstract]
Estimated Fair Value - Less than 12 Months	4,921	3,565
Estimated Fair Value - 12 Months or More	6,386	9,555
Estimated Fair Value	11,307	13,120
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Gross Unrealized Losses - Less than 12 Months	(100)	(65)
Gross Unrealized Losses - 12 Months or More	(431)	(760)
Gross Unrealized Losses	(531)	(825)
Corporate bonds
Debt Securities, Available-for-sale, Unrealized Loss Position, Estimated Fair Value [Abstract]
Estimated Fair Value - Less than 12 Months	1,903	1,559
Estimated Fair Value - 12 Months or More	3,316	4,959
Estimated Fair Value	5,219	6,518
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Gross Unrealized Losses - Less than 12 Months	(76)	(45)
Gross Unrealized Losses - 12 Months or More	(218)	(419)
Gross Unrealized Losses	(294)	(464)
U.S. government and government agencies
Debt Securities, Available-for-sale, Unrealized Loss Position, Estimated Fair Value [Abstract]
Estimated Fair Value - Less than 12 Months	1,815	1,066
Estimated Fair Value - 12 Months or More	571	941
Estimated Fair Value	2,386	2,007
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Gross Unrealized Losses - Less than 12 Months	(10)	(10)
Gross Unrealized Losses - 12 Months or More	(38)	(76)
Gross Unrealized Losses	(48)	(86)
Non-U.S. government securities
Debt Securities, Available-for-sale, Unrealized Loss Position, Estimated Fair Value [Abstract]
Estimated Fair Value - Less than 12 Months	614	365
Estimated Fair Value - 12 Months or More	743	897
Estimated Fair Value	1,357	1,262
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Gross Unrealized Losses - Less than 12 Months	(8)	(4)
Gross Unrealized Losses - 12 Months or More	(76)	(96)
Gross Unrealized Losses	(84)	(100)
Residential mortgage backed securities
Debt Securities, Available-for-sale, Unrealized Loss Position, Estimated Fair Value [Abstract]
Estimated Fair Value - Less than 12 Months	213	221
Estimated Fair Value - 12 Months or More	485	522
Estimated Fair Value	698	743
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Gross Unrealized Losses - Less than 12 Months	(2)	(3)
Gross Unrealized Losses - 12 Months or More	(48)	(63)
Gross Unrealized Losses	(50)	(66)
Asset backed securities
Debt Securities, Available-for-sale, Unrealized Loss Position, Estimated Fair Value [Abstract]
Estimated Fair Value - Less than 12 Months	199	234
Estimated Fair Value - 12 Months or More	442	1,112
Estimated Fair Value	641	1,346
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Gross Unrealized Losses - Less than 12 Months	(3)	(1)
Gross Unrealized Losses - 12 Months or More	(24)	(54)
Gross Unrealized Losses	(27)	(55)
Commercial mortgage backed securities
Debt Securities, Available-for-sale, Unrealized Loss Position, Estimated Fair Value [Abstract]
Estimated Fair Value - Less than 12 Months	176	100
Estimated Fair Value - 12 Months or More	644	909
Estimated Fair Value	820	1,009
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Gross Unrealized Losses - Less than 12 Months	(1)	(1)
Gross Unrealized Losses - 12 Months or More	(16)	(33)
Gross Unrealized Losses	(17)	(34)
Municipal bonds
Debt Securities, Available-for-sale, Unrealized Loss Position, Estimated Fair Value [Abstract]
Estimated Fair Value - Less than 12 Months	1	20
Estimated Fair Value - 12 Months or More	185	215
Estimated Fair Value	186	235
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Gross Unrealized Losses - Less than 12 Months	0	(1)
Gross Unrealized Losses - 12 Months or More	(11)	(19)
Gross Unrealized Losses	(11)	(20)
Short-term investments
Debt Securities, Available-for-sale, Unrealized Loss Position, Estimated Fair Value [Abstract]
Estimated Fair Value - Less than 12 Months	362	302
Estimated Fair Value - 12 Months or More	0	0
Estimated Fair Value	362	302
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Gross Unrealized Losses - Less than 12 Months	(2)	(2)
Gross Unrealized Losses - 12 Months or More	0	0
Gross Unrealized Losses	$ (2)	$ (2)

Investment Information - Maturi

Investment Information - Maturity profile of available for sale securities) (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Estimated Fair Value
Due in one year or less	$ 430	$ 480
Due after one year through five years	15,533	12,924
Due after five years through 10 years	6,572	5,249
Due after 10 years	451	334
Single maturity date	22,986	18,987
Estimated Fair Value	31,775	25,616
Amortized Cost
Due in one year or less	445	499
Due after one year through five years	15,457	13,101
Due after five years through 10 years	6,595	5,450
Due after 10 years	470	374
Single maturity date	22,967	19,424
Cost or Amortized Cost	31,803	26,195
Fixed maturities
Estimated Fair Value
Estimated Fair Value	28,434	23,553
Amortized Cost
Cost or Amortized Cost	28,466	24,131
Residential mortgage backed securities
Estimated Fair Value
Securities without single maturity date	1,313	1,103
Estimated Fair Value	1,313	1,103
Amortized Cost
Securities without single maturity date	1,349	1,162
Cost or Amortized Cost	1,349	1,162
Commercial mortgage backed securities
Estimated Fair Value
Securities without single maturity date	1,146	1,213
Estimated Fair Value	1,146	1,213
Amortized Cost
Securities without single maturity date	1,156	1,246
Cost or Amortized Cost	1,156	1,246
Asset backed securities
Estimated Fair Value
Securities without single maturity date	2,989	2,250
Estimated Fair Value	2,989	2,250
Amortized Cost
Securities without single maturity date	2,994	2,299
Cost or Amortized Cost	$ 2,994	$ 2,299

Investment Information - Other

Investment Information - Other investments, at fair value (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Schedule Of Other Investments [Line Items]
Other investments, at fair value	$ 3,261	$ 2,488
Other investments
Schedule Of Other Investments [Line Items]
Other investments, at fair value	2,096	1,777
Lending
Schedule Of Other Investments [Line Items]
Other investments, at fair value	957	754
Investment grade fixed income
Schedule Of Other Investments [Line Items]
Other investments, at fair value	499	272
Term loan investments
Schedule Of Other Investments [Line Items]
Other investments, at fair value	299	427
Private equity
Schedule Of Other Investments [Line Items]
Other investments, at fair value	212	182
Credit related funds
Schedule Of Other Investments [Line Items]
Other investments, at fair value	111	124
Energy
Schedule Of Other Investments [Line Items]
Other investments, at fair value	18	18
Fixed maturities
Schedule Of Other Investments [Line Items]
Other investments, at fair value	1,097	683
Short term investments
Schedule Of Other Investments [Line Items]
Other investments, at fair value	61	21
Equity securities
Schedule Of Other Investments [Line Items]
Other investments, at fair value	$ 7	$ 7

Investment Information - Net in

Investment Information - Net investment income (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Net investment income:
Gross investment income		$ 422	$ 289	$ 1,158	$ 768
Investment expenses		(23)	(20)	(68)	(58)
Net investment income		399	269	1,090	710
Fixed maturities
Net investment income:
Gross investment income		340	243	926	645
Short-term investments
Net investment income:
Gross investment income		38	19	102	48
Equity securities
Net investment income:
Gross investment income		9	5	27	15
Other
Net investment income:
Gross investment income	[1]	$ 35	$ 22	$ 103	$ 60
[1]Amounts include dividends and other distributions on investment funds, term loan investments, funds held balances, cash balances and other items.

Investment Information - Net re

Investment Information - Net realized gains and losses (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Available for sale securities:
Available for sale securities, gross gains on investment sales		$ 104	$ 12	$ 167	$ 51
Available for sale securities, gross losses on investment sales		(50)	(116)	(205)	(396)
Equity securities, at fair value:
Net realized gains (losses) on sales during the period		15	14	31	50
Net unrealized gains (losses) on equity securities still held at reporting date		58	(46)	147	17
Allowance for credit losses:
Allowance for credit losses - investments related		6	0	4	(23)
Allowance for credit losses - underwriting related		2	(1)	0	(2)
Derivative instruments	[1]	125	(102)	116	(61)
Other	[2]	4	4	225	4
Net realized gains (losses)		169	(248)	358	(354)
Fixed maturities
Available for sale securities:
Change in fair value of assets and liabilities accounted for using the fair value option		25	(16)	23	(12)
Other investments
Available for sale securities:
Change in fair value of assets and liabilities accounted for using the fair value option		$ (120)	$ 3	(150)	17
Equity securities
Available for sale securities:
Change in fair value of assets and liabilities accounted for using the fair value option				$ 0	$ 1
[1]See note 10 for information on the Company’s derivative instruments.

Investment Information - Invest

Investment Information - Investments accounted for using the equity method (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]
Investments accounted for using the equity method	$ 5,244	$ 4,566
Private equity
Schedule of Equity Method Investments [Line Items]
Investments accounted for using the equity method	1,737	1,175
Credit related funds
Schedule of Equity Method Investments [Line Items]
Investments accounted for using the equity method	1,366	1,258
Real estate
Schedule of Equity Method Investments [Line Items]
Investments accounted for using the equity method	721	666
Lending
Schedule of Equity Method Investments [Line Items]
Investments accounted for using the equity method	474	597
Fixed income
Schedule of Equity Method Investments [Line Items]
Investments accounted for using the equity method	377	277
Infrastructure
Schedule of Equity Method Investments [Line Items]
Investments accounted for using the equity method	323	320
Equity securities
Schedule of Equity Method Investments [Line Items]
Investments accounted for using the equity method	177	178
Energy
Schedule of Equity Method Investments [Line Items]
Investments accounted for using the equity method	$ 69	$ 95

Investment Information - Limite

Investment Information - Limited partnership interests (Details) - USD ($) $ in Millions		Sep. 30, 2024	Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]
Maximum Exposure to Loss		$ 5,327	$ 4,680
Aggregate unfunded commitments		4,500	3,600
Equity method investments
Schedule of Equity Method Investments [Line Items]
Maximum Exposure to Loss	[1]	5,244	4,566
Aggregate unfunded commitments		4,300	3,400
Fair value option
Schedule of Equity Method Investments [Line Items]
Maximum Exposure to Loss	[2]	83	114
Aggregate unfunded commitments		$ 21	$ 32
[1]Aggregate unfunded commitments were $4.3 billion at September 30, 2024, compared with $3.4 billion at December 31, 2023.[2]Aggregate unfunded commitments were $21 million at September 30, 2024, compared to $32 million at December 31, 2023

Investment Information - Inve_2

Investment Information - Investment in operating affiliates (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]
Investment in operating affiliates	$ 1,236		$ 1,236		$ 1,119
Income (loss) from operating affiliates	$ 36	$ 54	$ 136	$ 115
Coface
Schedule of Equity Method Investments [Line Items]
Percentage ownership	29.90%		29.90%
Investment in operating affiliates	$ 596		$ 596		570
Greysbridge Holdings Ltd
Schedule of Equity Method Investments [Line Items]
Percentage ownership	40%		40%
Investment in operating affiliates	$ 521		$ 521		$ 430
Issued Shares Excluding Treasury Stock | Coface
Schedule of Equity Method Investments [Line Items]
Percentage ownership	30%		30%

Investment Information - Allowa

Investment Information - Allowance for expected credit losses (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Allowance for expected credit losses
Balance at beginning of period				$ 28
Balance at end of period		$ 19		19
Fixed maturities
Allowance for expected credit losses
Balance at beginning of period		27	$ 61	28	$ 41
Additions for current-period provision for expected credit losses			6		7
Additions (reductions) for previously recognized expected credit losses		(6)	(3)	(4)	18
Reductions due to disposals		(2)	(7)	(5)	(9)
Balance at end of period		19	57	19	57
Structured securities
Allowance for expected credit losses
Balance at beginning of period	[1]	10	8	7	9
Additions for current-period provision for expected credit losses	[1]		2		2
Additions (reductions) for previously recognized expected credit losses	[1]	(3)	0	0	(1)
Reductions due to disposals	[1]	(1)	(2)	(1)	(2)
Balance at end of period	[1]	6	8	6	8
Corporate bonds
Allowance for expected credit losses
Balance at beginning of period		16	50	20	30
Additions for current-period provision for expected credit losses			4		5
Additions (reductions) for previously recognized expected credit losses		(3)	(3)	(4)	18
Reductions due to disposals		(1)	(4)	(4)	(6)
Balance at end of period		12	47	12	47
Non-U.S. government securities
Allowance for expected credit losses
Balance at beginning of period		1	3	1	2
Additions for current-period provision for expected credit losses			0		0
Additions (reductions) for previously recognized expected credit losses		0	0	0	1
Reductions due to disposals		0	(1)	0	(1)
Balance at end of period		$ 1	$ 2	$ 1	$ 2
[1]Includes asset backed securities, residential mortgage backed securities and commercial mortgage backed securities.

Investment Information - Restri

Investment Information - Restricted assets (Details) - USD ($) $ in Millions		Sep. 30, 2024	Dec. 31, 2023
Restricted Assets [Line Items]
Restricted assets		$ 13,321	$ 9,932
Collateral or guarantees - affiliated transactions
Restricted Assets [Line Items]
Restricted assets		5,306	4,854
Collateral or guarantees - third party agreements
Restricted Assets [Line Items]
Restricted assets		5,679	2,869
Deposits with US regulatory authorities
Restricted Assets [Line Items]
Restricted assets		883	833
Other
Restricted Assets [Line Items]
Restricted assets	[1]	$ 1,453	$ 1,376
[1]Primarily includes Funds at Lloyds, deposits with non-U.S. regulatory authorities and other restricted assets

Investment Information - Cash a

Investment Information - Cash and restricted cash (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Disclosure Investment Information [Abstract]
Cash	$ 1,025	$ 917
Restricted cash (included in ‘other assets’)	687	581
Cash and restricted cash	$ 1,712	$ 1,498	$ 1,355	$ 1,273

Investment Information - Narrat

Investment Information - Narrative (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($) lots	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) lots	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) lots
Continuous unrealized loss, qualitative disclosures:
Number of positions in an unrealized loss position (lots) | lots	6,710		6,710		7,100
Total number of positions (lots) | lots	19,840		19,840		15,720
Largest single loss	$ 4		$ 4		$ 6
Narrative items:
Equity securities, at fair value	1,623		1,623		$ 1,186
Equity in net (loss) income of investment funds accounted for using the equity method	$ 171	$ 59	$ 437	$ 176
Minimum
Narrative items:
Time lag for reporting			1 month
Maximum
Narrative items:
Time lag for reporting			3 months

Fair Value - Fair Value Hierarc

Fair Value - Fair Value Hierarchy (Details) - Recurring - USD ($) $ in Millions		Sep. 30, 2024	Dec. 31, 2023
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		$ 10,533	$ 8,745
Liabilities measured at fair value		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Derivative instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Residential mortgage loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		5,852	5,792
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed maturities | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		2	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed maturities | U.S. government and government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		5,850	5,792
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed maturities | Asset backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed maturities | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed maturities | Commercial mortgage backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed maturities | Residential mortgage backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed maturities | Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		3,081	1,786
Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		1,590	1,151
Quoted Prices in Active Markets for Identical Assets (Level 1) | Derivative instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value option
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		10	16
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value option | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value option | U.S. government and government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		4	13
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value option | Asset backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value			0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value option | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value option | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		3	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value option | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		3	3
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value option | Other investments fair value option
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		24,340	18,927
Liabilities measured at fair value		(81)	(119)
Significant Other Observable Inputs (Level 2) | Other liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value		0	0
Significant Other Observable Inputs (Level 2) | Derivative instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value		(81)	(119)
Significant Other Observable Inputs (Level 2) | Residential mortgage loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		13	2
Significant Other Observable Inputs (Level 2) | Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		22,441	17,614
Significant Other Observable Inputs (Level 2) | Fixed maturities | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		13,853	10,708
Significant Other Observable Inputs (Level 2) | Fixed maturities | U.S. government and government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		13	22
Significant Other Observable Inputs (Level 2) | Fixed maturities | Asset backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		2,989	2,250
Significant Other Observable Inputs (Level 2) | Fixed maturities | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		2,853	2,062
Significant Other Observable Inputs (Level 2) | Fixed maturities | Commercial mortgage backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		1,146	1,213
Significant Other Observable Inputs (Level 2) | Fixed maturities | Residential mortgage backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		1,313	1,103
Significant Other Observable Inputs (Level 2) | Fixed maturities | Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		274	256
Significant Other Observable Inputs (Level 2) | Short-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		163	193
Significant Other Observable Inputs (Level 2) | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		27	30
Significant Other Observable Inputs (Level 2) | Derivative instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		147	197
Significant Other Observable Inputs (Level 2) | Fair value option
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		1,549	891
Significant Other Observable Inputs (Level 2) | Fair value option | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		1,085	662
Significant Other Observable Inputs (Level 2) | Fair value option | U.S. government and government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Significant Other Observable Inputs (Level 2) | Fair value option | Asset backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value			2
Significant Other Observable Inputs (Level 2) | Fair value option | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		8	6
Significant Other Observable Inputs (Level 2) | Fair value option | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		43	11
Significant Other Observable Inputs (Level 2) | Fair value option | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Significant Other Observable Inputs (Level 2) | Fair value option | Other investments fair value option
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		413	210
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		553	356
Liabilities measured at fair value		(43)	(22)
Significant Unobservable Inputs (Level 3) | Other liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value		(43)	(22)
Significant Unobservable Inputs (Level 3) | Derivative instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value		0	0
Significant Unobservable Inputs (Level 3) | Residential mortgage loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Significant Unobservable Inputs (Level 3) | Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		141	147
Significant Unobservable Inputs (Level 3) | Fixed maturities | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		141	147
Significant Unobservable Inputs (Level 3) | Fixed maturities | U.S. government and government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Significant Unobservable Inputs (Level 3) | Fixed maturities | Asset backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Significant Unobservable Inputs (Level 3) | Fixed maturities | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Significant Unobservable Inputs (Level 3) | Fixed maturities | Commercial mortgage backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Significant Unobservable Inputs (Level 3) | Fixed maturities | Residential mortgage backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Significant Unobservable Inputs (Level 3) | Fixed maturities | Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Significant Unobservable Inputs (Level 3) | Short-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		97	84
Significant Unobservable Inputs (Level 3) | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		6	5
Significant Unobservable Inputs (Level 3) | Derivative instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Significant Unobservable Inputs (Level 3) | Fair value option
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		309	120
Significant Unobservable Inputs (Level 3) | Fair value option | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Significant Unobservable Inputs (Level 3) | Fair value option | U.S. government and government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Significant Unobservable Inputs (Level 3) | Fair value option | Asset backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value			0
Significant Unobservable Inputs (Level 3) | Fair value option | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		0	0
Significant Unobservable Inputs (Level 3) | Fair value option | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		15	10
Significant Unobservable Inputs (Level 3) | Fair value option | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		4	4
Significant Unobservable Inputs (Level 3) | Fair value option | Other investments fair value option
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		290	106
Estimated Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		36,819	29,489
Liabilities measured at fair value		(124)	(141)
Estimated Fair Value | Other liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value		(43)	(22)
Estimated Fair Value | Derivative instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value		(81)	(119)
Estimated Fair Value | Residential mortgage loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		13	2
Estimated Fair Value | Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		28,434	23,553
Estimated Fair Value | Fixed maturities | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		13,996	10,855
Estimated Fair Value | Fixed maturities | U.S. government and government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		5,863	5,814
Estimated Fair Value | Fixed maturities | Asset backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		2,989	2,250
Estimated Fair Value | Fixed maturities | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		2,853	2,062
Estimated Fair Value | Fixed maturities | Commercial mortgage backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		1,146	1,213
Estimated Fair Value | Fixed maturities | Residential mortgage backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		1,313	1,103
Estimated Fair Value | Fixed maturities | Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		274	256
Estimated Fair Value | Short-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		3,341	2,063
Estimated Fair Value | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		1,623	1,186
Estimated Fair Value | Derivative instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		147	197
Estimated Fair Value | Fair value option
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		3,261	2,488
Estimated Fair Value | Fair value option | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		1,085	662
Estimated Fair Value | Fair value option | U.S. government and government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		4	13
Estimated Fair Value | Fair value option | Asset backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value			2
Estimated Fair Value | Fair value option | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		8	6
Estimated Fair Value | Fair value option | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		61	21
Estimated Fair Value | Fair value option | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		7	7
Estimated Fair Value | Fair value option | Other investments fair value option
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		703	316
Estimated Fair Value | Fair value option | Other investments measured at net asset value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value	[1]	$ 1,393	$ 1,461
[1]In accordance with applicable accounting guidance, certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the consolidated balance sheets.

Fair Value - Rollforward of Lev

Fair Value - Rollforward of Level 3 assets and liabilities (Details) - Recurring - USD ($) $ in Millions		3 Months Ended				9 Months Ended
		Sep. 30, 2024		Sep. 30, 2023		Sep. 30, 2024	Sep. 30, 2023
Other liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period		$ (35)		$ (19)		$ (22)	$ (14)
Total gains or (losses) (realized/unrealized) - included in earnings	[1]	(1)		0		(1)	0
Total gains or (losses) (realized/unrealized) - included in other comprehensive income		0		0		0	0
Purchases, issuances, sales and settlements
Purchases		0		0		0	0
Issuances		(9)		(4)		(22)	(9)
Sales		0		0		0	0
Settlements		2		2		2	2
Transfers in and/or out of Level 3		0		0		0	0
Balance at end of period		(43)		(21)		(43)	(21)
Available for sale | Corporate bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period		160		100		147	121
Total gains or (losses) (realized/unrealized) - included in earnings	[1]	0		0		0	1
Total gains or (losses) (realized/unrealized) - included in other comprehensive income		0		(1)		2	(1)
Purchases, issuances, sales and settlements
Purchases		0		25		98	68
Issuances		0		0		0	0
Sales		0		0		0	0
Settlements		(19)		0		(106)	(65)
Transfers in and/or out of Level 3		0		0		0	0
Balance at end of period		141		124		141	124
Available for sale | Short-term investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period		97		0		84	0
Total gains or (losses) (realized/unrealized) - included in earnings		0	[1]	0	[1]	0	0
Total gains or (losses) (realized/unrealized) - included in other comprehensive income		0		0		1	0
Purchases, issuances, sales and settlements
Purchases		0		0		12	0
Issuances		0		0		0	0
Sales		0		0		0	0
Settlements		0		0		0	0
Transfers in and/or out of Level 3		0		0		0	0
Balance at end of period		97		0		97	0
Fair value option | Other investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period		144		86		106	33
Total gains or (losses) (realized/unrealized) - included in earnings	[1]	0		0		(4)	(1)
Total gains or (losses) (realized/unrealized) - included in other comprehensive income		0		0		0	0
Purchases, issuances, sales and settlements
Purchases		39		29		99	87
Issuances		0		0		0	0
Sales		(2)		(6)		(4)	(10)
Settlements		(14)		(9)		(30)	(9)
Transfers in and/or out of Level 3		123		0		123	0
Balance at end of period		290		100		290	100
Fair value option | Short term investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period		14		0		10	0
Total gains or (losses) (realized/unrealized) - included in earnings	[1]	0		0		0	0
Total gains or (losses) (realized/unrealized) - included in other comprehensive income		0		0		0	0
Purchases, issuances, sales and settlements
Purchases		5		4		15	4
Issuances		0		0		0	0
Sales		0		0		0	0
Settlements		(4)		0		(10)	0
Transfers in and/or out of Level 3		0		0		0	0
Balance at end of period		15		4		15	4
Fair value option | Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period		4		4		4	4
Total gains or (losses) (realized/unrealized) - included in earnings	[1]	0		0		0	0
Total gains or (losses) (realized/unrealized) - included in other comprehensive income		0		0		0	0
Purchases, issuances, sales and settlements
Purchases		0		0		0	0
Issuances		0		0		0	0
Sales		0		0		0	0
Settlements		0		0		0	0
Transfers in and/or out of Level 3		0		0		0	0
Balance at end of period		4		4		4	4
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period		6		5		5	4
Total gains or (losses) (realized/unrealized) - included in earnings	[1]	0		0		0	0
Total gains or (losses) (realized/unrealized) - included in other comprehensive income		0		0		0	0
Purchases, issuances, sales and settlements
Purchases		0		0		1	1
Issuances		0		0		0	0
Sales		0		0		0	0
Settlements		0		0		0	0
Transfers in and/or out of Level 3		0		0		0	0
Balance at end of period		$ 6		$ 5		$ 6	$ 5
[1]Gains or losses were included in net realized gains (losses).

Fair Value - Narrative (Details

Fair Value - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Total assets and liabilities measured at fair value	$ 36,900	$ 29,600
Total assets and liabilities measured at fair value priced using non-binding broker quotes	$ 146	$ 14
Total assets and liabilities measured at fair value priced using non-binding broker quotes (percentage)	0.40%	0%
Senior notes	$ 2,727	$ 2,726
Estimated fair value of senior notes	$ 2,600	$ 2,500

Derivative Instruments - Fair v

Derivative Instruments - Fair value and notional amount of derivatives (Details) - USD ($) $ in Millions		Sep. 30, 2024	Dec. 31, 2023
Derivative offsetting
Derivative assets subject to master netting agreements		$ 147	$ 197
Derivative liabilities subject to master netting agreements		$ 81	$ 119
Derivative Asset, Statement of Financial Position [Extensible Enumeration]		Other assets	Other assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]		Other liabilities	Other liabilities
Not designated as hedging instrument
Derivative [Line Items]
Asset derivatives - fair value		$ 147	$ 197
Liability derivatives - fair value		(81)	(119)
Not designated as hedging instrument | Futures contracts
Derivative [Line Items]
Asset derivatives - fair value	[1]	70	139
Liability derivatives - fair value	[1]	(6)	(61)
Net derivatives - notional value	[2]	3,030	3,746
Not designated as hedging instrument | Foreign currency forward contracts
Derivative [Line Items]
Asset derivatives - fair value	[1]	33	27
Liability derivatives - fair value	[1]	(38)	(32)
Net derivatives - notional value	[2]	1,400	1,224
Not designated as hedging instrument | Other
Derivative [Line Items]
Asset derivatives - fair value	[1],[3]	44	31
Liability derivatives - fair value	[1],[3]	(37)	(26)
Net derivatives - notional value	[2],[3]	$ 423	$ 512
[1]The fair value of asset derivatives are included in ‘ other assets other liabilities

Derivative Instruments - Summar

Derivative Instruments - Summary of net realized gains (losses) recorded in the consolidated statements of income (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Net realized gains (losses) on derivative instruments
Net realized gains (losses) on derivative instruments	[1]	$ 125	$ (102)	$ 116	$ (61)
Not designated as hedging instrument
Net realized gains (losses) on derivative instruments
Net realized gains (losses) on derivative instruments		125	(102)	116	(61)
Not designated as hedging instrument | Futures contracts
Net realized gains (losses) on derivative instruments
Net realized gains (losses) on derivative instruments		86	(87)	69	(73)
Not designated as hedging instrument | Foreign currency forward contracts
Net realized gains (losses) on derivative instruments
Net realized gains (losses) on derivative instruments		31	(20)	32	4
Not designated as hedging instrument | Other
Net realized gains (losses) on derivative instruments
Net realized gains (losses) on derivative instruments	[2]	$ 8	$ 5	$ 15	$ 8
[1]See note 10 for information on the Company’s derivative instruments.

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Investment commitments	$ 4,500		$ 3,600
Interest paid	$ 63	$ 63

Variable Interest Entities (Det

Variable Interest Entities (Details) - USD ($) $ in Millions		Sep. 30, 2024	Dec. 31, 2023
Variable Interest Entity [Line Items]
Total VIE Assets		$ 73,656	$ 58,906
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Total VIE Assets		1,133	1,242
Remaining Coverage, Amount		326
Variable Interest Entity, Not Primary Beneficiary | 2019-1 Ltd. (Mar-19)
Variable Interest Entity [Line Items]
Total VIE Assets		0	71
Remaining Coverage, Amount		0
Variable Interest Entity, Not Primary Beneficiary | 2019-3 Ltd. (Jul-19)
Variable Interest Entity [Line Items]
Total VIE Assets		0	99
Remaining Coverage, Amount		0
Variable Interest Entity, Not Primary Beneficiary | 2021-3 Ltd. (Sep-21)
Variable Interest Entity [Line Items]
Total VIE Assets		378	429
Remaining Coverage, Amount	[1]	101
Variable Interest Entity, Not Primary Beneficiary | 2022-1 Ltd. (Jan-22)
Variable Interest Entity [Line Items]
Total VIE Assets		216	256
Remaining Coverage, Amount	[1]	17
Variable Interest Entity, Not Primary Beneficiary | 2022-2 Ltd. (Sep-22)
Variable Interest Entity [Line Items]
Total VIE Assets		190	201
Remaining Coverage, Amount	[1]	120
Variable Interest Entity, Not Primary Beneficiary | 2023-1 Ltd. (Oct-23)
Variable Interest Entity [Line Items]
Total VIE Assets		186	186
Remaining Coverage, Amount	[1]	47
Variable Interest Entity, Not Primary Beneficiary | 2024-1 Ltd. (Aug-24)
Variable Interest Entity [Line Items]
Total VIE Assets		163	$ 0
Remaining Coverage, Amount		$ 41
[1]Coverage from a separate panel of reinsurers remaining at September 30, 2024.

Other Comprehensive Income (L_3

Other Comprehensive Income (Loss) - Amounts reclassified from accumulated other comprehensive income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Provision for credit losses	$ 6	$ 0	$ 4	$ (23)
Income (loss) before income taxes and income (loss) from operating affiliates	1,050	741	3,537	2,197
Income tax (expense) benefit	(98)	(72)	(296)	(203)
Net of tax	988	723	3,377	2,109
Reclassification out of accumulated other comprehensive income | Unrealized appreciation (decline) on available-for-sale investments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net realized gains (losses)	54	(104)	(38)	(345)
Provision for credit losses	6	0	4	(23)
Income (loss) before income taxes and income (loss) from operating affiliates	60	(104)	(34)	(368)
Income tax (expense) benefit	0	8	12	24
Net of tax	$ 60	$ (96)	$ (22)	$ (344)

Other Comprehensive Income (L_4

Other Comprehensive Income (Loss) - Components of other comprehensive income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Before tax amount:
Unrealized holding gains (losses) arising during period, before tax	$ 736	$ (208)	$ 549	$ (131)
Less reclassification of net realized gains included in net income, before tax	60	(104)	(34)	(368)
Foreign currency translation adjustments, before tax	25	(40)	(24)	(33)
Other comprehensive income (loss), before tax	701	(144)	559	204
Tax expense (benefit):
Unrealized holding gains (losses) arising during period, tax	91	(18)	71	(13)
Less reclassification of net realized gains included in net income, tax	0	(8)	(12)	(24)
Foreign currency translation adjustments, tax	0	0	0	0
Other comprehensive income (loss), tax	91	(10)	83	11
Net of tax amount:
Unrealized holding gains (losses) arising during period, net of tax	645	(190)	478	(118)
Less reclassification of net realized gains included in net income, net of tax	60	(96)	(22)	(344)
Foreign currency translation adjustments, net of tax	25	(40)	(24)	(33)
Net current period other comprehensive income (loss)	$ 610	$ (134)	$ 476	$ 193

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Effective tax rate on income before income taxes (percentage)	8.10%	8.80%
Net deferred tax asset	$ 1,500		$ 1,600
Income taxes paid (received)	$ 221	$ 127

Transactions With Related Par_2

Transactions With Related Parties (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Net premiums written	$ 4,047	$ 3,355	$ 11,913	$ 10,207
Net premiums earned	3,970	3,248	10,957	9,096
Reinsurance recoverable on unpaid and paid losses and loss adjustment expenses	7,948	$ 6,821	7,948	6,821	$ 7,473	$ 7,064	$ 6,717	$ 6,564
Reinsurance balances payable	2,586		2,586			2,000
Other assets	5,855		5,855			4,761
Other liabilities	2,835		2,835			1,942
Watford Insurance Company
Related Party Transaction [Line Items]
Total consideration paid	$ 35
Greysbridge Holdings Ltd
Related Party Transaction [Line Items]
Put/call option, proportion of shares	33.30%
Other assets	$ 261		261
Other liabilities	261		261
Operating affiliates | Premia
Related Party Transaction [Line Items]
Net premiums written				80
Net premiums earned				80
Funds held asset	137		137			158
Operating affiliates | Somers
Related Party Transaction [Line Items]
Net premiums written			581	$ 457
Reinsurance recoverable on unpaid and paid losses and loss adjustment expenses	1,600		1,600			1,300
Reinsurance balances payable	$ 546		$ 546			$ 475

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent Event - USD ($) $ / shares in Units, $ in Millions	Nov. 07, 2024	Oct. 30, 2024	Oct. 31, 2024	Oct. 29, 2024
Subsequent Event [Line Items]
Special cash dividend declared	$ 1,900
Special cash dividend (in dollars per share)	$ 5
LLOYDS BANK CORPORATE MARKETS | Amended L/C agreement
Subsequent Event [Line Items]
Maximum borrowing capacity		$ 700		$ 530
Increase in maximum borrowing capacity		$ 170
Letters of credit outstanding, amount			$ 700
Loss from Catastrophes | Hurricane Milton | Minimum
Subsequent Event [Line Items]
Estimate of loss, net of reinsurance and reinstatement premiums			275
Estimate of loss, industry			25,000
Loss from Catastrophes | Hurricane Milton | Maximum
Subsequent Event [Line Items]
Estimate of loss, net of reinsurance and reinstatement premiums			375
Estimate of loss, industry			$ 35,000