CNA FINANCIAL CORP, 10-K filed on 2/6/2024
Annual Report
v3.24.0.1
Cover Page - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Feb. 02, 2024
Jun. 30, 2023
Entity Information [Line Items]      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2023    
Current Fiscal Year End Date --12-31    
Document Transition Report false    
Entity File Number 1-5823    
Entity Registrant Name CNA FINANCIAL CORPORATION    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 36-6169860    
Entity Address, Address Line One 151 N. Franklin    
Entity Address, Postal Zip Code 60606    
Entity Address, City or Town Chicago,    
Entity Address, State or Province IL    
City Area Code 312    
Local Phone Number 822-5000    
Title of 12(b) Security Common Stock, Par value $2.50    
Trading Symbol CNA    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
Document Financial Statement Error Correction [Flag] false    
ICFR Auditor Attestation Flag true    
Entity Shell Company false    
Entity Common Stock, Shares Outstanding (in shares)   270,896,945  
Entity Public Float     $ 1,013
Documents Incorporated by Reference
DOCUMENTS INCORPORATED BY REFERENCE
Portions of the CNA Financial Corporation Proxy Statement prepared for the 2024 annual meeting of shareholders, pursuant to Regulation 14A, are incorporated by reference into Part III of this report.
    
Entity Central Index Key 0000021175    
Document Fiscal Year Focus 2023    
Document Fiscal Period Focus FY    
Amendment Flag false    
New York Stock Exchange      
Entity Information [Line Items]      
Security Exchange Name NYSE    
Chicago Stock Exchange      
Entity Information [Line Items]      
Security Exchange Name CHX    
v3.24.0.1
Audit Information
 12 Months Ended
Dec. 31, 2023
Audit Information [Abstract]  
Auditor Name DELOITTE & TOUCHE LLP
Auditor Location Chicago, Illinois
Auditor Firm ID 34
v3.24.0.1
Consolidated Statements of Operations - USD ($)
shares in Millions, $ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
 [1]
Dec. 31, 2021
 [1]
Revenues      
Net earned premiums $ 9,480 $ 8,667 $ 8,175
Net investment income 2,264 1,805 2,159
Net investment (losses) gains (99) (199) 120
Non-insurance warranty revenue 1,624 1,574 1,430
Other revenues 30 32 24
Total revenues 13,299 11,879 11,908
Claims, Benefits and Expenses      
Insurance claims and policyholders’ benefits (re-measurement gain (loss) of $(88), $(214), and $(8)) 7,068 6,653 6,371
Amortization of deferred acquisition costs 1,644 1,490 1,443
Non-insurance warranty expense 1,544 1,471 1,328
Other operating expenses 1,398 1,339 1,191
Interest 127 112 113
Total claims, benefits and expenses 11,781 11,065 10,446
Income before income tax 1,518 814 1,462
Income tax expense (313) (132) (278)
Net income $ 1,205 $ 682 $ 1,184
Basic earnings per share      
Basic earnings per share (in usd per share) $ 4.44 $ 2.51 $ 4.36
Diluted earnings per share      
Diluted earnings per share (in usd per share) $ 4.43 $ 2.51 $ 4.34
Weighted Average Outstanding Common Stock and Common Stock Equivalents      
Basic (in shares) 271.3 271.6 271.8
Diluted (in shares) 272.2 272.5 272.8
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Consolidated Statements of Operations - (Parenthetical) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Income Statement [Abstract]      
Insurance claims and policyholders benefits, including policyholders' dividends, remeasurement impact $ (88) $ (214) $ (8)
Accounting Standards Update [Extensible Enumeration] Accounting Standards Update 2018-12 [Member]    
v3.24.0.1
Consolidated Statements of Comprehensive Income (Loss) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
 [1]
Dec. 31, 2021
 [1]
Net income $ 1,205 $ 682 $ 1,184
Other Comprehensive Income (Loss), net of tax      
Net unrealized gains and losses on investments 1,120 (6,102) (989)
Impact of changes in discount rates used to measure long-duration contract liabilities (318) 3,959 941
Foreign currency translation adjustment 58 (108) (19)
Pension and postretirement benefits 66 13 244
Other comprehensive income (loss), net of tax 926 (2,238) 177
Total comprehensive income (loss) 2,131 (1,556) 1,361
Investments      
Other Comprehensive Income (Loss), net of tax      
Net unrealized gains and losses on investments (5) (5) (2)
Net unrealized gains and losses on other investments      
Other Comprehensive Income (Loss), net of tax      
Net unrealized gains and losses on investments $ 1,125 $ (6,097) $ (987)
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Consolidated Balance Sheets - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Investments:    
Fixed maturity securities at fair value (amortized cost of $42,414 and $41,032, less allowance for credit loss of $16 and $1) $ 40,425 $ 37,627 [1]
Equity securities at fair value (cost of $686 and $703) 683 674 [1]
Limited partnership investments 2,174 1,926 [1]
Other invested assets 80 78 [1]
Mortgage loans (less allowance for credit loss of $35 and $24) 1,035 1,040 [1]
Short-term investments 2,165 1,832 [1]
Total investments 46,562 43,177 [1]
Cash 345 475 [1]
Reinsurance receivables (less allowance for uncollectible receivables of $22 and $22) 5,412 5,416 [1]
Insurance receivables (less allowance for uncollectible receivables of $28 and $29) 3,442 3,158 [1]
Accrued investment income 444 402 [1]
Deferred acquisition costs 896 806 [1]
Deferred income taxes 1,016 1,251 [1]
Property and equipment at cost (less accumulated depreciation of $296 and $280) 253 226 [1]
Goodwill 146 144 [1]
Deferred non-insurance warranty acquisition expense 3,661 3,671 [1]
Other assets (includes $23 and $18 due from Loews Corporation) 2,534 2,274 [1]
Total assets 64,711 61,000 [1]
Insurance reserves:    
Claim and claim adjustment expenses 23,304 22,120 [1]
Unearned premiums 6,933 6,374 [1]
Future policy benefits 13,959 13,480 [1]
Short-term debt 550 243 [1]
Long-term debt 2,481 2,538 [1]
Deferred non-insurance warranty revenue 4,694 4,714 [1]
Other liabilities (includes $28 and $26 due to Loews Corporation) 2,897 2,983 [1]
Total liabilities 54,818 52,452 [1]
Commitments and contingencies (Notes B and G) [1]  
Stockholders' Equity    
Common stock ($2.50 par value; 500,000,000 shares authorized; 273,040,243 shares issued; 270,881,457 and 270,895,902 shares outstanding) 683 683 [1]
Additional paid-in capital 2,221 2,220 [1]
Retained earnings 9,755 9,336 [1]
Accumulated other comprehensive loss (2,672) (3,598) [1]
Treasury stock (2,158,786 and 2,144,341 shares), at cost (94) (93) [1]
Total stockholders’ equity 9,893 8,548 [1]
Total liabilities and stockholders' equity $ 64,711 $ 61,000 [1]
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Consolidated Balance Sheets - (Parenthetical) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Fixed maturities securities at amortized cost $ 42,414 $ 41,032
Marketable securities fixed maturities allowance for credit loss 16 1
Equity securities at cost 686 703
Mortgage loans on real estate commercial and consumer allowance for credit loss 35 24
Allowance for uncollectible reinsurance 22 22
Allowance for uncollectible insurance receivables 28 29
Accumulated depreciation on property and equipment 296 280
Other assets 2,534 2,274 [1]
Other liabilities $ 2,897 $ 2,983 [1]
Common stock, par value (in usd per share) $ 2.50 $ 2.50
Common stock, shares authorized (in shares) 500,000,000 500,000,000
Common stock, shares issued (in shares) 273,040,243 273,040,243
Common stock, shares outstanding (in shares) 270,881,457 270,895,902
Treasury stock, shares (in shares) 2,158,786 2,144,341
Related Party    
Other assets $ 23 $ 18
Other liabilities $ 28 $ 26
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Consolidated Statements of Cash Flows - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Cash Flows from Operating Activities      
Net income $ 1,205 $ 682 [1] $ 1,184 [1]
Adjustments to reconcile net income to net cash flows provided by operating activities:      
Deferred income tax expense (benefit) 2 (89) [1] 43 [1]
Trading portfolio activity 1 6 [1] 20 [1]
Net investment losses (gains) 99 199 [1] (120) [1]
Equity method investees (8) 250 [1] (127) [1]
Net amortization of investments (191) (129) [1] (81) [1]
Depreciation and amortization 73 51 [1] 54 [1]
Changes in:      
Receivables, net (245) (226) [1] (1,358) [1]
Accrued investment income (41) (29) [1] 3 [1]
Deferred acquisition costs (85) (79) [1] (30) [1]
Insurance reserves 1,667 2,058 [1] 2,485 [1]
Other, net (192) (192) [1] (76) [1]
Net cash flows provided by operating activities 2,285 2,502 [1] 1,997 [1]
Dispositions:      
Fixed maturity securities - sales 4,029 5,909 [1] 3,816 [1]
Fixed maturity securities - maturities, calls and redemptions 1,334 2,358 [1] 4,464 [1]
Equity securities 317 509 [1] 316 [1]
Limited partnerships 164 138 [1] 246 [1]
Mortgage loans 122 125 [1] 190 [1]
Purchases:      
Fixed maturity securities (6,616) (9,821) [1] (9,307) [1]
Equity securities (293) (294) [1] (304) [1]
Limited partnerships (402) (337) [1] (440) [1]
Mortgage loans (127) (200) [1] (95) [1]
Change in other investments (2) 8 [1] (6) [1]
Change in short-term investments (274) 155 [1] (83) [1]
Purchases of property and equipment (90) (52) [1] (26) [1]
Other, net (5) (10) [1] 1 [1]
Net cash flows used by investing activities (1,843) (1,512) [1] (1,228) [1]
Cash Flows from Financing Activities      
Dividends paid to common stockholders (787) (982) [1] (621) [1]
Proceeds from the issuance of debt 491 0 [1] 0 [1]
Repayment of debt (243) 0 [1] 0 [1]
Purchase of treasury stock (24) (39) [1] (18) [1]
Other, net (14) (11) [1] (9) [1]
Net cash flows used by financing activities (577) (1,032) [1] (648) [1]
Effect of foreign exchange rate changes on cash 5 (19) [1] (4) [1]
Net change in cash (130) (61) [1] 117 [1]
Cash, beginning of year [1] 475 536 419
Cash, end of year $ 345 $ 475 [1] $ 536 [1]
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Consolidated Statements of Stockholders' Equity - USD ($)
$ in Millions
Total
Prior to Adoption
Effect of Adoption
Common Stock
Additional Paid-in Capital
Retained Earnings
Retained Earnings
Prior to Adoption
Retained Earnings
Effect of Adoption
Accumulated Other Comprehensive (Loss)
Accumulated Other Comprehensive (Loss)
Prior to Adoption
Accumulated Other Comprehensive (Loss)
Effect of Adoption
Treasury Stock
Total stockholder's equity at beginning of period at Dec. 31, 2020 [1]       $ 683 $ 2,211 $ 9,075 $ 9,081 $ (6) $ (1,537) $ 803 $ (2,340) $ (71)
Increase (Decrease) in Stockholders' Equity [Roll Forward]                        
Stock-based compensation [1]         4             17
Dividends to common stockholders ($2.88, $3.60, and $2.27 per share) [1]           (620)            
Net income $ 1,184 [1] $ 1,202 $ (18)     1,184 [1]            
Other comprehensive income (loss) 177 [1] (483) 660           177 [1]      
Purchase of treasury stock [1]                       (18)
Total stockholder's equity at end of period at Dec. 31, 2021 [1] 11,105     683 2,215 9,639 9,663 (24) (1,360) 320 (1,680) (72)
Increase (Decrease) in Stockholders' Equity [Roll Forward]                        
Stock-based compensation [1]         5             18
Dividends to common stockholders ($2.88, $3.60, and $2.27 per share) [1]           (985)            
Net income 682 [1] 894 (212)     682 [1]            
Other comprehensive income (loss) (2,238) [1] (3,877) 1,639           (2,238) [1]      
Purchase of treasury stock [1]                       (39)
Total stockholder's equity at end of period at Dec. 31, 2022 8,548 [1] $ 8,825 $ (277) 683 [1] 2,220 [1] 9,336 [1] $ 9,572 $ (236) (3,598) [1] $ (3,557) $ (41) (93) [1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]                        
Stock-based compensation         1             23
Dividends to common stockholders ($2.88, $3.60, and $2.27 per share)           (786)            
Net income 1,205         1,205            
Other comprehensive income (loss) 926               926      
Purchase of treasury stock                       (24)
Total stockholder's equity at end of period at Dec. 31, 2023 $ 9,893     $ 683 $ 2,221 $ 9,755     $ (2,672)     $ (94)
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Consolidated Statements of Stockholders' Equity - (Parenthetical) - $ / shares
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Statement of Stockholders' Equity [Abstract]      
Dividends declared per share (usd per share) $ 2.88 $ 3.60 $ 2.27
v3.24.0.1
Summary of Significant Accounting Policies
 12 Months Ended
Dec. 31, 2023
Accounting Policies [Abstract]  
Summary of Significant Accounting Policies Summary of Significant Accounting Policies
Basis of Presentation
The Consolidated Financial Statements include the accounts of CNA Financial Corporation (CNAF) and its subsidiaries. Collectively, CNAF and its subsidiaries are referred to as CNA or the Company. Loews Corporation (Loews) owned approximately 92% of the outstanding common stock of CNAF as of December 31, 2023.
The accompanying Consolidated Financial Statements have been prepared in conformity with accounting principles generally accepted in the United States of America (GAAP). Intercompany amounts have been eliminated. The preparation of Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the Consolidated Financial Statements and the reported amounts of revenues and expenses during the reporting period. Actual results may differ from those estimates.
Recently Adopted Accounting Standards Updates (ASU)
ASU 2018-12: In August 2018, the Financial Accounting Standards Board (FASB) issued ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12; LDTI), which requires changes to the measurement and disclosure of long-duration contracts. Entities are required to review, and update if there is a change, cash flow assumptions (including morbidity and persistency) used to measure the liability for future policyholder benefits (LFPB) at least annually. The LFPB must also be updated for actual experience at least annually. The LFPB is reflected as Insurance reserves: Future policy benefits on the Consolidated Balance Sheet. The discount rate assumption used to measure the LFPB must be updated quarterly using an upper-medium grade (low credit risk) fixed-income instrument yield, commonly interpreted as a single-A rate. The effect of changes in cash flow assumptions and actual variances from expected experience are recorded in the Company's results of operations within Insurance claims and policyholders' benefits. The effect of changes in discount rate assumptions are recorded in Other comprehensive income (loss). In contrast, under legacy accounting guidance, cash flow and discount rate assumptions were locked-in unless a premium deficiency emerged. The discount rate assumption under legacy accounting guidance was determined using the Company’s internal investment portfolio yield, which was generally higher than a single-A yield.
The new guidance eliminates the need to hold shadow reserves associated with the Company’s long-term care reserves. Under legacy accounting guidance, to the extent that unrealized gains on fixed maturity securities supporting long-term care reserves would have resulted in a premium deficiency if realized, a related increase to Insurance reserves was recorded, net of tax, as a reduction of net unrealized gains (losses), through Other comprehensive income (loss) (shadow reserves).
The unit of account is the level at which reserves are measured. Under the new guidance, the unit of account used to measure the LFPB is the cohort. Cohorts are comprised of insurance contracts issued no more than one year apart, and must be further disaggregated according to policy benefit and insurance risk characteristics. Under legacy accounting guidance, the LFPB was generally measured at the individual policy level.
Under the new guidance, the Net Premium Ratio (NPR) is capped at 100%. To the extent that NPR would otherwise exceed 100%, the LFPB is increased and a loss is recognized immediately in the Company’s results of operations. The NPR cap is applied at the cohort level each quarter when the NPR is updated. In contrast, under legacy accounting guidance, premium deficiency testing was performed annually at the product level. See Note F to the Consolidated Financial Statements for further explanation of the NPR and LFPB calculations.
The Company adopted the new guidance effective January 1, 2023, using the modified retrospective method applied as of the transition date of January 1, 2021. The Company's run-off long-term care business is in scope of the new guidance. All prior periods presented in the financial statements have been adjusted to reflect application of the new guidance. The Company’s original locked in discount rate, utilized for purposes of
calculating the NPR under the new guidance, was based on the discount rate assumption used to calculate the LFPB immediately prior to the transition date. While the requirements of the new guidance represent a material change from legacy accounting, the new guidance does not impact capital and surplus under statutory accounting practices, cash flows or the underlying economics of the business.
In December 2022, the FASB issued ASU 2022-05, Financial Services-Insurance (Topic 944): Transition for Sold Contracts (ASU 2022-05). This guidance permits companies to make an election to exclude from the scope of ASU 2018-12 any insurance contracts that have been de-recognized prior to the effective date of ASU 2018-12, assuming that the company has no significant continuing involvement with the de-recognized contracts. In the fourth quarter of 2022, the Company novated its block of legacy annuity business, which was fully-ceded prior to novation. The Company has elected the ASU 2022-05 transition relief, and has excluded the novated legacy annuity business from the scope of ASU 2018-12.
Explanation of ASU 2018-12 Transition Impacts:
The following table presents a roll-forward of the pre-transition LFPB balance as of January 1, 2021:

(In millions)
Balance as of December 31, 2020, as previously reported$13,318 
Reclassification of reserves for policyholders currently receiving benefits to Future policy benefits (1)
2,844 
De-recognition of shadow reserves(3,293)
Re-measurement using an upper-medium grade fixed income instrument yield discount rate6,255 
Other adjustments8 
Balance as of January 1, 2021, as adjusted$19,132 
(1) In conjunction with the adoption of ASU 2018-12, at January 1, 2023, the Company reclassified the long-term care reserves for policyholders currently receiving benefits from Claim and claim adjustment expenses to Future policy benefits. This change was applied retrospectively as of January 1, 2021.
Shadow reserves associated with the Company’s long-term care business were de-recognized as of the transition date in Accumulated other comprehensive income (AOCI). The effect of re-measuring the LFPB at the single-A discount rate as of the transition date was similarly recorded in AOCI. The Company did not have any cohorts for which the NPR exceeded 100% at the transition date.
The Company’s practice under legacy accounting guidance was to calculate and record premium deficiency reserves at the policy level. Accordingly, an allocation methodology was not required to assign historical premium deficiency reserves to cohorts upon transition to ASU 2018-12.
The following table presents after tax adjustments to the opening balance of Stockholders’ equity resulting from adoption of ASU 2018-12:

(In millions)
Accumulated other comprehensive income (loss)Retained earnings
Balance as of December 31, 2020, as previously reported$803 $9,081 
De-recognition of shadow reserves2,601 — 
Re-measurement of LFPB using an upper-medium grade fixed income instrument yield discount rate(4,941)— 
     Other adjustments— (6)
Balance as of January 1, 2021, as adjusted$(1,537)$9,075 
The effects of adoption of ASU 2018-12 on the Consolidated Statement of Operations for the year ended December 31, 2022 were as follows:

(In millions)
Prior to AdoptionEffect of Adoption As reported
Insurance claims and policyholders’ benefits (1)
$6,386 $267 $6,653 
Income (loss) before income tax1,081 (267)814 
Income tax (expense) benefit(187)55 (132)
Net income894 (212)682 
Basic earnings (loss) per share3.29 (0.78)2.51 
Diluted earnings (loss) per share3.28 (0.77)2.51 
(1) The effect of adopting ASU 2018-12 on Insurance claims and policyholders’ benefits is inclusive of the re-measurement gain (loss) of $(214) million, which is presented parenthetically on the Consolidated Statement of Operations.
The effects of adoption of ASU 2018-12 on the Consolidated Statement of Operations for the year ended December 31, 2021 were as follows:

(In millions)
Prior to AdoptionEffect of Adoption As reported
Insurance claims and policyholders’ benefits (1)
$6,349 $22 $6,371 
Income (loss) before income tax1,484 (22)1,462 
Income tax (expense) benefit(282)4 (278)
Net income1,202 (18)1,184 
Basic earnings (loss) per share4.42 (0.06)4.36 
Diluted earnings (loss) per share4.41 (0.07)4.34 
(1) The effect of adopting ASU 2018-12 on Insurance claims and policyholders’ benefits is inclusive of the re-measurement gain (loss) of $(8) million, which is presented parenthetically on the Consolidated Statement of Operations.
The effects of adoption of ASU 2018-12 on the Consolidated Balance Sheet as of December 31, 2022 were as follows:

(In millions)
Prior to AdoptionEffect of AdoptionAs reported
Deferred income taxes$1,178 $73 $1,251 
Total assets60,927 73 61,000 
Claim and claim adjustment expenses (1)
25,099 (2,979)22,120 
Future policy benefits (1)
10,151 3,329 13,480 
Total liabilities52,102 350 52,452 
Retained earnings9,572 (236)9,336 
Accumulated other comprehensive income (loss)(3,557)(41)(3,598)
Total stockholders' equity8,825 (277)8,548 
(1) In conjunction with the adoption of ASU 2018-12, at January 1, 2023, the Company reclassified the long-term care reserves for policyholders currently receiving benefits from Claim and claim adjustment expenses to Future policy benefits. This change was applied retrospectively as of January 1, 2021.
The effects of adoption of ASU 2018-12 on the Consolidated Statement of Comprehensive Income (Loss) for the year ended December 31, 2022 were as follows:

(In millions)
Prior to AdoptionEffect of AdoptionAs reported
Changes in: Net unrealized gains and losses on other investments$(3,777)$(2,320)$(6,097)
Net unrealized gains and losses on investments(3,782)(2,320)(6,102)
Impact of changes in discount rates used to measure long-duration contract liabilities— 3,959 3,959 
Other comprehensive income (loss), net of tax(3,877)1,639 (2,238)
Total comprehensive income (loss)(2,983)1,427 (1,556)
The effects of adoption of ASU 2018-12 on the Consolidated Statement of Comprehensive Income (Loss) for the year ended December 31, 2021 were as follows:

(In millions)
Prior to AdoptionEffect of AdoptionAs reported
Changes in: Net unrealized gains and losses on other investments$(706)$(281)$(987)
Net unrealized gains and losses on investments(708)(281)(989)
Impact of changes in discount rates used to measure long-duration contract liabilities— 941 941 
Other comprehensive income (loss), net of tax(483)660 177 
Total comprehensive income (loss)719 642 1,361 
The effects of adoption of ASU 2018-12 on the Consolidated Statement of Cash Flows for the year ended December 31, 2022 were as follows:

(In millions)
Prior to AdoptionEffect of AdoptionAs reported
Net income$894 $(212)$682 
Deferred income tax expense (benefit)(34)(55)(89)
Changes in: Insurance reserves1,791 267 2,058 
The effects of adoption of ASU 2018-12 on the Consolidated Statement of Cash Flows for the year ended December 31, 2021 were as follows:

(In millions)
Prior to AdoptionEffect of AdoptionAs reported
Net income$1,202 $(18)$1,184 
Deferred income tax expense (benefit)47 (4)43 
Changes in: Insurance reserves2,463 22 2,485 
The effects of adoption of ASU 2018-12 on segment results of operations of the Life & Group segment for the year ended December 31, 2022 were as follows:

(In millions)
Prior to AdoptionEffect of AdoptionAs reported
Net incurred claims and benefits (1)
$1,202 $267 $1,469 
Core income (loss) before income tax(53)(267)(320)
Income tax (expense) benefit on core income (loss)44 55 99 
Core income (loss)(9)(212)(221)
(1) The effect of adopting ASU 2018-12 on Net incurred claims and benefits is inclusive of the re-measurement gain (loss) of $(214) million, which is presented parenthetically on the Consolidated Statement of Operations.
The effects of adoption of ASU 2018-12 on segment results of operations of the Life & Group segment for the year end ended December 31, 2021 were as follows:

(In millions)
Prior to AdoptionEffect of AdoptionAs reported
Net incurred claims and benefits (1)
$1,239 $22 $1,261 
Core income (loss) before income tax105 (22)83 
Income tax (expense) benefit on core income (loss)21 4 25 
Core income (loss)126 (18)108 
(1) The effect of adopting ASU 2018-12 on Net incurred claims and benefits is inclusive of the re-measurement gain (loss) of $(8) million, which is presented parenthetically on the Consolidated Statement of Operations.
The effects of adoption of ASU 2018-12 on segment results for selected balance sheet lines of the Life & Group segment as of December 31, 2022 were as follows:

(In millions)
Prior to AdoptionEffect of AdoptionAs reported
Claim and claim adjustment expenses (1)
$3,674 $(2,979)$695 
Future policy benefits (1)
10,151 3,329 13,480 
(1) In conjunction with the adoption of ASU 2018-12, at January 1, 2023, the Company reclassified the long-term care reserves for policyholders currently receiving benefits from Claim and claim adjustment expenses to Future policy benefits. This change was applied retrospectively as of January 1, 2021.
Accounting Standards Pending Adoption
In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. The updated accounting guidance requires expanded reportable segment disclosures, primarily related to significant segment expenses which are regularly provided to the company’s Chief Operating Decision Maker. The guidance is effective for fiscal years beginning after December 15, 2023, and interim periods within annual periods beginning after December 15, 2024. Retrospective application is required. The Company is currently evaluating the effect the updated guidance will have on the Company's financial statement disclosures.
In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The updated accounting guidance requires expanded income tax disclosures, including the disaggregation of existing disclosures related to the tax rate reconciliation and income taxes paid. The guidance is effective for annual periods beginning after December 15, 2024. Prospective application is required, with retrospective application permitted. The Company is currently evaluating the effect the updated guidance will have on the Company's financial statement disclosures.
Insurance Operations
Premiums: Insurance premiums on property and casualty insurance contracts are recognized in proportion to the underlying risk insured and are primarily earned ratably over the term of the policies. Premiums on long-term care contracts are earned ratably over the policy year in which they are due. The reserve for unearned premiums represents the portion of premiums written relating to the unexpired terms of coverage.
Property and casualty contracts that are retrospectively rated or subject to audit premiums contain provisions that result in an adjustment to the initial policy premium depending on the contract provisions. These provisions stipulate the adjustment due to loss experience of the insured during the coverage period, or changes in the level of exposure to insurance risk. For such contracts, the Company estimates the amount of ultimate premiums that the Company may earn upon completion of the coverage period and recognizes either an asset or a liability for the difference between the initial policy premium and the estimated ultimate premium. The Company either adjusts such estimated ultimate premium amounts during the course of the coverage period based on actual results to date, or by conducting premium audits after the policy has expired to determine the final exposure to insured risks. The resulting adjustment is recorded as either a reduction of or an increase to the earned premiums for the period.
Insurance receivables include balances due currently or in the future, including amounts due from insureds related to paid losses under high deductible policies, and are presented at unpaid balances, net of an allowance for uncollectible receivables. A loss rate methodology is used to determine expected credit losses for premium receivables. This methodology uses the Company’s historical annual credit losses relative to gross premium written to develop a range of credit loss rates for each dollar of gross written premium underwritten. Additionally, an expected credit loss for amounts due from insureds under high deductible and retrospectively rated policies is calculated on a pool basis, informed by historical default rate data obtained from major rating agencies. Changes in the allowance are presented as a component of Other operating expenses on the Consolidated Statements of Operations. Amounts are considered past due based on policy payment terms. Insurance receivables and any related allowance are written off after collection efforts are exhausted or a negotiated settlement is reached. See the Credit Losses section of this note for additional information on the Company’s allowances for expected credit losses.
Claim and claim adjustment expense reserves: Claim and claim adjustment expense reserves, except reserves for structured settlements not associated with asbestos and environmental pollution (A&EP) and workers' compensation lifetime claims, are not discounted and are based on i) case basis estimates for losses reported on direct business, adjusted in the aggregate for ultimate loss expectations; ii) estimates of incurred but not reported (IBNR) losses; iii) estimates of losses on assumed reinsurance; iv) estimates of future expenses to be incurred in the settlement of claims; v) estimates of salvage and subrogation recoveries and vi) estimates of amounts due from insureds related to losses under high deductible policies. Management considers current conditions and trends as well as past Company and industry experience in establishing these estimates. The effects of inflation, which can be significant, are implicitly considered in the reserving process and are part of the recorded reserve balance. Ceded claim and claim adjustment expense reserves are reported as a component of Reinsurance receivables on the Consolidated Balance Sheets.
Claim and claim adjustment expense reserves are presented net of anticipated amounts due from insureds related to losses under deductible policies of $1.2 billion and $1.1 billion as of December 31, 2023 and 2022. A significant portion of these amounts are supported by collateral. The Company has an allowance for uncollectible deductible amounts, which is presented as a component of the allowance for doubtful accounts included in Insurance receivables on the Consolidated Balance Sheets.
Structured settlements have been negotiated for certain property and casualty insurance claims. Structured settlements are agreements to provide fixed periodic payments to claimants. The Company's obligations for structured settlements not funded by annuities are included in claim and claim adjustment expense reserves and are discounted at a weighted average interest rate of 6.4% as of December 31, 2023 and 2022. This interest rate is based on the expected yield of the assets that support the reserves and reinvestment assumptions. As of December 31, 2023 and 2022, the discounted reserves for unfunded structured settlements were $465 million and $485 million, net of discount of $559 million and $590 million. For the years ended December 31, 2023, 2022 and 2021, the amount of interest recognized on the discounted reserves of unfunded structured settlements was $34 million, $36 million and $36 million, respectively. This interest accretion is presented as a component of Insurance claims and policyholders’ benefits on the Consolidated Statements of Operations, but is excluded from the Company’s disclosure of prior year loss reserve development.
Workers' compensation lifetime claim reserves are calculated using mortality assumptions determined through statutory regulation and economic factors. As of December 31, 2023 and 2022, workers' compensation lifetime claim reserves are discounted at a 3.5% interest rate. As of December 31, 2023 and 2022, the discounted reserves for workers’ compensation lifetime claim reserves were $196 million and $211 million, net of discount of $88 million and $93 million. For the years ended December 31, 2023, 2022 and 2021, the amount of interest accretion recognized on the discounted reserves of workers’ compensation lifetime claim reserves was $9 million, $9 million and $12 million, respectively. This interest accretion is presented as a component of Insurance claims and policyholders' benefits on the Consolidated Statements of Operations, but is excluded from the Company's disclosure of prior year loss reserve development.
Future policy benefit reserves: Future policy benefit reserves are associated with the Company's run-off long-term care business and relate to policyholders that are currently receiving benefits, including claims that have been incurred but are not yet reported, as well as policyholders that are not yet receiving benefits.
The LFPB is computed using the net level premium method, which incorporates cash flow assumptions and discount rate assumptions. Under the net level premium method, the LFPB is equal to the present value of future benefits and claim settlement expenses less the present value of future net premiums. Net premiums are equal to gross premiums multiplied by the NPR. The NPR is generally the ratio of the present value of benefits and expense payments to the present value of gross premiums, expected over the lifetime of the policy. As a result of the modified retrospective adoption of ASU 2018-12, the Company’s NPR calculation incorporates the original locked in discount rate and the reserve balance as of the transition date of January 1, 2021.
The key cash flow assumptions used to estimate the LFPB are morbidity, persistency (inclusive of mortality), anticipated future premium rate increases and expenses. Morbidity is the frequency and severity of injury, illness, sickness and diseases contracted. Persistency is the percentage of policies remaining in force and can be affected by policy lapses, benefit reductions and death. Future premium rate increases are generally subject to regulatory approval, and therefore the exact timing and size of the approved rate increases are unknown. Expense assumptions relate to claim adjudication. The Company has not elected the practical expedient that allows locking in the expense assumption. The carried LFPB discount rate is determined using the upper-medium grade fixed income instrument yield curve.
The Company has elected to update the NPR and the LFPB for actual experience on a quarterly basis. A quarterly assessment is also made as to whether evidence suggests that cash flow assumptions should be updated. Annually, in the third quarter, actuarial analysis is performed on policyholder morbidity, persistency, premium rate increases and expense experience. This analysis, combined with judgment, informs the setting of updated cash flow assumptions used to estimate the LFPB. Actuarial analysis includes predictive modeling, actual to expected experience comparisons and trend analysis. Applicable industry research is also considered.
Quarterly, to derive the upper-medium grade fixed income instrument yield discount rate assumption, the Company uses a published spot rate curve constructed from single-A rated U.S. dollar denominated corporate bonds. The Company uses linear interpolation to determine yield assumptions for tenors that fall between points for which observable rates are available. For cash flows that are projected to occur beyond the tenor for which market-observable rates are available, the Company applies judgment to estimate a normative rate which the Company grades to over 10 years.
Quarterly, the updated NPR is used to derive an updated LFPB as of the beginning of the current quarter measured at the original locked in discount rate. The updated LFPB is then compared to the existing carrying amount of the liability as of the same date (measured at the original locked in discount rate) to determine the re-measurement gain (loss), which is presented parenthetically within the Insurance claims and policyholders’ benefits line on the Consolidated Statements of Operations.
Insurance contracts are grouped into cohorts according to issue year. Contracts assumed through reinsurance are generally included within the same cohorts as contracts issued directly by the Company, according to issue year. The issue year for assumed contracts is defined according to the date that the Company’s assumption of insurance risk incepted. For assumed contracts that were reinsured concurrently with the issuance of the underlying direct contract, issue year is defined as the year that the underlying policy was issued. For contracts that were already in-force when assumed by the Company, issue year is defined as the year in which the reinsurance agreement incepted. For group long-term care business, issue year is defined as the year the individual insurance certificate was issued. Long-term care is the Company's only long-duration product line, therefore, cohorts are not further disaggregated by product.
Insurance-related assessments: Liabilities for insurance-related assessments are accrued when an assessment is probable, when it can be reasonably estimated and when the event obligating the entity to pay an imposed or probable assessment has occurred. Liabilities for insurance-related assessments are not discounted and are included as part of Other liabilities on the Consolidated Balance Sheets. As of December 31, 2023 and 2022, the liability balances were $84 million and $74 million.
Reinsurance: Reinsurance accounting allows for contractual cash flows to be reflected as premiums and losses. To qualify for reinsurance accounting, reinsurance agreements must include risk transfer. To meet risk transfer requirements, a reinsurance contract must include both insurance risk, consisting of underwriting and timing risk, and a reasonable possibility of a significant loss for the assuming entity.
Reinsurance receivables related to paid losses are presented at unpaid balances. Reinsurance receivables related to unpaid losses are estimated in a manner consistent with claim and claim adjustment expense reserves or future policy benefit reserves. Reinsurance receivables are reported net of an allowance for uncollectible amounts on the Consolidated Balance Sheets. The cost of reinsurance is primarily accounted for over the life of the underlying reinsured policies using assumptions consistent with those used to account for the underlying policies or over the reinsurance contract period. The ceding of insurance does not discharge the primary liability of the Company.
The Company has established an allowance for uncollectible reinsurance receivables which relates to both amounts already billed on ceded paid losses as well as ceded reserves that will be billed when losses are paid in the future. For assessing expected credit losses, the Company separates reinsurance receivables into two pools: voluntary reinsurance receivables and involuntary receivables related to mandatory pools. The Company has not recorded an allowance for involuntary pools as there is no perceived credit risk. The principal credit quality indicator used in the valuation of the allowance on voluntary reinsurance receivables is the financial strength rating of the reinsurer sourced from major rating agencies. If the reinsurer is unrated, an internal financial strength rating is assigned based on the Company’s historical loss experience and the Company’s assessment of the reinsurance counterparty's risk profile, which generally corresponds with a B rating. Reinsurer financial strength ratings are updated and reviewed on an annual basis or sooner if the Company becomes aware of significant changes related to a reinsurer. The allowance for uncollectible reinsurance receivables is estimated on the basis of periodic evaluations of balances due from reinsurers, reinsurer financial strength rating and solvency, industry experience and current and forecast economic conditions. Because billed receivables generally approximate 5% or less of total reinsurance receivables, the age of the reinsurance receivables related to paid losses is not a significant input into the allowance analysis. Changes in the allowance for uncollectible reinsurance receivables are presented as a component of Insurance claims and policyholders' benefits on the Consolidated Statements of Operations. See the Credit Losses section of this note for additional information on the Company's allowances for expected credit losses.
Amounts are considered past due based on the reinsurance contract terms. Reinsurance receivables related to paid losses and any related allowance are written off after collection efforts have been exhausted or a negotiated settlement is reached with the reinsurer. Reinsurance receivables from insolvent insurers related to paid losses are written off when the settlement due from the estate can be reasonably estimated. At the time reinsurance receivables related to paid losses are written off, any required adjustment to reinsurance receivables related to unpaid losses is recorded as a component of Insurance claims and policyholders' benefits on the Consolidated Statements of Operations.
A loss portfolio transfer is a retroactive reinsurance contract. If the cumulative claim and allocated claim adjustment expenses ceded under a loss portfolio transfer exceed the consideration paid, the resulting gain from such excess is deferred and amortized into earnings in future periods in proportion to actual recoveries under the loss portfolio transfer. In any period in which there is a revised estimate of claim and allocated claim adjustment expenses and the loss portfolio transfer is in a gain position, the deferred gain is recalculated as if the revised estimate was available at the inception date of the loss portfolio transfer and the change in the deferred gain is recognized in earnings.
Deferred acquisition costs: Deferrable acquisition costs include commissions, premium taxes and certain underwriting and policy issuance costs which are incremental direct costs of successful contract acquisitions. Acquisition costs related to property and casualty business are deferred and amortized ratably over the period the related premiums are earned. Deferred acquisition costs are presented net of ceding commissions and other ceded acquisition costs.
The Company evaluates deferred acquisition costs for recoverability. Anticipated investment income is considered in the determination of the recoverability of deferred acquisition costs. Adjustments, if necessary, are recorded in current period results of operations.
Policyholder dividends: Policyholder dividends are paid to participating policyholders within the workers' compensation and surety lines of business. Net written premiums for participating dividend policies were approximately 2%, 2% and 1% of total net written premiums for each of the years ended December 31, 2023, 2022 and 2021. Dividends to policyholders are accrued according to the Company's best estimate of the amount to be paid in accordance with contractual provisions and applicable state laws. Dividends to policyholders are presented as a component of Insurance claims & policyholders' benefits on the Consolidated Statements of Operations and Other liabilities on the Consolidated Balance Sheets.
Investments
The Company classifies its fixed maturity securities as either available-for-sale or trading, and as such, they are carried at fair value. Changes in fair value of trading securities are reported within Net investment income on the Consolidated Statements of Operations. Changes in fair value of available-for-sale securities are reported as a component of Other comprehensive income.
The cost of fixed maturity securities classified as available-for-sale is adjusted for amortization of premiums and accretion of discounts, which are included in Net investment income on the Consolidated Statements of Operations. The amortization of premium and accretion of discount for fixed maturity securities takes into consideration call and maturity dates that produce the lowest yield.
For asset-backed securities included in fixed maturity securities, the Company recognizes income using an effective yield based on anticipated prepayments and the estimated economic life of the securities. When estimates of prepayments change, the effective yield is recalculated to reflect actual payments to date and anticipated future payments predominantly using the retrospective method.
Equity securities are carried at fair value. The Company's non-redeemable preferred stock contain characteristics of debt securities, are priced similarly to bonds and are held primarily for income generation through periodic dividends. While recognition of gains and losses on these securities is not discretionary, management does not consider the changes in fair value of non-redeemable preferred stock to be reflective of our primary operations. As such, the changes in the fair value of these securities are recorded through Net investment gains (losses) on the Consolidated Statements of Operations. The Company owns certain common stock with the intention of holding the securities primarily for market appreciation and as such, the changes in the fair value of these securities are recorded through Net investment income.
The Company's carrying value of investments in limited partnerships is its share of the net asset value of each partnership, as determined by the general partner. Certain partnerships for which results are not available on a timely basis are reported on a lag, primarily three months or less. Changes in net asset values are accounted for under the equity method and recorded within Net investment income on the Consolidated Statements of Operations.
Mortgage loans are commercial in nature, are carried at unpaid principal balance, net of unamortized fees and an allowance for expected credit losses, and are recorded once funded. The allowance for expected credit losses is developed by assessing the credit quality of pools of mortgage loans in good standing using debt service coverage ratios (DSCR) and loan-to-value ratios (LTV). The DSCR compares a property’s net operating income to its debt service payments, including principal and interest. The LTV ratio compares the current unpaid principal balance of the loan to the estimated fair value of the underlying property collateralizing the loan. The pools developed to measure the credit loss allowance use increments of DSCR and LTV to draw distinctions between risk levels. The Company applies expected credit loss rates by pool to the outstanding receivable balances. Changes in the allowance for mortgage loans are presented as a component of Net investment gains (losses) on the Consolidated Statements of Operations. See the Credit Losses section of this note for additional information on the Company’s allowances for expected credit losses. Interest income from mortgage loans is recognized on an accrual basis using the effective yield method.
Other invested assets include overseas deposits. Overseas deposits are valued using the net asset value per share (or equivalent) practical expedient. They are primarily short-term government securities, agency securities and corporate bonds held in trusts that are managed by Lloyd's of London. These funds are required of Lloyd's syndicates to protect policyholders in overseas markets and may be denominated in local currency.
Short-term investments are carried at fair value, with the exception of cash accounts earning interest, which are carried at cost and approximate fair value. Changes in fair value are reported as a component of Other comprehensive income.
Purchases and sales of all securities are recorded on the trade date, except for private placement securities, including bank loan participations, which are recorded once funded. Net investment gains and losses are determined on the basis of the cost or amortized cost of the specific securities sold.
In the normal course of investing activities, the Company enters into relationships with variable interest entities (VIEs), as both an investor in limited partnerships and asset-backed securities issued by third-party VIEs. The Company is not the primary beneficiary of these VIEs, and therefore does not consolidate them. The Company determines whether it is the primary beneficiary of a VIE based on a qualitative assessment of the relative power and benefits of the Company and the other participants in the VIE. The Company’s maximum exposure to loss with respect to these investments is limited to the investment carrying values included in the Company’s Consolidated Balance Sheets and any unfunded commitments.
An available-for-sale security is impaired if the fair value of the security is less than its cost adjusted for accretion, amortization and allowance for credit losses. When a security is impaired, it is evaluated to determine whether the Company intends to sell the security before recovery of amortized cost or whether a credit loss exists. Losses on securities that the Company intends to sell are recognized as impairment losses within Net investment gains (losses) on the Consolidated Statements of Operations. If a credit loss exists, an allowance is established and the corresponding amount is recognized as an impairment loss within Net investment gains (losses) on the Consolidated Statements of Operations. The allowance for credit losses related to available-for-sale fixed maturity securities is the difference between the present value of cash flows expected to be collected and the amortized cost basis, limited by the amount that the fair value is less than the amortized cost basis. In subsequent periods, the allowance is reviewed, with any changes in the allowance presented as a component of Net investment gains (losses) on the Consolidated Statements of Operations. Changes in the difference between the amortized cost basis, net of the allowance, and the fair value, are recognized in Other comprehensive income.
Significant judgment is required in the determination of whether an impairment loss has occurred for a security. The Company follows a consistent and systematic process for determining and recording an impairment loss, including the evaluation of securities in an unrealized loss position and securities with an allowance for credit losses on at least a quarterly basis.
The Company’s assessment of whether an impairment loss has occurred incorporates both quantitative and qualitative information. A credit loss exists if the present value of cash flows expected to be collected is less than the amortized cost basis. Significant assumptions enter into these cash flow projections including delinquency rates, probable risk of default, loss severity upon a default, over collateralization and interest coverage triggers and credit support from lower level tranches. The Company considers all available evidence when determining whether an investment requires a credit loss write-down or allowance to be recorded. Examples of such evidence may include the financial condition and near-term and long-term prospects of the issuer, whether the issuer is current with interest and principal payments, credit ratings on the security or changes in ratings over time, general market conditions and industry, sector or other specific factors and whether it is likely that the Company will recover its amortized cost through the collection of cash flows. See the Credit Losses section of this note for additional information on the Company’s allowances for expected credit losses.
Credit Losses
The allowances for credit losses on fixed maturity securities, mortgage loans, reinsurance receivables and insurance receivables are valuation accounts that are reported as a reduction of a financial asset’s cost basis and are measured on a pool basis when similar risk characteristics exist. Management estimates the allowance using relevant available information from both internal and external sources. Historical credit loss experience provides the basis for the estimation of expected credit losses and adjustments may be made to reflect current conditions and reasonable and supportable forecasts. Adjustments to historical loss information are made for any additional factors that come to the Company’s attention. This could include significant shifts in
counterparty financial strength ratings, aging of past due receivables, amounts sent to collection agencies, or other underlying portfolio changes. Amounts are considered past due when payments have not been received according to contractual terms. The Company also considers current and forecast economic conditions, using a variety of economic metrics and forecast indices. The sensitivity of expected credit losses relative to changes to these forecast economic conditions can vary by financial asset class. The Company considers a reasonable and supportable forecast period to be up to 24 months from the balance sheet date. After the forecast period, the Company reverts to historical credit experience. The Company uses collateral arrangements such as letters of credit and amounts held in beneficiary trusts to mitigate credit risk, which are considered in the estimate of net amount expected to be collected. Amounts are written off against the allowance when determined to be uncollectible.
The Company has made a policy election to present accrued interest balances separately from the amortized cost basis of assets and has elected the practical expedient to exclude the accrued interest from the tabular disclosures for mortgage loans and available-for-sale securities. The Company has elected not to estimate an allowance for credit losses on accrued interest receivable. The accrual of interest income is discontinued and the asset is placed on nonaccrual status within 90 days of the interest becoming delinquent. Interest accrued but not received for assets on nonaccrual status is reversed through investment income. Interest received for assets that are on nonaccrual status is recognized as payment is received. The asset is returned to accrual status when the principal and interest amounts contractually due are brought current and future payments are expected. Interest receivable is presented as a component of accrued investment income on the Consolidated Balance Sheet.
Deferred Non-Insurance Warranty Revenue and Acquisition Expense
Non-insurance warranty revenue is primarily generated from separately-priced service contracts that provide mechanical breakdown and other coverages to vehicle or consumer goods owners. The warranty contracts generally provide coverage from 1 month to 10 years. For warranty products where the Company acts as the principal in the transaction, Non-insurance warranty revenue is reported on a gross basis, with amounts paid by customers reported as Non-insurance warranty revenue and commissions paid to agents and dealers reported as Non-insurance warranty expense.
Non-insurance warranty revenue is reported net of any premiums related to contractual liability coverage issued by the Company's insurance operations. Additionally, the Company provides warranty administration services for dealer and manufacturer obligor warranty products, which include limited warranties and guaranteed asset protection waivers. The Company recognizes Non-insurance warranty revenue over the service period in proportion to the actuarially determined expected claims emergence pattern. Customers predominantly pay in full at the inception of the warranty contract. The liability for deferred revenue represents the unearned portion of revenue in advance of the Company's performance. The deferred revenue balance includes amounts which are refundable on a pro rata basis upon cancellation.
Dealers, retailers and agents earn commission for assisting the Company in obtaining non-insurance warranty contracts. Additionally, the Company utilizes third-parties to perform warranty administrator services for its consumer goods warranties. These costs, which are deferred and recorded as Deferred non-insurance warranty acquisition expense, are amortized to Non-insurance warranty expense consistent with how the related revenue is recognized. The Company evaluates deferred costs for recoverability including consideration of anticipated investment income. Adjustments to deferred costs, if necessary, are recorded in the current period results of operations.
Income Taxes
The Company and its eligible subsidiaries (CNA Tax Group) are included in the consolidated federal income tax return of Loews and its eligible subsidiaries. The Company accounts for income taxes under the asset and liability method. Under the asset and liability method, deferred income taxes are recognized for temporary differences between the financial statement and tax return bases of assets and liabilities, based on enacted tax rates and other provisions of the tax law. The effect of a change in tax laws or rates on deferred tax assets and liabilities is recognized in income in the period in which such change is enacted. Future tax benefits are recognized to the extent that realization of such benefits is more likely than not, and a valuation allowance is
established for any portion of a deferred tax asset that management believes will not be realized. The Company releases tax effects from AOCI utilizing the security-by-security approach for Net unrealized gains (losses) on investments with an allowance for credit losses and Net unrealized gains (losses) on other investments. For Pension and postretirement benefits, tax effects from AOCI are released at enacted tax rates based on the pre-tax adjustments to pension liabilities or assets recognized within Other comprehensive income.
Pension and Postretirement Benefits
The Company recognizes the overfunded or underfunded status of its defined benefit plans in Other assets or Other liabilities on the Consolidated Balance Sheets. Changes in funded status related to prior service costs and credits, and actuarial gains and losses arising from differences between actual experience and actuarial assumptions, are recognized in the year in which the changes occur through Other comprehensive income. Unrecognized actuarial gains and losses in excess of 10% of the greater of the beginning of the year projected benefit obligation or fair value of plan assets (the corridor) are amortized as a component of net periodic pension cost (benefit) over the average remaining life expectancy of the plan participants. Annual service cost, interest cost, expected return on plan assets, amortization of prior service costs and credits and amortization of actuarial gains and losses are recognized on the Consolidated Statements of Operations.
The vested benefit obligation for the CNA Retirement Plan is determined based on eligible compensation and accrued service for previously entitled employees. Effective June 30, 2015, future benefit accruals under the CNA Retirement Plan were eliminated and the benefit obligations were frozen.
Stock-Based Compensation
The Company records compensation expense using the fair value method for all awards it grants, modifies or cancels primarily on a straight-line basis over the requisite service period, generally three years.
Foreign Currency
The Company's foreign subsidiaries' balance sheet accounts are translated at the exchange rates in effect at each reporting date and income statement accounts are either translated at the exchange rates on the date of the transaction or at average exchange rates. Foreign currency translation gains and losses are reflected in Stockholders' equity as a component of AOCI. Foreign currency transaction gains (losses) of $9 million, $(22) million and less than $(1) million were included in determining Net income for the years ended December 31, 2023, 2022 and 2021, respectively.
Leases
A lease provides the lessee the right to control the use of an identified asset for a period of time in exchange for consideration. Operating lease right-of-use (ROU) assets and lease liabilities are included in Other assets and Other liabilities on the Company's Consolidated Balance Sheets.
ROU assets represent the Company's right to use an underlying asset for the lease term and operating lease liabilities represent the Company's obligation to make lease payments arising from the lease. The Company determines if an arrangement is a lease at inception. Operating lease ROU assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. Most operating leases contain renewal options that provide for rent increases based on prevailing market conditions. Certain leases contain options to terminate before maturity. The lease term used to calculate the ROU asset includes any renewal options or lease termination options that the Company expects to exercise. The discount rate used to determine the commencement date present value of lease payments is typically the Company’s secured borrowing rate, as most of the Company’s leases do not provide an implicit rate. ROU assets include any lease payments required to be made prior to commencement and exclude lease incentives. The Company has elected to account for its lease and non-lease components as a single lease component. The Company’s non-lease components consist of variable lease costs not based on an index or rate and are excluded from the measurement of ROU assets and lease liabilities. Variable lease costs not based on an index or rate are treated as period costs, and represent charges for services provided by the landlord and the Company's reimbursement to the landlord for costs such as real estate taxes and insurance.
The Company occupies office facilities under lease agreements that expire at various dates. The Company's lease agreements do not contain significant residual value guarantees, restrictions or covenants. The Company does not have any significant finance leases.
Property and Equipment
Property and equipment are carried at cost less accumulated depreciation. Depreciation is based on the estimated useful lives of the various classes of property and equipment and is determined principally on the straight-line method. Furniture and fixtures are depreciated over seven years. Office equipment is depreciated over five years. The estimated lives for data processing equipment and software generally range from three to five years, but can be as long as ten years. Leasehold improvements are depreciated over the corresponding lease terms not to exceed the underlying asset life.
Goodwill
Goodwill represents the excess of purchase price over the fair value of the net assets of acquired entities and businesses. Goodwill in the International segment may change from period to period as a result of foreign currency translation.
Goodwill is tested for impairment annually or when certain triggering events require such tests. As a result of reviews completed for the year ended December 31, 2023, the Company determined that the estimated fair value of the reporting units were in excess of their carrying value including Goodwill. Changes in future periods in assumptions about the level of economic capital, business growth, earnings projections or the weighted average cost of capital could result in goodwill impairment.
Other Intangible Assets
Other intangible assets are reported within Other assets on the Consolidated Balance Sheets. Finite-lived intangible assets are amortized over their estimated useful lives. Indefinite-lived other intangible assets are tested for impairment annually or when certain triggering events require such tests.
Earnings (Loss) Per Share Data
Earnings (loss) per share is based on weighted average number of outstanding common shares. Basic earnings (loss) per share excludes the impact of dilutive securities and is computed by dividing Net income (loss) by the weighted average number of common shares outstanding for the period. Diluted earnings (loss) per share reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock.
For each of the years ended December 31, 2023, 2022 and 2021, approximately 1 million potential shares attributable to exercises or conversions into common stock under stock-based employee compensation plans were included in the calculation of diluted earnings per share. Excluded from the calculation of diluted earnings (loss) per share is the impact of potential shares attributable to exercises or conversions into common stock under stock-based employee compensation plans that would have been antidilutive during the respective periods.
Supplementary Cash Flow Information
Cash payments made for interest were $124 million, $109 million and $110 million for the years ended December 31, 2023, 2022 and 2021. Cash payments made for income taxes were $282 million, $277 million and $278 million for the years ended December 31, 2023, 2022 and 2021.
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Investments
 12 Months Ended
Dec. 31, 2023
Investments [Abstract]  
Investments Investments
The significant components of Net investment income are presented in the following table.
Years ended December 31
(In millions)202320222021
Fixed maturity securities$1,941 $1,787 $1,707 
Equity securities63 23 83 
Limited partnership investments174 (12)362 
Mortgage loans58 54 61 
Short-term investments75 16 1 
Trading portfolio4 4 9 
Other28 5 — 
Gross investment income2,343 1,877 2,223 
Investment expense(79)(72)(64)
Net investment income$2,264 $1,805 $2,159 
Net investment income (loss) recognized due to the change in fair value of common stock held as of December 31, 2023, 2022 and 2021$11 $47 $28 
The Company did not hold any non-income producing fixed maturity securities as of December 31, 2023 and 2022. As of December 31, 2023 and 2022, the Company held $20 million and $7 million of non-income producing mortgage loans, net of the allowance for credit losses. As of December 31, 2023 and 2022, no investments in a single issuer exceeded 10% of stockholders' equity, other than investments in securities issued by the U.S. Treasury and obligations of government-sponsored enterprises.
Net investment gains (losses) are presented in the following table.
Years ended December 31
(In millions)202320222021
Net investment gains (losses):
Fixed maturity securities:
Gross gains$75 $120 $186 
Gross losses(166)(261)(90)
Net investment gains (losses) on fixed maturity securities(91)(141)96 
Equity securities4 (116)4 
Derivatives(1)64 6 
Mortgage loans(11)(8)10 
Short-term investments and other— 2 4 
Net investment gains (losses)$(99)$(199)$120 
Net investment gains (losses) recognized due to the change in fair value of non-redeemable preferred stock held as of December 31, 2023, 2022 and 2021$14 $(75)$2 
Net investment gains (losses) for the year ended December 31, 2022 in the table above included an $18 million net gain related to the novation of a coinsurance agreement on the Company’s legacy annuity business, which was transacted on a funds withheld basis and gave rise to an embedded derivative. The net gain of $18 million was comprised of a $62 million gain on the associated embedded derivative partially offset by a $44 million loss on fixed maturity securities supporting the funds withheld liability, transferred with the novation, to recognize unrealized losses which had been included in AOCI since the inception of the coinsurance agreement. Taken together, this net gain was the final recognition of changes in the valuation of the funds held assets and offset previously recognized net investment losses on the associated embedded derivative. The coinsurance agreement was novated in the fourth quarter of 2022.
The available-for-sale impairment losses (gains) recognized in earnings by asset type are presented in the following table. The table includes losses (gains) on securities with an intention to sell and changes in the allowance for credit losses on securities since acquisition date.
Years ended December 31
(In millions)202320222021
Fixed maturity securities available-for-sale:
Corporate and other bonds$33 $62 $11 
Asset-backed11 — 20 
Impairment losses (gains) recognized in earnings$44 $62 $31 
For the years ended December 31, 2023, 2022, and 2021 the Company also recognized $11 million of losses, $8 million of losses and $10 million of gains related to mortgage loans primarily due to changes in expected credit losses.
The net change in unrealized gains (losses) on fixed maturity securities was $1,431 million, $(7,850) million and $(1,272) million for the years ended December 31, 2023, 2022 and 2021.
The following tables present a summary of fixed maturity securities.
December 31, 2023Cost or
Amortized
Cost		Gross
Unrealized
Gains		Gross
Unrealized
Losses		Allowance for Credit LossesEstimated
Fair
Value
(In millions)
Fixed maturity securities available-for-sale:
Corporate and other bonds$25,020 $597 $1,345 $4 $24,268 
States, municipalities and political subdivisions7,713 382 703 — 7,392 
Asset-backed:
Residential mortgage-backed3,411 16 425 — 3,002 
Commercial mortgage-backed1,862 7 230 8 1,631 
Other asset-backed3,515 13 256 4 3,268 
Total asset-backed8,788 36 911 12 7,901 
U.S. Treasury and obligations of government-sponsored enterprises152 1 2 — 151 
Foreign government741 6 34 — 713 
   Redeemable preferred stock— — — — — 
Total fixed maturity securities available-for-sale42,414 1,022 2,995 16 40,425 
Total fixed maturity securities trading— — — — — 
Total fixed maturity securities$42,414 $1,022 $2,995 $16 $40,425 
December 31, 2022Cost or
Amortized
Cost		Gross
Unrealized
Gains		Gross
Unrealized
Losses		Allowance for Credit LossesEstimated
Fair
Value
(In millions)
Fixed maturity securities available-for-sale:
Corporate and other bonds$23,137 $301 $2,009 $— $21,429 
States, municipalities and political subdivisions8,918 338 939 — 8,317 
Asset-backed:
Residential mortgage-backed3,073 5 447 — 2,631 
Commercial mortgage-backed1,886 4 255 — 1,635 
Other asset-backed3,287 2 361 1 2,927 
Total asset-backed8,246 11 1,063 1 7,193 
U.S. Treasury and obligations of government-sponsored enterprises111 1 2 — 110 
Foreign government617 1 43 — 575 
Redeemable preferred stock3 — — — 3 
Total fixed maturity securities available-for-sale41,032 652 4,056 1 37,627 
Total fixed maturity securities trading— — — — — 
Total fixed maturity securities$41,032 $652 $4,056 $1 $37,627 
The following tables present the estimated fair value and gross unrealized losses of fixed maturity securities in a gross unrealized loss position for which an allowance for credit loss has not been recorded, by the length of time in which the securities have continuously been in that position.
Less than 12 Months12 Months or LongerTotal
December 31, 2023Estimated
Fair Value		Gross
Unrealized
Losses		Estimated
Fair Value		Gross
Unrealized
Losses		Estimated
Fair Value		Gross
Unrealized
Losses
(In millions)
Fixed maturity securities available-for-sale:
Corporate and other bonds$1,943 $37 $13,406 $1,308 $15,349 $1,345 
States, municipalities and political subdivisions598 18 3,104 685 3,702 703 
Asset-backed:
Residential mortgage-backed233 4 2,212 421 2,445 425 
Commercial mortgage-backed200 5 1,184 225 1,384 230 
Other asset-backed392 8 1,869 248 2,261 256 
Total asset-backed825 17 5,265 894 6,090 911 
U.S. Treasury and obligations of government-sponsored enterprises65 1 23 1 88 2 
Foreign government52 1 450 33 502 34 
Total$3,483 $74 $22,248 $2,921 $25,731 $2,995 
Less than 12 Months12 Months or LongerTotal
December 31, 2022Estimated
Fair Value		Gross
Unrealized
Losses		Estimated
Fair Value		Gross
Unrealized
Losses		Estimated
Fair Value		Gross
Unrealized
Losses
(In millions)
Fixed maturity securities available-for-sale:
Corporate and other bonds$15,946 $1,585 $1,634 $424 $17,580 $2,009 
States, municipalities and political subdivisions4,079 769 456 170 4,535 939 
Asset-backed:
Residential mortgage-backed1,406 144 1,143 303 2,549 447 
Commercial mortgage-backed1,167 159 408 96 1,575 255 
Other asset-backed2,087 262 542 99 2,629 361 
Total asset-backed4,660 565 2,093 498 6,753 1,063 
U.S. Treasury and obligations of government-sponsored enterprises76 1 16 1 92 2 
   Foreign government473 26 78 17 551 43 
Total$25,234 $2,946 $4,277 $1,110 $29,511 $4,056 
The following table presents the estimated fair value and gross unrealized losses of fixed maturity securities in a gross unrealized loss position for which an allowance for credit loss has not been recorded, by ratings distribution.
December 31, 2023December 31, 2022

(In millions)		Estimated Fair ValueGross Unrealized LossesEstimated Fair ValueGross Unrealized Losses
U.S. Government, Government agencies and Government-sponsored enterprises$2,273 $309 $2,355 $337 
AAA1,524 261 1,559 298 
AA 3,817 658 4,327 817 
A5,652 517 6,615 749 
BBB11,523 1,095 13,226 1,621 
Non-investment grade942 155 1,429 234 
Total$25,731 $2,995 $29,511 $4,056 
Based on current facts and circumstances, the Company believes the unrealized losses presented in the December 31, 2023 securities in a gross unrealized loss position tables above are not indicative of the ultimate collectability of the current amortized cost of the securities, but rather are primarily attributable to changes in risk-free interest rates. In reaching this determination, the Company considered the volatility in risk-free rates and credit spreads as well as the fact that its unrealized losses are concentrated in investment grade issuers. Additionally, the Company has no current intent to sell securities with unrealized losses, nor is it more likely than not that it will be required to sell prior to recovery of amortized cost; accordingly, the Company has determined that there are no additional impairment losses to be recorded as of December 31, 2023.
The following tables present the activity related to the allowance on available-for-sale securities with credit impairments and purchased credit-deteriorated (PCD) assets. Accrued interest receivable on available-for-sale fixed maturity securities totaled $435 million and $394 million as of December 31, 2023 and 2022 and is excluded from the estimate of expected credit losses and the amortized cost basis in the table included within this Note.
(In millions)Corporate and other bondsAsset-backedTotal
Allowance for credit losses:
Balance as of January 1, 2023$— $1 $1 
Additions to the allowance for credit losses:
Securities for which credit losses were not previously recorded10 7 17 
Available-for-sale securities accounted for as PCD assets22 — 22 
Reductions to the allowance for credit losses:
Securities sold during the period (realized)6 — 6 
Intent to sell or more likely than not will be required to sell the security before recovery of its amortized cost basis8 — 8 
Write-offs charged against the allowance15 — 15 
Recoveries of amounts previously written off— — — 
Additional increases or (decreases) to the allowance for credit losses on securities that had an allowance recorded in a previous period1 4 5 
Balance as of December 31, 2023
$4 $12 $16 
(In millions)Corporate and other bondsAsset-backedTotal
Allowance for credit losses:
Balance as of January 1, 2022$11 $7 $18 
Additions to the allowance for credit losses:
Securities for which credit losses were not previously recorded— — — 
Available-for-sale securities accounted for as PCD assets— 3 3 
Reductions to the allowance for credit losses:
Securities sold during the period (realized)— — — 
Intent to sell or more likely than not will be required to sell the security before recovery of its amortized cost basis— — — 
Write-offs charged against the allowance12 — 12 
Recoveries of amounts previously written off— — — 
Additional increases or (decreases) to the allowance for credit losses on securities that had an allowance recorded in a previous period1 (9)(8)
Balance as of December 31, 2022
$— $1 $1 
Contractual Maturity
The following table presents available-for-sale fixed maturity securities by contractual maturity.
December 3120232022
(In millions)Cost or
Amortized
Cost		Estimated
Fair
Value		Cost or
Amortized
Cost		Estimated
Fair
Value
Due in one year or less$1,121 $1,091 $1,012 $1,001 
Due after one year through five years11,563 11,180 9,880 9,399 
Due after five years through ten years13,359 12,573 13,788 12,453 
Due after ten years16,371 15,581 16,352 14,774 
Total$42,414 $40,425 $41,032 $37,627 
Actual maturities may differ from contractual maturities because certain securities may be called or prepaid. Securities not due at a single date are allocated based on weighted average life.
Limited Partnerships
The carrying value of limited partnerships as of December 31, 2023 and 2022 was $2,174 million and $1,926 million, which includes net undistributed earnings of $250 million and $176 million. Limited partnerships comprising 17% of the total carrying value are reported on a current basis through December 31, 2023 with no reporting lag, 4% are reported on a one month lag and the remainder are reported on more than a one month lag. The number of limited partnerships held and the strategies employed provide diversification to the limited partnership portfolio and the overall invested asset portfolio.
Limited partnerships comprising 85% and 76% of the carrying value as of December 31, 2023 and 2022 were invested in private debt and equity. Limited partnerships comprising 15% and 24% of the carrying value as of December 31, 2023 and 2022 employ hedge fund strategies. Private debt and equity funds cover a broad range of investment strategies including buyout, co-investment, private credit, growth capital, distressed investing and real estate. Hedge fund strategies include both long and short positions in fixed income, equity and derivative instruments.
The ten largest limited partnership positions held totaled $622 million and $633 million as of December 31, 2023 and 2022. Based on the most recent information available regarding the Company’s percentage ownership of the individual limited partnerships, the carrying value reflected on the Consolidated Balance Sheets represents approximately 1% of the aggregate partnership equity as of December 31, 2023 and 2022, and the related income reflected on the Consolidated Statements of Operations represents approximately 1%, 2% and 2% of the changes in aggregate partnership equity for the years ended December 31, 2023, 2022 and 2021.
There are risks inherent in limited partnership investments which may result in losses due to short-selling, derivatives or other speculative investment practices. The use of leverage increases volatility generated by the underlying investment strategies.
The Company’s private debt, private equity and other non-hedge fund limited partnership investments generally do not permit voluntary withdrawals. The Company’s hedge fund limited partnership investments contain withdrawal provisions that generally limit liquidity for a period of thirty days up to one year or longer. Typically, hedge fund withdrawals require advance written notice of up to 90 days.
Derivative Financial Instruments
The Company may use derivatives in the normal course of business, primarily in an attempt to reduce its exposure to market risk (principally interest rate risk and foreign currency risk) stemming from various assets and liabilities. The Company's principal objective under such strategies is to achieve the desired reduction in economic risk, even if the position does not receive hedge accounting treatment.
The Company may enter into interest rate swaps, futures and forward commitments to purchase securities to manage interest rate risk. The Company may use foreign currency forward contracts to manage foreign currency risk.
Credit exposure associated with non-performance by the counterparties to derivative instruments is generally limited to the uncollateralized fair value of the asset related to the instruments recognized on the Consolidated Balance Sheets. The Company generally requires that all over-the-counter derivative contracts be governed by an International Swaps and Derivatives Association Master Agreement, and exchanges collateral under the terms of these agreements with its derivative investment counterparties depending on the amount of the exposure and the credit rating of the counterparty. Gross estimated fair values of derivative positions are presented in Other invested assets and Other liabilities on the Consolidated Balance Sheets. The Company does not offset derivative positions against the fair value of collateral provided or positions subject to netting arrangements. There would be no significant difference in the balance included in such accounts if the estimated fair values were presented net as of December 31, 2023 and 2022.
There was less than $1 million of cash collateral provided by the Company and no cash collateral received from counterparties as of December 31, 2023 and 2022.
During the year ended December 31, 2022, the Company held an embedded derivative on a funds withheld liability related to a coinsurance agreement on its legacy annuity business. The Company novated the coinsurance agreement during 2022 resulting in the transfer of $224 million of fixed maturity securities, $4 million of short-term investments and $2 million of accrued investment income in settlement of the $216 million funds withheld liability and associated $14 million embedded derivative.
Investment Commitments
As part of its overall investment strategy, the Company invests in various assets which require future purchase, sale or funding commitments. These investments are recorded once funded, and the related commitments may include future capital calls from various third-party limited partnerships, signed and accepted mortgage loan applications, and obligations related to private placement securities. As of December 31, 2023, the Company had commitments to purchase or fund approximately $1,555 million and sell approximately $35 million under the terms of these investments.
Investments on Deposit
Cash and securities with carrying values of approximately $3.1 billion and $2.8 billion were deposited by the Company’s insurance subsidiaries under requirements of regulatory authorities and others as of December 31, 2023 and 2022.
Cash and securities with carrying values of approximately $0.9 billion were deposited with financial institutions in trust accounts or as collateral for letters of credit to secure obligations with various third parties as of December 31, 2023 and 2022.
Mortgage Loans
The following table presents the amortized cost basis of mortgage loans for each credit quality indicator by year of origination. The primary credit quality indicators utilized are debt service coverage ratios (DSCR) and loan-to-value ratios (LTV).
December 31, 2023
Mortgage Loans Amortized Cost Basis by Origination Year (1)
(In millions)20232022202120202019PriorTotal
DSCR ≥1.6x
LTV less than 55%$33 $9 $8 $98 $60 $238 $446 
LTV 55% to 65%— — 5 — 8 — 13
LTV greater than 65%— 31 11 — — — 42
DSCR 1.2x - 1.6x
LTV less than 55%28 5 — 14 29 21 97
LTV 55% to 65%34 36 36 23 — 32 161
LTV greater than 65%— 65 — — — — 65
DSCR ≤1.2
LTV less than 55%6 34 — — — — 40
LTV 55% to 65%26 40 — — 43 — 109
LTV greater than 65%— 28 21 — 41 7 97
Total$127 $248 $81 $135 $181 $298 $1,070 
(1) The values in the table above reflect DSCR on a standardized amortization period and LTV based on the most recent appraised values trended forward using changes in a commercial real estate price index.

As of December 31, 2023, accrued interest receivable on mortgage loans totaled $4 million and is excluded from the amortized cost basis disclosed in the table above and the estimate of expected credit losses.
v3.24.0.1
Fair Value
 12 Months Ended
Dec. 31, 2023
Fair Value Disclosures [Abstract]  
Fair Value Fair Value
Fair value is the price that would be received upon sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The following fair value hierarchy is used in selecting inputs, with the highest priority given to Level 1, as these are the most transparent or reliable.
Level 1 - Quoted prices for identical instruments in active markets.
Level 2 - Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs are observable in active markets.
Level 3 - Valuations derived from valuation techniques in which one or more significant inputs are not observable.
Prices may fall within Level 1, 2 or 3 depending upon the methodology and inputs used to estimate fair value for each specific security. In general, the Company seeks to price securities using third-party pricing services. Securities not priced by pricing services are submitted to independent brokers for valuation and, if those are not available, internally developed pricing models are used to value assets using a methodology and inputs the Company believes market participants would use to value the assets. Prices obtained from third-party pricing services or brokers are not adjusted by the Company.
The Company performs control procedures over information obtained from pricing services and brokers to ensure prices received represent a reasonable estimate of fair value and to confirm representations regarding whether inputs are observable or unobservable. Procedures may include i) the review of pricing service methodologies or broker pricing qualifications, ii) back-testing, where past fair value estimates are compared to actual transactions executed in the market on similar dates, iii) exception reporting, where period-over-period changes in price are reviewed and challenged with the pricing service or broker based on exception criteria, and iv) deep dives, where the Company performs an independent analysis of the inputs and assumptions used to price individual securities.
Assets and Liabilities Measured at Fair Value
Assets and liabilities measured at fair value on a recurring basis are presented in the following tables. Corporate bonds and other includes obligations of the United States of America (U.S.) Treasury, government-sponsored enterprises, foreign governments and redeemable preferred stock.
December 31, 2023   Total
Assets/Liabilities
at Fair Value
(In millions)Level 1Level 2Level 3
Assets    
Fixed maturity securities:    
Corporate bonds and other$161 $23,926 $1,045 $25,132 
States, municipalities and political subdivisions— 7,348 44 7,392 
Asset-backed— 7,000 901 7,901 
Total fixed maturity securities 161 38,274 1,990 40,425 
Equity securities:
Common stock167 — 24 191 
Non-redeemable preferred stock52 440 — 492 
Total equity securities219 440 24 683 
Short term and other1,976 32 — 2,008 
Total assets$2,356 $38,746 $2,014 $43,116 
Liabilities
Other liabilities$— $1 $— $1 
Total liabilities$— $1 $— $1 

December 31, 2022   Total
Assets/Liabilities
at Fair Value
(In millions)Level 1Level 2Level 3
Assets    
Fixed maturity securities:    
Corporate bonds and other$120 $21,187 $810 $22,117 
States, municipalities and political subdivisions— 8,274 43 8,317 
Asset-backed— 6,405 788 7,193 
Total fixed maturity securities 120 35,866 1,641 37,627 
Equity securities:
Common stock150 — 35 185 
Non-redeemable preferred stock54 435 — 489 
Total equity securities204 435 35 674 
Short term and other1,608 71 — 1,679 
Total assets$1,932 $36,372 $1,676 $39,980 
Liabilities  
Other liabilities$— $1 $— $1 
Total liabilities$— $1 $— $1 
The tables below present a reconciliation for all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3).
Level 3
(In millions)
Corporate bonds and otherStates, municipalities and political subdivisionsAsset-backedEquity securitiesTotal
Balance as of January 1, 2023$810 $43 $788 $35 $1,676 
Total realized and unrealized investment gains (losses):
Reported in Net investment gains (losses)— — (4)— (4)
Reported in Net investment income— — 20 (7)13 
Reported in Other comprehensive income (loss)38 1 9 — 48 
Total realized and unrealized investment gains (losses)38 1 25 (7)57 
Purchases219 — 248 — 467 
Sales— — — (4)(4)
Settlements(33)— (64)— (97)
Transfers into Level 311 — 23 — 34 
Transfers out of Level 3— — (119)— (119)
Balance as of December 31, 2023$1,045 $44 $901 $24 $2,014 
Unrealized gains (losses) on Level 3 assets and liabilities held as of December 31, 2023 recognized in Net income (loss) in the period$— $— $— $(7)$(7)
Unrealized gains (losses) on Level 3 assets and liabilities held as of December 31, 2023 recognized in Other comprehensive income (loss) in the period38 1 9 — 48 

Level 3
(In millions)
Corporate bonds and otherStates, municipalities and political subdivisionsAsset-backedEquity securitiesTotal
Balance as of January 1, 2022$937 $56 $556 $29 $1,578 
Total realized and unrealized investment gains (losses):
Reported in Net investment gains (losses)(2)— 9 (6)1 
Reported in Net investment income1 — 16 (3)14 
Reported in Other comprehensive income (loss)(184)(13)(126)— (323)
Total realized and unrealized investment gains (losses)(185)(13)(101)(9)(308)
Purchases137 — 424 19 580 
Sales(5)— (2)(3)(10)
Settlements(84)— (70)9 (145)
Transfers into Level 310 — 75 — 85 
Transfers out of Level 3— — (94)(10)(104)
Balance as of December 31, 2022$810 $43 $788 $35 $1,676 
Unrealized gains (losses) on Level 3 assets and liabilities held as of December 31, 2022 recognized in Net income (loss) in the period$— $— $— $(4)$(4)
Unrealized gains (losses) on Level 3 assets and liabilities held as of December 31, 2022 recognized in Other comprehensive income (loss) in the period(183)(13)(125)— (321)
Securities may be transferred in or out of levels within the fair value hierarchy based on the availability of observable market information and quoted prices used to determine the fair value of the security. The availability of observable market information and quoted prices varies based on market conditions and trading volume.
Valuation Methodologies and Inputs
The following section describes the valuation methodologies and relevant inputs used to measure different financial instruments at fair value, including an indication of the level in the fair value hierarchy in which the instruments are generally classified.
Fixed Maturity Securities
Level 1 securities include highly liquid government securities and exchange traded bonds, valued using quoted market prices. Level 2 securities include most other fixed maturity securities as the significant inputs are observable in the marketplace. All classes of Level 2 fixed maturity securities are valued using a methodology based on information generated by market transactions involving identical or comparable assets, a discounted cash flow methodology, or a combination of both when necessary. Common inputs for all classes of fixed maturity securities include prices from recently executed transactions of similar securities, marketplace quotes, benchmark yields, spreads off benchmark yields, interest rates and U.S. Treasury or swap curves. Specifically for asset-backed securities, key inputs include prepayment and default projections based on past performance of the underlying collateral and current market data. Fixed maturity securities are primarily assigned to Level 3 in cases where broker/dealer quotes are significant inputs to the valuation and there is a lack of transparency as to whether these quotes are based on information that is observable in the marketplace. Level 3 securities also include private placement debt securities whose fair value is determined using internal models with some inputs that are not market observable.
Equity Securities
Level 1 equity securities include publicly traded securities valued using quoted market prices. Level 2 securities are primarily valued using pricing for similar securities, recently executed transactions and other pricing models utilizing market observable inputs. Level 3 securities are primarily priced using broker/dealer quotes and internal models with some inputs that are not market observable.
Short Term and Other Invested Assets
Securities that are actively traded or have quoted prices are classified as Level 1. These securities include money market funds and treasury bills. Level 2 primarily includes non-U.S. government securities for which all inputs are market observable. Fixed maturity securities purchased within one year of maturity are classified consistent with fixed maturity securities discussed above. Short-term investments as presented in the tables above differ from the amounts presented on the Consolidated Balance Sheets because certain short-term investments, such as time deposits, are not measured at fair value.
As of December 31, 2023 and December 31, 2022, there were $75 million and $72 million of overseas deposits within Other invested assets, which can be redeemed at net asset value in 90 days or less. Overseas deposits are excluded from the fair value hierarchy because their fair value is recorded using the net asset value per share (or equivalent) practical expedient.
Other Liabilities
Level 2 securities include currency forward contracts valued using observable market forward rates.
Significant Unobservable Inputs
The following tables present quantitative information about the significant unobservable inputs utilized by the Company in the fair value measurements of Level 3 assets. Valuations for assets and liabilities not presented in the tables below are primarily based on broker/dealer quotes for which there is a lack of transparency as to inputs used to develop the valuations. The quantitative detail of these unobservable inputs is neither provided nor reasonably available to the Company. The weighted average rate is calculated based on fair value.
December 31, 2023Estimated Fair Value
(In millions)		Valuation Technique(s)Unobservable Input(s)Range
 (Weighted Average)
Fixed maturity securities$1,495 Discounted cash flowCredit spread
1% - 7% (2%)
December 31, 2022Estimated Fair Value
(In millions)		Valuation Technique(s)Unobservable Input(s)Range
 (Weighted Average)
Fixed maturity securities$1,177 Discounted cash flowCredit spread
1% - 8% (2%)
For fixed maturity securities, an increase to the credit spread assumptions would result in a lower fair value measurement.
Financial Assets and Liabilities Not Measured at Fair Value
The carrying amount and estimated fair value of the Company's financial assets and liabilities which are not measured at fair value on the Consolidated Balance Sheets are presented in the following tables.
December 31, 2023Carrying
Amount		Estimated Fair Value
(In millions)Level 1Level 2Level 3Total
Assets
Mortgage loans$1,035 $— $— $997 $997 
Liabilities
Short-term debt$550 $— $546 $— $546 
Long-term debt2,481 — 2,385 — 2,385 
December 31, 2022Carrying
Amount		Estimated Fair Value
(In millions)Level 1Level 2Level 3Total
Assets
Mortgage loans$1,040 $— $— $973 $973 
Liabilities
Short-term debt$243 $— $248 $— $248 
Long-term debt2,538 — 2,349 — 2,349 
The carrying amounts reported on the Consolidated Balance Sheets for Cash, Short-term investments not carried at fair value, Accrued investment income and certain Other assets and Other liabilities approximate fair value due to the short term nature of these items. These assets and liabilities are not listed in the tables above.
v3.24.0.1
Income Taxes
 12 Months Ended
Dec. 31, 2023
Income Tax Disclosure [Abstract]  
Income Taxes Income Taxes
The CNA Tax Group is included in the consolidated federal income tax return of Loews and its eligible subsidiaries. Loews and the Company have agreed that for each taxable year, the Company will 1) be paid by Loews the amount, if any, by which the Loews consolidated federal income tax liability is reduced by virtue of the inclusion of the CNA Tax Group in the Loews consolidated federal income tax return, or 2) pay to Loews an amount, if any, equal to the federal income tax that would have been payable by the CNA Tax Group filing a separate consolidated tax return. In the event that Loews should have a net operating loss in the future computed on the basis of filing a separate consolidated tax return without the CNA Tax Group, the Company may be required to repay tax recoveries previously received from Loews. This agreement may be canceled by either party upon 30 days written notice.
For the years ended December 31, 2023, 2022 and 2021, the Company paid $263 million, $254 million and $238 million to Loews related to federal income taxes.
For 2021 through 2023, Loews and the Company participate in the Internal Revenue Service (IRS) Compliance Assurance Process (CAP), which is a voluntary program for large corporations. Under CAP, the IRS conducts a real-time audit and works contemporaneously with the Company to resolve any issues prior to the filing of the tax return. For 2021 and 2023, the Company was selected to participate in the phase of CAP reserved for taxpayers whose risk of noncompliance does not warrant use of IRS resources. The Company believes that this approach should reduce tax-related uncertainties, if any.
As of December 31, 2023 and 2022, there were no unrecognized tax benefits.
The Company recognizes interest accrued related to unrecognized tax benefits and tax refund claims in Income tax (expense) benefit on the Consolidated Statements of Operations. The Company recognizes penalties (if any) in Income tax (expense) benefit on the Consolidated Statements of Operations. During 2023, 2022 and 2021 the Company recognized no interest and no penalties. There were no amounts accrued for interest or penalties as of December 31, 2023 or 2022.
The following table presents a reconciliation between the Company's income tax expense at statutory rates and the recorded income tax expense.
Years ended December 31
(In millions)2023
2022 (1)
2021 (1)
Income tax expense at statutory rates$(319)$(172)$(308)
Tax benefit from tax exempt income30 41 51 
Foreign taxes and credits(5)15 (3)
State income tax expense(13)(10)(13)
Other tax expense(6)(6)(5)
Income tax expense$(313)$(132)$(278)
(1) As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
As of December 31, 2023, no deferred taxes are required on the undistributed earnings of subsidiaries subject to tax.
The following table presents the current and deferred components of the Company's income tax expense.
Years ended December 31
(In millions)2023
2022 (1)
2021 (1)
Current tax expense$(311)$(221)$(235)
Deferred tax (expense) benefit(2)89 (43)
Total income tax expense$(313)$(132)$(278)
(1) As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
Total income tax presented above includes foreign tax expense of approximately $52 million, $1 million and $18 million related to pretax income from foreign operations of approximately $198 million, $141 million and $124 million for the years ended December 31, 2023, 2022 and 2021. Foreign tax expense for the year ended December 31, 2022 included a $10 million tax benefit for the revaluation of net deferred tax assets related to a U.K. tax rate change.
The deferred tax effects of the significant components of the Company's deferred tax assets and liabilities are presented in the following table.
December 31
(In millions)2023
2022 (1)
Deferred Tax Assets:
Insurance reserves:
Property and casualty claim and claim adjustment expense reserves$202 $178 
Unearned premium reserves213 198 
Policyholder reserves160 75 
Deferred Revenue62 64 
Employee benefits23 35 
Deferred retroactive reinsurance benefit88 89 
Net unrealized losses418 706 
Other assets111 116 
Gross deferred tax assets1,277 1,461 
Deferred Tax Liabilities:
Investment valuation differences83 59 
Deferred acquisition costs126 113 
Net unrealized gains— — 
Software and hardware18 21 
Other liabilities34 17 
Gross deferred tax liabilities261 210 
Net deferred tax asset$1,016 $1,251 
(1) As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
As of December 31, 2023, the CNA Tax Group had no loss carryforwards and a tax credit carryforward of $2 million which expires in 2033. The foreign operations had loss carryforwards of $169 million, which have no expiration. The foreign operations had a tax credit carryforward of $9 million, which has no expiration.
Although realization of deferred tax assets is not assured, management believes it is more likely than not that the recognized net deferred tax asset will be realized through recoupment of ordinary and capital taxes paid in prior carryback years and through future earnings, reversal of existing temporary differences and available tax planning strategies. As a result, no valuation allowance was recorded as of December 31, 2023 or 2022.
v3.24.0.1
Claim and Claim Adjustment Expense Reserves
 12 Months Ended
Dec. 31, 2023
Liability for Claims and Claims Adjustment Expense [Abstract]  
Claim and Claim Adjustment Expense Reserve Claim and Claim Adjustment Expense Reserves
Claim and claim adjustment expense reserves represent the estimated amounts necessary to resolve all outstanding claims, including incurred but not reported (IBNR) claims as of the reporting date. The Company's reserve projections are based primarily on detailed analysis of the facts in each case, the Company's experience with similar cases and various historical development patterns. Consideration is given to historical patterns such as claim reserving trends and settlement practices, loss payments, pending levels of unpaid claims and product mix, economic, medical and social inflation, and public attitudes. All of these factors can affect the estimation of claim and claim adjustment expense reserves.
Establishing claim and claim adjustment expense reserves, including claim and claim adjustment expense reserves for catastrophic events that have occurred, is an estimation process. Many factors can ultimately affect the final settlement of a claim and, therefore, the necessary reserve. Changes in the law, results of litigation, medical costs, the cost of repair materials and labor rates can affect ultimate claim costs. In addition, time can be a critical part of reserving determinations since the longer the span between the incidence of a loss and the payment or settlement of the claim, the more variable the ultimate settlement amount can be. Accordingly, short-tail claims, such as property damage claims, tend to be more reasonably estimable than long-tail claims, such as workers' compensation, general liability and professional liability claims. Claim and claim adjustment expense reserves are also maintained for the Company's structured settlement obligations. In developing the claim and claim adjustment expense reserve estimates for structured settlement obligations, the Company's actuaries review mortality experience on an annual basis. Adjustments to prior year reserve estimates, if necessary, are reflected in the results of operations in the period that the need for such adjustments is determined. There can be no assurance that the Company's ultimate cost for insurance losses will not exceed current estimates.
Liability for Unpaid Claim and Claim Adjustment Expenses
The table below reconciles the net liability for unpaid claim and claim adjustment expenses to the amount presented on the Consolidated Balance Sheets.
As of December 31
(In millions)2023
Net liability for unpaid claim and claim adjustment expenses:
Specialty$5,916 
Commercial9,021 
International2,276 
Life & Group (1)
582 
Corporate & Other368 
Total net claim and claim adjustment expenses18,163 
Reinsurance receivables: (2)
Specialty1,215 
Commercial1,082 
International433 
Life & Group93 
Corporate & Other (3)
2,318 
Total reinsurance receivables5,141 
Total gross liability for unpaid claim and claim adjustment expenses$23,304 
(1) The Life & Group segment amounts are related to unfunded structured settlements arising from short-duration contracts.
(2) Reinsurance receivables presented are gross of the allowance for uncollectible reinsurance and do not include reinsurance receivables related to paid losses.
(3) The Corporate & Other Reinsurance receivables are primarily related to A&EP claims covered under the A&EP Loss Portfolio Transfer (LPT).
The following table presents a reconciliation between beginning and ending claim and claim adjustment expense reserves.
As of or for the years ended December 31
(In millions)2023
2022 (1)
2021 (1)
Reserves, beginning of year:
Gross$22,120 $21,269 $19,862 
Ceded5,191 4,969 4,005 
Net reserves, beginning of year16,929 16,300 15,857 
Reduction of net reserves due to Excess Workers' Compensation Loss Portfolio Transfer— — (632)
Net incurred claim and claim adjustment expenses:
Provision for insured events of current year5,667 5,181 5,021 
Increase (decrease) in provision for insured events of prior years48 (32)15 
Amortization of discount44 44 48 
Total net incurred (2)
5,759 5,193 5,084 
Net payments attributable to:
Current year events(922)(821)(933)
Prior year events(3,679)(3,481)(3,016)
Total net payments(4,601)(4,302)(3,949)
Foreign currency translation adjustment and other76 (262)(60)
Net reserves, end of year18,163 16,929 16,300 
Ceded reserves, end of year5,141 5,191 4,969 
Gross reserves, end of year$23,304 $22,120 $21,269 
(1) In conjunction with the Company's adoption of ASU 2018-12, at January 1, 2023, long-term care reserves for policyholders currently receiving benefits were reclassified from Claim and claim adjustment expenses into Future policy benefits and this change was applied retrospectively as of January 1, 2021. See Note A to the Consolidated Financial Statements for additional information.
(2) Total net incurred does not agree to Insurance claims and policyholders' benefits as reflected on the Consolidated Statements of Operations due to amounts related to retroactive reinsurance deferred gain accounting, the loss on the Excess Workers' Compensation LPT (EWC LPT) and uncollectible reinsurance, which are not reflected in the table above.
Reserving Methodology
In developing claim and claim adjustment expense reserve estimates, the Company's actuaries perform detailed reserve analyses that are staggered throughout the year. The data is organized at a reserve group level. Every reserve group is reviewed at least once during the year, but most are reviewed more frequently. The analyses generally review losses gross of ceded reinsurance and apply the ceded reinsurance terms to the gross estimates to establish estimates net of reinsurance. Factors considered include, but are not limited to, the historical pattern and volatility of the actuarial indications, the sensitivity of the actuarial indications to changes in paid and incurred loss patterns, the consistency of claims handling processes, the consistency of case reserving practices, changes in the Company's pricing and underwriting, pricing and underwriting trends in the insurance market and legal, judicial, social and economic trends. In addition to the detailed analyses, the Company reviews actual loss emergence for all products each quarter.
In developing the loss reserve estimates for property and casualty contracts, the Company generally projects ultimate losses using several common actuarial methods as listed below. The Company reviews the indications from the various methods and applies judgment to select an actuarial point estimate. The carried reserve may differ from the actuarial point estimate as a result of the Company's consideration of the factors noted above as well as the potential volatility of the projections associated with the specific product being analyzed and other factors affecting claims costs that may not be quantifiable through traditional actuarial analysis. The indicated required reserve is the difference between the selected ultimate loss and the inception-to-date paid losses. The difference between the selected ultimate loss and the case incurred or reported loss is IBNR. IBNR includes a provision for development on known cases as well as a provision for late reported incurred claims.
The most frequently utilized methods to project ultimate losses include the following:
•Paid development: The paid development method estimates ultimate losses by reviewing paid loss patterns and applying them to accident years with further expected changes in paid loss.
•Incurred development: The incurred development method is similar to the paid development method, but it uses case incurred losses instead of paid losses.
•Loss ratio: The loss ratio method multiplies premiums by an expected loss ratio to produce ultimate loss estimates for each accident year.
•Bornhuetter-Ferguson paid loss: The Bornhuetter-Ferguson paid loss method is a combination of the paid development approach and the loss ratio approach. This method normally determines expected loss ratios similar to the approach used to estimate the expected loss ratio for the loss ratio method.
•Bornhuetter-Ferguson incurred loss: The Bornhuetter-Ferguson incurred loss method is similar to the Bornhuetter-Ferguson using premiums and paid loss method except that it uses case incurred losses.
•Frequency times severity: The frequency times severity method multiplies a projected number of ultimate claims by an estimated ultimate average loss for each accident year to produce ultimate loss estimates.
•Stochastic modeling: The stochastic modeling method produces a range of possible outcomes based on varying assumptions related to the particular product being modeled.
For many exposures, especially those that can be considered long-tail, a particular accident or policy year may not have a sufficient volume of paid losses to produce a statistically reliable estimate of ultimate losses. In such a case, the Company's actuaries typically assign more weight to the incurred development method than to the paid development method. As claims continue to settle and the volume of paid loss increases, the actuaries may assign additional weight to the paid development method. For most of the Company's products, even the incurred losses for accident or policy years that are early in the claim settlement process will not be of sufficient volume to produce a reliable estimate of ultimate losses. In these cases, the Company may not assign much, if any weight to the paid and incurred development methods. The Company may use the loss ratio, Bornhuetter-Ferguson and/or frequency times severity methods. For short-tail exposures, the paid and incurred development methods can often be relied on sooner, primarily because the Company's history includes a sufficient number of years to cover the entire period over which paid and incurred losses are expected to change. However, the Company may also use the loss ratio, Bornhuetter-Ferguson and/or frequency times severity methods for short-
tail exposures. For other more complex reserve groups where the above methods may not produce reliable indications, the Company uses additional methods tailored to the characteristics of the specific situation.
The Company's reserving methodologies for mass tort and A&EP are similar as both are based on detailed reviews of large accounts with estimates of ultimate payments based on the facts in each case and the Company's view of applicable law and coverage litigation.
Gross and Net Carried Reserves
The following tables present the gross and net carried reserves.
December 31, 2023 Specialty CommercialInternationalLife & GroupCorporate & OtherTotal
(In millions)
Gross Case Reserves$1,604 $3,291 $864 $626 $1,353 $7,738 
Gross IBNR Reserves5,527 6,812 1,845 49 1,333 15,566 
Total Gross Carried Claim and Claim Adjustment Expense Reserves$7,131 $10,103 $2,709 $675 $2,686 $23,304 
Net Case Reserves$1,392 $2,878 $708 $556 $129 $5,663 
Net IBNR Reserves4,524 6,143 1,568 26 239 12,500 
Total Net Carried Claim and Claim Adjustment Expense Reserves$5,916 $9,021 $2,276 $582 $368 $18,163 
December 31, 2022 Specialty CommercialInternational
Life & Group(1)
Corporate & OtherTotal
(In millions)
Gross Case Reserves$1,529 $3,156 $817 $647 $1,428 $7,577 
Gross IBNR Reserves5,349 6,239 1,586 48 1,321 14,543 
Total Gross Carried Claim and Claim Adjustment Expense Reserves$6,878 $9,395 $2,403 $695 $2,749 $22,120 
Net Case Reserves$1,310 $2,809 $686 $567 $137 $5,509 
Net IBNR Reserves4,253 5,621 1,317 27 202 11,420 
Total Net Carried Claim and Claim Adjustment Expense Reserves$5,563 $8,430 $2,003 $594 $339 $16,929 
(1) In conjunction with the Company's adoption of ASU 2018-12, at January 1, 2023, long-term care reserves for policyholders currently receiving benefits were reclassified from Claim and claim adjustment expenses into Future policy benefits and this change was applied retrospectively as of January 1, 2021. See Note A to the Consolidated Financial Statements for additional information.
Net Prior Year Development
Changes in estimates of claim and claim adjustment expense reserves, net of reinsurance, for prior years are defined as net prior year loss reserve development (development). These changes can be favorable or unfavorable. The following table presents development recorded for the Specialty, Commercial, International and Corporate & Other segments.
Years ended December 31
(In millions)202320222021
Pretax (favorable) unfavorable development:
Specialty$(14)$(40)$(45)
Commercial(22)(43)(6)
International13 (13)2 
Corporate & Other71 6460 
Total pretax (favorable) unfavorable development$48 $(32)$11 
Unfavorable development of $71 million, $64 million, and $60 million was recorded within the Corporate & Other segment for the years ended December 31, 2023, 2022, and 2021 largely associated with legacy mass tort abuse claims. The 2022 unfavorable development also included the Diocese of Rochester proposed settlement.
Segment Development Tables
For the Specialty, Commercial and International segments, the following tables present further detail and commentary on the development reflected in the financial statements for each of the periods presented. Also presented are loss reserve development tables that illustrate the change over time of reserves established for claim and allocated claim adjustment expenses arising from short-duration insurance contracts for certain lines of business within each of these segments. Not all lines of business or segments are presented based on their context to the Company's overall loss reserves, calendar year reserve development, or calendar year net earned premiums. Insurance contracts are considered to be short-duration contracts when the contracts are not expected to remain in force for an extended period of time.
The Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses tables, reading across, show the cumulative net incurred claim and allocated claim adjustment expenses relating to each accident year at the end of the stated calendar year. Changes in the cumulative amount across time are the result of the Company's expanded awareness of additional facts and circumstances that pertain to the unsettled claims. The Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses tables, reading across, show the cumulative amount paid for claims for each accident year as of the end of the stated calendar year. The Net Strengthening or (Releases) of Prior Accident Year Reserves tables, reading across, show the net increase or decrease in the cumulative net incurred accident year claim and allocated claim adjustment expenses during each stated calendar year and indicates whether the reserves for that accident year were strengthened or released.
The information in the tables is reported on a net basis after reinsurance and does not include the effects of discounting. The information contained in calendar years 2022 and prior is unaudited. Information contained in the tables pertaining to the Company's International segment has been presented at the year-end 2023 foreign currency exchange rates for all periods presented to remove the effects of foreign currency exchange rate changes between calendar years. The Company has presented development information for the Hardy business prospectively from the date of acquisition and is presented as a separate table within the Company's International segment. To the extent the Company enters into a commutation, the transaction is reported on a prospective basis. To the extent that the Company enters into a disposition, the effects of the disposition are reported on a retrospective basis by removing the balances associated with the disposed of business.
The amounts reported for the cumulative number of reported claims include direct and assumed open and closed claims by accident year at the claimant level. The number excludes claim counts for claims within a policy deductible where the insured is responsible for payment of losses in the deductible layer. Claim count data for certain assumed reinsurance contracts is unavailable.
IBNR includes reserves for incurred but not reported losses and expected development on case reserves. The Company does not establish case reserves for allocated loss adjusted expenses (ALAE), therefore ALAE reserves are also included in the estimate of IBNR.
Specialty
The following table presents further detail of the development recorded for the Specialty segment.
Years ended December 31
(In millions)202320222021
Pretax (favorable) unfavorable development:
Medical Professional Liability$5 $18 $23 
Other Professional Liability and Management Liability37 50 24 
Surety(43)(83)(73)
Warranty(11)(21)(14)
Other(2)(4)(5)
Total pretax (favorable) unfavorable development$(14)$(40)$(45)
2023
Unfavorable development in other professional liability and management liability was primarily due to higher than expected claim severity and frequency in the Company’s professional errors and omissions (E&O) businesses in multiple accident years.
Favorable development in surety was primarily due to lower than expected frequency and lack of systemic activity in multiple accident years.
Favorable development in warranty was due to lower than expected loss emergence in a recent accident year.
2022
Unfavorable development in medical professional liability was due to higher than expected large loss activity in multiple accident years.
Unfavorable development in other professional liability and management liability was due to higher than expected claim severity and frequency in the Company’s cyber and professional E&O businesses in multiple accident years.
Favorable development in surety was primarily due to lower than expected frequency and lack of systemic activity in recent accident years.
Favorable development in warranty was due to lower than expected loss emergence in a recent accident year.
2021
Unfavorable development in medical professional liability was due to higher than expected large loss activity in recent accident years.
Unfavorable development in other professional liability and management liability was due to higher than expected frequency of large losses in multiple accident years, and higher than expected claim severity and frequency in the Company’s cyber business in recent accident years.
Favorable development in surety was primarily due to lower than expected frequency and lack of systemic activity in recent accident years.
Favorable development in warranty was due to lower than expected loss emergence in a recent accident year.
Specialty - Line of Business Composition
The table below provides the line of business composition of the net liability for unpaid claim and claim adjustment expenses for the Specialty segment.
As of December 31
(In millions)2023
Net liability for unpaid claim and claim adjustment expenses:
Medical Professional Liability$1,460 
Other Professional Liability and Management Liability3,897 
Surety468 
Warranty28 
Other63 
Total net liability for unpaid claim and claim adjustment expenses$5,916 
Specialty - Medical Professional Liability
Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar YearAs of December 31, 2023
(In millions, except reported claims data)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023IBNRCumulative Number of Claims
Accident Year
2014$450 $489 $537 $530 $535 $529 $527 $524 $527 $525 $6 19,830 
2015433 499 510 494 488 510 501 498 494 15 18,218 
2016427 487 485 499 508 510 508 514 17 16,169 
2017412 449 458 460 455 460 456 20 15,345 
2018404 429 431 448 470 495 41 15,266 
2019430 445 458 471 469 62 14,409 
2020477 476 455 447 180 11,129 
2021377 376 374 193 9,523 
2022329 329 206 9,237 
2023340 281 8,240 
Total$4,443 $1,021 
Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar Year
(In millions)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Accident Year
2014$23 $136 $258 $359 $417 $472 $489 $497 $504 $510 
201522 101 230 313 384 420 444 458 463 
201618 121 246 339 401 436 460 483 
201719 107 235 308 355 388 417 
201821 115 211 290 349 418 
201917 91 183 280 349 
202011 61 139 201 
202111 49 118 
202210 57 
202314 
Total$3,030 
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented$1,413 
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 201422 
Liability for unallocated claim adjustment expenses for accident years presented25 
Total net liability for unpaid claim and claim adjustment expenses$1,460 
            
Net strengthening (releases) of prior accident year reserves is presented in the following table.
For the years ended December 31Calendar Year
(In millions)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023Total
Accident Year
2014$39 $48 $(7)$5 $(6)$(2)$(3)$3 $(2)$75 
201566 11 (16)(6)22 (9)(3)(4)61 
201660 (2)14 9 2 (2)6 87 
201737 9 2 (5)5 (4)44 
201825 2 17 22 25 91 
201915 13 13 (2)39 
2020(1)(21)(8)(30)
2021(1)(2)(3)
2022— — 
Total net development for the accident years presented above14 16 9 
Total net development for accident years prior to 20142 (3)(4)
Total unallocated claim adjustment expense development7 5 — 
Total$23 $18 $5 
(1) Data presented for these calendar years is required supplemental information, which is unaudited.
Specialty - Other Professional Liability and Management Liability
Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar YearAs of December 31, 2023
(In millions, except reported claims data)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023IBNRCumulative Number of Claims
Accident Year
2014$878 $898 $885 $831 $835 $854 $845 $841 $842 $838 $26 17,585 
2015888 892 877 832 807 813 836 855 858 18 17,454 
2016901 900 900 904 907 891 888 906 39 17,987 
2017847 845 813 791 775 758 746 69 18,199 
2018850 864 869 906 923 941 101 20,038 
2019837 845 856 876 939 100 19,515 
2020930 944 951 945 281 19,437 
20211,037 1,038 1,009 532 18,259 
20221,120 1,112 706 18,165 
20231,149 971 16,469 
Total$9,443 $2,843 
Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar Year
(In millions)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Accident Year
2014$51 $223 $392 $515 $647 $707 $743 $787 $802 $806 
201560 234 404 542 612 677 725 794 808 
201664 248 466 625 701 736 784 826 
201757 222 394 498 557 596 630 
201854 282 473 599 706 779 
201964 263 422 567 699 
202067 248 400 523 
202158 217 356 
202264 225 
202364 
Total$5,716 
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented$3,727 
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014115 
Liability for unallocated claim adjustment expenses for accident years presented55 
Total net liability for unpaid claim and claim adjustment expenses$3,897 
Net strengthening (releases) of prior accident year reserves is presented in the following table.
For the years ended December 31Calendar Year
(In millions)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023Total
Accident Year
2014$20 $(13)$(54)$4 $19 $(9)$(4)$1 $(4)$(40)
20154 (15)(45)(25)6 23 19 3 (30)
2016(1)— 4 3 (16)(3)18 5 
2017(2)(32)(22)(16)(17)(12)(101)
201814 5 37 17 18 91 
20198 11 20 63 102 
202014 7 (6)15 
20211 (29)(28)
2022(8)(8)
Total net development for the accident years presented above49 45 43 
Total net development for accident years prior to 2014(27)5 (6)
Total unallocated claim adjustment expense development2 — — 
Total$24 $50 $37 
(1) Data presented for these calendar years is required supplemental information, which is unaudited.
Specialty - Surety
Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar YearAs of December 31, 2023
(In millions, except reported claims data)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023IBNRCumulative Number of Claims
Accident Year
2014$123 $124 $94 $69 $60 $45 $45 $43 $42 $41 $2 5,135 
2015131 131 104 79 63 58 53 45 45 2 5,085 
2016124 124 109 84 67 64 58 43 3 5,565 
2017120 115 103 84 71 66 67 4 5,883 
2018114 108 91 62 56 51 10 6,249 
2019119 112 98 87 82 12 6,152 
2020128 119 81 67 34 4,678 
2021137 129 110 68 4,645 
2022155 158 116 4,350 
2023175 167 2,750 
Total$839 $418 
Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar Year
(In millions)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Accident Year
2014$7 $30 $38 $36 $38 $38 $39 $39 $38 $38 
20157 26 38 40 42 44 42 42 43 
20165 37 45 45 43 43 41 40 
201723 37 41 46 49 62 62 
20185 25 34 39 40 41 
201912 34 44 59 70 
20204 20 28 33 
20215 20 35 
202212 35 
20238 
Total$405 
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented$434 
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 201413 
Liability for unallocated claim adjustment expenses for accident years presented21 
Total net liability for unpaid claim and claim adjustment expenses$468 
Net strengthening (releases) of prior accident year reserves is presented in the following table.
For the years ended December 31Calendar Year
(In millions)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023Total
Accident Year
2014$1 $(30)$(25)$(9)$(15)$— $(2)$(1)$(1)$(82)
2015— (27)(25)(16)(5)(5)(8)— (86)
2016— (15)(25)(17)(3)(6)(15)(81)
2017(5)(12)(19)(13)(5)1 (53)
2018(6)(17)(29)(6)(5)(63)
2019(7)(14)(11)(5)(37)
2020(9)(38)(14)(61)
2021(8)(19)(27)
20223 3 
Total net development for the accident years presented above(75)(83)(55)
Total net development for accident years prior to 20142 — 12 
Total unallocated claim adjustment expense development— — — 
Total$(73)$(83)$(43)
(1) Data presented for these calendar years is required supplemental information, which is unaudited.
Commercial
The following table presents further detail of the development recorded for the Commercial segment.
Years ended December 31
(In millions)202320222021
Pretax (favorable) unfavorable development:
Commercial Auto$33 $49 $53 
General Liability149 67 15 
Workers' Compensation(203)(152)(82)
Property and Other(1)(7)8 
Total pretax (favorable) unfavorable development$(22)$(43)$(6)
2023
Unfavorable development in commercial auto was due to higher than expected claim severity in the Company’s construction business in a recent accident year.
Unfavorable development in general liability was due to higher than expected claim severity in the Company’s construction and middle market businesses across multiple accident years.
Favorable development in workers’ compensation was due to favorable medical trends driving lower than expected severity in multiple accident years.
2022
Unfavorable development in commercial auto and general liability was due to higher than expected claim severity across multiple accident years.
Favorable development in workers’ compensation was due to favorable medical trends driving lower than expected severity in multiple accident years.
2021
Unfavorable development in commercial auto was due to higher than expected claim severity in the Company’s middle market and construction businesses in multiple accident years.
Unfavorable development in general liability was due to higher than expected claim severity in the Company’s construction and umbrella businesses in multiple accident years.
Favorable development in workers’ compensation was due to favorable medical trends driving lower than expected severity in multiple accident years.
Commercial - Line of Business Composition
The table below provides the line of business composition of the net liability for unpaid claim and claim adjustment expenses for the Commercial segment.
As of December 31
(In millions)2023
Net Claim and claim adjustment expenses:
Commercial Auto$926 
General Liability3,780 
Workers' Compensation3,645 
Property and Other670 
Total net liability for claim and claim adjustment expenses$9,021 
Commercial - Commercial Auto
Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar YearAs of December 31, 2023
(In millions, except reported claims data)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023IBNRCumulative Number of Claims
Accident Year
2014$234 $223 $212 $205 $205 $201 $201 $202 $201 $201 $1 33,633 
2015201 199 190 190 183 181 183 182 184 4 30,430 
2016198 186 186 186 190 195 200 197 4 30,455 
2017199 198 200 221 232 239 241 4 30,947 
2018229 227 227 245 254 255 1 34,333 
2019257 266 289 323 325 10 37,258 
2020310 303 304 298 21 29,142 
2021397 388 390 93 32,918 
2022437 465 137 36,777 
2023554 347 34,211 
Total$3,110 $622 
Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar Year
(In millions)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Accident Year
2014$64 $102 $137 $166 $187 $196 $198 $199 $199 $200 
201552 96 130 153 172 175 178 179 180 
201652 93 126 154 175 185 190 192 
201758 107 150 178 203 225 232 
201866 128 175 212 238 249 
201977 147 203 257 295 
202071 134 197 246 
202183 168 240 
2022112 236 
2023127 
Total$2,197 
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented$913 
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 20144 
Liability for unallocated claim adjustment expenses for accident years presented9 
Total net liability for unpaid claim and claim adjustment expenses$926 
Net strengthening (releases) of prior accident year reserves is presented in the following table.
For the years ended December 31Calendar Year
(In millions)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023Total
Accident Year
2014$(11)$(11)$(7)$— $(4)$— $1 $(1)$— $(33)
2015(2)(9)— (7)(2)2 (1)2 (17)
2016(12)— — 4 5 5 (3)(1)
2017(1)2 21 11 7 2 42 
2018(2)— 18 9 1 26 
20199 23 34 2 68 
2020(7)1 (6)(12)
2021(9)2 (7)
202228 28 
Total net development for the accident years presented above53 45 28 
Total net development for accident years prior to 2014— 4 2 
Total unallocated claim adjustment expense development— — 3 
Total$53 $49 $33 
(1) Data presented for these calendar years is required supplemental information, which is unaudited.
Commercial - General Liability
Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar YearAs of December 31, 2023
(In millions, except reported claims data)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023IBNRCumulative Number of Claims
Accident Year
2014$653 $658 $654 $631 $635 $658 $659 $659 $676 $679 $28 28,196 
2015581 576 574 589 600 602 617 625 639 28 24,261 
2016623 659 667 671 673 683 684 704 39 24,803 
2017632 632 632 634 630 652 690 36 22,471 
2018653 644 646 639 650 679 129 20,425 
2019680 682 682 691 720 174 19,647 
2020723 722 726 736 347 14,593 
2021782 784 793 401 15,121 
2022929 928 676 15,754 
20231,071 963 11,633 
Total$7,639 $2,821 
Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar Year
(In millions)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Accident Year
2014$31 $119 $247 $376 $481 $547 $569 $607 $624 $642 
201519 110 230 357 446 501 530 561 573 
201632 163 279 407 481 524 582 620 
201723 118 250 399 471 553 606 
201833 107 228 307 428 491 
201925 98 181 322 455 
202023 99 192 280 
202126 140 262 
202229 123 
202333 
Total$4,085 
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented$3,554 
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014162 
Liability for unallocated claim adjustment expenses for accident years presented64 
Total net liability for unpaid claim and claim adjustment expenses$3,780 
Net strengthening (releases) of prior accident year reserves is presented in the following table.
For the years ended December 31Calendar Year
(In millions)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023Total
Accident Year
2014$5 $(4)$(23)$4 $23 $1 $— $17 $3 $26 
2015(5)(2)15 11 2 15 8 14 58 
201636 8 4 2 10 1 20 81 
2017— — 2 (4)22 38 58 
2018(9)2 (7)11 29 26 
20192 — 9 29 40 
2020(1)4 10 13 
20212 9 11 
2022(1)(1)
Total net development for the accident years presented above13 74 151 
Total net development for accident years prior to 2014— (7)(2)
Total unallocated claim adjustment expense development2 — — 
Total$15 $67 $149 
(1) Data presented for these calendar years is required supplemental information, which is unaudited.
Commercial - Workers' Compensation
Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar YearAs of December 31, 2023
(In millions, except reported claims data)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023IBNRCumulative Number of Claims
Accident Year
2014$467 $480 $479 $452 $450 $446 $439 $448 $430 $419 $70 33,550 
2015422 431 406 408 394 382 372 353 334 59 31,904 
2016426 405 396 382 366 355 331 308 56 31,994 
2017440 432 421 400 402 399 398 78 33,142 
2018450 440 428 415 415 404 74 34,886 
2019452 449 437 436 419 78 34,349 
2020477 466 446 414 135 29,454 
2021468 454 432 146 30,066 
2022497 489 198 33,229 
2023555 344 31,549 
Total$4,172 $1,238 
Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar Year
(In millions)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Accident Year
2014$61 $159 $215 $258 $282 $290 $297 $306 $312 $319 
201551 131 180 212 231 243 251 256 259 
201653 129 169 198 219 227 234 235 
201763 151 207 243 265 279 287 
201868 163 229 259 280 298 
201971 169 223 262 291 
202065 147 200 228 
202167 164 222 
202279 192 
202387 
Total$2,418 
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented$1,754 
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 20141,842 
Other (2)
(23)
Liability for unallocated claim adjustment expenses for accident years presented72 
Total net liability for unpaid claim and claim adjustment expenses$3,645 
Net strengthening (releases) of prior accident year reserves is presented in the following table.
For the years ended December 31Calendar Year
(In millions)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023Total
Accident Year
2014$13 $(1)$(27)$(2)$(4)$(7)$9 $(18)$(11)$(48)
20159 (25)2 (14)(12)(10)(19)(19)(88)
2016(21)(9)(14)(16)(11)(24)(23)(118)
2017(8)(11)(21)2 (3)(1)(42)
2018(10)(12)(13)— (11)(46)
2019(3)(12)(1)(17)(33)
2020(11)(20)(32)(63)
2021(14)(22)(36)
2022(8)(8)
Total net development for the accident years presented above(46)(99)(144)
Adjustment for development on a discounted basis2 (3)(2)
Total net development for accident years prior to 2014(38)(60)(63)
Total unallocated claim adjustment expense development— 10 6 
Total$(82)$(152)$(203)
(1) Data presented for these calendar years is required supplemental information, which is unaudited.
(2) Other includes the effect of discounting lifetime claim reserves.
International
The following table presents further detail of the development recorded for the International segment.
Years ended December 31
(In millions)202320222021
Pretax (favorable) unfavorable development:
Commercial$(18)$(10)$(35)
Specialty35 (4)36 
Other(4)1 1 
Total pretax (favorable) unfavorable development $13 $(13)$2 

2023
Favorable development in Commercial was due to lower than expected loss emergence across multiple accident years.
Unfavorable development in Specialty was due to higher than expected large loss emergence in the Company’s medical treatment and professional liability businesses in multiple accident years.
2022
Favorable development in commercial was due to lower than expected loss emergence across multiple accident years.
2021
Favorable development in commercial was due to lower than expected loss emergence across multiple accident years.
Unfavorable development in specialty was due to higher than expected claim severity in the Company’s medical treatment and professional liability businesses in multiple accident years.
International - Line of Business Composition
The table below provides the composition of the net liability for unpaid claim and claim adjustment expenses for the International segment.
As of December 31
(In millions)2023
Net Claim and claim adjustment expenses:
International excluding Hardy$1,655 
Hardy621 
Total net liability for claim and claim adjustment expenses$2,276 
International, Excluding Hardy
Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar YearAs of December 31, 2023
(In millions, except reported claims data)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023IBNRCumulative Number of Claims
Accident Year
2014$276 $291 $291 $279 $272 $289 $290 $283 $286 $288 $15 25,130 
2015289 304 303 286 280 283 285 285 281 19 23,608 
2016284 302 288 285 276 290 292 309 36 18,079 
2017299 363 383 376 371 360 393 39 18,841 
2018367 385 389 388 401 411 48 21,327 
2019342 355 352 360 362 61 18,993 
2020381 372 362 347 107 15,744 
2021408 397 375 162 15,136 
2022428 438 227 11,899 
2023478 359 7,869 
Total$3,682 $1,073 
Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar Year
(In millions)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Accident Year
2014$51 $121 $149 $166 $182 $203 $236 $241 $248 $253 
201556 132 162 182 204 219 230 237 246 
201666 131 158 180 192 214 226 237 
201764 146 186 214 237 264 321 
201889 166 212 242 266 308 
201973 164 201 224 247 
202060 128 162 178 
202156 124 154 
202246 138 
202346 
Total$2,128 
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented$1,554 
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 201464 
Liability for unallocated claim adjustment expenses for accident years presented37 
Total net liability for unpaid claim and claim adjustment expenses$1,655 
Net strengthening (releases) of prior accident year reserves is presented in the following table.
For the years ended December 31Calendar Year
(In millions)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Total (2)
Accident Year
2014$15 $— $(12)$(7)$17 $1 $(7)$3 $2 $12 
201515 (1)(17)(6)3 2 — (4)(8)
201618 (14)(3)(9)14 2 17 25 
201764 20 (7)(5)(11)33 94 
201818 4 (1)13 10 44 
201913 (3)8 2 20 
2020(9)(10)(15)(34)
2021(11)(22)(33)
202210 10 
(1) Data presented for these calendar years is required supplemental information, which is unaudited.
(2) The amounts included in the loss reserve development tables above are presented at the year-end 2023 foreign currency exchange rates for all periods presented to remove the effects of foreign currency exchange rate fluctuations between calendar years. The amounts included within the table on page 110 presenting the detail of the development recorded within the International segment include the impact of fluctuations in foreign currency exchange rates.
International - Hardy
Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar YearAs of December 31, 2023
(In millions, except reported claims data)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023IBNRCumulative Number of Claims
Accident Year
2014$183 $182 $175 $169 $170 $170 $169 $167 $166 $167 $(1)8,534 
2015187 177 175 175 173 175 176 178 177 (3)9,741 
2016227 244 233 223 224 218 219 223 6 10,895 
2017243 252 242 243 251 251 239 (5)13,294 
2018268 298 302 307 307 324 36 15,366 
2019219 223 217 224 220 25 11,670 
2020210 201 195 192 55 7,036 
2021177 168 154 59 3,831 
2022190 186 96 2,371 
2023200 152 1,388 
Total$2,082 $420 
Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar Year
(In millions)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Accident Year
2014$56 $122 $140 $150 $155 $161 $162 $163 $164 $164 
201529 97 128 143 154 162 160 169 163 
201663 144 171 180 193 204 205 208 
201753 150 183 205 212 224 229 
201855 170 200 231 249 270 
201943 102 140 157 167 
202027 77 103 118 
202113 44 68 
202223 58 
202317 
Total$1,462 
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented$620 
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014(8)
Liability for unallocated claim adjustment expenses for accident years presented9 
Total net liability for unpaid claim and claim adjustment expenses$621 
Net strengthening (releases) of prior accident year reserves is presented in the following table.
For the years ended December 31Calendar Year
(In millions)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Total(2)
Accident Year
2014$(1)$(7)$(6)$1 $— $(1)$(2)$(1)$1 $(16)
2015(10)(2)— (2)2 1 2 (1)(10)
201617 (11)(10)1 (6)1 4 (4)
20179 (10)1 8 — (12)(4)
201830 4 5 — 17 56 
20194 (6)7 (4)1 
2020(9)(6)(3)(18)
2021(9)(14)(23)
2022(4)(4)
(1) Data presented for these calendar years is required supplemental information, which is unaudited.
(2) The amounts included in the loss reserve development tables above are presented at the year-end 2023 foreign currency exchange rates for all periods presented to remove the effects of foreign currency exchange rate fluctuations between calendar years. The amounts included within the table on page 110 presenting the detail of the development recorded within the International segment include the impact of fluctuations in foreign currency exchange rates.
The table below presents information about average historical claims duration as of December 31, 2023 and is presented as required supplementary information, which is unaudited.
Average Annual Percentage Payout of Ultimate Net Incurred Claim and Allocated Claim Adjustment Expenses in Year:
12345678910
Specialty
Medical Professional Liability3.7 %16.4 %22.1 %17.2 %12.4 %9.1 %4.8 %2.9 %1.2 %1.1 %
Other Professional Liability and Management Liability6.5 %19.8 %19.3 %14.9 %10.9 %6.3 %4.9 %6.0 %1.7 %0.5 %
Surety(1)
17.7 %46.6 %17.7 %3.4 %2.2 %5.2 %(1.7)%(0.8)%(0.1)%— %
Commercial
Commercial Auto25.2 %22.2 %18.2 %14.3 %10.6 %4.9 %2.0 %0.7 %0.3 %0.5 %
General Liability3.6 %12.8 %16.3 %17.4 %14.4 %9.1 %5.9 %5.3 %2.2 %2.7 %
Workers' Compensation16.0 %22.9 %13.8 %8.8 %6.0 %3.2 %2.1 %1.3 %1.2 %1.7 %
International
International - Excluding Hardy16.9 %21.8 %9.8 %6.5 %5.9 %7.4 %8.4 %2.6 %2.8 %1.7 %
International - Hardy18.0 %31.3 %13.7 %7.5 %4.7 %4.9 %0.5 %2.3 %(1.4)%— %
(1) Due to the nature of the Surety business, average annual percentage payout of ultimate net incurred claim and allocated claim adjustment expenses has been calculated using only the payouts of mature accident years presented in the loss reserve development tables.
A&EP Reserves
In 2010, Continental Casualty Company (CCC) together with several of the Company’s insurance subsidiaries completed a transaction with National Indemnity Company (NICO), a subsidiary of Berkshire Hathaway Inc., under which substantially all of the Company’s legacy A&EP liabilities were ceded to NICO through a LPT. At the effective date of the transaction, the Company ceded approximately $1.6 billion of net A&EP claim and allocated claim adjustment expense reserves to NICO under a retroactive reinsurance agreement with an aggregate limit of $4 billion. The $1.6 billion of claim and allocated claim adjustment expense reserves ceded to NICO was net of $1.2 billion of ceded claim and allocated claim adjustment expense reserves under existing third-party reinsurance contracts. The NICO LPT aggregate reinsurance limit also covers credit risk on the existing third-party reinsurance related to these liabilities. The Company paid NICO a reinsurance premium of $2 billion and transferred to NICO billed third-party reinsurance receivables related to A&EP claims with a net book value of $215 million, resulting in total consideration of $2.2 billion.
In years subsequent to the effective date of the LPT, the Company recognized adverse prior year development on its A&EP reserves resulting in additional amounts ceded under the LPT. As a result, the cumulative amounts ceded under the LPT have exceeded the $2.2 billion consideration paid, resulting in the NICO LPT moving into a gain position, requiring retroactive reinsurance accounting. Under retroactive reinsurance accounting, this gain is deferred and only recognized in earnings in proportion to actual paid recoveries under the LPT. Over the life of the contract, there is no economic impact as long as any additional losses incurred are within the limit of the LPT. In a period in which the Company recognizes a change in the estimate of A&EP reserves that increases or decreases the amounts ceded under the LPT, the proportion of actual paid recoveries to total ceded losses is affected and the change in the deferred gain is recognized in earnings as if the revised estimate of ceded losses was available at the effective date of the LPT. The effect of the deferred retroactive reinsurance benefit is recorded in Insurance claims and policyholders' benefits in the Consolidated Statements of Operations.
The following table presents the impact of the Loss Portfolio Transfer on the Consolidated Statements of Operations.
Years ended December 31
(In millions)202320222021
Additional amounts ceded under LPT:
Net A&EP adverse development before consideration of LPT$86 $92 $143 
Provision for uncollectible third-party reinsurance on A&EP— (5)(5)
Total additional amounts ceded under LPT86 87 138 
Retroactive reinsurance benefit recognized(94)(91)(107)
Pretax impact of deferred retroactive reinsurance$(8)$(4)$31 
Net unfavorable prior year development of $86 million, $92 million and $143 million was recognized before consideration of cessions to the LPT for the years ended December 31, 2023, 2022 and 2021. The unfavorable development in 2023, 2022 and 2021 was primarily driven by higher than anticipated defense and indemnity costs on known direct asbestos and environmental accounts and a reduction in estimated reinsurance recoverable. Additionally, in both 2022 and 2021, the Company released $5 million of its provision for uncollectible third-party reinsurance. The Company did not release any of its provision for uncollectible third-party reinsurance in 2023.
As of December 31, 2023 and 2022, the cumulative amounts ceded under the LPT were $3.6 billion and $3.5 billion. The unrecognized deferred retroactive reinsurance benefit was $417 million and $425 million as of December 31, 2023 and 2022 and is included within Other liabilities on the Consolidated Balance Sheets.
NICO established a collateral trust account as security for its obligations to the Company. The fair value of the collateral trust account was $2.5 billion as of December 31, 2023. In addition, Berkshire Hathaway Inc. guaranteed the payment obligations of NICO up to the aggregate reinsurance limit as well as certain of NICO’s performance obligations under the trust agreement. NICO is responsible for claims handling and billing and collection from third-party reinsurers related to the majority of the Company’s A&EP claims.
Excess Workers' Compensation LPT
On February 5, 2021, CCC completed a transaction with Cavello Bay Reinsurance Limited (Cavello), a subsidiary of Enstar Group Limited, under which certain legacy excess workers' compensation (EWC) liabilities were ceded to Cavello. Under the terms of the transaction, based on reserves in place as of January 1, 2020, the Company ceded approximately $690 million of net EWC claim and allocated claim adjustment expense reserves to Cavello under an LPT with an aggregate limit of $1 billion. The Company paid Cavello a reinsurance premium of $697 million, less claims paid between January 1, 2020 and the closing date of the agreement of $64 million. After transaction costs, the Company recognized an after-tax loss of approximately $12 million in the Corporate & Other segment in the first quarter of 2021 related to the EWC LPT.
As of December 31, 2023, the cumulative amount ceded under the EWC LPT was $690 million.
Cavello established a collateral trust as security for its obligations to the Company. The fair value of the collateral trust was $440 million as of December 31, 2023.
v3.24.0.1
Future Policy Benefit Reserves
 12 Months Ended
Dec. 31, 2023
Insurance [Abstract]  
Future Policy Benefit Reserves Future Policy Benefits Reserves
Future policy benefits reserves are associated with the Company's run-off long-term care business, which is included in the Life & Group segment, and relate to policyholders that are currently receiving benefits, including claims that have been incurred but are not yet reported, as well as policyholders that are not yet receiving benefits.
The determination of Future policy benefits reserves requires management to make estimates and assumptions about expected policyholder experience over the remaining life of the policy. Since policies may be in force for several decades, these assumptions are subject to significant estimation risk. As a result of this variability, the Company’s future policy benefits reserves may be subject to material increases if actual experience develops adversely to the Company’s expectations.
The LFPB is computed using the net level premium method, which incorporates cash flow assumptions and discount rate assumptions. As a result of the modified retrospective adoption of ASU 2018-12, the Company’s NPR calculation incorporates the original locked in discount rate and the reserve balance as of the transition date of January 1, 2021. The key cash flow assumptions used to estimate the LFPB are morbidity, persistency (inclusive of mortality), anticipated future premium rate increases and expenses. The carried LFPB discount rate is determined using the upper-medium grade fixed income instrument yield curve.
The Company has elected to update the NPR and the LFPB for actual experience on a quarterly basis. A quarterly assessment is also made as to whether evidence suggests that cash flow assumptions should be updated. Annually in the third quarter, actuarial analysis is performed on policyholder morbidity, persistency, premium rate increases and expense experience, which, combined with judgment, informs the setting of updated cash flow assumptions used to estimate the LFPB.
The cash flow assumption updates completed in the third quarter of 2023 resulted in an $8 million pretax increase in the LFPB. Persistency updates were unfavorable due to revisions to lapse rates. Morbidity updates were favorable driven by claim severity assumption updates, and there was a favorable impact from outperformance on premium rate assumptions. Adjusted to reflect the application of the LDTI accounting standard, the cash flow assumption updates completed in the third quarter of 2022 resulted in a $186 million pretax increase to the LFPB, primarily driven by the unfavorable impact of increased cost of care inflation offset by favorable premium rate assumptions.
The following table summarizes balances and changes in the LFPB.
(In millions)
202320222021
Present value of future net premiums
Balance, January 1$3,991 $4,735 $5,086 
     Effect of changes in discount rate(74)(880)(1,140)
Balance, January 1, at original locked in discount rate3,917 3,855 3,946 
     Effect of changes in cash flow assumptions (1)
28 352 173 
     Effect of actual variances from expected experience (1)
(126)(49)(24)
Adjusted balance, January 13,819 4,158 4,095 
Interest accrual202 216 219 
     Net premiums: earned during period(436)(457)(459)
Balance, end of period at original locked in discount rate3,585 3,917 3,855 
     Effect of changes in discount rate125 74 880 
Balance, December 31$3,710 $3,991 $4,735 
Present value of future benefits & expenses
Balance, January 1$17,471 $22,745 $23,955 
     Effect of changes in discount rate(125)(5,942)(7,395)
Balance, January 1, at original locked in discount rate17,346 16,803 16,560 
     Effect of changes in cash flow assumptions (1)
36 538 176 
     Effect of actual variances from expected experience (1)
(46)(21)(19)
Adjusted balance, January 117,336 17,320 16,717 
Interest accrual962 979 973 
     Benefit & expense payments(1,207)(953)(887)
Balance, end of period at original locked in discount rate17,091 17,346 16,803 
     Effect of changes in discount rate578 125 5,942 
Balance, December 31$17,669 $17,471 $22,745 
Net LFPB$13,959 $13,480 $18,010 
(1) As of December 31, 2023, 2022 and 2021 the re-measurement gain (loss) of $(88) million, $(214) million and $(8) million presented parenthetically on the Consolidated Statement of Operations is comprised of the effect of changes in cash flow assumptions and the effect of actual variances from expected experience.
The following table presents earned premiums and interest expense associated with the Company’s long-term care business recognized on the Consolidated Statement of Operations.
Years ended December 31
(In millions)
202320222021
Earned premiums$451 $473 $491 
Interest expense760 763 754 
The following table presents undiscounted expected future benefit and expense payments, and undiscounted expected future gross premiums.
As of December 31
(In millions)
20232022
  Expected future benefit and expense payments$32,851 $34,261 
  Expected future gross premiums5,414 5,910 
Discounted expected future gross premiums at the upper-medium grade fixed income instrument yield discount rate were $3,824 million and $4,070 million as of December 31, 2023 and 2022.
The weighted average effective duration of the LFPB calculated using the original locked in discount rate was 11 years and 12 years as of December 31, 2023 and 2022.
The weighted average interest rates in the table below are calculated based on the rate used to discount all future cash flows.
As of December 31
20232022
   Original locked in discount rate5.22 %5.27 %
Upper-medium grade fixed income instrument discount rate4.94 5.23 
For the years ended December 31, 2023 and 2022, immediate charges to net income resulting from adverse development that caused the NPR to exceed 100% for certain cohorts were $164 million and $178 million. For the years ended December 31, 2023 and 2022, the portion of losses recognized in a prior period due to NPR exceeding 100% for certain cohorts which, due to favorable development, was reversed through net income was $42 million and $12 million.
v3.24.0.1
Legal Proceedings, Contingencies and Guarantees
 12 Months Ended
Dec. 31, 2023
Legal Proceedings, Commitments and Contingencies, and Guarantees [Abstract]  
Legal Proceedings, Contingencies and Guarantees Legal Proceedings, Contingencies and Guarantees
The Company is a party to various claims and litigation incidental to its business, which, based on the facts and circumstances currently known, are not material to the Company's results of operations or financial position.
Guarantees
The Company has provided guarantees, if the primary obligor fails to perform, to holders of structured settlement annuities issued by a previously owned subsidiary. As of December 31, 2023, the potential amount of future payments the Company could be required to pay under these guarantees was approximately $1.5 billion, which will be paid over the lifetime of the annuitants. The Company does not believe any payment is likely under these guarantees, as the Company is the beneficiary of a trust that must be maintained at a level that approximates the discounted reserves for these annuities.
v3.24.0.1
Reinsurance
 12 Months Ended
Dec. 31, 2023
Reinsurance Disclosures [Abstract]  
Reinsurance Reinsurance
The Company cedes insurance to reinsurers to limit its maximum loss, provide greater diversification of risk, minimize exposures on larger risks and to exit certain lines of business. The ceding of insurance does not discharge the primary liability of the Company. A credit exposure exists with respect to reinsurance ceded to the extent that any reinsurer is unable to meet its obligations. A collectibility exposure also exists to the extent that the reinsurer disputes the liabilities assumed under reinsurance agreements. Property and casualty reinsurance coverages are tailored to the specific risk characteristics of each product line and the Company's retained amount varies by type of coverage. Reinsurance contracts are purchased to protect specific lines of business such as property and workers' compensation. Corporate catastrophe reinsurance is also purchased for property and workers' compensation exposure. The Company also utilizes facultative reinsurance in certain lines. In addition, the Company assumes reinsurance primarily through Hardy and as a member of various reinsurance pools and associations.
The following table presents the amounts receivable from reinsurers.
December 31
(In millions)20232022
Reinsurance receivables related to insurance reserves:
Ceded claim and claim adjustment expenses$5,141 $5,191 
Reinsurance receivables related to paid losses293 247 
Reinsurance receivables5,434 5,438 
Allowance for uncollectible reinsurance(22)(22)
Reinsurance receivables, net of allowance for uncollectible reinsurance$5,412 $5,416 
The Company has established an allowance for uncollectible voluntary reinsurance receivables which relates to both amounts already billed on ceded paid losses as well as ceded reserves that will be billed when losses are paid in the future. The following table summarizes the outstanding amount of voluntary reinsurance receivables, gross of any collateral arrangements, by financial strength rating.
(In millions)December 31, 2023
A- to A++$4,047 
B- to B++769 
Insolvent7 
Total voluntary reinsurance outstanding balance (1)
$4,823 
(1)    Expected credit losses for legacy A&EP receivables are ceded to NICO and the reinsurance limit on the LPT has not been exhausted, therefore no allowance is recorded for these receivables and they are excluded from the table above. Refer to Note E to the Consolidated Financial Statements for information regarding the LPT. The Company has also excluded receivables from involuntary pools.
The Company attempts to mitigate its credit risk related to reinsurance by entering into reinsurance arrangements with reinsurers that have credit ratings above certain levels and by obtaining collateral. On a limited basis, the Company may enter into reinsurance agreements with reinsurers that are not rated, primarily captive reinsurers. Receivables from captive reinsurers are backed by collateral arrangements and comprise the majority of the voluntary reinsurance receivables within the B- to B++ rating distribution in the table above. The primary methods of obtaining collateral are through reinsurance trusts, letters of credit and funds withheld balances. Such collateral, limited by the balance of open recoverables, was approximately $3.6 billion and $3.7 billion as of December 31, 2023 and 2022.
The Company's largest recoverables from a single reinsurer as of December 31, 2023, including ceded unearned premium reserves, were approximately $1.8 billion from subsidiaries of the Berkshire Hathaway Insurance Group, $576 million from Cavello Bay Reinsurance Limited and $410 million from the Swiss Reinsurance Group. These amounts are substantially collateralized or otherwise secured. The recoverable from subsidiaries of the Berkshire Hathaway Insurance Group includes amounts related to third-party reinsurance for which
NICO has assumed the credit risk under the terms of the LPT as discussed in Note E to the Consolidated Financial Statements.
The effects of reinsurance on earned premiums and written premiums are presented in the following tables.
(In millions)DirectAssumedCededNetAssumed/
Net %
2023 Earned Premiums
Property and casualty$13,908 $223 $5,102 $9,029 2.5 %
Long-term care407 44 — 451 9.8 %
Total earned premiums$14,315 $267 $5,102 $9,480 2.8 %
2022 Earned Premiums
Property and casualty$13,097 $231 $5,134 $8,194 2.8 %
Long-term care427 46 — 473 9.7 %
Total earned premiums$13,524 $277 $5,134 $8,667 3.2 %
2021 Earned Premiums
Property and casualty$12,554 $240 $5,110 $7,684 3.1 %
Long-term care443 48 — 491 9.8 %
Total earned premiums$12,997 $288 $5,110 $8,175 3.5 %
(In millions)DirectAssumedCededNetAssumed/
Net %
2023 Written Premiums
Property and casualty$14,498 $219 $5,272 $9,445 2.3 %
Long-term care404 43 — 447 9.6 %
Total written premiums$14,902 $262 $5,272 $9,892 2.6 %
2022 Written Premiums
Property and casualty$13,843 $235 $5,417 $8,661 2.7 %
Long-term care421 46 — 467 9.9 %
Total written premiums$14,264 $281 $5,417 $9,128 3.1 %
2021 Written Premiums
Property and casualty$13,150 $255 $5,485 $7,920 3.2 %
Long-term care437 48 — 485 9.9 %
Total written premiums$13,587 $303 $5,485 $8,405 3.6 %
Included in the direct and ceded earned premiums for the years ended December 31, 2023, 2022 and 2021 are $2,907 million, $3,270 million and $3,638 million related to property business that is 100% reinsured under a significant third-party captive program. The third-party captives that participate in this program are affiliated with the non-insurance company policyholders, therefore this program provides a means for the policyholders to self-insure this property risk. The Company receives and retains a ceding commission.
Insurance claims and policyholders' benefits reported on the Consolidated Statements of Operations are net of estimated reinsurance recoveries of $2,772 million, $2,631 million and $3,058 million for the years ended December 31, 2023, 2022 and 2021, including $1,512 million, $1,796 million and $2,003 million, respectively, related to the significant third-party captive program discussed above.
Long-term care premiums are from long-duration contracts; property and casualty premiums are from short-duration contracts.
v3.24.0.1
Debt
 12 Months Ended
Dec. 31, 2023
Debt Disclosure [Abstract]  
Debt Debt
Debt is composed of the following long-term obligations.
December 31
(In millions)20232022
Short-term debt:
Debenture of CNAF, 7.250%, face amount of $243, due November 15, 2023
$— $243 
Senior notes of CNAF:
3.950%, face amount of $550, due May 15, 2024
550 — 
Total short-term debt550 243 
Long-term debt:
Senior notes of CNAF:
3.950%, face amount of $550, due May 15, 2024
— 549 
4.500%, face amount of $500, due March 1, 2026
500 499 
3.450%, face amount of $500, due August 15, 2027
498 497 
3.900%, face amount of $500, due May 1, 2029
497 497 
2.050%, face amount of $500, due August 15, 2030
496 496 
5.500%, face amount of $500, due June 15, 2033
490 — 
Total long-term debt2,481 2,538 
Total debt$3,031 $2,781 
CCC is a member of the Federal Home Loan Bank of Chicago (FHLBC). FHLBC membership provides participants with access to additional sources of liquidity through various programs and services. As a requirement of membership in the FHLBC, CCC held $5 million of FHLBC stock as of December 31, 2023 giving it immediate access to approximately $106 million of additional liquidity. As of December 31, 2023 and 2022, CCC had no outstanding borrowings from the FHLBC.
During 2023, the Company amended and restated its existing credit agreement with a syndicate of banks. The agreement provides a five-year $250 million senior unsecured revolving credit facility which is intended to be used for general corporate purposes. At the Company's election, the commitments under the agreement may be increased from time to time up to an additional aggregate amount of $100 million, and two one-year extensions are available prior to any anniversary of the closing date, each subject to applicable consents. Under the agreement, the Company is required to pay a facility fee which would adjust in the event of a change in the Company's ratio of consolidated indebtedness to consolidated total capitalization, calculated in accordance with the agreement. The agreement includes several covenants, including maintenance of a minimum consolidated net worth and a specified ratio of consolidated indebtedness to consolidated total capitalization. The minimum consolidated net worth, as defined, at December 31, 2023, was $8.7 billion.  The calculation of minimum consolidated net worth excludes AOCI. As of December 31, 2023 and 2022, the Company had no outstanding borrowings under the credit agreement.
The Company's debt obligations contain customary covenants for investment grade issuers. The Company was in compliance with all covenants as of and for the years ended December 31, 2023 and 2022.
The combined aggregate maturities for debt as of December 31, 2023 are presented in the following table.
(In millions)
2024$550 
2025— 
2026500 
2027500 
2028— 
Thereafter1,500 
Less: discount(19)
Total$3,031 
v3.24.0.1
Benefit Plans
 12 Months Ended
Dec. 31, 2023
Retirement Benefits [Abstract]  
Benefit Plans Benefit Plans
Pension and Postretirement Health Care Benefit Plans
CNA sponsors noncontributory defined benefit pension plans, primarily through the CNA Retirement Plan, covering certain eligible employees. These plans are closed to new entrants. CNA's funding policy for defined benefit pension plans is to make contributions in accordance with applicable governmental regulatory requirements with consideration of the funded status of the plans.
Effective January 1, 2000, the CNA Retirement Plan was closed to new participants. Existing participants at that time were given a choice to either continue to accrue benefits under the CNA Retirement Plan or to cease accruals effective December 31, 1999. Employees who chose to continue to accrue benefits under the plan received benefits in accordance with plan provisions through June 30, 2015 as discussed further below. Participants who elected to cease accruals at December 31, 1999 received the present value of their accrued benefit in an accrued pension account that is credited with interest based on the annual rate of interest on 30-year Treasury securities. These employees also receive certain enhanced employer contributions in the CNA 401k Plan.
Effective June 30, 2015, the Company eliminated future benefit accruals associated with the CNA Retirement Plan. Participants who were continuing to accrue benefits under the CNA Retirement Plan up until that date are entitled to an accrued benefit payable based on their eligible compensation and accrued service through June 30, 2015. These affected participants now also receive enhanced employer contributions in the CNA 401k Plan similar to participants who elected to cease accruals effective December 31, 1999. Employees who elected to cease accruals effective December 31, 1999 were not affected by this curtailment.
In 2023, the CNA Retirement Plan paid $80 million to settle its obligation to certain retirees through the purchase of a group annuity contract from a third party insurance company (group annuity purchase). The group annuity purchase reduced the plan's projected benefit obligation by $86 million.
CNA provides certain postretirement health care benefits to eligible retired employees, their covered dependents and their beneficiaries primarily through the CNA Health and Group Benefits Program. These postretirement benefits have largely been eliminated for active employees.
The following table presents a reconciliation of benefit obligations and plan assets.
Pension BenefitsPostretirement Benefits
(In millions)2023202220232022
Benefit obligation as of January 1$1,931 $2,561 $4 $6 
Changes in benefit obligation:
Interest cost98 67 — — 
Participants' contributions— — 1 2 
Actuarial (gain) loss27 (514)4 — 
Benefits paid(168)(171)(4)(4)
Foreign currency translation and other5 (12)— — 
Settlement through group annuity purchase(86)— — — 
Benefit obligation as of December 311,807 1,931 5 4 
Fair value of plan assets as of January 12,025 2,577 — — 
Change in plan assets:
Actual return on plan assets194 (374)— — 
Company contributions8 7 3 2 
Participants' contributions— — 1 2 
Benefits paid(168)(171)(4)(4)
Foreign currency translation and other5 (14)— — 
Settlement through group annuity purchase(80)— — — 
Fair value of plan assets as of December 311,984 2,025 — — 
Funded status$177 $94 $(5)$(4)
Amounts recognized on the Consolidated Balance Sheets as of December 31:
Other assets$223 $143 $— $— 
Other liabilities(46)(49)(5)(4)
Net amount recognized$177 $94 $(5)$(4)
Amounts recognized in Accumulated other comprehensive income, not yet recognized in net periodic cost (benefit):
Net actuarial (gain) loss$658 $743 $3 $1 
Net amount recognized$658 $743 $3 $1 
The accumulated benefit obligation for all defined benefit pension plans was $1,807 million and $1,931 million as of December 31, 2023 and 2022. Changes for the years ended December 31, 2023 and 2022 include an actuarial loss of $27 million and a gain of $514 million primarily driven by changes in the discount rate used to determine the defined benefit pension obligations.
For pension plans with a benefit obligation in excess of plan assets, the benefit obligation was $46 million and $49 million and the aggregate plan assets were $0 at December 31, 2023 and 2022.
The components of net periodic pension cost (benefit) are presented in the following table.
Years ended December 31
(In millions)202320222021
Net periodic pension cost (benefit)
Interest cost on projected benefit obligation$98 $67 $62 
Expected return on plan assets(119)(152)(154)
Amortization of net actuarial loss (gain) 33 30 46 
Settlement loss— — 1 
Total net periodic pension cost (benefit)$12 $(55)$(45)
The following table indicates the line items in which the non-service cost (benefit) is presented in the Consolidated Statements of Operations.
Years ended December 31
(In millions)202320222021
Non-Service Cost (benefit):
Insurance claims and policyholder's benefits$3 $(15)$(13)
Other operating expenses9 (40)(32)
Total net periodic pension cost (benefit)$12 $(55)$(45)
The amounts recognized in Other comprehensive income are presented in the following table.
Years ended December 31
(In millions)202320222021
Pension and postretirement benefits
Amounts arising during the period$50 $(12)$262 
Settlement— — 1 
Reclassification adjustment relating to prior service credit— — — 
Reclassification adjustment relating to actuarial loss34 30 46 
Total increase (decrease) in Other comprehensive income$84 $18 $309 
    
Actuarial assumptions used for the CNA Retirement Plan and CNA Health and Group Benefits Program to determine benefit obligations are presented in the following table. The interest crediting rate is the weighted average interest rate applied to the individual pension balances for employees who elected to cease accruals effective December 31, 1999.
December 3120232022
Pension benefits
Discount rate5.100 %5.350 %
Interest crediting rate4.500 3.500 
Postretirement benefits
Discount rate5.100 %5.250 %
Actuarial assumptions used for the CNA Retirement Plan and CNA Health and Group Benefits Program to determine net cost or benefit are presented in the following table.
Years ended December 31202320222021
Pension benefits
Discount rate5.350 %2.750 %2.350 %
Expected long-term rate of return6.250 6.250 6.750 
Interest crediting rate3.500 3.000 3.000 
Postretirement benefits
Discount rate5.250 %2.250 %1.600 %
To determine the discount rate assumption as of the year-end measurement date for the CNA Retirement Plan and CNA Health and Group Benefits Program, the Company considered the estimated timing of plan benefit payments and available yields on high quality fixed income debt securities. For this purpose, high quality is considered a rating of Aa or better by Moody's Investors Service, Inc. (Moody's) or a rating of AA or better from Standard & Poor's (S&P). The Company reviewed several yield curves constructed using the cash flow characteristics of the plans as well as bond indices as of the measurement date. The trend of those data points was also considered.
In determining the expected long-term rate of return on plan assets assumption for the CNA Retirement Plan, CNA considered the historical performance of the benefit plan investment portfolio as well as long-term market return expectations based on the investment mix of the portfolio and the expected investment horizon.
The CNA Health and Group Benefits Program has limited its share of the health care trend rate to a cost-of-living adjustment of 4% per year. For all participants, the employer subsidy on health care costs will not increase by more than 4% per year. As a result, the assumed health care cost trend rate used in measuring the accumulated postretirement benefit obligation for the CNA Health and Group Benefits Program was 4% per year in 2023, 2022 and 2021.
CNA employs a total return approach whereby a mix of equity, limited partnerships and fixed maturity securities are used to maximize the long-term return of retirement plan assets for a prudent level of risk and to manage cash flows according to plan requirements. The target allocation of plan assets is 0% to 40% invested in equity securities and limited partnerships, with the remainder primarily invested in fixed maturity securities. Alternative investments, including limited partnerships, are used to enhance risk adjusted long-term returns while improving portfolio diversification. The intent of this strategy is to minimize the Company's expense related to funding the plan by generating investment returns that exceed the growth of the plan liabilities over the long run. Risk tolerance is established after careful consideration of the plan liabilities, plan funded status and corporate financial conditions.
As of December 31, 2023, the Plan had committed approximately $100 million to future capital calls from various third-party limited partnership investments in exchange for an ownership interest in the related partnerships. Derivatives may be used to gain market exposure in an efficient and timely manner. Investment risk is measured and monitored on an ongoing basis through annual liability measurements, periodic asset/liability studies and quarterly investment portfolio reviews.
Pension plan assets measured at fair value on a recurring basis are presented in the following tables.
December 31, 2023
(In millions)Level 1Level 2Level 3Total
Assets
Fixed maturity securities:
Corporate bonds and other$10 $1,041 $6 $1,057 
States, municipalities and political subdivisions— 50 — 50 
Asset-backed— 233 8 241 
Total fixed maturity securities10 1,324 14 1,348 
Equity securities119 6 — 125 
Short-term investments96 — — 96 
Other assets— 15 — 15 
Total assets measured at fair value$225 $1,345 $14 1,584 
Total equity securities measured at net asset value(1)
25 
Total limited partnerships measured at net asset value (1)
375 
Total$1,984 
December 31, 2022
(In millions)Level 1Level 2Level 3Total
Assets
Fixed maturity securities:
Corporate bonds and other$— $859 $7 $866 
States, municipalities and political subdivisions— 49 — 49 
Asset-backed— 157 9 166 
Total fixed maturity securities— 1,065 16 1,081 
Equity securities218 13 — 231 
Short-term investments145 1 — 146 
Other assets— 12 — 12 
Total assets measured at fair value$363 $1,091 $16 1,470 
Total equity securities measured at net asset value (1)
21 
Total limited partnerships measured at net asset value (1)
534 
Total$2,025 
(1) 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 for these investments are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the Plan's Statement of Financial Position.
The limited partnership investments held within the plan are recorded at fair value, which represents the plan's share of net asset value of each partnership, as determined by each limited partnership's general partner. Limited partnerships comprising 94% and 62% of the carrying value as of December 31, 2022 and 2021 were invested in private debt and equity. Limited partnerships comprising 6% and 38% of the carrying value as of December 31, 2023 and 2022 employ hedge fund strategies. Private debt and equity funds cover a broad range of investment strategies including buyout, private credit, growth capital and distressed investing. Hedge fund strategies include both long and short positions in fixed income, equity and derivative investments.
For a discussion of the fair value levels and the valuation methodologies used to measure fixed maturity securities, equities, derivatives and short-term investments, see Note C to the Consolidated Financial Statements.
The table below presents the estimated future minimum benefit payments to participants as of December 31, 2023.
(In millions)Pension BenefitsPostretirement Benefits
2024$164 $1 
2025163 1 
2026161 1 
2027158 — 
2028154 — 
2029-2033692 1 
In 2024, CNA expects to contribute $6 million to its pension plans and $1 million to its postretirement health care benefit plans.
Savings Plans
CNA sponsors savings plans, which are generally contributory plans that allow eligible employees to contribute a maximum of 50% of their eligible compensation, subject to certain limitations prescribed by the IRS. The Company contributes matching amounts to participants amounting to 100% of the first 6% of annual eligible compensation contributed by the employee. In addition, eligible employees also receive a Company contribution of 5% of their annual eligible compensation, referred to as a basic contribution. Company contributions vest ratably over participants first five years of service.
Benefit expense for the Company's savings plans was $82 million, $71 million and $65 million for the years ended December 31, 2023, 2022 and 2021.
v3.24.0.1
Stock-Based Compensation
 12 Months Ended
Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]  
Stock-Based Compensation Stock-Based Compensation
The CNAF Incentive Compensation Plan (the Plan) authorizes the grant of stock-based compensation to certain management personnel for up to 16 million shares of CNAF common stock. The Plan provides for awards of stock options, stock appreciation rights (SARs), restricted shares, restricted stock units (RSUs), performance-based RSUs and performance share units. Grants to employees are not designed to be spring-loaded. The number of remaining shares available for the granting of stock-based compensation under the Plan as of December 31, 2023 was approximately 3.6 million.
Substantially all of the Company's stock-based compensation is awarded under the Annual Performance Share Plan (PSP). The PSP provides officers with an opportunity to earn an award based upon attainment of specific performance goals achieved over a one-year performance period. Awards are granted in the form of performance share units at the beginning of each performance year and are generally subject to a two-year cliff vesting period after the Company’s annual performance has been determined. The performance share units become payable within a range of 0% to 200% of the number of performance share units initially granted.
Additionally, the Company may grant RSUs under the Plan in certain circumstances. These awards generally vest over a one to three-year service period following the grant date.
Stock-based compensation that is not fully vested prior to termination is generally forfeited upon termination, except in cases of retirement, death or disability, and as otherwise provided by contractual obligations. The fair value of stock-based compensation awards is based on the market value of the Company's common stock as of the date of grant, except for awards made to foreign participants, which is based on the current market value of the Company’s common stock. Payments made under the PSP are made entirely in shares of common stock granted under the Plan, except for awards made to foreign participants, which are paid in cash.
The Company recorded stock-based compensation expense related to the Plan of $38 million, $36 million and $32 million for the years ended December 31, 2023, 2022 and 2021. The related income tax benefit recognized was $8 million, $8 million and $6 million for the years ended December 31, 2023, 2022 and 2021. The compensation cost not yet recognized was $44 million, and the weighted average period over which it is expected to be recognized is 1.8 years as of December 31, 2023.
The total fair value of RSUs and performance share units that vested during the years ended December 31, 2023, 2022 and 2021 was $34 million, $35 million and $36 million, respectively.
The weighted average grant date fair value for RSUs and performance share units granted during the years ended December 31, 2023, 2022 and 2021 was $37.06, $46.78 and $45.82, respectively.
The following table presents activity for non-vested RSUs and performance share units under the Plan in 2023.
Number of AwardsWeighted Average Grant Date Fair Value
Balance as of January 1, 20232,465,752 $43.10 
Awards granted1,437,605 37.06 
Awards vested(950,620)38.06 
Awards forfeited, canceled or expired(478,823)42.28 
Performance-based adjustment152,399 36.87 
Balance as of December 31, 20232,626,313 41.40 
v3.24.0.1
Other Intangible Assets
 12 Months Ended
Dec. 31, 2023
Intangible Assets, Gross (Excluding Goodwill) [Abstract]  
Other Intangible Assets Other Intangible Assets
Other intangible assets are presented in the following table.
December 3120232022
(In millions)Economic Useful LifeGross Carrying AmountAccumulated AmortizationGross Carrying AmountAccumulated Amortization
Finite-lived intangible assets:
Distribution channel15 years$10 $8 $10 $7 
Indefinite-lived intangible assets:
Syndicate capacity45 42 
Agency force16 16 
Insurance licenses15 10 
Total indefinite-lived intangible assets76 68 
Total other intangible assets$86 $8 $78 $7 
The Company's other intangible assets primarily relate to the acquisitions of Hardy, Inverin Insurance Company and Bantry Insurance Company. The amortization of the finite-lived intangible assets is included in the Statement of Operations for the International segment. The gross carrying amounts and accumulated amortization in the table above may change from period to period as a result of foreign currency translation.
v3.24.0.1
Leases
 12 Months Ended
Dec. 31, 2023
Leases [Abstract]  
Leases Leases
Total lease expense was $55 million, $59 million and $57 million for the years ended December 31, 2023, 2022 and 2021. Total lease expense includes operating lease expense of $34 million, $36 million and $38 million and variable lease expense of $21 million, $23 million and $19 million for the years ended December 31, 2023, 2022 and 2021. Cash paid for amounts included in operating lease liabilities was $38 million, $42 million and $44 million for the years ended December 31, 2023, 2022 and 2021. Operating lease ROU assets obtained in exchange for lease obligations was $28 million, $20 million and $11 million for the years ended December 31, 2023, 2022 and 2021.
In the fourth quarter of 2023, the Company committed to consolidate some of its offices, which resulted in a $24 million charge within Other operating expense on the Consolidated Statement of Operations, recorded in the Corporate & Other Segment. The charge primarily relates to the abandonment of certain fixed assets and operating lease ROU assets that are no longer in use.
The following table presents operating lease ROU assets and lease liabilities.
(In millions)December 31, 2023December 31, 2022
Operating lease ROU assets$140 $155 
Operating lease liabilities215 220 
The following table presents the maturities of operating lease liabilities.
(In millions)December 31, 2023
2024$36 
202532 
202630
202728 
202825
Thereafter103 
Total lease payments254 
Less: Discount(39)
Total operating lease liabilities$215 
As of December 31, 2023, the Company had $12 million of additional operating lease commitments that have not yet commenced. These leases will commence in 2024 with lease terms ranging from 3 to 10 years.
The following table presents the weighted average remaining lease term for operating leases and weighted average discount rate used in calculating operating lease ROU assets.
December 31, 2023December 31, 2022
Weighted average remaining lease term8.4 years9.2 years
Weighted average discount rate3.7 %3.4 %
v3.24.0.1
Stockholders' Equity and Statutory Accounting Practices
 12 Months Ended
Dec. 31, 2023
Stockholders' Equity and Statutory Accounting Practices [Abstract]  
Stockholders' Equity And Statutory Accounting Practices Stockholders’ Equity and Statutory Accounting Practices
Common Stock Dividends
There are no restrictions on the retained earnings or net income of CNAF with regard to payment of dividends to its stockholders. However, given the holding company nature of CNAF, its ability to pay a dividend is dependent on the receipt of dividends from its subsidiaries, particularly CCC, which directly or indirectly owns the vast majority of all significant subsidiaries. See the Statutory Accounting Practices section below for a discussion of the regulatory restrictions on CCC's availability to pay dividends.
CNAF's ability to pay dividends may be indirectly limited by the minimum consolidated net worth covenant in the Company's line of credit agreement. See Note I to the Consolidated Financial Statements for further discussion of the Company's debt obligations.
Statutory Accounting Practices
CNAF’s insurance subsidiaries are domiciled in various jurisdictions. These subsidiaries prepare statutory financial statements in accordance with accounting practices prescribed or permitted by the respective jurisdictions’ insurance regulators. Domestic prescribed statutory accounting practices are set forth in a variety of publications of the National Association of Insurance Commissioners (NAIC) as well as state laws, regulations and general administrative rules. These statutory accounting principles vary in certain respects from GAAP. In converting from statutory accounting principles to GAAP, the more significant adjustments include deferral of policy acquisition costs and the inclusion of net unrealized holding gains or losses in stockholders’ equity relating to certain fixed maturity securities.
The Company has a prescribed practice as it relates to the accounting under Statement of Statutory Accounting Principles No. 62R, Property and Casualty Reinsurance, paragraphs 87 and 88 in conjunction with the 2010 LPT with NICO which is further discussed in Note E to the Consolidated Financial Statements.  The prescribed practice allows the Company to aggregate all third-party A&EP reinsurance balances administered by NICO in Schedule F and to utilize the LPT as collateral for the underlying third-party reinsurance balances for purposes of calculating the statutory reinsurance penalty. This prescribed practice increased statutory capital and surplus by $92 million and $74 million at December 31, 2023 and 2022.
The payment of dividends by CNAF's insurance subsidiaries without prior approval of the insurance department of each subsidiary’s domiciliary jurisdiction is generally limited by formula. Dividends in excess of these amounts are subject to prior approval by the respective insurance regulator.
Dividends from CCC are subject to the insurance holding company laws of the State of Illinois, the domiciliary state of CCC. Under these laws, ordinary dividends, or dividends that do not require prior approval by the Illinois Department of Insurance (the Department), are determined based on the greater of the prior year's statutory net income or 10% of statutory surplus as of the end of the prior year, as well as the timing and amount of dividends paid in the preceding twelve months. Additionally, ordinary dividends may only be paid from earned surplus, which is calculated by removing unrealized gains from unassigned surplus. As of December 31, 2023, CCC is in a positive earned surplus position. The maximum allowable dividend CCC could pay during 2024 that would not be subject to the Department’s prior approval is $1,105 million, less dividends paid during the preceding twelve months measured at that point in time. CCC paid dividends of $1,055 million in 2023. The actual level of dividends paid in any year is determined after an assessment of available dividend capacity, holding company liquidity and cash needs as well as the impact the dividends will have on the statutory surplus of the applicable insurance company.
Combined statutory capital and surplus and statutory net income (loss) for the Combined Continental Casualty Companies are presented in the table below, determined in accordance with accounting practices prescribed or permitted by insurance and/or other regulatory authorities.
Statutory Capital and SurplusStatutory Net Income (Loss)
December 31Years ended December 31
(In millions)
2023 (1)
2022
2023 (1)
20222021
Combined Continental Casualty Companies$10,946 $10,572 $1,172 $1,072 $1,253 
(1) Information derived from the statutory-basis financial statements to be filed with insurance regulators.
CNAF’s domestic insurance subsidiaries are subject to risk-based capital (RBC) requirements. RBC is a method developed by the NAIC to determine the minimum amount of statutory capital appropriate for an insurance company to support its overall business operations in consideration of its size and risk profile. The formula for determining the amount of RBC specifies various factors, weighted based on the perceived degree of risk, which are applied to certain financial balances and financial activity. The adequacy of a company's actual capital is evaluated by a comparison to the RBC results, as determined by the formula. Companies below minimum RBC requirements are classified within certain levels, each of which requires specified corrective action.
The statutory capital and surplus presented above for CCC was approximately 225% and 238% of company action level RBC as of December 31, 2023 and 2022. Company action level RBC is the level of RBC which triggers a heightened level of regulatory supervision. The statutory capital and surplus of the Company's foreign insurance subsidiaries, which is not significant to the overall statutory capital and surplus, also met or exceeded their respective regulatory and other capital requirements.
v3.24.0.1
Accumulated Other Comprehensive Income (Loss) by Component
 12 Months Ended
Dec. 31, 2023
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]  
Accumulated Other Comprehensive Income (Loss) by Component Accumulated Other Comprehensive Income (Loss) by Component
The tables below display the changes in Accumulated other comprehensive income (loss) by component.
(In millions)Net unrealized gains (losses) on investments with an allowance for credit losses
Net unrealized gains (losses) on other investments(1)
Pension and postretirement benefits
Cumulative impact of changes in discount rates used to measure long duration contracts(1)
Cumulative foreign currency translation adjustmentTotal
Balance as of January 1, 2023, as previously reported$(7)$(2,738)$(591)$— $(221)$(3,557)
Cumulative effect adjustment from accounting change for adoption of ASU 2018-12(1) net of tax (expense) benefit of $—, $—, $—, $11, $— and $11
— — — (41)— (41)
Balance as of January 1, 2023(7)(2,738)(591)(41)(221)(3,598)
Other comprehensive income (loss) before reclassifications(24)1,072 39 (318)58 827 
Amounts reclassified from accumulated other comprehensive income (loss) net of tax (expense) benefit of $5, $14, $7, $—, $— and $26
(19)(53)(27)— — (99)
Other comprehensive income (loss) net of tax (expense) benefit of $1, $(304), $(17), $85, $— and $(235)
(5)1,125 66 (318)58 926 
Balance as of December 31, 2023$(12)$(1,613)$(525)$(359)$(163)$(2,672)
(In millions)Net unrealized gains (losses) on investments with an allowance for credit losses
Net unrealized gains (losses) on other investments(1)
Pension and postretirement benefits
Cumulative impact of changes in discount rates used to measure long duration contracts(1)
Cumulative foreign currency translation adjustmentTotal
Balance as of January 1, 2022, as previously reported$(2)$1,039 $(604)$— $(113)$320 
Cumulative effect adjustment from accounting change for adoption of ASU 2018-12(1) net of tax (expense) benefit of $—, $(617), $—, $1,063, $— and $446
— 2,320 — (4,000)— (1,680)
Balance as of January 1, 2022, as adjusted(2)3,359 (604)(4,000)(113)(1,360)
Other comprehensive income (loss) before reclassifications— (6,223)(11)3,959 (108)(2,383)
Amounts reclassified from accumulated other comprehensive income (loss) net of tax (expense) benefit of $(1), $21, $6, $—, $— and $26
5 (126)(24)— — (145)
Other comprehensive income (loss) net of tax (expense) benefit of $1, $1,622, $(3), $(1,052), $— and $568
(5)(6,097)13 3,959 (108)(2,238)
Balance as of December 31, 2022$(7)$(2,738)$(591)$(41)$(221)$(3,598)
(In millions)Net unrealized gains (losses) on investments with an allowance for credit losses
Net unrealized gains (losses) on other investments(1)
Pension and postretirement benefits
Cumulative impact of changes in discount rates used to measure long duration contracts(1)
Cumulative foreign currency translation adjustmentTotal
Balance as of January 1, 2021, as previously reported$— $1,745 $(848)$— $(94)$803 
Cumulative effect adjustment from accounting change for adoption of ASU 2018-12(1) net of tax (expense) benefit of $—, $(691), $—, $1,313, $— and $622
— 2,601 — (4,941)— (2,340)
Balance as of January 1, 2021, as adjusted— 4,346 (848)(4,941)(94)(1,537)
Other comprehensive income (loss) before reclassifications(7)(906)207 941 (19)216 
Amounts reclassified from accumulated other comprehensive income (loss) net of tax (expense) benefit of $1, $(21), $10, $—, $— and $(10)
(5)81 (37)— — 39 
Other comprehensive income (loss) net of tax (expense) benefit of $1, $263, $(65), $(250), $— and $(51)
(2)(987)244 941 (19)177 
Balance as of December 31, 2021$(2)$3,359 $(604)$(4,000)$(113)$(1,360)
1) See Note A to the Consolidated Financial Statements for additional information.
Amounts reclassified from Accumulated other comprehensive income (loss) shown above are reported in Net income (loss) as follows:
Component of AOCIConsolidated Statements of Operations Line Item Affected by Reclassifications
Net unrealized gains (losses) on investments with an allowance for credit losses and Net unrealized gains (losses) on other investmentsNet investment gains (losses)
Pension and postretirement benefitsOther operating expenses and Insurance claims and policyholders' benefits
v3.24.0.1
Business Segments
 12 Months Ended
Dec. 31, 2023
Segment Reporting [Abstract]  
Business Segments Business Segments
The Company's property and casualty commercial insurance operations are managed and reported in three business segments: Specialty, Commercial and International. These three segments are collectively referred to as Property & Casualty Operations. Specialty provides management and professional liability and other coverages through property and casualty products and services using a network of brokers, independent agencies and managing general underwriters. Commercial works with a network of brokers and independent agents to market a broad range of property and casualty insurance products to all types of insureds targeting small business, construction, middle markets and other commercial customers. The International segment underwrites property and casualty coverages on a global basis through a branch operation in Canada, a European business consisting of insurance companies based in the U.K. and Luxembourg and Hardy, the Company's Lloyd's syndicate.
The Company's operations outside of Property & Casualty Operations are managed and reported in two segments: Life & Group and Corporate & Other. Life & Group primarily includes the results of the long-term care business that is in run-off. Corporate & Other primarily includes certain corporate expenses, including interest on corporate debt and the results of certain property and casualty business in run-off, including CNA Re, A&EP, a legacy portfolio of EWC policies and certain legacy mass tort reserves.
The accounting policies of the segments are the same as those described in Note A to the Consolidated Financial Statements. The Company manages most of its assets on a legal entity basis, while segment operations are generally conducted across legal entities. As such, only Insurance and Reinsurance receivables, Insurance reserves, Deferred acquisition costs, Goodwill and Deferred non-insurance warranty acquisition expense and revenue are readily identifiable for individual segments. Distinct investment portfolios are not maintained for every individual segment; accordingly, allocation of assets to each segment is not performed. Therefore, a significant portion of Net investment income and Net investment gains or losses are allocated primarily based on each segment's net carried insurance reserves, as adjusted. All significant intersegment income and expense have been eliminated. Income taxes have been allocated on the basis of the taxable income of the segments.
Approximately 11%, 10% and 10% of the Company's direct written premiums were derived from outside the United States for the years ended December 31, 2023, 2022 and 2021.
In the following tables, certain financial measures are presented to provide information used by management to monitor the Company's operating performance. Management utilizes these financial measures to monitor the Company's insurance operations and investment portfolio.
The performance of the Company's insurance operations is monitored by management through core income (loss), which is derived from certain income statement amounts. The Company's investment portfolio is monitored by management through analysis of various factors including unrealized gains and losses on securities, portfolio duration and exposure to market and credit risk.
Core income (loss) is calculated by excluding from net income (loss) the after-tax effects of net investment gains or losses. The calculation of core income (loss) excludes net investment gains or losses because net investment gains or losses are generally driven by economic factors that are not necessarily reflective of our primary operations.
The Company's results of operations and selected balance sheet items by segment are presented in the following tables.
Year ended December 31, 2023
Specialty
Commercial		InternationalLife &
Group		Corporate
& Other		  
(In millions)EliminationsTotal
Net written premiums$3,329 $4,880 $1,237 $447 $— $(1)$9,892 
Operating revenues 
Net earned premiums$3,307 $4,547 $1,176 $451 $— $(1)$9,480 
Net investment income558 645 103 896 62 — 2,264 
Non-insurance warranty revenue1,624 — — — — — 1,624 
Other revenues1 29 — (1)11 (10)30 
Total operating revenues5,490 5,221 1,279 1,346 73 (11)13,398 
Claims, benefits and expenses      
Net incurred claims and benefits1,923 2,995 722 1,317 82 — 7,039 
Policyholders’ dividends8 21 — — — — 29 
Amortization of deferred acquisition costs686 729 229 — — — 1,644 
Non-insurance warranty expense1,544 — — — — — 1,544 
Other insurance related expenses373 620 139 118 2 (1)1,251 
Other expenses53 30 (4)1 204 (10)274 
Total claims, benefits and expenses4,587 4,395 1,086 1,436 288 (11)11,781 
Core income (loss) before income tax903 826 193 (90)(215)— 1,617 
Income tax (expense) benefit on core income (loss)(195)(174)(48)42 42 — (333)
Core income (loss) $708 $652 $145 $(48)$(173)$— 1,284 
Net investment gains (losses)(99)
Income tax (expense) benefit on net investment gains (losses)20 
Net investment gains (losses), after tax(79)
Net income (loss)$1,205 
December 31, 2023
(In millions)      
Reinsurance receivables$1,281 $1,218 $468 $93 $2,374 $— $5,434 
Insurance receivables1,053 2,024 388 5 — — 3,470 
Deferred acquisition costs392 371 133 — — — 896 
Goodwill117 — 29 — — — 146 
Deferred non-insurance warranty acquisition expense3,661 — — — — — 3,661 
Insurance reserves 
Claim and claim adjustment expenses7,131 10,103 2,709 675 2,686 — 23,304 
Unearned premiums3,227 2,858 749 99 — — 6,933 
Future policy benefits— — — 13,959 — — 13,959 
Deferred non-insurance warranty revenue4,694 — — — — — 4,694 
Year ended December 31, 2022
Specialty
Commercial		International
Life &
Group (1)
Corporate
& Other		  
(In millions)Eliminations
Total (1)
Net written premiums$3,306 $4,193 $1,164 $467 $(1)$(1)$9,128 
Operating revenues 
Net earned premiums$3,203 $3,923 $1,070 $473 $(1)$(1)$8,667 
Net investment income431 488 63 804 19 — 1,805 
Non-insurance warranty revenue1,574 — — — — — 1,574 
Other revenues1 30 1 (1)6 (5)32 
Total operating revenues5,209 4,441 1,134 1,276 24 (6)12,078 
Claims, benefits and expenses    
Net incurred claims and benefits1,839 2,607 637 1,469 76 — 6,628 
Policyholders’ dividends6 19 — — — — 25 
Amortization of deferred acquisition costs656 634 200 — — — 1,490 
Non-insurance warranty expense1,471 — — — — — 1,471 
Other insurance related expenses336 557 146 118 4 (1)1,160 
Other expenses51 36 26 9 174 (5)291 
Total claims, benefits and expenses4,359 3,853 1,009 1,596 254 (6)11,065 
Core income (loss) before income tax850 588 125 (320)(230)— 1,013 
Income tax (expense) benefit on core income (loss)(182)(122)(19)99 47 — (177)
Core income (loss)$668 $466 $106 $(221)$(183)$— 836 
Net investment gains (losses)(199)
Income tax (expense) benefit on net investment gains (losses)45 
Net investment gains (losses), after tax(154)
Net income (loss)$682 
December 31, 2022
(In millions)
Reinsurance receivables$1,384 $1,062 $414 $101 $2,477 $— $5,438 
Insurance receivables1,082 1,728 369 8 — — 3,187 
Deferred acquisition costs381 321 104 — — — 806 
Goodwill117 — 27 — — — 144 
Deferred non-insurance warranty acquisition expense3,671 — — — — — 3,671 
Insurance reserves 
Claim and claim adjustment expenses6,878 9,395 2,403 695 2,749 — 22,120 
Unearned premiums3,193 2,425 653 103 — — 6,374 
Future policy benefits— — — 13,480 — — 13,480 
Deferred non-insurance warranty revenue4,714 — — — — — 4,714 
(1) As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
Year ended December 31, 2021
Specialty
Commercial
Life &
Group (1)
Corporate
& Other
(In millions)InternationalEliminations
Total (1)
Net written premiums$3,225 $3,595 $1,101 $485 $— $(1)$8,405 
Operating revenues 
Net earned premiums$3,076 $3,552 $1,057 $491 $— $(1)$8,175 
Net investment income497 624 57 966 15 — 2,159 
Non-insurance warranty revenue1,430 — — — — — 1,430 
Other revenues1 23 — — 6 (6)24 
Total operating revenues5,004 4,199 1,114 1,457 21 (7)11,788 
Claims, benefits and expenses     
Net incurred claims and benefits1,787 2,540 652 1,261 109 — 6,349 
Policyholders’ dividends3 19 — — — — 22 
Amortization of deferred acquisition costs643 594 206 — — — 1,443 
Non-insurance warranty expense1,328 — — — — — 1,328 
Other insurance related expenses296 511 144 103 9 (1)1,062 
Other expenses47 38 (2)10 155 (6)242 
Total claims, benefits and expenses4,104 3,702 1,000 1,374 273 (7)10,446 
Core income (loss) before income tax900 497 114 83 (252)— 1,342 
Income tax (expense) benefit on core income (loss)(196)(103)(28)25 48 — (254)
Core income (loss)$704 $394 $86 $108 $(204)$— 1,088 
Net investment gains (losses)120 
Income tax (expense) benefit on net investment gains (losses)(24)
Net investment gains (losses), after tax96 
Net income (loss)$1,184 
Year ended December 31, 2021
(In millions)
Reinsurance receivables$1,200 $923 $381 $401 $2,579 $— $5,484 
Insurance receivables1,136 1,488 340 6 4 — 2,974 
Deferred acquisition costs363 278 96 — — — 737 
Goodwill117 — 31 — — — 148 
Deferred non-insurance warranty acquisition expense3,476 — — — — — 3,476 
Insurance reserves 
Claim and claim adjustment expenses6,433 8,890 2,280 848 2,817 — 21,268 
Unearned premiums3,001 2,066 585 109 — — 5,761 
Future policy benefits— — — 18,298 — — 18,298 
Deferred non-insurance warranty revenue4,503 — — — — — 4,503 
(1) As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
The following table presents operating revenues by line of business for each reportable segment.
Years ended December 31
(In millions)202320222021
Specialty
Management & Professional Liability$2,931 $2,771 $2,776 
Surety731 652 604 
Warranty & Alternative Risks1,828 1,786 1,624 
Specialty revenues5,490 5,209 5,004 
Commercial
Middle Market1,696 1,532 1,508 
Construction1,678 1,421 1,322 
Small Business631 581 558 
Other Commercial1,216 907 811 
Commercial revenues5,221 4,441 4,199 
International
Canada383 366 344 
Europe532 466 473 
Hardy364 302 297 
International revenues1,279 1,134 1,114 
Life & Group revenues1,346 1,276 1,457 
Corporate & Other revenues 73 24 21 
Eliminations(11)(6)(7)
Total operating revenues13,398 12,078 11,788 
Net investment gains (losses)(99)(199)120 
Total revenues$13,299 $11,879 $11,908 
v3.24.0.1
Quarterly Financial Data (Unaudited)
 12 Months Ended
Dec. 31, 2023
Quarterly Financial Data [Abstract]  
Quarterly Financial Data (Unaudited) Quarterly Financial Data (Unaudited)
The following table presents the effect of adoption of ASU 2018-12 on selected 2022 financial data.
2022
(In millions, except per share data)Q1Q2Q3Q4Full Year
Components of Income (Loss)
Core income (loss)
Prior to adoption$316 $245 $213 $274 $1,048 
Effect of adoption(18)(15)(170)(9)(212)
As reported$298 $230 $43 $265 $836 
Net income (loss)
Prior to adoption$313 $205 $128 $248 $894 
Effect of adoption(18)(15)(170)(9)(212)
As reported$295 $190 $(42)$239 $682 
Other comprehensive income (loss), net of tax
Prior to adoption$(1,623)$(1,410)$(1,426)$582 $(3,877)
Effect of adoption603 627 586 (177)1,639 
As reported$(1,020)$(783)$(840)$405 $(2,238)
Diluted Earnings (Loss) Per Common Share
Core income (loss)
Prior to adoption$1.16 $0.90 $0.78 $1.01 
Effect of adoption(0.07)(0.06)(0.62)(0.04)
As reported$1.09 $0.84 $0.16 $0.97 
Net income (loss)
Prior to adoption$1.15 $0.75 $0.47 $0.91 
Effect of adoption(0.07)(0.06)(0.62)(0.04)
As reported$1.08 $0.69 $(0.15)$0.87 
As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
Core income (loss) and Net income (loss) for 2022 decreased from what was previously reported under legacy accounting guidance generally driven by the cumulative effect of assumption differences and differences in reserving methodologies between legacy and new accounting guidance.
Core income (loss) and Net income (loss) for the third quarter of 2022 decreased $170 million from what was previously reported under legacy accounting guidance, primarily related to the third quarter 2022 annual review of cash flow reserving assumptions. Under legacy accounting guidance, the third quarter 2022 gross premium valuation assessment indicated a pretax margin of $125 million and no unlocking event occurred. Under the new guidance favorable changes to the upper-medium grade fixed income instrument discount rate were recorded through Accumulated other comprehensive income quarterly, while the net unfavorable impact of increased cost of care inflation offset by favorable premium rate action assumptions was recorded in income.
Other comprehensive income (loss), net of tax, for 2022 decreased from what was previously reported under legacy accounting guidance driven by increases in the upper-medium grade fixed-income instrument yield, which was used as the discount rate to re-measure the LFPB.
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Related Party Transactions
 12 Months Ended
Dec. 31, 2023
Related Party Transactions [Abstract]  
Related Party Transactions Related Party TransactionsThe Company reimburses Loews for, or pays directly, fees and expenses of investment facilities and services provided to the Company. Additionally, the Company provides investment-related processing services to Loews and charges Loews for these services. The net amounts incurred by the Company for these fees, expenses and services were $55 million, $51 million and $47 million for the years ended December 31, 2023, 2022 and 2021. Net amounts due to Loews related to these services, included in Other liabilities and payable in the first quarter of the subsequent year, were $28 million and $26 million as of December 31, 2023 and 2022. In addition, the Company reimbursed Loews for general corporate services and related travel expenses of $1 million for the years ended December 31, 2023 and 2022. The CNA Tax Group is included in the consolidated federal income tax return of Loews and its eligible subsidiaries. The related receivable from Loews, included in Other assets, was $23 million and $18 million for the years ended December 31, 2023 and 2022. For a detailed description of the income tax agreement with Loews see Note D to the Consolidated Financial Statements. In 2021, the Company wrote an appeal bond for Loews at standard rates, which was increased in 2022, resulting in additional premium from Loews. The aforementioned appeal bond expired in December 2022. In addition, the Company writes, at standard rates, a limited amount of insurance for Loews and its subsidiaries. The earned premiums for each of the years ended December 31, 2023, 2022 and 2021 were $2 million, $3 million, and $2 million.
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Non-Insurance Revenues from Contracts with Customers
 12 Months Ended
Dec. 31, 2023
Revenue from Contract with Customer [Abstract]  
Non-Insurance Revenues from Contracts with Customers Non-Insurance Revenues from Contracts with Customers
Non-Insurance revenue is recognized when obligations under the terms of a contract with a customer are satisfied; generally this occurs over time as obligations are fulfilled. Revenue is measured as the amount of consideration the Company expects to receive in exchange for providing services.
Deferred Non-Insurance Warranty Revenue
The Company had a deferred non-insurance warranty revenue balance of $4.7 billion reported in Deferred non-insurance warranty revenue as of December 31, 2023 and 2022. For the year ended December 31, 2023, the Company recognized $1.4 billion of revenues that were included in the deferred revenue balance as of January 1, 2023. For the year ended December 31, 2022, the Company recognized $1.3 billion of revenues that were included in the deferred revenue balance as of January 1, 2022. For the years ended December 31, 2023 and 2022, Non-insurance warranty revenue recognized from performance obligations related to prior periods due to a change in estimate was not material. The Company expects to recognize approximately $1.4 billion of the deferred revenue in 2024, $1.1 billion in 2025, $0.8 billion in 2026 and $1.4 billion thereafter.
Cost to Obtain and Fulfill Non-Insurance Warranty Contracts with Customers
For each of the years ended December 31, 2023 and 2022, capitalized commission costs were $3.6 billion and capitalized administrator service costs were $62 million and $53 million. For each the years ended December 31, 2023 and 2022, the amount of amortization of capitalized costs was $1.2 billion and there were no impairment losses related to the costs capitalized. There were no adjustments to deferred costs recorded for the years ended December 31, 2023 and 2022.
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Schedule I. Summary of Investments - Other Than Investments in Related Parties
 12 Months Ended
Dec. 31, 2023
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Abstract]  
Schedule I. Summary of Investments - Other than Investments in Related Parties
SCHEDULE I. SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES
Incorporated herein by reference to Note B to the Consolidated Financial Statements included under Item 8.
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Schedule II. Condensed Financial Information of Registrant (Parent Company)
 12 Months Ended
Dec. 31, 2023
Condensed Financial Information Disclosure [Abstract]  
Schedule II. Condensed Financial Information of Registrant (Parent Company)
SCHEDULE II. CONDENSED FINANCIAL INFORMATION OF REGISTRANT (PARENT COMPANY)
CNA Financial Corporation
Statements of Operations and Comprehensive Income
Years ended December 31
(In millions)2023
2022 (1)
2021 (1)
Revenues
Net investment income$41 $8 $— 
Total revenues41 8 — 
Expenses
Administrative and general2 1 1 
Interest126 112 112 
Total expenses128 113 113 
Loss from operations before income taxes and equity in net income of subsidiaries(87)(105)(113)
Income tax benefit4 6 11 
Loss before equity in net income of subsidiaries(83)(99)(102)
Equity in net income of subsidiaries1,288 781 1,286 
Net income1,205 682 1,184 
Equity in other comprehensive income (loss) of subsidiaries926 (2,238)177 
Total comprehensive income (loss)$2,131 $(1,556)$1,361 
(1) As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
See accompanying Notes to Condensed Financial Information as well as the
Consolidated Financial Statements and accompanying Notes.
CNA Financial Corporation
Balance Sheets
December 31
(In millions, except share data)2023
2022 (1)
Assets
Investment in subsidiaries$11,948 $10,786 
Cash1 2 
Short-term investments1,009 578 
Amounts due from affiliates4 4 
Other assets1 — 
Total assets$12,963 $11,370 
Liabilities
Short-term debt$550 $243 
Long-term debt2,481 2,538 
Other liabilities39 41 
Total liabilities3,070 2,822 
Stockholders' Equity
Common stock ($2.50 par value; 500,000,000 shares authorized; 273,040,243 shares issued; 270,881,457 and 270,895,902 shares outstanding)
683 683 
Additional paid-in capital2,221 2,220 
Retained earnings9,755 9,336 
Accumulated other comprehensive loss(2,672)(3,598)
Treasury stock (2,158,786 and 2,144,341 shares), at cost
(94)(93)
Total stockholders' equity9,893 8,548 
Total liabilities and stockholders' equity$12,963 $11,370 
(1) As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
See accompanying Notes to Condensed Financial Information as well as the
Consolidated Financial Statements and accompanying Notes.
CNA Financial Corporation
Statements of Cash Flows
Years ended December 31
(In millions)2023
2022 (1)
2021 (1)
Cash Flows from Operating Activities
Net income$1,205 $682 $1,184 
Adjustments to reconcile net income to net cash flows provided by operating activities:
Equity in net income of subsidiaries(1,288)(781)(1,286)
Dividends received from subsidiaries1,055 990 880 
Other, net2 28 33 
Net cash flows provided by operating activities974 919 811 
Cash Flows from Investing Activities
Change in short-term investments(395)114 (163)
Capital contributions to subsidiaries(3)— — 
Net cash flows (used) provided by investing activities(398)114 (163)
Cash Flows from Financing Activities
Dividends paid to common stockholders(787)(982)(621)
Proceeds from the issuance of debt491 — — 
Repayment of debt(243)— — 
Purchase of treasury stock(24)(39)(18)
Other, net(14)(11)(8)
Net cash flows used by financing activities(577)(1,032)(647)
Net change in cash(1)1 1 
Cash, beginning of year2 1 — 
Cash, end of year$1 $2 $1 
(1)    As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.

See accompanying Notes to Condensed Financial Information as well as the
Consolidated Financial Statements and accompanying Notes.
Notes to Condensed Financial Information
A. Summary of Significant Accounting Policies
Basis of Presentation
The condensed financial information of CNA Financial Corporation (CNAF or the Parent Company) should be read in conjunction with the Consolidated Financial Statements and Notes thereto included in Item 8 of this Form 10-K. CNAF’s subsidiaries are accounted for using the equity method of accounting. Equity in net income of these subsidiaries is presented on the Condensed Statements of Operations as Equity in net income of subsidiaries. Loews owned approximately 92% of the outstanding common stock of CNAF as of December 31, 2023.
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Schedule III. Supplementary Insurance Information
 12 Months Ended
Dec. 31, 2023
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Abstract]  
Schedule III. Supplementary Insurance Information
SCHEDULE III. SUPPLEMENTARY INSURANCE INFORMATION
Incorporated herein by reference to Note P to the Consolidated Financial Statements included under Item 8.
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Schedule IV. Reinsurance
 12 Months Ended
Dec. 31, 2023
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract]  
Schedule IV. Reinsurance
SCHEDULE IV. REINSURANCE
Incorporated herein by reference to Note H to the Consolidated Financial Statements included under Item 8.
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Schedule V. Valuation and Qualifying Accounts
 12 Months Ended
Dec. 31, 2023
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]  
Schedule V. Valuation and Qualifying Accounts
SCHEDULE V. VALUATION AND QUALIFYING ACCOUNTS
(In millions)Balance at Beginning of PeriodCharged to Costs and ExpensesCharged to Other AccountsDeductionsBalance at End of Period
Year ended December 31, 2023
Allowance for uncollectible:
Mortgage loan receivables
$24 $— $11 $— $35 
Insurance and reinsurance receivables$51 $11 $— $(12)$50 
Allowance for credit losses:
Fixed maturity securities
$1 $— $44 $(29)$16 
Year ended December 31, 2022
Allowance for uncollectible:
Mortgage loan receivables
$16 $— $8 $— $24 
Insurance and reinsurance receivables$50 $8 $— $(7)$51 
Allowance for credit losses:
Fixed maturity securities
$18 $— $4 $(21)$1 
Year ended December 31, 2021
Allowance for uncollectible:
Mortgage loan receivables
$26 $— $(10)$— $16 
Insurance and reinsurance receivables$54 $4 $— $(8)$50 
Allowance for credit losses:
Fixed maturity securities
$40 $— $30 $(52)$18 
Effects of foreign currency translation, changes in the estimate of the allowance for uncollectible mortgage loan receivables, increases in the estimate of the allowance for credit losses on fixed maturity securities and allowances established with respect to assets purchased with credit deterioration are presented within the Charged to Other Accounts column in the table above. Write-offs of uncollectible amounts and reductions to the allowance for credit losses due to securities sold during the period or the reversal for securities that had an allowance recorded in a previous period are presented within the Deductions column in the table above.
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Schedule VI. Supplemental Information Concerning Property and Casualty Insurance Operations
 12 Months Ended
Dec. 31, 2023
SEC Schedule, 12-18, Supplemental Information, Property-Casualty Insurance Underwriters [Abstract]  
Schedule VI. Supplemental Information Concerning Property and Casualty Insurance Operations
SCHEDULE VI. SUPPLEMENTAL INFORMATION CONCERNING PROPERTY AND CASUALTY INSURANCE OPERATIONS
As of and for the years ended December 31Consolidated Property and Casualty Operations
(In millions)2023
2022 (1)
2021 (1)
Balance Sheet Data
Deferred acquisition costs$896 $806 
Reserves for unpaid claim and claim adjustment expenses23,304 22,120 
Discount deducted from claim and claim adjustment expense reserves above (based on interest rates ranging from 3.5% to 6.4%)
647 683 
Unearned premiums6,933 6,374 
Statement of Operations Data
Net written premiums$9,892 $9,128 $8,405 
Net earned premiums9,480 8,667 8,175 
Net investment income2,163 1,751 2,111 
Incurred claim and claim adjustment expenses related to current year5,667 5,181 5,021 
Incurred claim and claim adjustment expenses related to prior years48 (32)15 
Amortization of deferred acquisition costs1,644 1,490 1,443 
Paid claim and claim adjustment expenses4,601 4,302 3,949 
(1) As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Summary of Significant Accounting Policies (Policies)
 12 Months Ended
Dec. 31, 2023
Accounting Policies [Abstract]  
Basis of Presentation
The Consolidated Financial Statements include the accounts of CNA Financial Corporation (CNAF) and its subsidiaries. Collectively, CNAF and its subsidiaries are referred to as CNA or the Company. Loews Corporation (Loews) owned approximately 92% of the outstanding common stock of CNAF as of December 31, 2023.
The accompanying Consolidated Financial Statements have been prepared in conformity with accounting principles generally accepted in the United States of America (GAAP). Intercompany amounts have been eliminated.
Use of Estimates The preparation of Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the Consolidated Financial Statements and the reported amounts of revenues and expenses during the reporting period. Actual results may differ from those estimates.
Recently Adopted Accounting Standards Updates and Accounting Standards Pending Adoption
ASU 2018-12: In August 2018, the Financial Accounting Standards Board (FASB) issued ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12; LDTI), which requires changes to the measurement and disclosure of long-duration contracts. Entities are required to review, and update if there is a change, cash flow assumptions (including morbidity and persistency) used to measure the liability for future policyholder benefits (LFPB) at least annually. The LFPB must also be updated for actual experience at least annually. The LFPB is reflected as Insurance reserves: Future policy benefits on the Consolidated Balance Sheet. The discount rate assumption used to measure the LFPB must be updated quarterly using an upper-medium grade (low credit risk) fixed-income instrument yield, commonly interpreted as a single-A rate. The effect of changes in cash flow assumptions and actual variances from expected experience are recorded in the Company's results of operations within Insurance claims and policyholders' benefits. The effect of changes in discount rate assumptions are recorded in Other comprehensive income (loss). In contrast, under legacy accounting guidance, cash flow and discount rate assumptions were locked-in unless a premium deficiency emerged. The discount rate assumption under legacy accounting guidance was determined using the Company’s internal investment portfolio yield, which was generally higher than a single-A yield.
The new guidance eliminates the need to hold shadow reserves associated with the Company’s long-term care reserves. Under legacy accounting guidance, to the extent that unrealized gains on fixed maturity securities supporting long-term care reserves would have resulted in a premium deficiency if realized, a related increase to Insurance reserves was recorded, net of tax, as a reduction of net unrealized gains (losses), through Other comprehensive income (loss) (shadow reserves).
The unit of account is the level at which reserves are measured. Under the new guidance, the unit of account used to measure the LFPB is the cohort. Cohorts are comprised of insurance contracts issued no more than one year apart, and must be further disaggregated according to policy benefit and insurance risk characteristics. Under legacy accounting guidance, the LFPB was generally measured at the individual policy level.
Under the new guidance, the Net Premium Ratio (NPR) is capped at 100%. To the extent that NPR would otherwise exceed 100%, the LFPB is increased and a loss is recognized immediately in the Company’s results of operations. The NPR cap is applied at the cohort level each quarter when the NPR is updated. In contrast, under legacy accounting guidance, premium deficiency testing was performed annually at the product level. See Note F to the Consolidated Financial Statements for further explanation of the NPR and LFPB calculations.
The Company adopted the new guidance effective January 1, 2023, using the modified retrospective method applied as of the transition date of January 1, 2021. The Company's run-off long-term care business is in scope of the new guidance. All prior periods presented in the financial statements have been adjusted to reflect application of the new guidance. The Company’s original locked in discount rate, utilized for purposes of
calculating the NPR under the new guidance, was based on the discount rate assumption used to calculate the LFPB immediately prior to the transition date. While the requirements of the new guidance represent a material change from legacy accounting, the new guidance does not impact capital and surplus under statutory accounting practices, cash flows or the underlying economics of the business.
In December 2022, the FASB issued ASU 2022-05, Financial Services-Insurance (Topic 944): Transition for Sold Contracts (ASU 2022-05). This guidance permits companies to make an election to exclude from the scope of ASU 2018-12 any insurance contracts that have been de-recognized prior to the effective date of ASU 2018-12, assuming that the company has no significant continuing involvement with the de-recognized contracts. In the fourth quarter of 2022, the Company novated its block of legacy annuity business, which was fully-ceded prior to novation. The Company has elected the ASU 2022-05 transition relief, and has excluded the novated legacy annuity business from the scope of ASU 2018-12.
In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. The updated accounting guidance requires expanded reportable segment disclosures, primarily related to significant segment expenses which are regularly provided to the company’s Chief Operating Decision Maker. The guidance is effective for fiscal years beginning after December 15, 2023, and interim periods within annual periods beginning after December 15, 2024. Retrospective application is required. The Company is currently evaluating the effect the updated guidance will have on the Company's financial statement disclosures.
In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The updated accounting guidance requires expanded income tax disclosures, including the disaggregation of existing disclosures related to the tax rate reconciliation and income taxes paid. The guidance is effective for annual periods beginning after December 15, 2024. Prospective application is required, with retrospective application permitted. The Company is currently evaluating the effect the updated guidance will have on the Company's financial statement disclosures.
Premiums Insurance premiums on property and casualty insurance contracts are recognized in proportion to the underlying risk insured and are primarily earned ratably over the term of the policies. Premiums on long-term care contracts are earned ratably over the policy year in which they are due. The reserve for unearned premiums represents the portion of premiums written relating to the unexpired terms of coverage.
Property and casualty contracts that are retrospectively rated or subject to audit premiums contain provisions that result in an adjustment to the initial policy premium depending on the contract provisions. These provisions stipulate the adjustment due to loss experience of the insured during the coverage period, or changes in the level of exposure to insurance risk. For such contracts, the Company estimates the amount of ultimate premiums that the Company may earn upon completion of the coverage period and recognizes either an asset or a liability for the difference between the initial policy premium and the estimated ultimate premium. The Company either adjusts such estimated ultimate premium amounts during the course of the coverage period based on actual results to date, or by conducting premium audits after the policy has expired to determine the final exposure to insured risks. The resulting adjustment is recorded as either a reduction of or an increase to the earned premiums for the period.
Insurance receivables include balances due currently or in the future, including amounts due from insureds related to paid losses under high deductible policies, and are presented at unpaid balances, net of an allowance for uncollectible receivables. A loss rate methodology is used to determine expected credit losses for premium receivables. This methodology uses the Company’s historical annual credit losses relative to gross premium written to develop a range of credit loss rates for each dollar of gross written premium underwritten. Additionally, an expected credit loss for amounts due from insureds under high deductible and retrospectively rated policies is calculated on a pool basis, informed by historical default rate data obtained from major rating agencies. Changes in the allowance are presented as a component of Other operating expenses on the Consolidated Statements of Operations. Amounts are considered past due based on policy payment terms. Insurance receivables and any related allowance are written off after collection efforts are exhausted or a negotiated settlement is reached. See the Credit Losses section of this note for additional information on the Company’s allowances for expected credit losses.
Claim and claim adjustment expense reserves Claim and claim adjustment expense reserves, except reserves for structured settlements not associated with asbestos and environmental pollution (A&EP) and workers' compensation lifetime claims, are not discounted and are based on i) case basis estimates for losses reported on direct business, adjusted in the aggregate for ultimate loss expectations; ii) estimates of incurred but not reported (IBNR) losses; iii) estimates of losses on assumed reinsurance; iv) estimates of future expenses to be incurred in the settlement of claims; v) estimates of salvage and subrogation recoveries and vi) estimates of amounts due from insureds related to losses under high deductible policies. Management considers current conditions and trends as well as past Company and industry experience in establishing these estimates. The effects of inflation, which can be significant, are implicitly considered in the reserving process and are part of the recorded reserve balance. Ceded claim and claim adjustment expense reserves are reported as a component of Reinsurance receivables on the Consolidated Balance Sheets.
Future policy benefits reserves Future policy benefit reserves are associated with the Company's run-off long-term care business and relate to policyholders that are currently receiving benefits, including claims that have been incurred but are not yet reported, as well as policyholders that are not yet receiving benefits.
The LFPB is computed using the net level premium method, which incorporates cash flow assumptions and discount rate assumptions. Under the net level premium method, the LFPB is equal to the present value of future benefits and claim settlement expenses less the present value of future net premiums. Net premiums are equal to gross premiums multiplied by the NPR. The NPR is generally the ratio of the present value of benefits and expense payments to the present value of gross premiums, expected over the lifetime of the policy. As a result of the modified retrospective adoption of ASU 2018-12, the Company’s NPR calculation incorporates the original locked in discount rate and the reserve balance as of the transition date of January 1, 2021.
The key cash flow assumptions used to estimate the LFPB are morbidity, persistency (inclusive of mortality), anticipated future premium rate increases and expenses. Morbidity is the frequency and severity of injury, illness, sickness and diseases contracted. Persistency is the percentage of policies remaining in force and can be affected by policy lapses, benefit reductions and death. Future premium rate increases are generally subject to regulatory approval, and therefore the exact timing and size of the approved rate increases are unknown. Expense assumptions relate to claim adjudication. The Company has not elected the practical expedient that allows locking in the expense assumption. The carried LFPB discount rate is determined using the upper-medium grade fixed income instrument yield curve.
The Company has elected to update the NPR and the LFPB for actual experience on a quarterly basis. A quarterly assessment is also made as to whether evidence suggests that cash flow assumptions should be updated. Annually, in the third quarter, actuarial analysis is performed on policyholder morbidity, persistency, premium rate increases and expense experience. This analysis, combined with judgment, informs the setting of updated cash flow assumptions used to estimate the LFPB. Actuarial analysis includes predictive modeling, actual to expected experience comparisons and trend analysis. Applicable industry research is also considered.
Quarterly, to derive the upper-medium grade fixed income instrument yield discount rate assumption, the Company uses a published spot rate curve constructed from single-A rated U.S. dollar denominated corporate bonds. The Company uses linear interpolation to determine yield assumptions for tenors that fall between points for which observable rates are available. For cash flows that are projected to occur beyond the tenor for which market-observable rates are available, the Company applies judgment to estimate a normative rate which the Company grades to over 10 years.
Quarterly, the updated NPR is used to derive an updated LFPB as of the beginning of the current quarter measured at the original locked in discount rate. The updated LFPB is then compared to the existing carrying amount of the liability as of the same date (measured at the original locked in discount rate) to determine the re-measurement gain (loss), which is presented parenthetically within the Insurance claims and policyholders’ benefits line on the Consolidated Statements of Operations.
Insurance contracts are grouped into cohorts according to issue year. Contracts assumed through reinsurance are generally included within the same cohorts as contracts issued directly by the Company, according to issue year. The issue year for assumed contracts is defined according to the date that the Company’s assumption of insurance risk incepted. For assumed contracts that were reinsured concurrently with the issuance of the underlying direct contract, issue year is defined as the year that the underlying policy was issued. For contracts that were already in-force when assumed by the Company, issue year is defined as the year in which the reinsurance agreement incepted. For group long-term care business, issue year is defined as the year the individual insurance certificate was issued. Long-term care is the Company's only long-duration product line, therefore, cohorts are not further disaggregated by product.
Insurance-relate assessments Liabilities for insurance-related assessments are accrued when an assessment is probable, when it can be reasonably estimated and when the event obligating the entity to pay an imposed or probable assessment has occurred. Liabilities for insurance-related assessments are not discounted and are included as part of Other liabilities on the Consolidated Balance Sheets.
Reinsurance Reinsurance accounting allows for contractual cash flows to be reflected as premiums and losses. To qualify for reinsurance accounting, reinsurance agreements must include risk transfer. To meet risk transfer requirements, a reinsurance contract must include both insurance risk, consisting of underwriting and timing risk, and a reasonable possibility of a significant loss for the assuming entity.
Reinsurance receivables related to paid losses are presented at unpaid balances. Reinsurance receivables related to unpaid losses are estimated in a manner consistent with claim and claim adjustment expense reserves or future policy benefit reserves. Reinsurance receivables are reported net of an allowance for uncollectible amounts on the Consolidated Balance Sheets. The cost of reinsurance is primarily accounted for over the life of the underlying reinsured policies using assumptions consistent with those used to account for the underlying policies or over the reinsurance contract period. The ceding of insurance does not discharge the primary liability of the Company.
The Company has established an allowance for uncollectible reinsurance receivables which relates to both amounts already billed on ceded paid losses as well as ceded reserves that will be billed when losses are paid in the future. For assessing expected credit losses, the Company separates reinsurance receivables into two pools: voluntary reinsurance receivables and involuntary receivables related to mandatory pools. The Company has not recorded an allowance for involuntary pools as there is no perceived credit risk. The principal credit quality indicator used in the valuation of the allowance on voluntary reinsurance receivables is the financial strength rating of the reinsurer sourced from major rating agencies. If the reinsurer is unrated, an internal financial strength rating is assigned based on the Company’s historical loss experience and the Company’s assessment of the reinsurance counterparty's risk profile, which generally corresponds with a B rating. Reinsurer financial strength ratings are updated and reviewed on an annual basis or sooner if the Company becomes aware of significant changes related to a reinsurer. The allowance for uncollectible reinsurance receivables is estimated on the basis of periodic evaluations of balances due from reinsurers, reinsurer financial strength rating and solvency, industry experience and current and forecast economic conditions. Because billed receivables generally approximate 5% or less of total reinsurance receivables, the age of the reinsurance receivables related to paid losses is not a significant input into the allowance analysis. Changes in the allowance for uncollectible reinsurance receivables are presented as a component of Insurance claims and policyholders' benefits on the Consolidated Statements of Operations. See the Credit Losses section of this note for additional information on the Company's allowances for expected credit losses.
Amounts are considered past due based on the reinsurance contract terms. Reinsurance receivables related to paid losses and any related allowance are written off after collection efforts have been exhausted or a negotiated settlement is reached with the reinsurer. Reinsurance receivables from insolvent insurers related to paid losses are written off when the settlement due from the estate can be reasonably estimated. At the time reinsurance receivables related to paid losses are written off, any required adjustment to reinsurance receivables related to unpaid losses is recorded as a component of Insurance claims and policyholders' benefits on the Consolidated Statements of Operations.
A loss portfolio transfer is a retroactive reinsurance contract. If the cumulative claim and allocated claim adjustment expenses ceded under a loss portfolio transfer exceed the consideration paid, the resulting gain from such excess is deferred and amortized into earnings in future periods in proportion to actual recoveries under the loss portfolio transfer. In any period in which there is a revised estimate of claim and allocated claim adjustment expenses and the loss portfolio transfer is in a gain position, the deferred gain is recalculated as if the revised estimate was available at the inception date of the loss portfolio transfer and the change in the deferred gain is recognized in earnings.
Deferred acquisition costs Deferrable acquisition costs include commissions, premium taxes and certain underwriting and policy issuance costs which are incremental direct costs of successful contract acquisitions. Acquisition costs related to property and casualty business are deferred and amortized ratably over the period the related premiums are earned. Deferred acquisition costs are presented net of ceding commissions and other ceded acquisition costs.The Company evaluates deferred acquisition costs for recoverability. Anticipated investment income is considered in the determination of the recoverability of deferred acquisition costs. Adjustments, if necessary, are recorded in current period results of operations.
Policyholder dividends Policyholder dividends are paid to participating policyholders within the workers' compensation and surety lines of business. Net written premiums for participating dividend policies were approximately 2%, 2% and 1% of total net written premiums for each of the years ended December 31, 2023, 2022 and 2021. Dividends to policyholders are accrued according to the Company's best estimate of the amount to be paid in accordance with contractual provisions and applicable state laws. Dividends to policyholders are presented as a component of Insurance claims & policyholders' benefits on the Consolidated Statements of Operations and Other liabilities on the Consolidated Balance Sheets.
Investments
The Company classifies its fixed maturity securities as either available-for-sale or trading, and as such, they are carried at fair value. Changes in fair value of trading securities are reported within Net investment income on the Consolidated Statements of Operations. Changes in fair value of available-for-sale securities are reported as a component of Other comprehensive income.
The cost of fixed maturity securities classified as available-for-sale is adjusted for amortization of premiums and accretion of discounts, which are included in Net investment income on the Consolidated Statements of Operations. The amortization of premium and accretion of discount for fixed maturity securities takes into consideration call and maturity dates that produce the lowest yield.
For asset-backed securities included in fixed maturity securities, the Company recognizes income using an effective yield based on anticipated prepayments and the estimated economic life of the securities. When estimates of prepayments change, the effective yield is recalculated to reflect actual payments to date and anticipated future payments predominantly using the retrospective method.
Equity securities are carried at fair value. The Company's non-redeemable preferred stock contain characteristics of debt securities, are priced similarly to bonds and are held primarily for income generation through periodic dividends. While recognition of gains and losses on these securities is not discretionary, management does not consider the changes in fair value of non-redeemable preferred stock to be reflective of our primary operations. As such, the changes in the fair value of these securities are recorded through Net investment gains (losses) on the Consolidated Statements of Operations. The Company owns certain common stock with the intention of holding the securities primarily for market appreciation and as such, the changes in the fair value of these securities are recorded through Net investment income.
The Company's carrying value of investments in limited partnerships is its share of the net asset value of each partnership, as determined by the general partner. Certain partnerships for which results are not available on a timely basis are reported on a lag, primarily three months or less. Changes in net asset values are accounted for under the equity method and recorded within Net investment income on the Consolidated Statements of Operations.
Mortgage loans are commercial in nature, are carried at unpaid principal balance, net of unamortized fees and an allowance for expected credit losses, and are recorded once funded. The allowance for expected credit losses is developed by assessing the credit quality of pools of mortgage loans in good standing using debt service coverage ratios (DSCR) and loan-to-value ratios (LTV). The DSCR compares a property’s net operating income to its debt service payments, including principal and interest. The LTV ratio compares the current unpaid principal balance of the loan to the estimated fair value of the underlying property collateralizing the loan. The pools developed to measure the credit loss allowance use increments of DSCR and LTV to draw distinctions between risk levels. The Company applies expected credit loss rates by pool to the outstanding receivable balances. Changes in the allowance for mortgage loans are presented as a component of Net investment gains (losses) on the Consolidated Statements of Operations. See the Credit Losses section of this note for additional information on the Company’s allowances for expected credit losses. Interest income from mortgage loans is recognized on an accrual basis using the effective yield method.
Other invested assets include overseas deposits. Overseas deposits are valued using the net asset value per share (or equivalent) practical expedient. They are primarily short-term government securities, agency securities and corporate bonds held in trusts that are managed by Lloyd's of London. These funds are required of Lloyd's syndicates to protect policyholders in overseas markets and may be denominated in local currency.
Short-term investments are carried at fair value, with the exception of cash accounts earning interest, which are carried at cost and approximate fair value. Changes in fair value are reported as a component of Other comprehensive income.
Purchases and sales of all securities are recorded on the trade date, except for private placement securities, including bank loan participations, which are recorded once funded. Net investment gains and losses are determined on the basis of the cost or amortized cost of the specific securities sold.
Variable interest entities
In the normal course of investing activities, the Company enters into relationships with variable interest entities (VIEs), as both an investor in limited partnerships and asset-backed securities issued by third-party VIEs. The Company is not the primary beneficiary of these VIEs, and therefore does not consolidate them. The Company determines whether it is the primary beneficiary of a VIE based on a qualitative assessment of the relative power and benefits of the Company and the other participants in the VIE. The Company’s maximum exposure to loss with respect to these investments is limited to the investment carrying values included in the Company’s Consolidated Balance Sheets and any unfunded commitments.
An available-for-sale security is impaired if the fair value of the security is less than its cost adjusted for accretion, amortization and allowance for credit losses. When a security is impaired, it is evaluated to determine whether the Company intends to sell the security before recovery of amortized cost or whether a credit loss exists. Losses on securities that the Company intends to sell are recognized as impairment losses within Net investment gains (losses) on the Consolidated Statements of Operations. If a credit loss exists, an allowance is established and the corresponding amount is recognized as an impairment loss within Net investment gains (losses) on the Consolidated Statements of Operations. The allowance for credit losses related to available-for-sale fixed maturity securities is the difference between the present value of cash flows expected to be collected and the amortized cost basis, limited by the amount that the fair value is less than the amortized cost basis. In subsequent periods, the allowance is reviewed, with any changes in the allowance presented as a component of Net investment gains (losses) on the Consolidated Statements of Operations. Changes in the difference between the amortized cost basis, net of the allowance, and the fair value, are recognized in Other comprehensive income.
Impairments, other than temporary
Significant judgment is required in the determination of whether an impairment loss has occurred for a security. The Company follows a consistent and systematic process for determining and recording an impairment loss, including the evaluation of securities in an unrealized loss position and securities with an allowance for credit losses on at least a quarterly basis.
The Company’s assessment of whether an impairment loss has occurred incorporates both quantitative and qualitative information. A credit loss exists if the present value of cash flows expected to be collected is less than the amortized cost basis. Significant assumptions enter into these cash flow projections including delinquency rates, probable risk of default, loss severity upon a default, over collateralization and interest coverage triggers and credit support from lower level tranches. The Company considers all available evidence when determining whether an investment requires a credit loss write-down or allowance to be recorded. Examples of such evidence may include the financial condition and near-term and long-term prospects of the issuer, whether the issuer is current with interest and principal payments, credit ratings on the security or changes in ratings over time, general market conditions and industry, sector or other specific factors and whether it is likely that the Company will recover its amortized cost through the collection of cash flows. See the Credit Losses section of this note for additional information on the Company’s allowances for expected credit losses.
Credit Losses
The allowances for credit losses on fixed maturity securities, mortgage loans, reinsurance receivables and insurance receivables are valuation accounts that are reported as a reduction of a financial asset’s cost basis and are measured on a pool basis when similar risk characteristics exist. Management estimates the allowance using relevant available information from both internal and external sources. Historical credit loss experience provides the basis for the estimation of expected credit losses and adjustments may be made to reflect current conditions and reasonable and supportable forecasts. Adjustments to historical loss information are made for any additional factors that come to the Company’s attention. This could include significant shifts in
counterparty financial strength ratings, aging of past due receivables, amounts sent to collection agencies, or other underlying portfolio changes. Amounts are considered past due when payments have not been received according to contractual terms. The Company also considers current and forecast economic conditions, using a variety of economic metrics and forecast indices. The sensitivity of expected credit losses relative to changes to these forecast economic conditions can vary by financial asset class. The Company considers a reasonable and supportable forecast period to be up to 24 months from the balance sheet date. After the forecast period, the Company reverts to historical credit experience. The Company uses collateral arrangements such as letters of credit and amounts held in beneficiary trusts to mitigate credit risk, which are considered in the estimate of net amount expected to be collected. Amounts are written off against the allowance when determined to be uncollectible.
The Company has made a policy election to present accrued interest balances separately from the amortized cost basis of assets and has elected the practical expedient to exclude the accrued interest from the tabular disclosures for mortgage loans and available-for-sale securities. The Company has elected not to estimate an allowance for credit losses on accrued interest receivable. The accrual of interest income is discontinued and the asset is placed on nonaccrual status within 90 days of the interest becoming delinquent. Interest accrued but not received for assets on nonaccrual status is reversed through investment income. Interest received for assets that are on nonaccrual status is recognized as payment is received. The asset is returned to accrual status when the principal and interest amounts contractually due are brought current and future payments are expected. Interest receivable is presented as a component of accrued investment income on the Consolidated Balance Sheet.
Deferred Non-Insurance Warranty Revenue and Acquisition Expense
Non-insurance warranty revenue is primarily generated from separately-priced service contracts that provide mechanical breakdown and other coverages to vehicle or consumer goods owners. The warranty contracts generally provide coverage from 1 month to 10 years. For warranty products where the Company acts as the principal in the transaction, Non-insurance warranty revenue is reported on a gross basis, with amounts paid by customers reported as Non-insurance warranty revenue and commissions paid to agents and dealers reported as Non-insurance warranty expense.
Non-insurance warranty revenue is reported net of any premiums related to contractual liability coverage issued by the Company's insurance operations. Additionally, the Company provides warranty administration services for dealer and manufacturer obligor warranty products, which include limited warranties and guaranteed asset protection waivers. The Company recognizes Non-insurance warranty revenue over the service period in proportion to the actuarially determined expected claims emergence pattern. Customers predominantly pay in full at the inception of the warranty contract. The liability for deferred revenue represents the unearned portion of revenue in advance of the Company's performance. The deferred revenue balance includes amounts which are refundable on a pro rata basis upon cancellation.
Dealers, retailers and agents earn commission for assisting the Company in obtaining non-insurance warranty contracts. Additionally, the Company utilizes third-parties to perform warranty administrator services for its consumer goods warranties. These costs, which are deferred and recorded as Deferred non-insurance warranty acquisition expense, are amortized to Non-insurance warranty expense consistent with how the related revenue is recognized. The Company evaluates deferred costs for recoverability including consideration of anticipated investment income. Adjustments to deferred costs, if necessary, are recorded in the current period results of operations.
Income Taxes
The Company and its eligible subsidiaries (CNA Tax Group) are included in the consolidated federal income tax return of Loews and its eligible subsidiaries. The Company accounts for income taxes under the asset and liability method. Under the asset and liability method, deferred income taxes are recognized for temporary differences between the financial statement and tax return bases of assets and liabilities, based on enacted tax rates and other provisions of the tax law. The effect of a change in tax laws or rates on deferred tax assets and liabilities is recognized in income in the period in which such change is enacted. Future tax benefits are recognized to the extent that realization of such benefits is more likely than not, and a valuation allowance is
established for any portion of a deferred tax asset that management believes will not be realized. The Company releases tax effects from AOCI utilizing the security-by-security approach for Net unrealized gains (losses) on investments with an allowance for credit losses and Net unrealized gains (losses) on other investments. For Pension and postretirement benefits, tax effects from AOCI are released at enacted tax rates based on the pre-tax adjustments to pension liabilities or assets recognized within Other comprehensive income.
Pension and Postretirement Benefits
The Company recognizes the overfunded or underfunded status of its defined benefit plans in Other assets or Other liabilities on the Consolidated Balance Sheets. Changes in funded status related to prior service costs and credits, and actuarial gains and losses arising from differences between actual experience and actuarial assumptions, are recognized in the year in which the changes occur through Other comprehensive income. Unrecognized actuarial gains and losses in excess of 10% of the greater of the beginning of the year projected benefit obligation or fair value of plan assets (the corridor) are amortized as a component of net periodic pension cost (benefit) over the average remaining life expectancy of the plan participants. Annual service cost, interest cost, expected return on plan assets, amortization of prior service costs and credits and amortization of actuarial gains and losses are recognized on the Consolidated Statements of Operations.
The vested benefit obligation for the CNA Retirement Plan is determined based on eligible compensation and accrued service for previously entitled employees. Effective June 30, 2015, future benefit accruals under the CNA Retirement Plan were eliminated and the benefit obligations were frozen.
Stock-Based Compensation
The Company records compensation expense using the fair value method for all awards it grants, modifies or cancels primarily on a straight-line basis over the requisite service period, generally three years.
Foreign Currency The Company's foreign subsidiaries' balance sheet accounts are translated at the exchange rates in effect at each reporting date and income statement accounts are either translated at the exchange rates on the date of the transaction or at average exchange rates. Foreign currency translation gains and losses are reflected in Stockholders' equity as a component of AOCI.
Leases
A lease provides the lessee the right to control the use of an identified asset for a period of time in exchange for consideration. Operating lease right-of-use (ROU) assets and lease liabilities are included in Other assets and Other liabilities on the Company's Consolidated Balance Sheets.
ROU assets represent the Company's right to use an underlying asset for the lease term and operating lease liabilities represent the Company's obligation to make lease payments arising from the lease. The Company determines if an arrangement is a lease at inception. Operating lease ROU assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. Most operating leases contain renewal options that provide for rent increases based on prevailing market conditions. Certain leases contain options to terminate before maturity. The lease term used to calculate the ROU asset includes any renewal options or lease termination options that the Company expects to exercise. The discount rate used to determine the commencement date present value of lease payments is typically the Company’s secured borrowing rate, as most of the Company’s leases do not provide an implicit rate. ROU assets include any lease payments required to be made prior to commencement and exclude lease incentives. The Company has elected to account for its lease and non-lease components as a single lease component. The Company’s non-lease components consist of variable lease costs not based on an index or rate and are excluded from the measurement of ROU assets and lease liabilities. Variable lease costs not based on an index or rate are treated as period costs, and represent charges for services provided by the landlord and the Company's reimbursement to the landlord for costs such as real estate taxes and insurance.
Property and Equipment
Property and equipment are carried at cost less accumulated depreciation. Depreciation is based on the estimated useful lives of the various classes of property and equipment and is determined principally on the straight-line method. Furniture and fixtures are depreciated over seven years. Office equipment is depreciated over five years. The estimated lives for data processing equipment and software generally range from three to five years, but can be as long as ten years. Leasehold improvements are depreciated over the corresponding lease terms not to exceed the underlying asset life.
Goodwill
Goodwill represents the excess of purchase price over the fair value of the net assets of acquired entities and businesses. Goodwill in the International segment may change from period to period as a result of foreign currency translation.
Goodwill is tested for impairment annually or when certain triggering events require such tests. As a result of reviews completed for the year ended December 31, 2023, the Company determined that the estimated fair value of the reporting units were in excess of their carrying value including Goodwill. Changes in future periods in assumptions about the level of economic capital, business growth, earnings projections or the weighted average cost of capital could result in goodwill impairment.
Other Intangible Assets
Other intangible assets are reported within Other assets on the Consolidated Balance Sheets. Finite-lived intangible assets are amortized over their estimated useful lives. Indefinite-lived other intangible assets are tested for impairment annually or when certain triggering events require such tests.
Earnings (Loss) Per Share Data
Earnings (loss) per share is based on weighted average number of outstanding common shares. Basic earnings (loss) per share excludes the impact of dilutive securities and is computed by dividing Net income (loss) by the weighted average number of common shares outstanding for the period. Diluted earnings (loss) per share reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock.
v3.24.0.1
Significant Accounting Policies (Tables)
 12 Months Ended
Dec. 31, 2023
Accounting Policies [Abstract]  
Schedule of new accounting pronouncements and changes in accounting principles
The following table presents a roll-forward of the pre-transition LFPB balance as of January 1, 2021:

(In millions)
Balance as of December 31, 2020, as previously reported$13,318 
Reclassification of reserves for policyholders currently receiving benefits to Future policy benefits (1)
2,844 
De-recognition of shadow reserves(3,293)
Re-measurement using an upper-medium grade fixed income instrument yield discount rate6,255 
Other adjustments8 
Balance as of January 1, 2021, as adjusted$19,132 
(1) In conjunction with the adoption of ASU 2018-12, at January 1, 2023, the Company reclassified the long-term care reserves for policyholders currently receiving benefits from Claim and claim adjustment expenses to Future policy benefits. This change was applied retrospectively as of January 1, 2021.
The following table presents after tax adjustments to the opening balance of Stockholders’ equity resulting from adoption of ASU 2018-12:

(In millions)
Accumulated other comprehensive income (loss)Retained earnings
Balance as of December 31, 2020, as previously reported$803 $9,081 
De-recognition of shadow reserves2,601 — 
Re-measurement of LFPB using an upper-medium grade fixed income instrument yield discount rate(4,941)— 
     Other adjustments— (6)
Balance as of January 1, 2021, as adjusted$(1,537)$9,075 
The effects of adoption of ASU 2018-12 on the Consolidated Statement of Operations for the year ended December 31, 2022 were as follows:

(In millions)
Prior to AdoptionEffect of Adoption As reported
Insurance claims and policyholders’ benefits (1)
$6,386 $267 $6,653 
Income (loss) before income tax1,081 (267)814 
Income tax (expense) benefit(187)55 (132)
Net income894 (212)682 
Basic earnings (loss) per share3.29 (0.78)2.51 
Diluted earnings (loss) per share3.28 (0.77)2.51 
(1) The effect of adopting ASU 2018-12 on Insurance claims and policyholders’ benefits is inclusive of the re-measurement gain (loss) of $(214) million, which is presented parenthetically on the Consolidated Statement of Operations.
The effects of adoption of ASU 2018-12 on the Consolidated Statement of Operations for the year ended December 31, 2021 were as follows:

(In millions)
Prior to AdoptionEffect of Adoption As reported
Insurance claims and policyholders’ benefits (1)
$6,349 $22 $6,371 
Income (loss) before income tax1,484 (22)1,462 
Income tax (expense) benefit(282)4 (278)
Net income1,202 (18)1,184 
Basic earnings (loss) per share4.42 (0.06)4.36 
Diluted earnings (loss) per share4.41 (0.07)4.34 
(1) The effect of adopting ASU 2018-12 on Insurance claims and policyholders’ benefits is inclusive of the re-measurement gain (loss) of $(8) million, which is presented parenthetically on the Consolidated Statement of Operations.
The effects of adoption of ASU 2018-12 on the Consolidated Balance Sheet as of December 31, 2022 were as follows:

(In millions)
Prior to AdoptionEffect of AdoptionAs reported
Deferred income taxes$1,178 $73 $1,251 
Total assets60,927 73 61,000 
Claim and claim adjustment expenses (1)
25,099 (2,979)22,120 
Future policy benefits (1)
10,151 3,329 13,480 
Total liabilities52,102 350 52,452 
Retained earnings9,572 (236)9,336 
Accumulated other comprehensive income (loss)(3,557)(41)(3,598)
Total stockholders' equity8,825 (277)8,548 
(1) In conjunction with the adoption of ASU 2018-12, at January 1, 2023, the Company reclassified the long-term care reserves for policyholders currently receiving benefits from Claim and claim adjustment expenses to Future policy benefits. This change was applied retrospectively as of January 1, 2021.
The effects of adoption of ASU 2018-12 on the Consolidated Statement of Comprehensive Income (Loss) for the year ended December 31, 2022 were as follows:

(In millions)
Prior to AdoptionEffect of AdoptionAs reported
Changes in: Net unrealized gains and losses on other investments$(3,777)$(2,320)$(6,097)
Net unrealized gains and losses on investments(3,782)(2,320)(6,102)
Impact of changes in discount rates used to measure long-duration contract liabilities— 3,959 3,959 
Other comprehensive income (loss), net of tax(3,877)1,639 (2,238)
Total comprehensive income (loss)(2,983)1,427 (1,556)
The effects of adoption of ASU 2018-12 on the Consolidated Statement of Comprehensive Income (Loss) for the year ended December 31, 2021 were as follows:

(In millions)
Prior to AdoptionEffect of AdoptionAs reported
Changes in: Net unrealized gains and losses on other investments$(706)$(281)$(987)
Net unrealized gains and losses on investments(708)(281)(989)
Impact of changes in discount rates used to measure long-duration contract liabilities— 941 941 
Other comprehensive income (loss), net of tax(483)660 177 
Total comprehensive income (loss)719 642 1,361 
The effects of adoption of ASU 2018-12 on the Consolidated Statement of Cash Flows for the year ended December 31, 2022 were as follows:

(In millions)
Prior to AdoptionEffect of AdoptionAs reported
Net income$894 $(212)$682 
Deferred income tax expense (benefit)(34)(55)(89)
Changes in: Insurance reserves1,791 267 2,058 
The effects of adoption of ASU 2018-12 on the Consolidated Statement of Cash Flows for the year ended December 31, 2021 were as follows:

(In millions)
Prior to AdoptionEffect of AdoptionAs reported
Net income$1,202 $(18)$1,184 
Deferred income tax expense (benefit)47 (4)43 
Changes in: Insurance reserves2,463 22 2,485 
The effects of adoption of ASU 2018-12 on segment results of operations of the Life & Group segment for the year ended December 31, 2022 were as follows:

(In millions)
Prior to AdoptionEffect of AdoptionAs reported
Net incurred claims and benefits (1)
$1,202 $267 $1,469 
Core income (loss) before income tax(53)(267)(320)
Income tax (expense) benefit on core income (loss)44 55 99 
Core income (loss)(9)(212)(221)
(1) The effect of adopting ASU 2018-12 on Net incurred claims and benefits is inclusive of the re-measurement gain (loss) of $(214) million, which is presented parenthetically on the Consolidated Statement of Operations.
The effects of adoption of ASU 2018-12 on segment results of operations of the Life & Group segment for the year end ended December 31, 2021 were as follows:

(In millions)
Prior to AdoptionEffect of AdoptionAs reported
Net incurred claims and benefits (1)
$1,239 $22 $1,261 
Core income (loss) before income tax105 (22)83 
Income tax (expense) benefit on core income (loss)21 4 25 
Core income (loss)126 (18)108 
(1) The effect of adopting ASU 2018-12 on Net incurred claims and benefits is inclusive of the re-measurement gain (loss) of $(8) million, which is presented parenthetically on the Consolidated Statement of Operations.
The effects of adoption of ASU 2018-12 on segment results for selected balance sheet lines of the Life & Group segment as of December 31, 2022 were as follows:

(In millions)
Prior to AdoptionEffect of AdoptionAs reported
Claim and claim adjustment expenses (1)
$3,674 $(2,979)$695 
Future policy benefits (1)
10,151 3,329 13,480 
(1) In conjunction with the adoption of ASU 2018-12, at January 1, 2023, the Company reclassified the long-term care reserves for policyholders currently receiving benefits from Claim and claim adjustment expenses to Future policy benefits. This change was applied retrospectively as of January 1, 2021.
v3.24.0.1
Investments (Tables)
 12 Months Ended
Dec. 31, 2023
Investments [Abstract]  
Net investment income
The significant components of Net investment income are presented in the following table.
Years ended December 31
(In millions)202320222021
Fixed maturity securities$1,941 $1,787 $1,707 
Equity securities63 23 83 
Limited partnership investments174 (12)362 
Mortgage loans58 54 61 
Short-term investments75 16 1 
Trading portfolio4 4 9 
Other28 5 — 
Gross investment income2,343 1,877 2,223 
Investment expense(79)(72)(64)
Net investment income$2,264 $1,805 $2,159 
Net investment income (loss) recognized due to the change in fair value of common stock held as of December 31, 2023, 2022 and 2021$11 $47 $28 
Net realized investment gains (losses)
Net investment gains (losses) are presented in the following table.
Years ended December 31
(In millions)202320222021
Net investment gains (losses):
Fixed maturity securities:
Gross gains$75 $120 $186 
Gross losses(166)(261)(90)
Net investment gains (losses) on fixed maturity securities(91)(141)96 
Equity securities4 (116)4 
Derivatives(1)64 6 
Mortgage loans(11)(8)10 
Short-term investments and other— 2 4 
Net investment gains (losses)$(99)$(199)$120 
Net investment gains (losses) recognized due to the change in fair value of non-redeemable preferred stock held as of December 31, 2023, 2022 and 2021$14 $(75)$2 
Components of net other than temporary impairment losses recognized in earnings by asset type The table includes losses (gains) on securities with an intention to sell and changes in the allowance for credit losses on securities since acquisition date.
Years ended December 31
(In millions)202320222021
Fixed maturity securities available-for-sale:
Corporate and other bonds$33 $62 $11 
Asset-backed11 — 20 
Impairment losses (gains) recognized in earnings$44 $62 $31 
Summary of fixed maturity securities
The following tables present a summary of fixed maturity securities.
December 31, 2023Cost or
Amortized
Cost		Gross
Unrealized
Gains		Gross
Unrealized
Losses		Allowance for Credit LossesEstimated
Fair
Value
(In millions)
Fixed maturity securities available-for-sale:
Corporate and other bonds$25,020 $597 $1,345 $4 $24,268 
States, municipalities and political subdivisions7,713 382 703 — 7,392 
Asset-backed:
Residential mortgage-backed3,411 16 425 — 3,002 
Commercial mortgage-backed1,862 7 230 8 1,631 
Other asset-backed3,515 13 256 4 3,268 
Total asset-backed8,788 36 911 12 7,901 
U.S. Treasury and obligations of government-sponsored enterprises152 1 2 — 151 
Foreign government741 6 34 — 713 
   Redeemable preferred stock— — — — — 
Total fixed maturity securities available-for-sale42,414 1,022 2,995 16 40,425 
Total fixed maturity securities trading— — — — — 
Total fixed maturity securities$42,414 $1,022 $2,995 $16 $40,425 
December 31, 2022Cost or
Amortized
Cost		Gross
Unrealized
Gains		Gross
Unrealized
Losses		Allowance for Credit LossesEstimated
Fair
Value
(In millions)
Fixed maturity securities available-for-sale:
Corporate and other bonds$23,137 $301 $2,009 $— $21,429 
States, municipalities and political subdivisions8,918 338 939 — 8,317 
Asset-backed:
Residential mortgage-backed3,073 5 447 — 2,631 
Commercial mortgage-backed1,886 4 255 — 1,635 
Other asset-backed3,287 2 361 1 2,927 
Total asset-backed8,246 11 1,063 1 7,193 
U.S. Treasury and obligations of government-sponsored enterprises111 1 2 — 110 
Foreign government617 1 43 — 575 
Redeemable preferred stock3 — — — 3 
Total fixed maturity securities available-for-sale41,032 652 4,056 1 37,627 
Total fixed maturity securities trading— — — — — 
Total fixed maturity securities$41,032 $652 $4,056 $1 $37,627 
Debt securities, available-for-sale, unrealized loss position, fair value
The following tables present the estimated fair value and gross unrealized losses of fixed maturity securities in a gross unrealized loss position for which an allowance for credit loss has not been recorded, by the length of time in which the securities have continuously been in that position.
Less than 12 Months12 Months or LongerTotal
December 31, 2023Estimated
Fair Value		Gross
Unrealized
Losses		Estimated
Fair Value		Gross
Unrealized
Losses		Estimated
Fair Value		Gross
Unrealized
Losses
(In millions)
Fixed maturity securities available-for-sale:
Corporate and other bonds$1,943 $37 $13,406 $1,308 $15,349 $1,345 
States, municipalities and political subdivisions598 18 3,104 685 3,702 703 
Asset-backed:
Residential mortgage-backed233 4 2,212 421 2,445 425 
Commercial mortgage-backed200 5 1,184 225 1,384 230 
Other asset-backed392 8 1,869 248 2,261 256 
Total asset-backed825 17 5,265 894 6,090 911 
U.S. Treasury and obligations of government-sponsored enterprises65 1 23 1 88 2 
Foreign government52 1 450 33 502 34 
Total$3,483 $74 $22,248 $2,921 $25,731 $2,995 
Less than 12 Months12 Months or LongerTotal
December 31, 2022Estimated
Fair Value		Gross
Unrealized
Losses		Estimated
Fair Value		Gross
Unrealized
Losses		Estimated
Fair Value		Gross
Unrealized
Losses
(In millions)
Fixed maturity securities available-for-sale:
Corporate and other bonds$15,946 $1,585 $1,634 $424 $17,580 $2,009 
States, municipalities and political subdivisions4,079 769 456 170 4,535 939 
Asset-backed:
Residential mortgage-backed1,406 144 1,143 303 2,549 447 
Commercial mortgage-backed1,167 159 408 96 1,575 255 
Other asset-backed2,087 262 542 99 2,629 361 
Total asset-backed4,660 565 2,093 498 6,753 1,063 
U.S. Treasury and obligations of government-sponsored enterprises76 1 16 1 92 2 
   Foreign government473 26 78 17 551 43 
Total$25,234 $2,946 $4,277 $1,110 $29,511 $4,056 
The following table presents the estimated fair value and gross unrealized losses of fixed maturity securities in a gross unrealized loss position for which an allowance for credit loss has not been recorded, by ratings distribution.
December 31, 2023December 31, 2022

(In millions)		Estimated Fair ValueGross Unrealized LossesEstimated Fair ValueGross Unrealized Losses
U.S. Government, Government agencies and Government-sponsored enterprises$2,273 $309 $2,355 $337 
AAA1,524 261 1,559 298 
AA 3,817 658 4,327 817 
A5,652 517 6,615 749 
BBB11,523 1,095 13,226 1,621 
Non-investment grade942 155 1,429 234 
Total$25,731 $2,995 $29,511 $4,056 
Debt securities, available-for-sale, allowance for credit loss
(In millions)Corporate and other bondsAsset-backedTotal
Allowance for credit losses:
Balance as of January 1, 2023$— $1 $1 
Additions to the allowance for credit losses:
Securities for which credit losses were not previously recorded10 7 17 
Available-for-sale securities accounted for as PCD assets22 — 22 
Reductions to the allowance for credit losses:
Securities sold during the period (realized)6 — 6 
Intent to sell or more likely than not will be required to sell the security before recovery of its amortized cost basis8 — 8 
Write-offs charged against the allowance15 — 15 
Recoveries of amounts previously written off— — — 
Additional increases or (decreases) to the allowance for credit losses on securities that had an allowance recorded in a previous period1 4 5 
Balance as of December 31, 2023
$4 $12 $16 
(In millions)Corporate and other bondsAsset-backedTotal
Allowance for credit losses:
Balance as of January 1, 2022$11 $7 $18 
Additions to the allowance for credit losses:
Securities for which credit losses were not previously recorded— — — 
Available-for-sale securities accounted for as PCD assets— 3 3 
Reductions to the allowance for credit losses:
Securities sold during the period (realized)— — — 
Intent to sell or more likely than not will be required to sell the security before recovery of its amortized cost basis— — — 
Write-offs charged against the allowance12 — 12 
Recoveries of amounts previously written off— — — 
Additional increases or (decreases) to the allowance for credit losses on securities that had an allowance recorded in a previous period1 (9)(8)
Balance as of December 31, 2022
$— $1 $1 
Contractual maturity
The following table presents available-for-sale fixed maturity securities by contractual maturity.
December 3120232022
(In millions)Cost or
Amortized
Cost		Estimated
Fair
Value		Cost or
Amortized
Cost		Estimated
Fair
Value
Due in one year or less$1,121 $1,091 $1,012 $1,001 
Due after one year through five years11,563 11,180 9,880 9,399 
Due after five years through ten years13,359 12,573 13,788 12,453 
Due after ten years16,371 15,581 16,352 14,774 
Total$42,414 $40,425 $41,032 $37,627 
Financing receivable credit quality indicators
The following table presents the amortized cost basis of mortgage loans for each credit quality indicator by year of origination. The primary credit quality indicators utilized are debt service coverage ratios (DSCR) and loan-to-value ratios (LTV).
December 31, 2023
Mortgage Loans Amortized Cost Basis by Origination Year (1)
(In millions)20232022202120202019PriorTotal
DSCR ≥1.6x
LTV less than 55%$33 $9 $8 $98 $60 $238 $446 
LTV 55% to 65%— — 5 — 8 — 13
LTV greater than 65%— 31 11 — — — 42
DSCR 1.2x - 1.6x
LTV less than 55%28 5 — 14 29 21 97
LTV 55% to 65%34 36 36 23 — 32 161
LTV greater than 65%— 65 — — — — 65
DSCR ≤1.2
LTV less than 55%6 34 — — — — 40
LTV 55% to 65%26 40 — — 43 — 109
LTV greater than 65%— 28 21 — 41 7 97
Total$127 $248 $81 $135 $181 $298 $1,070 
(1) The values in the table above reflect DSCR on a standardized amortization period and LTV based on the most recent appraised values trended forward using changes in a commercial real estate price index.
v3.24.0.1
Fair Value (Tables)
 12 Months Ended
Dec. 31, 2023
Fair Value Disclosures [Abstract]  
Assets and liabilities measured at fair value on a recurring basis
Assets and liabilities measured at fair value on a recurring basis are presented in the following tables. Corporate bonds and other includes obligations of the United States of America (U.S.) Treasury, government-sponsored enterprises, foreign governments and redeemable preferred stock.
December 31, 2023   Total
Assets/Liabilities
at Fair Value
(In millions)Level 1Level 2Level 3
Assets    
Fixed maturity securities:    
Corporate bonds and other$161 $23,926 $1,045 $25,132 
States, municipalities and political subdivisions— 7,348 44 7,392 
Asset-backed— 7,000 901 7,901 
Total fixed maturity securities 161 38,274 1,990 40,425 
Equity securities:
Common stock167 — 24 191 
Non-redeemable preferred stock52 440 — 492 
Total equity securities219 440 24 683 
Short term and other1,976 32 — 2,008 
Total assets$2,356 $38,746 $2,014 $43,116 
Liabilities
Other liabilities$— $1 $— $1 
Total liabilities$— $1 $— $1 

December 31, 2022   Total
Assets/Liabilities
at Fair Value
(In millions)Level 1Level 2Level 3
Assets    
Fixed maturity securities:    
Corporate bonds and other$120 $21,187 $810 $22,117 
States, municipalities and political subdivisions— 8,274 43 8,317 
Asset-backed— 6,405 788 7,193 
Total fixed maturity securities 120 35,866 1,641 37,627 
Equity securities:
Common stock150 — 35 185 
Non-redeemable preferred stock54 435 — 489 
Total equity securities204 435 35 674 
Short term and other1,608 71 — 1,679 
Total assets$1,932 $36,372 $1,676 $39,980 
Liabilities  
Other liabilities$— $1 $— $1 
Total liabilities$— $1 $— $1 
Table of reconciliation for assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs
The tables below present a reconciliation for all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3).
Level 3
(In millions)
Corporate bonds and otherStates, municipalities and political subdivisionsAsset-backedEquity securitiesTotal
Balance as of January 1, 2023$810 $43 $788 $35 $1,676 
Total realized and unrealized investment gains (losses):
Reported in Net investment gains (losses)— — (4)— (4)
Reported in Net investment income— — 20 (7)13 
Reported in Other comprehensive income (loss)38 1 9 — 48 
Total realized and unrealized investment gains (losses)38 1 25 (7)57 
Purchases219 — 248 — 467 
Sales— — — (4)(4)
Settlements(33)— (64)— (97)
Transfers into Level 311 — 23 — 34 
Transfers out of Level 3— — (119)— (119)
Balance as of December 31, 2023$1,045 $44 $901 $24 $2,014 
Unrealized gains (losses) on Level 3 assets and liabilities held as of December 31, 2023 recognized in Net income (loss) in the period$— $— $— $(7)$(7)
Unrealized gains (losses) on Level 3 assets and liabilities held as of December 31, 2023 recognized in Other comprehensive income (loss) in the period38 1 9 — 48 

Level 3
(In millions)
Corporate bonds and otherStates, municipalities and political subdivisionsAsset-backedEquity securitiesTotal
Balance as of January 1, 2022$937 $56 $556 $29 $1,578 
Total realized and unrealized investment gains (losses):
Reported in Net investment gains (losses)(2)— 9 (6)1 
Reported in Net investment income1 — 16 (3)14 
Reported in Other comprehensive income (loss)(184)(13)(126)— (323)
Total realized and unrealized investment gains (losses)(185)(13)(101)(9)(308)
Purchases137 — 424 19 580 
Sales(5)— (2)(3)(10)
Settlements(84)— (70)9 (145)
Transfers into Level 310 — 75 — 85 
Transfers out of Level 3— — (94)(10)(104)
Balance as of December 31, 2022$810 $43 $788 $35 $1,676 
Unrealized gains (losses) on Level 3 assets and liabilities held as of December 31, 2022 recognized in Net income (loss) in the period$— $— $— $(4)$(4)
Unrealized gains (losses) on Level 3 assets and liabilities held as of December 31, 2022 recognized in Other comprehensive income (loss) in the period(183)(13)(125)— (321)
Quantitative information about significant unobservable inputs in the fair value measurement of level 3 assets
The following tables present quantitative information about the significant unobservable inputs utilized by the Company in the fair value measurements of Level 3 assets. Valuations for assets and liabilities not presented in the tables below are primarily based on broker/dealer quotes for which there is a lack of transparency as to inputs used to develop the valuations. The quantitative detail of these unobservable inputs is neither provided nor reasonably available to the Company. The weighted average rate is calculated based on fair value.
December 31, 2023Estimated Fair Value
(In millions)		Valuation Technique(s)Unobservable Input(s)Range
 (Weighted Average)
Fixed maturity securities$1,495 Discounted cash flowCredit spread
1% - 7% (2%)
December 31, 2022Estimated Fair Value
(In millions)		Valuation Technique(s)Unobservable Input(s)Range
 (Weighted Average)
Fixed maturity securities$1,177 Discounted cash flowCredit spread
1% - 8% (2%)
Carrying amount and estimated fair value of financial instrument assets and liabilities not measured at fair value
The carrying amount and estimated fair value of the Company's financial assets and liabilities which are not measured at fair value on the Consolidated Balance Sheets are presented in the following tables.
December 31, 2023Carrying
Amount		Estimated Fair Value
(In millions)Level 1Level 2Level 3Total
Assets
Mortgage loans$1,035 $— $— $997 $997 
Liabilities
Short-term debt$550 $— $546 $— $546 
Long-term debt2,481 — 2,385 — 2,385 
December 31, 2022Carrying
Amount		Estimated Fair Value
(In millions)Level 1Level 2Level 3Total
Assets
Mortgage loans$1,040 $— $— $973 $973 
Liabilities
Short-term debt$243 $— $248 $— $248 
Long-term debt2,538 — 2,349 — 2,349 
v3.24.0.1
Income Taxes (Tables)
 12 Months Ended
Dec. 31, 2023
Income Tax Disclosure [Abstract]  
Reconciliation between the Company's federal income tax (expense) benefit at statutory rates and the recorded income tax (expense) benefit
The following table presents a reconciliation between the Company's income tax expense at statutory rates and the recorded income tax expense.
Years ended December 31
(In millions)2023
2022 (1)
2021 (1)
Income tax expense at statutory rates$(319)$(172)$(308)
Tax benefit from tax exempt income30 41 51 
Foreign taxes and credits(5)15 (3)
State income tax expense(13)(10)(13)
Other tax expense(6)(6)(5)
Income tax expense$(313)$(132)$(278)
(1) As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
Current and deferred components of the Company's income tax (expense) benefit
The following table presents the current and deferred components of the Company's income tax expense.
Years ended December 31
(In millions)2023
2022 (1)
2021 (1)
Current tax expense$(311)$(221)$(235)
Deferred tax (expense) benefit(2)89 (43)
Total income tax expense$(313)$(132)$(278)
(1) As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
Significant components of the Company's deferred tax assets and liabilities
The deferred tax effects of the significant components of the Company's deferred tax assets and liabilities are presented in the following table.
December 31
(In millions)2023
2022 (1)
Deferred Tax Assets:
Insurance reserves:
Property and casualty claim and claim adjustment expense reserves$202 $178 
Unearned premium reserves213 198 
Policyholder reserves160 75 
Deferred Revenue62 64 
Employee benefits23 35 
Deferred retroactive reinsurance benefit88 89 
Net unrealized losses418 706 
Other assets111 116 
Gross deferred tax assets1,277 1,461 
Deferred Tax Liabilities:
Investment valuation differences83 59 
Deferred acquisition costs126 113 
Net unrealized gains— — 
Software and hardware18 21 
Other liabilities34 17 
Gross deferred tax liabilities261 210 
Net deferred tax asset$1,016 $1,251 
(1) As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Tables)
 12 Months Ended
Dec. 31, 2023
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]  
Short-duration insurance contracts, reconciliation of claims development to liability
The table below reconciles the net liability for unpaid claim and claim adjustment expenses to the amount presented on the Consolidated Balance Sheets.
As of December 31
(In millions)2023
Net liability for unpaid claim and claim adjustment expenses:
Specialty$5,916 
Commercial9,021 
International2,276 
Life & Group (1)
582 
Corporate & Other368 
Total net claim and claim adjustment expenses18,163 
Reinsurance receivables: (2)
Specialty1,215 
Commercial1,082 
International433 
Life & Group93 
Corporate & Other (3)
2,318 
Total reinsurance receivables5,141 
Total gross liability for unpaid claim and claim adjustment expenses$23,304 
(1) The Life & Group segment amounts are related to unfunded structured settlements arising from short-duration contracts.
(2) Reinsurance receivables presented are gross of the allowance for uncollectible reinsurance and do not include reinsurance receivables related to paid losses.
(3) The Corporate & Other Reinsurance receivables are primarily related to A&EP claims covered under the A&EP Loss Portfolio Transfer (LPT).
Schedule of liability for unpaid claims and claims adjustment expense
The following table presents a reconciliation between beginning and ending claim and claim adjustment expense reserves.
As of or for the years ended December 31
(In millions)2023
2022 (1)
2021 (1)
Reserves, beginning of year:
Gross$22,120 $21,269 $19,862 
Ceded5,191 4,969 4,005 
Net reserves, beginning of year16,929 16,300 15,857 
Reduction of net reserves due to Excess Workers' Compensation Loss Portfolio Transfer— — (632)
Net incurred claim and claim adjustment expenses:
Provision for insured events of current year5,667 5,181 5,021 
Increase (decrease) in provision for insured events of prior years48 (32)15 
Amortization of discount44 44 48 
Total net incurred (2)
5,759 5,193 5,084 
Net payments attributable to:
Current year events(922)(821)(933)
Prior year events(3,679)(3,481)(3,016)
Total net payments(4,601)(4,302)(3,949)
Foreign currency translation adjustment and other76 (262)(60)
Net reserves, end of year18,163 16,929 16,300 
Ceded reserves, end of year5,141 5,191 4,969 
Gross reserves, end of year$23,304 $22,120 $21,269 
(1) In conjunction with the Company's adoption of ASU 2018-12, at January 1, 2023, long-term care reserves for policyholders currently receiving benefits were reclassified from Claim and claim adjustment expenses into Future policy benefits and this change was applied retrospectively as of January 1, 2021. See Note A to the Consolidated Financial Statements for additional information.
(2) Total net incurred does not agree to Insurance claims and policyholders' benefits as reflected on the Consolidated Statements of Operations due to amounts related to retroactive reinsurance deferred gain accounting, the loss on the Excess Workers' Compensation LPT (EWC LPT) and uncollectible reinsurance, which are not reflected in the table above.
Gross and net carried claim and claim adjustment expense reserves
The following tables present the gross and net carried reserves.
December 31, 2023 Specialty CommercialInternationalLife & GroupCorporate & OtherTotal
(In millions)
Gross Case Reserves$1,604 $3,291 $864 $626 $1,353 $7,738 
Gross IBNR Reserves5,527 6,812 1,845 49 1,333 15,566 
Total Gross Carried Claim and Claim Adjustment Expense Reserves$7,131 $10,103 $2,709 $675 $2,686 $23,304 
Net Case Reserves$1,392 $2,878 $708 $556 $129 $5,663 
Net IBNR Reserves4,524 6,143 1,568 26 239 12,500 
Total Net Carried Claim and Claim Adjustment Expense Reserves$5,916 $9,021 $2,276 $582 $368 $18,163 
December 31, 2022 Specialty CommercialInternational
Life & Group(1)
Corporate & OtherTotal
(In millions)
Gross Case Reserves$1,529 $3,156 $817 $647 $1,428 $7,577 
Gross IBNR Reserves5,349 6,239 1,586 48 1,321 14,543 
Total Gross Carried Claim and Claim Adjustment Expense Reserves$6,878 $9,395 $2,403 $695 $2,749 $22,120 
Net Case Reserves$1,310 $2,809 $686 $567 $137 $5,509 
Net IBNR Reserves4,253 5,621 1,317 27 202 11,420 
Total Net Carried Claim and Claim Adjustment Expense Reserves$5,563 $8,430 $2,003 $594 $339 $16,929 
(1) In conjunction with the Company's adoption of ASU 2018-12, at January 1, 2023, long-term care reserves for policyholders currently receiving benefits were reclassified from Claim and claim adjustment expenses into Future policy benefits and this change was applied retrospectively as of January 1, 2021. See Note A to the Consolidated Financial Statements for additional information.
Net prior year development The following table presents development recorded for the Specialty, Commercial, International and Corporate & Other segments.
Years ended December 31
(In millions)202320222021
Pretax (favorable) unfavorable development:
Specialty$(14)$(40)$(45)
Commercial(22)(43)(6)
International13 (13)2 
Corporate & Other71 6460 
Total pretax (favorable) unfavorable development$48 $(32)$11 
Impact of loss portfolio transfer on the consolidated statement of operations
The following table presents the impact of the Loss Portfolio Transfer on the Consolidated Statements of Operations.
Years ended December 31
(In millions)202320222021
Additional amounts ceded under LPT:
Net A&EP adverse development before consideration of LPT$86 $92 $143 
Provision for uncollectible third-party reinsurance on A&EP— (5)(5)
Total additional amounts ceded under LPT86 87 138 
Retroactive reinsurance benefit recognized(94)(91)(107)
Pretax impact of deferred retroactive reinsurance$(8)$(4)$31 
Specialty  
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]  
Short-duration insurance contracts, reconciliation of claims development to liability
The table below provides the line of business composition of the net liability for unpaid claim and claim adjustment expenses for the Specialty segment.
As of December 31
(In millions)2023
Net liability for unpaid claim and claim adjustment expenses:
Medical Professional Liability$1,460 
Other Professional Liability and Management Liability3,897 
Surety468 
Warranty28 
Other63 
Total net liability for unpaid claim and claim adjustment expenses$5,916 
Net prior year claim and allocated claim adjustment expense reserve development
The following table presents further detail of the development recorded for the Specialty segment.
Years ended December 31
(In millions)202320222021
Pretax (favorable) unfavorable development:
Medical Professional Liability$5 $18 $23 
Other Professional Liability and Management Liability37 50 24 
Surety(43)(83)(73)
Warranty(11)(21)(14)
Other(2)(4)(5)
Total pretax (favorable) unfavorable development$(14)$(40)$(45)
Commercial  
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]  
Short-duration insurance contracts, reconciliation of claims development to liability
The table below provides the line of business composition of the net liability for unpaid claim and claim adjustment expenses for the Commercial segment.
As of December 31
(In millions)2023
Net Claim and claim adjustment expenses:
Commercial Auto$926 
General Liability3,780 
Workers' Compensation3,645 
Property and Other670 
Total net liability for claim and claim adjustment expenses$9,021 
Net prior year claim and allocated claim adjustment expense reserve development
The following table presents further detail of the development recorded for the Commercial segment.
Years ended December 31
(In millions)202320222021
Pretax (favorable) unfavorable development:
Commercial Auto$33 $49 $53 
General Liability149 67 15 
Workers' Compensation(203)(152)(82)
Property and Other(1)(7)8 
Total pretax (favorable) unfavorable development$(22)$(43)$(6)
International  
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]  
Short-duration insurance contracts, reconciliation of claims development to liability
The table below provides the composition of the net liability for unpaid claim and claim adjustment expenses for the International segment.
As of December 31
(In millions)2023
Net Claim and claim adjustment expenses:
International excluding Hardy$1,655 
Hardy621 
Total net liability for claim and claim adjustment expenses$2,276 
Net prior year claim and allocated claim adjustment expense reserve development
The following table presents further detail of the development recorded for the International segment.
Years ended December 31
(In millions)202320222021
Pretax (favorable) unfavorable development:
Commercial$(18)$(10)$(35)
Specialty35 (4)36 
Other(4)1 1 
Total pretax (favorable) unfavorable development $13 $(13)$2 
CNAF Consolidated  
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]  
Schedule of historical claims duration
The table below presents information about average historical claims duration as of December 31, 2023 and is presented as required supplementary information, which is unaudited.
Average Annual Percentage Payout of Ultimate Net Incurred Claim and Allocated Claim Adjustment Expenses in Year:
12345678910
Specialty
Medical Professional Liability3.7 %16.4 %22.1 %17.2 %12.4 %9.1 %4.8 %2.9 %1.2 %1.1 %
Other Professional Liability and Management Liability6.5 %19.8 %19.3 %14.9 %10.9 %6.3 %4.9 %6.0 %1.7 %0.5 %
Surety(1)
17.7 %46.6 %17.7 %3.4 %2.2 %5.2 %(1.7)%(0.8)%(0.1)%— %
Commercial
Commercial Auto25.2 %22.2 %18.2 %14.3 %10.6 %4.9 %2.0 %0.7 %0.3 %0.5 %
General Liability3.6 %12.8 %16.3 %17.4 %14.4 %9.1 %5.9 %5.3 %2.2 %2.7 %
Workers' Compensation16.0 %22.9 %13.8 %8.8 %6.0 %3.2 %2.1 %1.3 %1.2 %1.7 %
International
International - Excluding Hardy16.9 %21.8 %9.8 %6.5 %5.9 %7.4 %8.4 %2.6 %2.8 %1.7 %
International - Hardy18.0 %31.3 %13.7 %7.5 %4.7 %4.9 %0.5 %2.3 %(1.4)%— %
(1) Due to the nature of the Surety business, average annual percentage payout of ultimate net incurred claim and allocated claim adjustment expenses has been calculated using only the payouts of mature accident years presented in the loss reserve development tables.
Hardy | International  
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]  
Short-duration contracts net incurred claims and allocated claim adjustment expenses
Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar YearAs of December 31, 2023
(In millions, except reported claims data)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023IBNRCumulative Number of Claims
Accident Year
2014$183 $182 $175 $169 $170 $170 $169 $167 $166 $167 $(1)8,534 
2015187 177 175 175 173 175 176 178 177 (3)9,741 
2016227 244 233 223 224 218 219 223 6 10,895 
2017243 252 242 243 251 251 239 (5)13,294 
2018268 298 302 307 307 324 36 15,366 
2019219 223 217 224 220 25 11,670 
2020210 201 195 192 55 7,036 
2021177 168 154 59 3,831 
2022190 186 96 2,371 
2023200 152 1,388 
Total$2,082 $420 
Short-duration contracts net cumulative paid claim adjustment expenses reconciliation of total liability for unpaid claim and claim adjustment expense
Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar Year
(In millions)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Accident Year
2014$56 $122 $140 $150 $155 $161 $162 $163 $164 $164 
201529 97 128 143 154 162 160 169 163 
201663 144 171 180 193 204 205 208 
201753 150 183 205 212 224 229 
201855 170 200 231 249 270 
201943 102 140 157 167 
202027 77 103 118 
202113 44 68 
202223 58 
202317 
Total$1,462 
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented$620 
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014(8)
Liability for unallocated claim adjustment expenses for accident years presented9 
Total net liability for unpaid claim and claim adjustment expenses$621 
Short-duration contracts reserve development
Net strengthening (releases) of prior accident year reserves is presented in the following table.
For the years ended December 31Calendar Year
(In millions)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Total(2)
Accident Year
2014$(1)$(7)$(6)$1 $— $(1)$(2)$(1)$1 $(16)
2015(10)(2)— (2)2 1 2 (1)(10)
201617 (11)(10)1 (6)1 4 (4)
20179 (10)1 8 — (12)(4)
201830 4 5 — 17 56 
20194 (6)7 (4)1 
2020(9)(6)(3)(18)
2021(9)(14)(23)
2022(4)(4)
(1) Data presented for these calendar years is required supplemental information, which is unaudited.
(2) The amounts included in the loss reserve development tables above are presented at the year-end 2023 foreign currency exchange rates for all periods presented to remove the effects of foreign currency exchange rate fluctuations between calendar years. The amounts included within the table on page 110 presenting the detail of the development recorded within the International segment include the impact of fluctuations in foreign currency exchange rates.
Medical Professional Liability | Specialty  
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]  
Short-duration contracts net incurred claims and allocated claim adjustment expenses
Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar YearAs of December 31, 2023
(In millions, except reported claims data)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023IBNRCumulative Number of Claims
Accident Year
2014$450 $489 $537 $530 $535 $529 $527 $524 $527 $525 $6 19,830 
2015433 499 510 494 488 510 501 498 494 15 18,218 
2016427 487 485 499 508 510 508 514 17 16,169 
2017412 449 458 460 455 460 456 20 15,345 
2018404 429 431 448 470 495 41 15,266 
2019430 445 458 471 469 62 14,409 
2020477 476 455 447 180 11,129 
2021377 376 374 193 9,523 
2022329 329 206 9,237 
2023340 281 8,240 
Total$4,443 $1,021 
Short-duration contracts net cumulative paid claim adjustment expenses reconciliation of total liability for unpaid claim and claim adjustment expense
Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar Year
(In millions)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Accident Year
2014$23 $136 $258 $359 $417 $472 $489 $497 $504 $510 
201522 101 230 313 384 420 444 458 463 
201618 121 246 339 401 436 460 483 
201719 107 235 308 355 388 417 
201821 115 211 290 349 418 
201917 91 183 280 349 
202011 61 139 201 
202111 49 118 
202210 57 
202314 
Total$3,030 
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented$1,413 
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 201422 
Liability for unallocated claim adjustment expenses for accident years presented25 
Total net liability for unpaid claim and claim adjustment expenses$1,460 
Short-duration contracts reserve development
Net strengthening (releases) of prior accident year reserves is presented in the following table.
For the years ended December 31Calendar Year
(In millions)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023Total
Accident Year
2014$39 $48 $(7)$5 $(6)$(2)$(3)$3 $(2)$75 
201566 11 (16)(6)22 (9)(3)(4)61 
201660 (2)14 9 2 (2)6 87 
201737 9 2 (5)5 (4)44 
201825 2 17 22 25 91 
201915 13 13 (2)39 
2020(1)(21)(8)(30)
2021(1)(2)(3)
2022— — 
Total net development for the accident years presented above14 16 9 
Total net development for accident years prior to 20142 (3)(4)
Total unallocated claim adjustment expense development7 5 — 
Total$23 $18 $5 
(1) Data presented for these calendar years is required supplemental information, which is unaudited.
Other Professional Liability and Management Liability | Specialty  
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]  
Short-duration contracts net incurred claims and allocated claim adjustment expenses
Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar YearAs of December 31, 2023
(In millions, except reported claims data)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023IBNRCumulative Number of Claims
Accident Year
2014$878 $898 $885 $831 $835 $854 $845 $841 $842 $838 $26 17,585 
2015888 892 877 832 807 813 836 855 858 18 17,454 
2016901 900 900 904 907 891 888 906 39 17,987 
2017847 845 813 791 775 758 746 69 18,199 
2018850 864 869 906 923 941 101 20,038 
2019837 845 856 876 939 100 19,515 
2020930 944 951 945 281 19,437 
20211,037 1,038 1,009 532 18,259 
20221,120 1,112 706 18,165 
20231,149 971 16,469 
Total$9,443 $2,843 
Short-duration contracts net cumulative paid claim adjustment expenses reconciliation of total liability for unpaid claim and claim adjustment expense
Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar Year
(In millions)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Accident Year
2014$51 $223 $392 $515 $647 $707 $743 $787 $802 $806 
201560 234 404 542 612 677 725 794 808 
201664 248 466 625 701 736 784 826 
201757 222 394 498 557 596 630 
201854 282 473 599 706 779 
201964 263 422 567 699 
202067 248 400 523 
202158 217 356 
202264 225 
202364 
Total$5,716 
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented$3,727 
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014115 
Liability for unallocated claim adjustment expenses for accident years presented55 
Total net liability for unpaid claim and claim adjustment expenses$3,897 
Short-duration contracts reserve development
Net strengthening (releases) of prior accident year reserves is presented in the following table.
For the years ended December 31Calendar Year
(In millions)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023Total
Accident Year
2014$20 $(13)$(54)$4 $19 $(9)$(4)$1 $(4)$(40)
20154 (15)(45)(25)6 23 19 3 (30)
2016(1)— 4 3 (16)(3)18 5 
2017(2)(32)(22)(16)(17)(12)(101)
201814 5 37 17 18 91 
20198 11 20 63 102 
202014 7 (6)15 
20211 (29)(28)
2022(8)(8)
Total net development for the accident years presented above49 45 43 
Total net development for accident years prior to 2014(27)5 (6)
Total unallocated claim adjustment expense development2 — — 
Total$24 $50 $37 
(1) Data presented for these calendar years is required supplemental information, which is unaudited.
Surety | Specialty  
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]  
Short-duration contracts net incurred claims and allocated claim adjustment expenses
Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar YearAs of December 31, 2023
(In millions, except reported claims data)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023IBNRCumulative Number of Claims
Accident Year
2014$123 $124 $94 $69 $60 $45 $45 $43 $42 $41 $2 5,135 
2015131 131 104 79 63 58 53 45 45 2 5,085 
2016124 124 109 84 67 64 58 43 3 5,565 
2017120 115 103 84 71 66 67 4 5,883 
2018114 108 91 62 56 51 10 6,249 
2019119 112 98 87 82 12 6,152 
2020128 119 81 67 34 4,678 
2021137 129 110 68 4,645 
2022155 158 116 4,350 
2023175 167 2,750 
Total$839 $418 
Short-duration contracts net cumulative paid claim adjustment expenses reconciliation of total liability for unpaid claim and claim adjustment expense
Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar Year
(In millions)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Accident Year
2014$7 $30 $38 $36 $38 $38 $39 $39 $38 $38 
20157 26 38 40 42 44 42 42 43 
20165 37 45 45 43 43 41 40 
201723 37 41 46 49 62 62 
20185 25 34 39 40 41 
201912 34 44 59 70 
20204 20 28 33 
20215 20 35 
202212 35 
20238 
Total$405 
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented$434 
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 201413 
Liability for unallocated claim adjustment expenses for accident years presented21 
Total net liability for unpaid claim and claim adjustment expenses$468 
Short-duration contracts reserve development
Net strengthening (releases) of prior accident year reserves is presented in the following table.
For the years ended December 31Calendar Year
(In millions)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023Total
Accident Year
2014$1 $(30)$(25)$(9)$(15)$— $(2)$(1)$(1)$(82)
2015— (27)(25)(16)(5)(5)(8)— (86)
2016— (15)(25)(17)(3)(6)(15)(81)
2017(5)(12)(19)(13)(5)1 (53)
2018(6)(17)(29)(6)(5)(63)
2019(7)(14)(11)(5)(37)
2020(9)(38)(14)(61)
2021(8)(19)(27)
20223 3 
Total net development for the accident years presented above(75)(83)(55)
Total net development for accident years prior to 20142 — 12 
Total unallocated claim adjustment expense development— — — 
Total$(73)$(83)$(43)
(1) Data presented for these calendar years is required supplemental information, which is unaudited.
Commercial Auto | Commercial  
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]  
Short-duration contracts net incurred claims and allocated claim adjustment expenses
Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar YearAs of December 31, 2023
(In millions, except reported claims data)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023IBNRCumulative Number of Claims
Accident Year
2014$234 $223 $212 $205 $205 $201 $201 $202 $201 $201 $1 33,633 
2015201 199 190 190 183 181 183 182 184 4 30,430 
2016198 186 186 186 190 195 200 197 4 30,455 
2017199 198 200 221 232 239 241 4 30,947 
2018229 227 227 245 254 255 1 34,333 
2019257 266 289 323 325 10 37,258 
2020310 303 304 298 21 29,142 
2021397 388 390 93 32,918 
2022437 465 137 36,777 
2023554 347 34,211 
Total$3,110 $622 
Short-duration contracts net cumulative paid claim adjustment expenses reconciliation of total liability for unpaid claim and claim adjustment expense
Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar Year
(In millions)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Accident Year
2014$64 $102 $137 $166 $187 $196 $198 $199 $199 $200 
201552 96 130 153 172 175 178 179 180 
201652 93 126 154 175 185 190 192 
201758 107 150 178 203 225 232 
201866 128 175 212 238 249 
201977 147 203 257 295 
202071 134 197 246 
202183 168 240 
2022112 236 
2023127 
Total$2,197 
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented$913 
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 20144 
Liability for unallocated claim adjustment expenses for accident years presented9 
Total net liability for unpaid claim and claim adjustment expenses$926 
Short-duration contracts reserve development
Net strengthening (releases) of prior accident year reserves is presented in the following table.
For the years ended December 31Calendar Year
(In millions)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023Total
Accident Year
2014$(11)$(11)$(7)$— $(4)$— $1 $(1)$— $(33)
2015(2)(9)— (7)(2)2 (1)2 (17)
2016(12)— — 4 5 5 (3)(1)
2017(1)2 21 11 7 2 42 
2018(2)— 18 9 1 26 
20199 23 34 2 68 
2020(7)1 (6)(12)
2021(9)2 (7)
202228 28 
Total net development for the accident years presented above53 45 28 
Total net development for accident years prior to 2014— 4 2 
Total unallocated claim adjustment expense development— — 3 
Total$53 $49 $33 
(1) Data presented for these calendar years is required supplemental information, which is unaudited.
General Liability | Commercial  
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]  
Short-duration contracts net incurred claims and allocated claim adjustment expenses
Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar YearAs of December 31, 2023
(In millions, except reported claims data)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023IBNRCumulative Number of Claims
Accident Year
2014$653 $658 $654 $631 $635 $658 $659 $659 $676 $679 $28 28,196 
2015581 576 574 589 600 602 617 625 639 28 24,261 
2016623 659 667 671 673 683 684 704 39 24,803 
2017632 632 632 634 630 652 690 36 22,471 
2018653 644 646 639 650 679 129 20,425 
2019680 682 682 691 720 174 19,647 
2020723 722 726 736 347 14,593 
2021782 784 793 401 15,121 
2022929 928 676 15,754 
20231,071 963 11,633 
Total$7,639 $2,821 
Short-duration contracts net cumulative paid claim adjustment expenses reconciliation of total liability for unpaid claim and claim adjustment expense
Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar Year
(In millions)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Accident Year
2014$31 $119 $247 $376 $481 $547 $569 $607 $624 $642 
201519 110 230 357 446 501 530 561 573 
201632 163 279 407 481 524 582 620 
201723 118 250 399 471 553 606 
201833 107 228 307 428 491 
201925 98 181 322 455 
202023 99 192 280 
202126 140 262 
202229 123 
202333 
Total$4,085 
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented$3,554 
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014162 
Liability for unallocated claim adjustment expenses for accident years presented64 
Total net liability for unpaid claim and claim adjustment expenses$3,780 
Short-duration contracts reserve development
Net strengthening (releases) of prior accident year reserves is presented in the following table.
For the years ended December 31Calendar Year
(In millions)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023Total
Accident Year
2014$5 $(4)$(23)$4 $23 $1 $— $17 $3 $26 
2015(5)(2)15 11 2 15 8 14 58 
201636 8 4 2 10 1 20 81 
2017— — 2 (4)22 38 58 
2018(9)2 (7)11 29 26 
20192 — 9 29 40 
2020(1)4 10 13 
20212 9 11 
2022(1)(1)
Total net development for the accident years presented above13 74 151 
Total net development for accident years prior to 2014— (7)(2)
Total unallocated claim adjustment expense development2 — — 
Total$15 $67 $149 
(1) Data presented for these calendar years is required supplemental information, which is unaudited.
Workers' Compensation | Commercial  
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]  
Short-duration contracts net incurred claims and allocated claim adjustment expenses
Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar YearAs of December 31, 2023
(In millions, except reported claims data)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023IBNRCumulative Number of Claims
Accident Year
2014$467 $480 $479 $452 $450 $446 $439 $448 $430 $419 $70 33,550 
2015422 431 406 408 394 382 372 353 334 59 31,904 
2016426 405 396 382 366 355 331 308 56 31,994 
2017440 432 421 400 402 399 398 78 33,142 
2018450 440 428 415 415 404 74 34,886 
2019452 449 437 436 419 78 34,349 
2020477 466 446 414 135 29,454 
2021468 454 432 146 30,066 
2022497 489 198 33,229 
2023555 344 31,549 
Total$4,172 $1,238 
Short-duration contracts net cumulative paid claim adjustment expenses reconciliation of total liability for unpaid claim and claim adjustment expense
Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar Year
(In millions)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Accident Year
2014$61 $159 $215 $258 $282 $290 $297 $306 $312 $319 
201551 131 180 212 231 243 251 256 259 
201653 129 169 198 219 227 234 235 
201763 151 207 243 265 279 287 
201868 163 229 259 280 298 
201971 169 223 262 291 
202065 147 200 228 
202167 164 222 
202279 192 
202387 
Total$2,418 
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented$1,754 
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 20141,842 
Other (2)
(23)
Liability for unallocated claim adjustment expenses for accident years presented72 
Total net liability for unpaid claim and claim adjustment expenses$3,645 
Short-duration contracts reserve development
Net strengthening (releases) of prior accident year reserves is presented in the following table.
For the years ended December 31Calendar Year
(In millions)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023Total
Accident Year
2014$13 $(1)$(27)$(2)$(4)$(7)$9 $(18)$(11)$(48)
20159 (25)2 (14)(12)(10)(19)(19)(88)
2016(21)(9)(14)(16)(11)(24)(23)(118)
2017(8)(11)(21)2 (3)(1)(42)
2018(10)(12)(13)— (11)(46)
2019(3)(12)(1)(17)(33)
2020(11)(20)(32)(63)
2021(14)(22)(36)
2022(8)(8)
Total net development for the accident years presented above(46)(99)(144)
Adjustment for development on a discounted basis2 (3)(2)
Total net development for accident years prior to 2014(38)(60)(63)
Total unallocated claim adjustment expense development— 10 6 
Total$(82)$(152)$(203)
(1) Data presented for these calendar years is required supplemental information, which is unaudited.
(2) Other includes the effect of discounting lifetime claim reserves.
Excluding Hardy | International  
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]  
Short-duration contracts net incurred claims and allocated claim adjustment expenses
Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar YearAs of December 31, 2023
(In millions, except reported claims data)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023IBNRCumulative Number of Claims
Accident Year
2014$276 $291 $291 $279 $272 $289 $290 $283 $286 $288 $15 25,130 
2015289 304 303 286 280 283 285 285 281 19 23,608 
2016284 302 288 285 276 290 292 309 36 18,079 
2017299 363 383 376 371 360 393 39 18,841 
2018367 385 389 388 401 411 48 21,327 
2019342 355 352 360 362 61 18,993 
2020381 372 362 347 107 15,744 
2021408 397 375 162 15,136 
2022428 438 227 11,899 
2023478 359 7,869 
Total$3,682 $1,073 
Short-duration contracts net cumulative paid claim adjustment expenses reconciliation of total liability for unpaid claim and claim adjustment expense
Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table.
As of December 31Calendar Year
(In millions)
2014(1)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Accident Year
2014$51 $121 $149 $166 $182 $203 $236 $241 $248 $253 
201556 132 162 182 204 219 230 237 246 
201666 131 158 180 192 214 226 237 
201764 146 186 214 237 264 321 
201889 166 212 242 266 308 
201973 164 201 224 247 
202060 128 162 178 
202156 124 154 
202246 138 
202346 
Total$2,128 
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented$1,554 
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 201464 
Liability for unallocated claim adjustment expenses for accident years presented37 
Total net liability for unpaid claim and claim adjustment expenses$1,655 
Short-duration contracts reserve development
Net strengthening (releases) of prior accident year reserves is presented in the following table.
For the years ended December 31Calendar Year
(In millions)
2015(1)
2016(1)
2017(1)
2018(1)
2019(1)
2020(1)
2021(1)
2022(1)
2023
Total (2)
Accident Year
2014$15 $— $(12)$(7)$17 $1 $(7)$3 $2 $12 
201515 (1)(17)(6)3 2 — (4)(8)
201618 (14)(3)(9)14 2 17 25 
201764 20 (7)(5)(11)33 94 
201818 4 (1)13 10 44 
201913 (3)8 2 20 
2020(9)(10)(15)(34)
2021(11)(22)(33)
202210 10 
(1) Data presented for these calendar years is required supplemental information, which is unaudited.
(2) The amounts included in the loss reserve development tables above are presented at the year-end 2023 foreign currency exchange rates for all periods presented to remove the effects of foreign currency exchange rate fluctuations between calendar years. The amounts included within the table on page 110 presenting the detail of the development recorded within the International segment include the impact of fluctuations in foreign currency exchange rates.
v3.24.0.1
Future Policy Benefit Reserves (Tables)
 12 Months Ended
Dec. 31, 2023
Insurance [Abstract]  
Liability for Future Policy Benefit, Activity
The following table summarizes balances and changes in the LFPB.
(In millions)
202320222021
Present value of future net premiums
Balance, January 1$3,991 $4,735 $5,086 
     Effect of changes in discount rate(74)(880)(1,140)
Balance, January 1, at original locked in discount rate3,917 3,855 3,946 
     Effect of changes in cash flow assumptions (1)
28 352 173 
     Effect of actual variances from expected experience (1)
(126)(49)(24)
Adjusted balance, January 13,819 4,158 4,095 
Interest accrual202 216 219 
     Net premiums: earned during period(436)(457)(459)
Balance, end of period at original locked in discount rate3,585 3,917 3,855 
     Effect of changes in discount rate125 74 880 
Balance, December 31$3,710 $3,991 $4,735 
Present value of future benefits & expenses
Balance, January 1$17,471 $22,745 $23,955 
     Effect of changes in discount rate(125)(5,942)(7,395)
Balance, January 1, at original locked in discount rate17,346 16,803 16,560 
     Effect of changes in cash flow assumptions (1)
36 538 176 
     Effect of actual variances from expected experience (1)
(46)(21)(19)
Adjusted balance, January 117,336 17,320 16,717 
Interest accrual962 979 973 
     Benefit & expense payments(1,207)(953)(887)
Balance, end of period at original locked in discount rate17,091 17,346 16,803 
     Effect of changes in discount rate578 125 5,942 
Balance, December 31$17,669 $17,471 $22,745 
Net LFPB$13,959 $13,480 $18,010 
(1) As of December 31, 2023, 2022 and 2021 the re-measurement gain (loss) of $(88) million, $(214) million and $(8) million presented parenthetically on the Consolidated Statement of Operations is comprised of the effect of changes in cash flow assumptions and the effect of actual variances from expected experience.
The following table presents earned premiums and interest expense associated with the Company’s long-term care business recognized on the Consolidated Statement of Operations.
Years ended December 31
(In millions)
202320222021
Earned premiums$451 $473 $491 
Interest expense760 763 754 
The following table presents undiscounted expected future benefit and expense payments, and undiscounted expected future gross premiums.
As of December 31
(In millions)
20232022
  Expected future benefit and expense payments$32,851 $34,261 
  Expected future gross premiums5,414 5,910 
The weighted average interest rates in the table below are calculated based on the rate used to discount all future cash flows.
As of December 31
20232022
   Original locked in discount rate5.22 %5.27 %
Upper-medium grade fixed income instrument discount rate4.94 5.23 
v3.24.0.1
Reinsurance (Tables)
 12 Months Ended
Dec. 31, 2023
Reinsurance Disclosures [Abstract]  
Components of Reinsurance Receivables
The following table presents the amounts receivable from reinsurers.
December 31
(In millions)20232022
Reinsurance receivables related to insurance reserves:
Ceded claim and claim adjustment expenses$5,141 $5,191 
Reinsurance receivables related to paid losses293 247 
Reinsurance receivables5,434 5,438 
Allowance for uncollectible reinsurance(22)(22)
Reinsurance receivables, net of allowance for uncollectible reinsurance$5,412 $5,416 
Reinsurance Recoverable, Credit Quality Indicator The following table summarizes the outstanding amount of voluntary reinsurance receivables, gross of any collateral arrangements, by financial strength rating.
(In millions)December 31, 2023
A- to A++$4,047 
B- to B++769 
Insolvent7 
Total voluntary reinsurance outstanding balance (1)
$4,823 
(1)    Expected credit losses for legacy A&EP receivables are ceded to NICO and the reinsurance limit on the LPT has not been exhausted, therefore no allowance is recorded for these receivables and they are excluded from the table above. Refer to Note E to the Consolidated Financial Statements for information regarding the LPT. The Company has also excluded receivables from involuntary pools.
Components of Earned and Written Premiums
The effects of reinsurance on earned premiums and written premiums are presented in the following tables.
(In millions)DirectAssumedCededNetAssumed/
Net %
2023 Earned Premiums
Property and casualty$13,908 $223 $5,102 $9,029 2.5 %
Long-term care407 44 — 451 9.8 %
Total earned premiums$14,315 $267 $5,102 $9,480 2.8 %
2022 Earned Premiums
Property and casualty$13,097 $231 $5,134 $8,194 2.8 %
Long-term care427 46 — 473 9.7 %
Total earned premiums$13,524 $277 $5,134 $8,667 3.2 %
2021 Earned Premiums
Property and casualty$12,554 $240 $5,110 $7,684 3.1 %
Long-term care443 48 — 491 9.8 %
Total earned premiums$12,997 $288 $5,110 $8,175 3.5 %
(In millions)DirectAssumedCededNetAssumed/
Net %
2023 Written Premiums
Property and casualty$14,498 $219 $5,272 $9,445 2.3 %
Long-term care404 43 — 447 9.6 %
Total written premiums$14,902 $262 $5,272 $9,892 2.6 %
2022 Written Premiums
Property and casualty$13,843 $235 $5,417 $8,661 2.7 %
Long-term care421 46 — 467 9.9 %
Total written premiums$14,264 $281 $5,417 $9,128 3.1 %
2021 Written Premiums
Property and casualty$13,150 $255 $5,485 $7,920 3.2 %
Long-term care437 48 — 485 9.9 %
Total written premiums$13,587 $303 $5,485 $8,405 3.6 %
v3.24.0.1
Debt (Tables)
 12 Months Ended
Dec. 31, 2023
Debt Disclosure [Abstract]  
Schedule of debt instruments
Debt is composed of the following long-term obligations.
December 31
(In millions)20232022
Short-term debt:
Debenture of CNAF, 7.250%, face amount of $243, due November 15, 2023
$— $243 
Senior notes of CNAF:
3.950%, face amount of $550, due May 15, 2024
550 — 
Total short-term debt550 243 
Long-term debt:
Senior notes of CNAF:
3.950%, face amount of $550, due May 15, 2024
— 549 
4.500%, face amount of $500, due March 1, 2026
500 499 
3.450%, face amount of $500, due August 15, 2027
498 497 
3.900%, face amount of $500, due May 1, 2029
497 497 
2.050%, face amount of $500, due August 15, 2030
496 496 
5.500%, face amount of $500, due June 15, 2033
490 — 
Total long-term debt2,481 2,538 
Total debt$3,031 $2,781 
Maturity of debt
The combined aggregate maturities for debt as of December 31, 2023 are presented in the following table.
(In millions)
2024$550 
2025— 
2026500 
2027500 
2028— 
Thereafter1,500 
Less: discount(19)
Total$3,031 
v3.24.0.1
Benefit Plans (Tables)
 12 Months Ended
Dec. 31, 2023
Retirement Benefits [Abstract]  
Funded status
The following table presents a reconciliation of benefit obligations and plan assets.
Pension BenefitsPostretirement Benefits
(In millions)2023202220232022
Benefit obligation as of January 1$1,931 $2,561 $4 $6 
Changes in benefit obligation:
Interest cost98 67 — — 
Participants' contributions— — 1 2 
Actuarial (gain) loss27 (514)4 — 
Benefits paid(168)(171)(4)(4)
Foreign currency translation and other5 (12)— — 
Settlement through group annuity purchase(86)— — — 
Benefit obligation as of December 311,807 1,931 5 4 
Fair value of plan assets as of January 12,025 2,577 — — 
Change in plan assets:
Actual return on plan assets194 (374)— — 
Company contributions8 7 3 2 
Participants' contributions— — 1 2 
Benefits paid(168)(171)(4)(4)
Foreign currency translation and other5 (14)— — 
Settlement through group annuity purchase(80)— — — 
Fair value of plan assets as of December 311,984 2,025 — — 
Funded status$177 $94 $(5)$(4)
Amounts recognized on the Consolidated Balance Sheets as of December 31:
Other assets$223 $143 $— $— 
Other liabilities(46)(49)(5)(4)
Net amount recognized$177 $94 $(5)$(4)
Amounts recognized in Accumulated other comprehensive income, not yet recognized in net periodic cost (benefit):
Net actuarial (gain) loss$658 $743 $3 $1 
Net amount recognized$658 $743 $3 $1 
Components of net periodic cost (benefit)
The components of net periodic pension cost (benefit) are presented in the following table.
Years ended December 31
(In millions)202320222021
Net periodic pension cost (benefit)
Interest cost on projected benefit obligation$98 $67 $62 
Expected return on plan assets(119)(152)(154)
Amortization of net actuarial loss (gain) 33 30 46 
Settlement loss— — 1 
Total net periodic pension cost (benefit)$12 $(55)$(45)
The following table indicates the line items in which the non-service cost (benefit) is presented in the Consolidated Statements of Operations.
Years ended December 31
(In millions)202320222021
Non-Service Cost (benefit):
Insurance claims and policyholder's benefits$3 $(15)$(13)
Other operating expenses9 (40)(32)
Total net periodic pension cost (benefit)$12 $(55)$(45)
Schedule of amounts recognized in Other comprehensive income
The amounts recognized in Other comprehensive income are presented in the following table.
Years ended December 31
(In millions)202320222021
Pension and postretirement benefits
Amounts arising during the period$50 $(12)$262 
Settlement— — 1 
Reclassification adjustment relating to prior service credit— — — 
Reclassification adjustment relating to actuarial loss34 30 46 
Total increase (decrease) in Other comprehensive income$84 $18 $309 
Actuarial assumptions for benefit obligations and for net cost or benefit
Actuarial assumptions used for the CNA Retirement Plan and CNA Health and Group Benefits Program to determine benefit obligations are presented in the following table. The interest crediting rate is the weighted average interest rate applied to the individual pension balances for employees who elected to cease accruals effective December 31, 1999.
December 3120232022
Pension benefits
Discount rate5.100 %5.350 %
Interest crediting rate4.500 3.500 
Postretirement benefits
Discount rate5.100 %5.250 %
Actuarial assumptions used for the CNA Retirement Plan and CNA Health and Group Benefits Program to determine net cost or benefit are presented in the following table.
Years ended December 31202320222021
Pension benefits
Discount rate5.350 %2.750 %2.350 %
Expected long-term rate of return6.250 6.250 6.750 
Interest crediting rate3.500 3.000 3.000 
Postretirement benefits
Discount rate5.250 %2.250 %1.600 %
Fair value of plan assets measured on a recurring basis
Pension plan assets measured at fair value on a recurring basis are presented in the following tables.
December 31, 2023
(In millions)Level 1Level 2Level 3Total
Assets
Fixed maturity securities:
Corporate bonds and other$10 $1,041 $6 $1,057 
States, municipalities and political subdivisions— 50 — 50 
Asset-backed— 233 8 241 
Total fixed maturity securities10 1,324 14 1,348 
Equity securities119 6 — 125 
Short-term investments96 — — 96 
Other assets— 15 — 15 
Total assets measured at fair value$225 $1,345 $14 1,584 
Total equity securities measured at net asset value(1)
25 
Total limited partnerships measured at net asset value (1)
375 
Total$1,984 
December 31, 2022
(In millions)Level 1Level 2Level 3Total
Assets
Fixed maturity securities:
Corporate bonds and other$— $859 $7 $866 
States, municipalities and political subdivisions— 49 — 49 
Asset-backed— 157 9 166 
Total fixed maturity securities— 1,065 16 1,081 
Equity securities218 13 — 231 
Short-term investments145 1 — 146 
Other assets— 12 — 12 
Total assets measured at fair value$363 $1,091 $16 1,470 
Total equity securities measured at net asset value (1)
21 
Total limited partnerships measured at net asset value (1)
534 
Total$2,025 
(1) 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 for these investments are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the Plan's Statement of Financial Position.
Schedule of expected benefit payments
The table below presents the estimated future minimum benefit payments to participants as of December 31, 2023.
(In millions)Pension BenefitsPostretirement Benefits
2024$164 $1 
2025163 1 
2026161 1 
2027158 — 
2028154 — 
2029-2033692 1 
v3.24.0.1
Stock-Based Compensation (Tables)
 12 Months Ended
Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]  
Restricted shares, performance-based restricted share units and performance share unit activity
The following table presents activity for non-vested RSUs and performance share units under the Plan in 2023.
Number of AwardsWeighted Average Grant Date Fair Value
Balance as of January 1, 20232,465,752 $43.10 
Awards granted1,437,605 37.06 
Awards vested(950,620)38.06 
Awards forfeited, canceled or expired(478,823)42.28 
Performance-based adjustment152,399 36.87 
Balance as of December 31, 20232,626,313 41.40 
v3.24.0.1
Other Intangible Assets (Tables)
 12 Months Ended
Dec. 31, 2023
Intangible Assets, Gross (Excluding Goodwill) [Abstract]  
Schedule of Other Intangible Assets
Other intangible assets are presented in the following table.
December 3120232022
(In millions)Economic Useful LifeGross Carrying AmountAccumulated AmortizationGross Carrying AmountAccumulated Amortization
Finite-lived intangible assets:
Distribution channel15 years$10 $8 $10 $7 
Indefinite-lived intangible assets:
Syndicate capacity45 42 
Agency force16 16 
Insurance licenses15 10 
Total indefinite-lived intangible assets76 68 
Total other intangible assets$86 $8 $78 $7 
v3.24.0.1
Leases (Tables)
 12 Months Ended
Dec. 31, 2023
Leases [Abstract]  
Assets and liabilities
The following table presents operating lease ROU assets and lease liabilities.
(In millions)December 31, 2023December 31, 2022
Operating lease ROU assets$140 $155 
Operating lease liabilities215 220 
Operating lease, liability, maturity
The following table presents the maturities of operating lease liabilities.
(In millions)December 31, 2023
2024$36 
202532 
202630
202728 
202825
Thereafter103 
Total lease payments254 
Less: Discount(39)
Total operating lease liabilities$215 
Lease cost
The following table presents the weighted average remaining lease term for operating leases and weighted average discount rate used in calculating operating lease ROU assets.
December 31, 2023December 31, 2022
Weighted average remaining lease term8.4 years9.2 years
Weighted average discount rate3.7 %3.4 %
v3.24.0.1
Stockholders' Equity and Statutory Accounting Practices (Tables)
 12 Months Ended
Dec. 31, 2023
Stockholders' Equity and Statutory Accounting Practices [Abstract]  
Combined statutory capital and surplus and net income (loss)
Combined statutory capital and surplus and statutory net income (loss) for the Combined Continental Casualty Companies are presented in the table below, determined in accordance with accounting practices prescribed or permitted by insurance and/or other regulatory authorities.
Statutory Capital and SurplusStatutory Net Income (Loss)
December 31Years ended December 31
(In millions)
2023 (1)
2022
2023 (1)
20222021
Combined Continental Casualty Companies$10,946 $10,572 $1,172 $1,072 $1,253 
(1) Information derived from the statutory-basis financial statements to be filed with insurance regulators.
v3.24.0.1
Accumulated Other Comprehensive Income (Loss) by Component (Tables)
 12 Months Ended
Dec. 31, 2023
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]  
Accumulated Other Comprehensive Income (Loss) by Component
The tables below display the changes in Accumulated other comprehensive income (loss) by component.
(In millions)Net unrealized gains (losses) on investments with an allowance for credit losses
Net unrealized gains (losses) on other investments(1)
Pension and postretirement benefits
Cumulative impact of changes in discount rates used to measure long duration contracts(1)
Cumulative foreign currency translation adjustmentTotal
Balance as of January 1, 2023, as previously reported$(7)$(2,738)$(591)$— $(221)$(3,557)
Cumulative effect adjustment from accounting change for adoption of ASU 2018-12(1) net of tax (expense) benefit of $—, $—, $—, $11, $— and $11
— — — (41)— (41)
Balance as of January 1, 2023(7)(2,738)(591)(41)(221)(3,598)
Other comprehensive income (loss) before reclassifications(24)1,072 39 (318)58 827 
Amounts reclassified from accumulated other comprehensive income (loss) net of tax (expense) benefit of $5, $14, $7, $—, $— and $26
(19)(53)(27)— — (99)
Other comprehensive income (loss) net of tax (expense) benefit of $1, $(304), $(17), $85, $— and $(235)
(5)1,125 66 (318)58 926 
Balance as of December 31, 2023$(12)$(1,613)$(525)$(359)$(163)$(2,672)
(In millions)Net unrealized gains (losses) on investments with an allowance for credit losses
Net unrealized gains (losses) on other investments(1)
Pension and postretirement benefits
Cumulative impact of changes in discount rates used to measure long duration contracts(1)
Cumulative foreign currency translation adjustmentTotal
Balance as of January 1, 2022, as previously reported$(2)$1,039 $(604)$— $(113)$320 
Cumulative effect adjustment from accounting change for adoption of ASU 2018-12(1) net of tax (expense) benefit of $—, $(617), $—, $1,063, $— and $446
— 2,320 — (4,000)— (1,680)
Balance as of January 1, 2022, as adjusted(2)3,359 (604)(4,000)(113)(1,360)
Other comprehensive income (loss) before reclassifications— (6,223)(11)3,959 (108)(2,383)
Amounts reclassified from accumulated other comprehensive income (loss) net of tax (expense) benefit of $(1), $21, $6, $—, $— and $26
5 (126)(24)— — (145)
Other comprehensive income (loss) net of tax (expense) benefit of $1, $1,622, $(3), $(1,052), $— and $568
(5)(6,097)13 3,959 (108)(2,238)
Balance as of December 31, 2022$(7)$(2,738)$(591)$(41)$(221)$(3,598)
(In millions)Net unrealized gains (losses) on investments with an allowance for credit losses
Net unrealized gains (losses) on other investments(1)
Pension and postretirement benefits
Cumulative impact of changes in discount rates used to measure long duration contracts(1)
Cumulative foreign currency translation adjustmentTotal
Balance as of January 1, 2021, as previously reported$— $1,745 $(848)$— $(94)$803 
Cumulative effect adjustment from accounting change for adoption of ASU 2018-12(1) net of tax (expense) benefit of $—, $(691), $—, $1,313, $— and $622
— 2,601 — (4,941)— (2,340)
Balance as of January 1, 2021, as adjusted— 4,346 (848)(4,941)(94)(1,537)
Other comprehensive income (loss) before reclassifications(7)(906)207 941 (19)216 
Amounts reclassified from accumulated other comprehensive income (loss) net of tax (expense) benefit of $1, $(21), $10, $—, $— and $(10)
(5)81 (37)— — 39 
Other comprehensive income (loss) net of tax (expense) benefit of $1, $263, $(65), $(250), $— and $(51)
(2)(987)244 941 (19)177 
Balance as of December 31, 2021$(2)$3,359 $(604)$(4,000)$(113)$(1,360)
1) See Note A to the Consolidated Financial Statements for additional information.
Reclassification out of Accumulated Other Comprehensive Income
Amounts reclassified from Accumulated other comprehensive income (loss) shown above are reported in Net income (loss) as follows:
Component of AOCIConsolidated Statements of Operations Line Item Affected by Reclassifications
Net unrealized gains (losses) on investments with an allowance for credit losses and Net unrealized gains (losses) on other investmentsNet investment gains (losses)
Pension and postretirement benefitsOther operating expenses and Insurance claims and policyholders' benefits
v3.24.0.1
Business Segments (Tables)
 12 Months Ended
Dec. 31, 2023
Segment Reporting [Abstract]  
Significant components of the Company's continuing operations and selected balance sheet items
The Company's results of operations and selected balance sheet items by segment are presented in the following tables.
Year ended December 31, 2023
Specialty
Commercial		InternationalLife &
Group		Corporate
& Other		  
(In millions)EliminationsTotal
Net written premiums$3,329 $4,880 $1,237 $447 $— $(1)$9,892 
Operating revenues 
Net earned premiums$3,307 $4,547 $1,176 $451 $— $(1)$9,480 
Net investment income558 645 103 896 62 — 2,264 
Non-insurance warranty revenue1,624 — — — — — 1,624 
Other revenues1 29 — (1)11 (10)30 
Total operating revenues5,490 5,221 1,279 1,346 73 (11)13,398 
Claims, benefits and expenses      
Net incurred claims and benefits1,923 2,995 722 1,317 82 — 7,039 
Policyholders’ dividends8 21 — — — — 29 
Amortization of deferred acquisition costs686 729 229 — — — 1,644 
Non-insurance warranty expense1,544 — — — — — 1,544 
Other insurance related expenses373 620 139 118 2 (1)1,251 
Other expenses53 30 (4)1 204 (10)274 
Total claims, benefits and expenses4,587 4,395 1,086 1,436 288 (11)11,781 
Core income (loss) before income tax903 826 193 (90)(215)— 1,617 
Income tax (expense) benefit on core income (loss)(195)(174)(48)42 42 — (333)
Core income (loss) $708 $652 $145 $(48)$(173)$— 1,284 
Net investment gains (losses)(99)
Income tax (expense) benefit on net investment gains (losses)20 
Net investment gains (losses), after tax(79)
Net income (loss)$1,205 
December 31, 2023
(In millions)      
Reinsurance receivables$1,281 $1,218 $468 $93 $2,374 $— $5,434 
Insurance receivables1,053 2,024 388 5 — — 3,470 
Deferred acquisition costs392 371 133 — — — 896 
Goodwill117 — 29 — — — 146 
Deferred non-insurance warranty acquisition expense3,661 — — — — — 3,661 
Insurance reserves 
Claim and claim adjustment expenses7,131 10,103 2,709 675 2,686 — 23,304 
Unearned premiums3,227 2,858 749 99 — — 6,933 
Future policy benefits— — — 13,959 — — 13,959 
Deferred non-insurance warranty revenue4,694 — — — — — 4,694 
Year ended December 31, 2022
Specialty
Commercial		International
Life &
Group (1)
Corporate
& Other		  
(In millions)Eliminations
Total (1)
Net written premiums$3,306 $4,193 $1,164 $467 $(1)$(1)$9,128 
Operating revenues 
Net earned premiums$3,203 $3,923 $1,070 $473 $(1)$(1)$8,667 
Net investment income431 488 63 804 19 — 1,805 
Non-insurance warranty revenue1,574 — — — — — 1,574 
Other revenues1 30 1 (1)6 (5)32 
Total operating revenues5,209 4,441 1,134 1,276 24 (6)12,078 
Claims, benefits and expenses    
Net incurred claims and benefits1,839 2,607 637 1,469 76 — 6,628 
Policyholders’ dividends6 19 — — — — 25 
Amortization of deferred acquisition costs656 634 200 — — — 1,490 
Non-insurance warranty expense1,471 — — — — — 1,471 
Other insurance related expenses336 557 146 118 4 (1)1,160 
Other expenses51 36 26 9 174 (5)291 
Total claims, benefits and expenses4,359 3,853 1,009 1,596 254 (6)11,065 
Core income (loss) before income tax850 588 125 (320)(230)— 1,013 
Income tax (expense) benefit on core income (loss)(182)(122)(19)99 47 — (177)
Core income (loss)$668 $466 $106 $(221)$(183)$— 836 
Net investment gains (losses)(199)
Income tax (expense) benefit on net investment gains (losses)45 
Net investment gains (losses), after tax(154)
Net income (loss)$682 
December 31, 2022
(In millions)
Reinsurance receivables$1,384 $1,062 $414 $101 $2,477 $— $5,438 
Insurance receivables1,082 1,728 369 8 — — 3,187 
Deferred acquisition costs381 321 104 — — — 806 
Goodwill117 — 27 — — — 144 
Deferred non-insurance warranty acquisition expense3,671 — — — — — 3,671 
Insurance reserves 
Claim and claim adjustment expenses6,878 9,395 2,403 695 2,749 — 22,120 
Unearned premiums3,193 2,425 653 103 — — 6,374 
Future policy benefits— — — 13,480 — — 13,480 
Deferred non-insurance warranty revenue4,714 — — — — — 4,714 
(1) As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
Year ended December 31, 2021
Specialty
Commercial
Life &
Group (1)
Corporate
& Other
(In millions)InternationalEliminations
Total (1)
Net written premiums$3,225 $3,595 $1,101 $485 $— $(1)$8,405 
Operating revenues 
Net earned premiums$3,076 $3,552 $1,057 $491 $— $(1)$8,175 
Net investment income497 624 57 966 15 — 2,159 
Non-insurance warranty revenue1,430 — — — — — 1,430 
Other revenues1 23 — — 6 (6)24 
Total operating revenues5,004 4,199 1,114 1,457 21 (7)11,788 
Claims, benefits and expenses     
Net incurred claims and benefits1,787 2,540 652 1,261 109 — 6,349 
Policyholders’ dividends3 19 — — — — 22 
Amortization of deferred acquisition costs643 594 206 — — — 1,443 
Non-insurance warranty expense1,328 — — — — — 1,328 
Other insurance related expenses296 511 144 103 9 (1)1,062 
Other expenses47 38 (2)10 155 (6)242 
Total claims, benefits and expenses4,104 3,702 1,000 1,374 273 (7)10,446 
Core income (loss) before income tax900 497 114 83 (252)— 1,342 
Income tax (expense) benefit on core income (loss)(196)(103)(28)25 48 — (254)
Core income (loss)$704 $394 $86 $108 $(204)$— 1,088 
Net investment gains (losses)120 
Income tax (expense) benefit on net investment gains (losses)(24)
Net investment gains (losses), after tax96 
Net income (loss)$1,184 
Year ended December 31, 2021
(In millions)
Reinsurance receivables$1,200 $923 $381 $401 $2,579 $— $5,484 
Insurance receivables1,136 1,488 340 6 4 — 2,974 
Deferred acquisition costs363 278 96 — — — 737 
Goodwill117 — 31 — — — 148 
Deferred non-insurance warranty acquisition expense3,476 — — — — — 3,476 
Insurance reserves 
Claim and claim adjustment expenses6,433 8,890 2,280 848 2,817 — 21,268 
Unearned premiums3,001 2,066 585 109 — — 5,761 
Future policy benefits— — — 18,298 — — 18,298 
Deferred non-insurance warranty revenue4,503 — — — — — 4,503 
(1) As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
Revenues by line of business
The following table presents operating revenues by line of business for each reportable segment.
Years ended December 31
(In millions)202320222021
Specialty
Management & Professional Liability$2,931 $2,771 $2,776 
Surety731 652 604 
Warranty & Alternative Risks1,828 1,786 1,624 
Specialty revenues5,490 5,209 5,004 
Commercial
Middle Market1,696 1,532 1,508 
Construction1,678 1,421 1,322 
Small Business631 581 558 
Other Commercial1,216 907 811 
Commercial revenues5,221 4,441 4,199 
International
Canada383 366 344 
Europe532 466 473 
Hardy364 302 297 
International revenues1,279 1,134 1,114 
Life & Group revenues1,346 1,276 1,457 
Corporate & Other revenues 73 24 21 
Eliminations(11)(6)(7)
Total operating revenues13,398 12,078 11,788 
Net investment gains (losses)(99)(199)120 
Total revenues$13,299 $11,879 $11,908 
v3.24.0.1
Quarterly Financial Data (Unaudited) (Tables)
 12 Months Ended
Dec. 31, 2023
Quarterly Financial Data [Abstract]  
Schedule of quarterly financial information
The following table presents the effect of adoption of ASU 2018-12 on selected 2022 financial data.
2022
(In millions, except per share data)Q1Q2Q3Q4Full Year
Components of Income (Loss)
Core income (loss)
Prior to adoption$316 $245 $213 $274 $1,048 
Effect of adoption(18)(15)(170)(9)(212)
As reported$298 $230 $43 $265 $836 
Net income (loss)
Prior to adoption$313 $205 $128 $248 $894 
Effect of adoption(18)(15)(170)(9)(212)
As reported$295 $190 $(42)$239 $682 
Other comprehensive income (loss), net of tax
Prior to adoption$(1,623)$(1,410)$(1,426)$582 $(3,877)
Effect of adoption603 627 586 (177)1,639 
As reported$(1,020)$(783)$(840)$405 $(2,238)
Diluted Earnings (Loss) Per Common Share
Core income (loss)
Prior to adoption$1.16 $0.90 $0.78 $1.01 
Effect of adoption(0.07)(0.06)(0.62)(0.04)
As reported$1.09 $0.84 $0.16 $0.97 
Net income (loss)
Prior to adoption$1.15 $0.75 $0.47 $0.91 
Effect of adoption(0.07)(0.06)(0.62)(0.04)
As reported$1.08 $0.69 $(0.15)$0.87 
v3.24.0.1
Summary of Significant Accounting Policies (Narrative) (Details) - USD ($)
shares in Thousands, $ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Accounting Standards Update [Extensible Enumeration] Accounting Standards Update 2018-12 [Member]    
Anticipated amounts due from insureds related to losses under deductible policies $ 1,200 $ 1,100  
Structured settlement annuities, interest rate, low end 6.40% 6.40%  
Discounted reserves for unfunded structured settlements $ 465 $ 485  
Discounted reserves for unfunded structure settlements, discount amount 559 590  
Amount of interest recognized on the discounted reserves of unfunded structured settlements $ 34 $ 36 $ 36
Interest rates at which workers' compensation lifetime claim reserves are discounted at 3.50% 3.50%  
Workers' compensation liability $ 196 $ 211  
Amount of interest accretion recognized on the discounted reserves of workers’ compensation lifetime claim reserves $ 9 9 $ 12
Future policy benefit reserves, cash flows projected to occur beyond tenor with market-observable rates available, grading period 10 years    
Liability balance for guaranty fund $ 84 $ 74  
Percentage of billed receivables compared to total reinsurance receivable 5.00%    
Policyholder dividends, rate on policy earnings 2.00% 2.00% 1.00%
Foreign currency transaction gain (loss), before tax $ 9 $ (22) $ (1)
Operating lease, right-of-use asset, statement of financial position [Extensible List] Other assets Other assets  
Operating lease, liability, statement of financial position [Extensible List] Other liabilities Other liabilities  
Weighted average number diluted shares outstanding adjustment (in shares) 1,000 1,000 1,000
Interest paid, net $ 124 $ 109 $ 110
Income taxes paid 282 277 $ 278
Workers' Compensation Insurance      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Short-duration contracts, discounted liabilities, amount $ 88 $ 93  
Furniture and Fixtures      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Property, plant and equipment, useful life 7 years    
Office Equipment      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Property, plant and equipment, useful life 5 years    
Computer Software, Intangible Asset      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Property, plant and equipment, useful life 10 years    
Minimum      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Warranty coverage term 1 month    
Requisite service period for stock- based compensation expense 3 years    
Minimum | Computer Software, Intangible Asset      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Property, plant and equipment, useful life 3 years    
Maximum      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Warranty coverage term 10 years    
Maximum | Computer Software, Intangible Asset      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Property, plant and equipment, useful life 5 years    
CNAF Consolidated | Loews      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Noncontrolling interest, ownership percentage by parent 92.00%    
v3.24.0.1
Summary of Significant Accounting Policies (Pre-Transition LFPB to Adjusted Opening Balance) (Details) - USD ($)
$ in Millions
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Present value of future net premiums      
Effect of change in cash flow assumptions $ 36 $ 538 $ 176
Reclassification of reserves for policyholders on claim to Future policy benefits      
Present value of future net premiums      
Effect of change in cash flow assumptions     2,844
De-recognition of shadow reserves      
Present value of future net premiums      
Effect of change in cash flow assumptions     (3,293)
Re-measurement of LFPB using an upper-medium grade fixed income instrument yield discount rate      
Present value of future net premiums      
Effect of change in cash flow assumptions     6,255
Other adjustments      
Present value of future net premiums      
Effect of change in cash flow assumptions     $ 8
v3.24.0.1
Summary of Significant Accounting Policies (Effects of Adoption of ASU 2018-12, Stockholders' Equity) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
 [1]
Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Total stockholders' equity $ 9,893 $ 8,548 [1] $ 11,105  
Accumulated other comprehensive income (loss)        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Total stockholders' equity (2,672) (3,598) [1] (1,360) $ (1,537) [1]
Retained Earnings        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Total stockholders' equity $ 9,755 9,336 [1] 9,639 9,075 [1]
Prior to Adoption        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Total stockholders' equity   8,825    
Prior to Adoption | Accumulated other comprehensive income (loss)        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Total stockholders' equity   (3,557) 320 803 [1]
Prior to Adoption | Retained Earnings        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Total stockholders' equity   $ 9,572 $ 9,663 9,081 [1]
De-recognition of shadow reserves | Accumulated other comprehensive income (loss)        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Total stockholders' equity       2,601
De-recognition of shadow reserves | Retained Earnings        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Total stockholders' equity       0
Re-measurement of LFPB using an upper-medium grade fixed income instrument yield discount rate | Accumulated other comprehensive income (loss)        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Total stockholders' equity       (4,941)
Re-measurement of LFPB using an upper-medium grade fixed income instrument yield discount rate | Retained Earnings        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Total stockholders' equity       0
Other adjustments | Accumulated other comprehensive income (loss)        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Total stockholders' equity       0
Other adjustments | Retained Earnings        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Total stockholders' equity       $ (6)
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Summary of Significant Accounting Policies (Effects of Adoption of ASU 2018-12, Operations) (Details) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2022
Sep. 30, 2022
Jun. 30, 2022
Mar. 31, 2022
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Insurance claims and policyholders' benefits         $ 7,068 $ 6,653 [1] $ 6,371 [1]
Income (loss) before income tax         1,518 814 [1] 1,462 [1]
Income tax (expense) benefit         313 132 [1] 278 [1]
Net income $ 239 $ (42) $ 190 $ 295 $ 1,205 $ 682 [1] $ 1,184 [1]
Basic earnings (loss) per share (in usd per share)         $ 4.44 $ 2.51 [1] $ 4.36 [1]
Diluted earnings (loss) per share (in usd per share) $ 0.87 $ (0.15) $ 0.69 $ 1.08 $ 4.43 $ 2.51 [1] $ 4.34 [1]
Insurance claims and policyholders benefits, including policyholders' dividends, remeasurement impact         $ (88) $ (214) $ (8)
Prior to Adoption              
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Insurance claims and policyholders' benefits           6,386 6,349
Income (loss) before income tax           1,081 1,484
Income tax (expense) benefit           187 282
Net income $ 248 $ 128 $ 205 $ 313   $ 894 $ 1,202
Basic earnings (loss) per share (in usd per share)           $ 3.29 $ 4.42
Diluted earnings (loss) per share (in usd per share) $ 0.91 $ 0.47 $ 0.75 $ 1.15   $ 3.28 $ 4.41
Effect of Adoption              
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Insurance claims and policyholders' benefits           $ 267 $ 22
Income (loss) before income tax           (267) (22)
Income tax (expense) benefit           (55) (4)
Net income $ (9) $ (170) $ (15) $ (18)   $ (212) $ (18)
Basic earnings (loss) per share (in usd per share)           $ (0.78) $ (0.06)
Diluted earnings (loss) per share (in usd per share) $ (0.04) $ (0.62) $ (0.06) $ (0.07)   $ (0.77) $ (0.07)
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Summary of Significant Accounting Policies (Effects of Adoption of ASU 2018-12, Balance Sheet) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Deferred income taxes $ 1,016 $ 1,251 [1]    
Total assets 64,711 61,000 [1]    
Claim and claim adjustment expenses 23,304 22,120 [1] $ 21,268  
Future policy benefits 13,959 13,480 [1] 18,010 $ 19,132
Total liabilities 54,818 52,452 [1]    
Retained earnings 9,755 9,336 [1]    
Accumulated other comprehensive loss (2,672) (3,598) [1]    
Total stockholders' equity $ 9,893 8,548 [1] $ 11,105 [1]  
Prior to Adoption        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Deferred income taxes   1,178    
Total assets   60,927    
Claim and claim adjustment expenses   25,099    
Future policy benefits   10,151   $ 13,318
Total liabilities   52,102    
Retained earnings   9,572    
Accumulated other comprehensive loss   (3,557)    
Total stockholders' equity   8,825    
Effect of Adoption        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Deferred income taxes   73    
Total assets   73    
Claim and claim adjustment expenses   (2,979)    
Future policy benefits   3,329    
Total liabilities   350    
Retained earnings   (236)    
Accumulated other comprehensive loss   (41)    
Total stockholders' equity   $ (277)    
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Summary of Significant Accounting Policies (Effects of Adoption of ASU 2018-12, Comprehensive Income (Loss)) (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2022
Sep. 30, 2022
Jun. 30, 2022
Mar. 31, 2022
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Net unrealized gains and losses on investments         $ 1,120 $ (6,102) [1] $ (989) [1]
Impact of changes in discount rates used to measure long-duration contract liabilities         (318) 3,959 [1] 941 [1]
Other comprehensive income (loss) $ 405 $ (840) $ (783) $ (1,020) 926 (2,238) [1] 177 [1]
Total comprehensive income (loss)         2,131 (1,556) [1] 1,361 [1]
Net unrealized gains and losses on other investments              
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Net unrealized gains and losses on investments         $ 1,125 (6,097) [1] (987) [1]
Prior to Adoption              
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Net unrealized gains and losses on investments           (3,782) (708)
Impact of changes in discount rates used to measure long-duration contract liabilities           0 0
Other comprehensive income (loss) 582 (1,426) (1,410) (1,623)   (3,877) (483)
Total comprehensive income (loss)           (2,983) 719
Prior to Adoption | Net unrealized gains and losses on other investments              
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Net unrealized gains and losses on investments           (3,777) (706)
Effect of Adoption              
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Net unrealized gains and losses on investments           (2,320) (281)
Impact of changes in discount rates used to measure long-duration contract liabilities           3,959 941
Other comprehensive income (loss) $ (177) $ 586 $ 627 $ 603   1,639 660
Total comprehensive income (loss)           1,427 642
Effect of Adoption | Net unrealized gains and losses on other investments              
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Net unrealized gains and losses on investments           $ (2,320) $ (281)
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Summary of Significant Accounting Policies (Effects of Adoption ASU 2018-12, Cash Flows) (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2022
Sep. 30, 2022
Jun. 30, 2022
Mar. 31, 2022
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Net income $ 239 $ (42) $ 190 $ 295 $ 1,205 $ 682 [1] $ 1,184 [1]
Deferred income tax expense (benefit)         2 (89) [1] 43 [1]
Insurance reserves         $ 1,667 2,058 [1] 2,485 [1]
Prior to Adoption              
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Net income 248 128 205 313   894 1,202
Deferred income tax expense (benefit)           (34) 47
Insurance reserves           1,791 2,463
Effect of Adoption              
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Net income $ (9) $ (170) $ (15) $ (18)   (212) (18)
Deferred income tax expense (benefit)           (55) (4)
Insurance reserves           $ 267 $ 22
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Summary of Significant Accounting Policies (Effects of Adoption ASU 2018-12, Segment Results) (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2022
Sep. 30, 2022
Jun. 30, 2022
Mar. 31, 2022
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                
Net incurred claims and benefits         $ 7,039 $ 6,628 $ 6,349  
Core income (loss) before income tax         1,617 1,013 1,342  
Income tax (expense) benefit on core income (loss)         (333) (177) (254)  
Core income (loss) $ 265 $ 43 $ 230 $ 298 1,284 836 1,088  
Insurance claims and policyholders benefits, including policyholders' dividends, remeasurement impact         (88) (214) (8)  
Claim and claim adjustment expenses 22,120 [1]       23,304 22,120 [1] 21,268  
Future policy benefits 13,480 [1]       13,959 13,480 [1] 18,010 $ 19,132
Life & Group | Operating Segments                
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                
Net incurred claims and benefits         1,317 1,469 1,261  
Core income (loss) before income tax         (90) (320) 83  
Income tax (expense) benefit on core income (loss)         42 99 25  
Core income (loss)         (48) (221) 108  
Claim and claim adjustment expenses 695       675 695 848  
Future policy benefits 13,480       $ 13,959 13,480    
Prior to Adoption                
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                
Core income (loss) 274 213 245 316   1,048    
Claim and claim adjustment expenses 25,099         25,099    
Future policy benefits 10,151         10,151   $ 13,318
Prior to Adoption | Life & Group | Operating Segments                
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                
Net incurred claims and benefits           1,202 1,239  
Core income (loss) before income tax           (53) 105  
Income tax (expense) benefit on core income (loss)           44 21  
Core income (loss)           (9) 126  
Claim and claim adjustment expenses 3,674         3,674    
Future policy benefits 10,151         10,151    
Effect of Adoption                
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                
Core income (loss) (9) $ (170) $ (15) $ (18)   (212)    
Claim and claim adjustment expenses (2,979)         (2,979)    
Future policy benefits 3,329         3,329    
Effect of Adoption | Life & Group | Operating Segments                
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                
Net incurred claims and benefits           267 22  
Core income (loss) before income tax           (267) (22)  
Income tax (expense) benefit on core income (loss)           55 4  
Core income (loss)           (212) $ (18)  
Claim and claim adjustment expenses (2,979)         (2,979)    
Future policy benefits $ 3,329         $ 3,329    
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Investments (Net investment income) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Net Investment Income [Line Items]      
Gross investment income $ 2,343 $ 1,877 $ 2,223
Investment expense (79) (72) (64)
Net investment income 2,264 1,805 2,159
Fixed maturity securities      
Net Investment Income [Line Items]      
Gross investment income 1,941 1,787 1,707
Equity securities      
Net Investment Income [Line Items]      
Gross investment income 63 23 83
Limited partnership investments      
Net Investment Income [Line Items]      
Gross investment income 174   362
Gross investment loss   (12)  
Mortgage loans      
Net Investment Income [Line Items]      
Gross investment income 58 54 61
Short-term investments      
Net Investment Income [Line Items]      
Gross investment income 75 16 1
Trading portfolio      
Net Investment Income [Line Items]      
Gross investment income 4 4 9
Other      
Net Investment Income [Line Items]      
Gross investment income 28 5 0
Common Stock      
Net Investment Income [Line Items]      
Equity securities, FV-NI, gain (loss) 11 47 28
Non-redeemable preferred stock      
Net Investment Income [Line Items]      
Equity securities, FV-NI, gain (loss) $ 14 $ (75) $ 2
v3.24.0.1
Investments (Narrative) (Details) - USD ($)
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Gain (Loss) on Securities [Line Items]      
Non-income producing fixed maturity securities $ 0 $ 0  
Non-income producing mortgage loans 20,000,000 7,000,000  
Investments that exceed ten percent of stockholders' equity 0 0  
Investment and derivative, realized gain (loss), coinsurance agreement   18,000,000  
Gross gains 75,000,000 120,000,000 $ 186,000,000
Debt securities, available-for-sale, realized loss 166,000,000 261,000,000 90,000,000
Mortgage loan losses due to changes in expected credit losses 11,000,000 8,000,000 $ (10,000,000)
Limited partnership investments 2,174,000,000 1,926,000,000 [1]  
Undistributed earnings of limited partnership investments $ 250,000,000 $ 176,000,000  
Percentage of limited partnerships reported on a current basis 17.00%    
Percentage of limited partnerships reported on a one month lag 4.00%    
Limited partnerships invested in private debt and equity 85.00% 76.00%  
Percentage of limited partnerships employing hedge fund strategies focused on fixed income and equity investments 15.00% 24.00%  
Carrying value of ten largest limited partnerships $ 622,000,000 $ 633,000,000  
Carrying value of limited partnerships as percentage of aggregate partnership equity 1.00% 1.00%  
Income as percentage of change in partnership equity for all limited partnerships 1.00% 2.00% 2.00%
Obligation to return cash $ 1,000,000    
Derivative liability, subject to master netting arrangement, collateral, right to reclaim cash offset 0 $ 0  
Increase (decrease) fixed maturity securities 224,000,000    
Increase (decrease) short term investments 4,000,000    
Increase (decrease) accrued investment income 2,000,000    
Increase (decrease) funds withheld liability 216,000,000    
Embedded derivative, fair value of embedded derivative liability 14,000,000    
Commitments to purchase or fund privately placed debt securities 1,555,000,000    
Commitments to sell various privately placed debt securities 35,000,000    
Carrying value of securities deposited under requirements of regulatory authorities 3,100,000,000 2,800,000,000  
Cash and securities deposited as collateral for letters of credit 900,000,000    
Fixed maturity securities      
Gain (Loss) on Securities [Line Items]      
OCI, debt securities, available-for-sale, gain (loss), after adjustment, before tax 1,431,000,000 (7,850,000,000) $ (1,272,000,000)
Debt securities, available-for-sale, accrued interest, after allowance for credit loss 435,000,000 394,000,000  
Mortgage loans      
Gain (Loss) on Securities [Line Items]      
Financing receivable, accrued interest, after allowance for credit loss $ 4,000,000    
Funds Withheld Liability Securities      
Gain (Loss) on Securities [Line Items]      
Gross gains   62,000,000  
Debt securities, available-for-sale, realized loss   $ 44,000,000  
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Investments (Net realized investment gains (losses)) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Fixed maturity securities:      
Gross gains $ 75 $ 120 $ 186
Gross losses (166) (261) (90)
Net investment gains (losses) on fixed maturity securities (91) (141) 96
Equity securities 4 (116) 4
Derivatives (1) 64 6
Mortgage loans (11) (8) 10
Short-term investments and other 0 2 4
Net investment gains (losses) $ (99) $ (199) [1] $ 120 [1]
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Investments (Components of other-than-temporary impairment losses recognized in earnings) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]      
Impairment losses (gains) recognized in earnings $ 44 $ 62 $ 31
Corporate and other bonds      
Debt Securities, Available-for-sale [Line Items]      
Impairment losses (gains) recognized in earnings 33 62 11
Asset-backed      
Debt Securities, Available-for-sale [Line Items]      
Impairment losses (gains) recognized in earnings $ 11 $ 0 $ 20
v3.24.0.1
Investments (Summary of fixed maturity and equity securities) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Fixed maturity securities available-for-sale:      
Cost or Amortized Cost $ 42,414 $ 41,032  
Gross Unrealized Gains 1,022 652  
Gross Unrealized Losses 2,995 4,056  
Allowance for Credit Losses 16 1 $ 18
Estimated Fair Value 40,425 37,627  
Debt Securities, Trading, Unrealized Gain (Loss) [Abstract]      
Total fixed maturity securities trading 0 0  
Total fixed maturity securities trading 0 0  
Debt securities, amortized cost 42,414 41,032  
Total fixed maturity securities 40,425 37,627 [1]  
Corporate and other bonds      
Fixed maturity securities available-for-sale:      
Cost or Amortized Cost 25,020 23,137  
Gross Unrealized Gains 597 301  
Gross Unrealized Losses 1,345 2,009  
Allowance for Credit Losses 4 0 11
Estimated Fair Value 24,268 21,429  
Debt Securities, Trading, Unrealized Gain (Loss) [Abstract]      
Total fixed maturity securities 25,132 22,117  
States, municipalities and political subdivisions      
Fixed maturity securities available-for-sale:      
Cost or Amortized Cost 7,713 8,918  
Gross Unrealized Gains 382 338  
Gross Unrealized Losses 703 939  
Allowance for Credit Losses 0 0  
Estimated Fair Value 7,392 8,317  
Debt Securities, Trading, Unrealized Gain (Loss) [Abstract]      
Total fixed maturity securities 7,392 8,317  
Residential mortgage-backed      
Fixed maturity securities available-for-sale:      
Cost or Amortized Cost 3,411 3,073  
Gross Unrealized Gains 16 5  
Gross Unrealized Losses 425 447  
Allowance for Credit Losses 0 0  
Estimated Fair Value 3,002 2,631  
Commercial mortgage-backed      
Fixed maturity securities available-for-sale:      
Cost or Amortized Cost 1,862 1,886  
Gross Unrealized Gains 7 4  
Gross Unrealized Losses 230 255  
Allowance for Credit Losses 8 0  
Estimated Fair Value 1,631 1,635  
Other asset-backed      
Fixed maturity securities available-for-sale:      
Cost or Amortized Cost 3,515 3,287  
Gross Unrealized Gains 13 2  
Gross Unrealized Losses 256 361  
Allowance for Credit Losses 4 1  
Estimated Fair Value 3,268 2,927  
Asset-backed      
Fixed maturity securities available-for-sale:      
Cost or Amortized Cost 8,788 8,246  
Gross Unrealized Gains 36 11  
Gross Unrealized Losses 911 1,063  
Allowance for Credit Losses 12 1 $ 7
Estimated Fair Value 7,901 7,193  
Debt Securities, Trading, Unrealized Gain (Loss) [Abstract]      
Total fixed maturity securities 7,901 7,193  
U.S. Treasury and obligations of government-sponsored enterprises      
Fixed maturity securities available-for-sale:      
Cost or Amortized Cost 152 111  
Gross Unrealized Gains 1 1  
Gross Unrealized Losses 2 2  
Allowance for Credit Losses 0 0  
Estimated Fair Value 151 110  
Foreign government      
Fixed maturity securities available-for-sale:      
Cost or Amortized Cost 741 617  
Gross Unrealized Gains 6 1  
Gross Unrealized Losses 34 43  
Allowance for Credit Losses 0 0  
Estimated Fair Value 713 575  
Redeemable preferred stock      
Fixed maturity securities available-for-sale:      
Cost or Amortized Cost 0 3  
Gross Unrealized Gains 0 0  
Gross Unrealized Losses 0 0  
Allowance for Credit Losses 0 0  
Estimated Fair Value $ 0 $ 3  
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Investments (Securities in a gross unrealized loss position) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value, Less than 12 months $ 3,483 $ 25,234
Gross Unrealized Losses, Less than 12 Months 74 2,946
Estimated Fair Value, 12 Months or Longer 22,248 4,277
Gross Unrealized Losses, 12 Months or Longer 2,921 1,110
Estimated Fair Value, Total 25,731 29,511
Gross Unrealized Losses, Total 2,995 4,056
Corporate and other bonds    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value, Less than 12 months 1,943 15,946
Gross Unrealized Losses, Less than 12 Months 37 1,585
Estimated Fair Value, 12 Months or Longer 13,406 1,634
Gross Unrealized Losses, 12 Months or Longer 1,308 424
Estimated Fair Value, Total 15,349 17,580
Gross Unrealized Losses, Total 1,345 2,009
States, municipalities and political subdivisions    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value, Less than 12 months 598 4,079
Gross Unrealized Losses, Less than 12 Months 18 769
Estimated Fair Value, 12 Months or Longer 3,104 456
Gross Unrealized Losses, 12 Months or Longer 685 170
Estimated Fair Value, Total 3,702 4,535
Gross Unrealized Losses, Total 703 939
Residential mortgage-backed    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value, Less than 12 months 233 1,406
Gross Unrealized Losses, Less than 12 Months 4 144
Estimated Fair Value, 12 Months or Longer 2,212 1,143
Gross Unrealized Losses, 12 Months or Longer 421 303
Estimated Fair Value, Total 2,445 2,549
Gross Unrealized Losses, Total 425 447
Commercial mortgage-backed    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value, Less than 12 months 200 1,167
Gross Unrealized Losses, Less than 12 Months 5 159
Estimated Fair Value, 12 Months or Longer 1,184 408
Gross Unrealized Losses, 12 Months or Longer 225 96
Estimated Fair Value, Total 1,384 1,575
Gross Unrealized Losses, Total 230 255
Other asset-backed    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value, Less than 12 months 392 2,087
Gross Unrealized Losses, Less than 12 Months 8 262
Estimated Fair Value, 12 Months or Longer 1,869 542
Gross Unrealized Losses, 12 Months or Longer 248 99
Estimated Fair Value, Total 2,261 2,629
Gross Unrealized Losses, Total 256 361
Asset-backed    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value, Less than 12 months 825 4,660
Gross Unrealized Losses, Less than 12 Months 17 565
Estimated Fair Value, 12 Months or Longer 5,265 2,093
Gross Unrealized Losses, 12 Months or Longer 894 498
Estimated Fair Value, Total 6,090 6,753
Gross Unrealized Losses, Total 911 1,063
U.S. Treasury and obligations of government-sponsored enterprises    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value, Less than 12 months 65 76
Gross Unrealized Losses, Less than 12 Months 1 1
Estimated Fair Value, 12 Months or Longer 23 16
Gross Unrealized Losses, 12 Months or Longer 1 1
Estimated Fair Value, Total 88 92
Gross Unrealized Losses, Total 2 2
Foreign government    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value, Less than 12 months 52 473
Gross Unrealized Losses, Less than 12 Months 1 26
Estimated Fair Value, 12 Months or Longer 450 78
Gross Unrealized Losses, 12 Months or Longer 33 17
Estimated Fair Value, Total 502 551
Gross Unrealized Losses, Total $ 34 $ 43
v3.24.0.1
Investments (Securities in a gross unrealized loss position by ratings) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value $ 25,731 $ 29,511
Gross Unrealized Losses 2,995 4,056
U.S. Government, Government agencies and Government-sponsored enterprises    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value 2,273 2,355
Gross Unrealized Losses 309 337
AAA    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value 1,524 1,559
Gross Unrealized Losses 261 298
AA    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value 3,817 4,327
Gross Unrealized Losses 658 817
A    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value 5,652 6,615
Gross Unrealized Losses 517 749
BBB    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value 11,523 13,226
Gross Unrealized Losses 1,095 1,621
Non-investment grade    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value 942 1,429
Gross Unrealized Losses $ 155 $ 234
v3.24.0.1
Investments (Allowance on available-for-sale securities with credit impairments and PCD assets activity) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Allowance for credit losses:    
Balance, beginning of period $ 1 $ 18
Additions to the allowance for credit losses:    
Securities for which credit losses were not previously recorded 17 0
Available-for-sale securities accounted for as PCD assets 22 3
Reductions to the allowance for credit losses:    
Securities sold during the period (realized) 6 0
Intent to sell or more likely than not will be required to sell the security before recovery of its amortized cost basis 8 0
Write-offs charged against the allowance 15 12
Recoveries of amounts previously written off 0 0
Additional increases or (decreases) to the allowance for credit losses on securities that had an allowance recorded in a previous period 5 (8)
Balance, end of period 16 1
Corporate and other bonds    
Allowance for credit losses:    
Balance, beginning of period 0 11
Additions to the allowance for credit losses:    
Securities for which credit losses were not previously recorded 10 0
Available-for-sale securities accounted for as PCD assets 22 0
Reductions to the allowance for credit losses:    
Securities sold during the period (realized) 6 0
Intent to sell or more likely than not will be required to sell the security before recovery of its amortized cost basis 8 0
Write-offs charged against the allowance 15 12
Recoveries of amounts previously written off 0 0
Additional increases or (decreases) to the allowance for credit losses on securities that had an allowance recorded in a previous period 1 1
Balance, end of period 4 0
Asset-backed    
Allowance for credit losses:    
Balance, beginning of period 1 7
Additions to the allowance for credit losses:    
Securities for which credit losses were not previously recorded 7 0
Available-for-sale securities accounted for as PCD assets 0 3
Reductions to the allowance for credit losses:    
Securities sold during the period (realized) 0 0
Intent to sell or more likely than not will be required to sell the security before recovery of its amortized cost basis 0 0
Write-offs charged against the allowance 0 0
Recoveries of amounts previously written off 0 0
Additional increases or (decreases) to the allowance for credit losses on securities that had an allowance recorded in a previous period 4 (9)
Balance, end of period $ 12 $ 1
v3.24.0.1
Investments (Contractual maturity) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Investments [Abstract]    
Due in one year or less, cost or amortized cost $ 1,121 $ 1,012
Due after one year through five years, cost or amortized cost 11,563 9,880
Due after five years through ten years, cost or amortized cost 13,359 13,788
Due after ten years, cost or amortized cost 16,371 16,352
Cost or Amortized Cost 42,414 41,032
Due in one year or less, estimated fair value 1,091 1,001
Due after one year through five years, estimated fair value 11,180 9,399
Due after five years through ten years, estimated fair value 12,573 12,453
Due after ten years, estimated fair value 15,581 14,774
Estimated Fair Value $ 40,425 $ 37,627
v3.24.0.1
Investments (Credit quality indicator) (Details) - Mortgage loans
$ in Millions
Dec. 31, 2023
USD ($)
Debt Securities, Available-for-sale [Line Items]  
2023 $ 127
2022 248
2021 81
2020 135
2019 181
Prior 298
Total 1,070
DSCR ≥1.6x | LTV less than 55%  
Debt Securities, Available-for-sale [Line Items]  
2023 33
2022 9
2021 8
2020 98
2019 60
Prior 238
Total 446
DSCR ≥1.6x | LTV 55% to 65%  
Debt Securities, Available-for-sale [Line Items]  
2023 0
2022 0
2021 5
2020 0
2019 8
Prior 0
Total 13
DSCR ≥1.6x | LTV greater than 65%  
Debt Securities, Available-for-sale [Line Items]  
2023 0
2022 31
2021 11
2020 0
2019 0
Prior 0
Total 42
DSCR 1.2x - 1.6x | LTV less than 55%  
Debt Securities, Available-for-sale [Line Items]  
2023 28
2022 5
2021 0
2020 14
2019 29
Prior 21
Total 97
DSCR 1.2x - 1.6x | LTV 55% to 65%  
Debt Securities, Available-for-sale [Line Items]  
2023 34
2022 36
2021 36
2020 23
2019 0
Prior 32
Total 161
DSCR 1.2x - 1.6x | LTV greater than 65%  
Debt Securities, Available-for-sale [Line Items]  
2023 0
2022 65
2021 0
2020 0
2019 0
Prior 0
Total 65
DSCR ≤1.2 | LTV less than 55%  
Debt Securities, Available-for-sale [Line Items]  
2023 6
2022 34
2021 0
2020 0
2019 0
Prior 0
Total 40
DSCR ≤1.2 | LTV 55% to 65%  
Debt Securities, Available-for-sale [Line Items]  
2023 26
2022 40
2021 0
2020 0
2019 43
Prior 0
Total 109
DSCR ≤1.2 | LTV greater than 65%  
Debt Securities, Available-for-sale [Line Items]  
2023 0
2022 28
2021 21
2020 0
2019 41
Prior 7
Total $ 97
v3.24.0.1
Fair Value (Assets and liabilities measured at fair value on a recurring basis) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Fixed maturity securities:    
Fixed maturity securities $ 40,425 $ 37,627 [1]
Equity securities:    
Equity securities 683 674 [1]
Short term and other 2,008 1,679
Total assets 43,116 39,980
Other liabilities 1 1
Total liabilities 1 1
Corporate and other bonds    
Fixed maturity securities:    
Fixed maturity securities 25,132 22,117
States, municipalities and political subdivisions    
Fixed maturity securities:    
Fixed maturity securities 7,392 8,317
Asset-backed    
Fixed maturity securities:    
Fixed maturity securities 7,901 7,193
Common Stock    
Equity securities:    
Equity securities 191 185
Non-redeemable preferred stock    
Equity securities:    
Equity securities 492 489
Level 1    
Fixed maturity securities:    
Fixed maturity securities 161 120
Equity securities:    
Equity securities 219 204
Short term and other 1,976 1,608
Total assets 2,356 1,932
Other liabilities 0 0
Total liabilities 0 0
Level 1 | Corporate and other bonds    
Fixed maturity securities:    
Fixed maturity securities 161 120
Level 1 | States, municipalities and political subdivisions    
Fixed maturity securities:    
Fixed maturity securities 0 0
Level 1 | Asset-backed    
Fixed maturity securities:    
Fixed maturity securities 0 0
Level 1 | Common Stock    
Equity securities:    
Equity securities 167 150
Level 1 | Non-redeemable preferred stock    
Equity securities:    
Equity securities 52 54
Level 2    
Fixed maturity securities:    
Fixed maturity securities 38,274 35,866
Equity securities:    
Equity securities 440 435
Short term and other 32 71
Total assets 38,746 36,372
Other liabilities 1 1
Total liabilities 1 1
Level 2 | Corporate and other bonds    
Fixed maturity securities:    
Fixed maturity securities 23,926 21,187
Level 2 | States, municipalities and political subdivisions    
Fixed maturity securities:    
Fixed maturity securities 7,348 8,274
Level 2 | Asset-backed    
Fixed maturity securities:    
Fixed maturity securities 7,000 6,405
Level 2 | Common Stock    
Equity securities:    
Equity securities 0 0
Level 2 | Non-redeemable preferred stock    
Equity securities:    
Equity securities 440 435
Level 3    
Fixed maturity securities:    
Fixed maturity securities 1,990 1,641
Equity securities:    
Equity securities 24 35
Short term and other 0 0
Total assets 2,014 1,676
Other liabilities 0 0
Total liabilities 0 0
Level 3 | Corporate and other bonds    
Fixed maturity securities:    
Fixed maturity securities 1,045 810
Level 3 | States, municipalities and political subdivisions    
Fixed maturity securities:    
Fixed maturity securities 44 43
Level 3 | Asset-backed    
Fixed maturity securities:    
Fixed maturity securities 901 788
Level 3 | Common Stock    
Equity securities:    
Equity securities 24 35
Level 3 | Non-redeemable preferred stock    
Equity securities:    
Equity securities $ 0 $ 0
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Fair Value (Table of reconciliation for assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Balance, Beginning, Assets $ 1,676 $ 1,578
Reported in Net investment gains (losses) $ (4) $ 1
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Net investment (losses) gains Net investment (losses) gains
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration] Other comprehensive income (loss) Other comprehensive income (loss)
Reported in Other comprehensive income (loss) $ 48 $ (323)
Total realized and unrealized investment gains (losses) 57 (308)
Purchases 467 580
Sales (4) (10)
Settlements (97) (145)
Transfers into Level 3 34 85
Transfers out of Level 3 (119) (104)
Balance, Ending, Assets 2,014 1,676
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period (7) (4)
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period 48 (321)
Corporate and other bonds    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Balance, Beginning, Assets 810 937
Reported in Net investment gains (losses) 0 (2)
Reported in Other comprehensive income (loss) 38 (184)
Total realized and unrealized investment gains (losses) 38 (185)
Purchases 219 137
Sales 0 (5)
Settlements (33) (84)
Transfers into Level 3 11 10
Transfers out of Level 3 0 0
Balance, Ending, Assets 1,045 810
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period 0 0
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period 38 (183)
States, municipalities and political subdivisions    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Balance, Beginning, Assets 43 56
Reported in Net investment gains (losses) 0 0
Reported in Other comprehensive income (loss) 1 (13)
Total realized and unrealized investment gains (losses) 1 (13)
Purchases 0 0
Sales 0 0
Settlements 0 0
Transfers into Level 3 0 0
Transfers out of Level 3 0 0
Balance, Ending, Assets 44 43
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period 0 0
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period 1 (13)
Asset-backed    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Balance, Beginning, Assets 788 556
Reported in Net investment gains (losses) (4) 9
Reported in Other comprehensive income (loss) 9 (126)
Total realized and unrealized investment gains (losses) 25 (101)
Purchases 248 424
Sales 0 (2)
Settlements (64) (70)
Transfers into Level 3 23 75
Transfers out of Level 3 (119) (94)
Balance, Ending, Assets 901 788
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period 0 0
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period 9 (125)
Equity securities    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Balance, Beginning, Assets 35 29
Reported in Net investment gains (losses) 0 (6)
Reported in Other comprehensive income (loss) 0 0
Total realized and unrealized investment gains (losses) (7) (9)
Purchases 0 19
Sales (4) (3)
Settlements 0 9
Transfers into Level 3 0 0
Transfers out of Level 3 0 (10)
Balance, Ending, Assets 24 35
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Net income (loss) in the period (7) (4)
Unrealized gains (losses) on Level 3 assets and liabilities recognized in Other comprehensive income (loss) in the period 0 0
Reported in Net investment income    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Reported in Net investment income 13 14
Reported in Net investment income | Corporate and other bonds    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Reported in Net investment income 0 1
Reported in Net investment income | States, municipalities and political subdivisions    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Reported in Net investment income 0 0
Reported in Net investment income | Asset-backed    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Reported in Net investment income 20 16
Reported in Net investment income | Equity securities    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Reported in Net investment income $ (7) $ (3)
v3.24.0.1
Fair Value (Narrative) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Fair Value Disclosures [Abstract]    
Other invested assets overseas deposit $ 75 $ 72
v3.24.0.1
Fair Value (Quantitative information about significant unobservable inputs in the fair value measurement of level 3 assets) (Details)
$ in Millions
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Estimated fair value $ 43,116 $ 39,980
Fixed maturity securities | Discounted cash flow    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Estimated fair value $ 1,495 $ 1,177
Credit spread | Discounted cash flow | Minimum    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Debt securities, available-for-sale, measurement Input 0.01 0.01
Credit spread | Discounted cash flow | Maximum    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Debt securities, available-for-sale, measurement Input 0.07 0.08
Credit spread | Discounted cash flow | Weighted Average    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Debt securities, available-for-sale, measurement Input 0.02 0.02
v3.24.0.1
Fair Value (Carrying amount and estimated fair value of financial instrument assets and liabilities which are not measured at fair value) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Assets    
Mortgage loans $ 1,035 $ 1,040 [1]
Liabilities    
Long-term debt 2,481 2,538 [1]
Carrying Amount    
Assets    
Mortgage loans 1,035 1,040
Liabilities    
Short-term debt 550 243
Long-term debt 2,481 2,538
Estimated Fair Value    
Assets    
Mortgage loans 997 973
Liabilities    
Short-term debt 546 248
Long-term debt 2,385 2,349
Level 1 | Estimated Fair Value    
Assets    
Mortgage loans 0 0
Liabilities    
Short-term debt 0 0
Long-term debt 0 0
Level 2 | Estimated Fair Value    
Assets    
Mortgage loans 0 0
Liabilities    
Short-term debt 546 248
Long-term debt 2,385 2,349
Level 3 | Estimated Fair Value    
Assets    
Mortgage loans 997 973
Liabilities    
Short-term debt 0 0
Long-term debt $ 0 $ 0
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Income Taxes (Narrative) (Details) - USD ($)
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Income Tax Contingency [Line Items]      
Unrecognized tax benefits $ 0 $ 0  
Interest income (expense) 0 0 $ 0
Income tax penalties expense 0 0 0
Accrued interest and penalties 0 0  
Deferred tax liability on undistributed income related to a foreign subsidiary 0    
Foreign tax expense (benefit) on income from continuing operations 52,000,000 1,000,000 18,000,000
Income (loss) from continuing foreign operations 198,000,000 141,000,000 124,000,000
Current foreign income tax benefit   10,000,000  
Operating loss carryforwards 0    
Tax credit carryforward, amount 2,000,000    
Valuation allowance 0 0  
Federal Income Taxes      
Income Tax Contingency [Line Items]      
Related party transaction, amounts of transaction 263,000,000 $ 254,000,000 $ 238,000,000
Foreign Tax Authority      
Income Tax Contingency [Line Items]      
Operating loss carryforwards 169,000,000    
Tax credit carryforward, amount $ 9,000,000    
v3.24.0.1
Income Taxes (Reconciliation between the Company's federal income tax (expense) benefit at statutory rates and the recorded income tax (expense) benefit) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Income Tax Disclosure [Abstract]      
Income tax expense at statutory rates $ (319) $ (172) $ (308)
Tax benefit from tax exempt income 30 41 51
Foreign taxes and credits (5) 15 (3)
State income tax expense (13) (10) (13)
Other tax expense (6) (6) (5)
Income tax expense $ (313) $ (132) [1] $ (278) [1]
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Income Taxes (Current and deferred components of the Company's income tax (expense) benefit) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Income Tax Disclosure [Abstract]      
Current tax expense $ (311) $ (221) $ (235)
Deferred tax (expense) benefit (2) 89 [1] (43) [1]
Income tax expense $ (313) $ (132) [1] $ (278) [1]
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Income Taxes (Significant components of the Company's deferred tax assets and liabilities) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Deferred Tax Assets:    
Property and casualty claim and claim adjustment expense reserves $ 202 $ 178
Unearned premium reserves 213 198
Policyholder reserves 160 75
Deferred Revenue 62 64
Employee benefits 23 35
Deferred retroactive reinsurance benefit 88 89
Net unrealized losses 418 706
Other assets 111 116
Gross deferred tax assets 1,277 1,461
Deferred Tax Liabilities:    
Investment valuation differences 83 59
Deferred acquisition costs 126 113
Net unrealized gains 0 0
Software and hardware 18 21
Other liabilities 34 17
Gross deferred tax liabilities 261 210
Net deferred tax asset $ 1,016 $ 1,251
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Reconciliation of Liability for Unpaid Claim and Claim Adjustment Expense) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Liability for Claims and Claims Adjustment Expense [Line Items]        
Total Net Carried Claim and Claim Adjustment Expense Reserves $ 18,163 $ 16,929 $ 16,300 $ 15,857
Reinsurance receivables 5,141      
Total gross liability for unpaid claim and claim adjustment expenses 23,304 22,120 [1] $ 21,268  
Specialty        
Liability for Claims and Claims Adjustment Expense [Line Items]        
Total Net Carried Claim and Claim Adjustment Expense Reserves 5,916 5,563    
Reinsurance receivables 1,215      
Commercial        
Liability for Claims and Claims Adjustment Expense [Line Items]        
Total Net Carried Claim and Claim Adjustment Expense Reserves 9,021 8,430    
Reinsurance receivables 1,082      
International        
Liability for Claims and Claims Adjustment Expense [Line Items]        
Total Net Carried Claim and Claim Adjustment Expense Reserves 2,276 2,003    
Reinsurance receivables 433      
Life and Group        
Liability for Claims and Claims Adjustment Expense [Line Items]        
Total Net Carried Claim and Claim Adjustment Expense Reserves 582      
Reinsurance receivables 93      
Corporate & Other        
Liability for Claims and Claims Adjustment Expense [Line Items]        
Total Net Carried Claim and Claim Adjustment Expense Reserves 368 $ 339    
Reinsurance receivables $ 2,318      
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Reconciliation of Claim and Claim Adjustment Expense Reserves) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Reserves, beginning of year:      
Gross $ 22,120 $ 21,269 $ 19,862
Ceded 5,191 4,969 4,005
Net reserves, beginning of year 16,929 16,300 15,857
Reduction of net reserves due to Excess Workers' Compensation Loss Portfolio Transfer 0 0 (632)
Net incurred claim and claim adjustment expenses:      
Provision for insured events of current year 5,667 5,181 5,021
Increase (decrease) in provision for insured events of prior years 48 (32) 15
Amortization of discount 44 44 48
Total net incurred 5,759 5,193 5,084
Net payments attributable to:      
Current year events (922) (821) (933)
Prior year events (3,679) (3,481) (3,016)
Total net payments (4,601) (4,302) (3,949)
Foreign currency translation adjustment and other 76 (262) (60)
Net reserves, end of year 18,163 16,929 16,300
Ceded reserves, end of year 5,141 5,191 4,969
Gross reserves, end of year $ 23,304 $ 22,120 $ 21,269
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Gross and Net Carried Claim and Claim Adjustment Expense Reserves) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Liability for Claims and Claims Adjustment Expense [Line Items]        
Gross Case Reserves $ 7,738 $ 7,577    
Gross IBNR Reserves 15,566 14,543    
Total Gross Carried Claim and Claim Adjustment Expense Reserves 23,304 22,120 $ 21,269 $ 19,862
Net Case Reserves 5,663 5,509    
Net IBNR Reserves 12,500 11,420    
Total Net Carried Claim and Claim Adjustment Expense Reserves 18,163 16,929 $ 16,300 $ 15,857
Specialty        
Liability for Claims and Claims Adjustment Expense [Line Items]        
Gross Case Reserves 1,604 1,529    
Gross IBNR Reserves 5,527 5,349    
Total Gross Carried Claim and Claim Adjustment Expense Reserves 7,131 6,878    
Net Case Reserves 1,392 1,310    
Net IBNR Reserves 4,524 4,253    
Total Net Carried Claim and Claim Adjustment Expense Reserves 5,916 5,563    
Commercial        
Liability for Claims and Claims Adjustment Expense [Line Items]        
Gross Case Reserves 3,291 3,156    
Gross IBNR Reserves 6,812 6,239    
Total Gross Carried Claim and Claim Adjustment Expense Reserves 10,103 9,395    
Net Case Reserves 2,878 2,809    
Net IBNR Reserves 6,143 5,621    
Total Net Carried Claim and Claim Adjustment Expense Reserves 9,021 8,430    
International        
Liability for Claims and Claims Adjustment Expense [Line Items]        
Gross Case Reserves 864 817    
Gross IBNR Reserves 1,845 1,586    
Total Gross Carried Claim and Claim Adjustment Expense Reserves 2,709 2,403    
Net Case Reserves 708 686    
Net IBNR Reserves 1,568 1,317    
Total Net Carried Claim and Claim Adjustment Expense Reserves 2,276 2,003    
Life & Group        
Liability for Claims and Claims Adjustment Expense [Line Items]        
Gross Case Reserves 626 647    
Gross IBNR Reserves 49 48    
Total Gross Carried Claim and Claim Adjustment Expense Reserves 675 695    
Net Case Reserves 556 567    
Net IBNR Reserves 26 27    
Total Net Carried Claim and Claim Adjustment Expense Reserves 582 594    
Corporate & Other        
Liability for Claims and Claims Adjustment Expense [Line Items]        
Gross Case Reserves 1,353 1,428    
Gross IBNR Reserves 1,333 1,321    
Total Gross Carried Claim and Claim Adjustment Expense Reserves 2,686 2,749    
Net Case Reserves 129 137    
Net IBNR Reserves 239 202    
Total Net Carried Claim and Claim Adjustment Expense Reserves $ 368 $ 339    
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Net Prior Year Development) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Segment Reporting Information [Line Items]      
Pretax (favorable) unfavorable premium development, excluding Life & Group $ 48 $ (32) $ 11
Specialty      
Segment Reporting Information [Line Items]      
Pretax (favorable) unfavorable premium development, excluding Life & Group (14) (40) (45)
Commercial      
Segment Reporting Information [Line Items]      
Pretax (favorable) unfavorable premium development, excluding Life & Group (22) (43) (6)
International      
Segment Reporting Information [Line Items]      
Pretax (favorable) unfavorable premium development, excluding Life & Group 13 (13) 2
Corporate & Other      
Segment Reporting Information [Line Items]      
Pretax (favorable) unfavorable premium development, excluding Life & Group $ 71 $ 64 $ 60
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Narrative) (Details) - USD ($)
 3 Months Ended 12 Months Ended 13 Months Ended
Feb. 05, 2021
Mar. 31, 2021
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Feb. 05, 2021
Dec. 31, 2011
Dec. 31, 2010
Liability for Claims and Claims Adjustment Expense [Line Items]                
Pretax (favorable) unfavorable premium development, excluding Life & Group     $ 48,000,000 $ (32,000,000) $ 11,000,000      
Funds held under reinsurance agreements, liability $ 690,000,000   3,600,000,000 3,700,000,000   $ 690,000,000    
Retroactive reinsurance agreement, maximum 1,000,000,000         1,000,000,000    
Reinsurance premiums paid $ 697,000,000         $ 64,000,000    
Reinsurance, loss on uncollectible accounts in period, amount   $ 12,000,000            
Securities held as collateral, at fair value     440,000,000          
Corporate & Other                
Liability for Claims and Claims Adjustment Expense [Line Items]                
Pretax (favorable) unfavorable premium development, excluding Life & Group     71,000,000 64,000,000 60,000,000      
Commercial                
Liability for Claims and Claims Adjustment Expense [Line Items]                
Pretax (favorable) unfavorable premium development, excluding Life & Group     (22,000,000) (43,000,000) (6,000,000)      
Asbestos and Environmental Reserves                
Liability for Claims and Claims Adjustment Expense [Line Items]                
Net A&EP claim and allocated claim adjustment expense reserves ceded to NICO               $ 1,600,000,000
Aggregate limit under A&EP Loss Portfolio Transfer               4,000,000,000
A&EP claim and allocated claim adjustment expense reserves ceded under existing third party reinsurance contracts transferred to NICO under A&EP Loss Portfolio Transfer               1,200,000,000
Reinsurance premium paid to NICO under A&EP Loss Portfolio Transfer               2,000,000,000
Net reinsurance receivables transferred to NICO under A&EP Loss Portfolio Transfer               215,000,000
Total consideration paid to NICO under AEP Loss Portfolio Transfer             $ 2,200,000,000 $ 2,200,000,000
Net A&EP adverse development before consideration of LPT     86,000,000 92,000,000 143,000,000      
Provision for uncollectible third-party reinsurance, released     0 5,000,000 $ 5,000,000      
Cumulative amounts ceded under AEP Loss Portfolio Transfer     3,600,000,000 3,500,000,000        
Deferred reinsurance benefit yet to be recognized     417,000,000 $ 425,000,000        
Fair value of collateral trust account established by NICO under A&EP Loss Portfolio Transfer     2,500,000,000          
Excess Workers' Compensation LPT                
Liability for Claims and Claims Adjustment Expense [Line Items]                
Funds held under reinsurance agreements, liability     $ 690,000,000          
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Specialty - Net Prior Year Claim and Allocated Claim Adjustment Expense Reserve Development) (Details) - Specialty - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Liability for Claims and Claims Adjustment Expense [Line Items]      
Medical Professional Liability $ 5 $ 18 $ 23
Other Professional Liability and Management Liability 37 50 24
Surety (43) (83) (73)
Warranty (11) (21) (14)
Other (2) (4) (5)
Total pretax (favorable) unfavorable development $ (14) $ (40) $ (45)
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Specialty - Line of Business Composition) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Total net liability for unpaid claim and claim adjustment expenses $ 18,163 $ 16,929 $ 16,300 $ 15,857
Specialty        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Total net liability for unpaid claim and claim adjustment expenses 5,916 $ 5,563    
Medical Professional Liability | Specialty        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Total net liability for unpaid claim and claim adjustment expenses 1,460      
Other Professional Liability and Management Liability | Specialty        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Total net liability for unpaid claim and claim adjustment expenses 3,897      
Surety | Specialty        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Total net liability for unpaid claim and claim adjustment expenses 468      
Warranty | Specialty        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Total net liability for unpaid claim and claim adjustment expenses 28      
Other | Specialty        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Total net liability for unpaid claim and claim adjustment expenses $ 63      
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Specialty - Medical Professional Liability - Cumulative Net Incurred Claims and Allocated Claim Adjustment Expenses) (Details) - Medical Professional Liability - Specialty
$ in Millions
Dec. 31, 2023
USD ($)
claim
Dec. 31, 2022
USD ($)
Dec. 31, 2021
USD ($)
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 4,443                  
IBNR 1,021                  
2014                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net 525 $ 527 $ 524 $ 527 $ 529 $ 535 $ 530 $ 537 $ 489 $ 450
IBNR $ 6                  
Cumulative Number of Claims | claim 19,830                  
2015                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 494 498 501 510 488 494 510 499 $ 433  
IBNR $ 15                  
Cumulative Number of Claims | claim 18,218                  
2016                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 514 508 510 508 499 485 487 $ 427    
IBNR $ 17                  
Cumulative Number of Claims | claim 16,169                  
2017                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 456 460 455 460 458 449 $ 412      
IBNR $ 20                  
Cumulative Number of Claims | claim 15,345                  
2018                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 495 470 448 431 429 $ 404        
IBNR $ 41                  
Cumulative Number of Claims | claim 15,266                  
2019                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 469 471 458 445 $ 430          
IBNR $ 62                  
Cumulative Number of Claims | claim 14,409                  
2020                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 447 455 476 $ 477            
IBNR $ 180                  
Cumulative Number of Claims | claim 11,129                  
2021                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 374 376 $ 377              
IBNR $ 193                  
Cumulative Number of Claims | claim 9,523                  
2022                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 329 $ 329                
IBNR $ 206                  
Cumulative Number of Claims | claim 9,237                  
2023                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 340                  
IBNR $ 281                  
Cumulative Number of Claims | claim 8,240                  
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Specialty - Medical Professional Liability - Net Cumulative Paid Claim and Claim Adjustment Expenses) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Total net liability for unpaid claim and claim adjustment expenses $ 18,163 $ 16,929 $ 16,300 $ 15,857            
Specialty                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Total net liability for unpaid claim and claim adjustment expenses 5,916 5,563                
Medical Professional Liability | Specialty                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 3,030                  
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented 1,413                  
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014 22                  
Liability for unallocated claim adjustment expenses for accident years presented 25                  
Total net liability for unpaid claim and claim adjustment expenses 1,460                  
Medical Professional Liability | 2014 | Specialty                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 510 504 497 489 $ 472 $ 417 $ 359 $ 258 $ 136 $ 23
Medical Professional Liability | 2015 | Specialty                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 463 458 444 420 384 313 230 101 $ 22  
Medical Professional Liability | 2016 | Specialty                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 483 460 436 401 339 246 121 $ 18    
Medical Professional Liability | 2017 | Specialty                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 417 388 355 308 235 107 $ 19      
Medical Professional Liability | 2018 | Specialty                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 418 349 290 211 115 $ 21        
Medical Professional Liability | 2019 | Specialty                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 349 280 183 91 $ 17          
Medical Professional Liability | 2020 | Specialty                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 201 139 61 $ 11            
Medical Professional Liability | 2021 | Specialty                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 118 49 $ 11              
Medical Professional Liability | 2022 | Specialty                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 57 $ 10                
Medical Professional Liability | 2023 | Specialty                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net $ 14                  
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Specialty - Medical Professional Liability - Net Strengthening or Releasing of Prior Accident Year Reserves) (Details) - Specialty - USD ($)
$ in Millions
 12 Months Ended 24 Months Ended 36 Months Ended 48 Months Ended 60 Months Ended 72 Months Ended 84 Months Ended 96 Months Ended 108 Months Ended 120 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Claims Development [Line Items]                                    
Total $ 5 $ 18 $ 23                              
Medical Professional Liability                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims 9 16 14                              
Total net development for accident years prior to 2014 (4) (3) 2                              
Total unallocated claim adjustment expense development 0 5 7                              
Total 5 18 23                              
Medical Professional Liability | 2014                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims (2) 3 (3) $ (2) $ (6) $ 5 $ (7) $ 48 $ 39                 $ 75
Medical Professional Liability | 2015                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims (4) (3) (9) 22 (6) (16) 11 $ 66                 $ 61  
Medical Professional Liability | 2016                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims 6 (2) 2 9 14 (2) $ 60                 $ 87    
Medical Professional Liability | 2017                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims (4) 5 (5) 2 9 $ 37                 $ 44      
Medical Professional Liability | 2018                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims 25 22 17 2 $ 25                 $ 91        
Medical Professional Liability | 2019                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims (2) 13 13 $ 15                 $ 39          
Medical Professional Liability | 2020                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims (8) (21) $ (1)                 $ (30)            
Medical Professional Liability | 2021                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims (2) $ (1)                 $ (3)              
Medical Professional Liability | 2022                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims $ 0                 $ 0                
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Specialty - Other Professional Liability and Management Liability - Net Incurred Claims and Allocated Claim Adjustment Expenses) (Details) - Other Professional Liability and Management Liability - Specialty
$ in Millions
Dec. 31, 2023
USD ($)
claim
Dec. 31, 2022
USD ($)
Dec. 31, 2021
USD ($)
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 9,443                  
IBNR 2,843                  
2014                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net 838 $ 842 $ 841 $ 845 $ 854 $ 835 $ 831 $ 885 $ 898 $ 878
IBNR $ 26                  
Cumulative Number of Claims | claim 17,585                  
2015                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 858 855 836 813 807 832 877 892 $ 888  
IBNR $ 18                  
Cumulative Number of Claims | claim 17,454                  
2016                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 906 888 891 907 904 900 900 $ 901    
IBNR $ 39                  
Cumulative Number of Claims | claim 17,987                  
2017                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 746 758 775 791 813 845 $ 847      
IBNR $ 69                  
Cumulative Number of Claims | claim 18,199                  
2018                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 941 923 906 869 864 $ 850        
IBNR $ 101                  
Cumulative Number of Claims | claim 20,038                  
2019                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 939 876 856 845 $ 837          
IBNR $ 100                  
Cumulative Number of Claims | claim 19,515                  
2020                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 945 951 944 $ 930            
IBNR $ 281                  
Cumulative Number of Claims | claim 19,437                  
2021                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 1,009 1,038 $ 1,037              
IBNR $ 532                  
Cumulative Number of Claims | claim 18,259                  
2022                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 1,112 $ 1,120                
IBNR $ 706                  
Cumulative Number of Claims | claim 18,165                  
2023                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 1,149                  
IBNR $ 971                  
Cumulative Number of Claims | claim 16,469                  
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Specialty - Other Professional Liability and Management Liability - Net Cumulative Paid Claim and Claim Adjustment Expenses) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Total net liability for unpaid claim and claim adjustment expenses $ 18,163 $ 16,929 $ 16,300 $ 15,857            
Specialty                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Total net liability for unpaid claim and claim adjustment expenses 5,916 5,563                
Other Professional Liability and Management Liability | Specialty                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 5,716                  
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented 3,727                  
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014 115                  
Liability for unallocated claim adjustment expenses for accident years presented 55                  
Total net liability for unpaid claim and claim adjustment expenses 3,897                  
Other Professional Liability and Management Liability | 2014 | Specialty                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 806 802 787 743 $ 707 $ 647 $ 515 $ 392 $ 223 $ 51
Other Professional Liability and Management Liability | 2015 | Specialty                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 808 794 725 677 612 542 404 234 $ 60  
Other Professional Liability and Management Liability | 2016 | Specialty                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 826 784 736 701 625 466 248 $ 64    
Other Professional Liability and Management Liability | 2017 | Specialty                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 630 596 557 498 394 222 $ 57      
Other Professional Liability and Management Liability | 2018 | Specialty                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 779 706 599 473 282 $ 54        
Other Professional Liability and Management Liability | 2019 | Specialty                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 699 567 422 263 $ 64          
Other Professional Liability and Management Liability | 2020 | Specialty                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 523 400 248 $ 67            
Other Professional Liability and Management Liability | 2021 | Specialty                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 356 217 $ 58              
Other Professional Liability and Management Liability | 2022 | Specialty                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 225 $ 64                
Other Professional Liability and Management Liability | 2023 | Specialty                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net $ 64                  
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Specialty - Other Professional Liability and Management Liability - Net Strengthening or Releasing of Prior Accident Year Reserves) (Details) - Specialty - USD ($)
$ in Millions
 12 Months Ended 24 Months Ended 36 Months Ended 48 Months Ended 60 Months Ended 72 Months Ended 84 Months Ended 96 Months Ended 108 Months Ended 120 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Claims Development [Line Items]                                    
Total $ 37 $ 50 $ 24                              
Other Professional Liability and Management Liability                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims 43 45 49                              
Total net development for accident years prior to 2014 (6) 5 (27)                              
Total unallocated claim adjustment expense development 0 0 2                              
Total 37 50 24                              
Other Professional Liability and Management Liability | 2014                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims (4) 1 (4) $ (9) $ 19 $ 4 $ (54) $ (13) $ 20                 $ (40)
Other Professional Liability and Management Liability | 2015                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims 3 19 23 6 (25) (45) (15) $ 4                 $ (30)  
Other Professional Liability and Management Liability | 2016                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims 18 (3) (16) 3 4 0 $ (1)                 $ 5    
Other Professional Liability and Management Liability | 2017                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims (12) (17) (16) (22) (32) $ (2)                 $ (101)      
Other Professional Liability and Management Liability | 2018                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims 18 17 37 5 $ 14                 $ 91        
Other Professional Liability and Management Liability | 2019                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims 63 20 11 $ 8                 $ 102          
Other Professional Liability and Management Liability | 2020                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims (6) 7 $ 14                 $ 15            
Other Professional Liability and Management Liability | 2021                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims (29) $ 1                 $ (28)              
Other Professional Liability and Management Liability | 2022                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims $ (8)                 $ (8)                
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Specialty - Surety - Net Incurred Claims and Allocated Claim Adjustment Expenses) (Details) - Surety - Specialty
$ in Millions
Dec. 31, 2023
USD ($)
claim
Dec. 31, 2022
USD ($)
Dec. 31, 2021
USD ($)
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 839                  
IBNR 418                  
2014                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net 41 $ 42 $ 43 $ 45 $ 45 $ 60 $ 69 $ 94 $ 124 $ 123
IBNR $ 2                  
Cumulative Number of Claims | claim 5,135                  
2015                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 45 45 53 58 63 79 104 131 $ 131  
IBNR $ 2                  
Cumulative Number of Claims | claim 5,085                  
2016                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 43 58 64 67 84 109 124 $ 124    
IBNR $ 3                  
Cumulative Number of Claims | claim 5,565                  
2017                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 67 66 71 84 103 115 $ 120      
IBNR $ 4                  
Cumulative Number of Claims | claim 5,883                  
2018                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 51 56 62 91 108 $ 114        
IBNR $ 10                  
Cumulative Number of Claims | claim 6,249                  
2019                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 82 87 98 112 $ 119          
IBNR $ 12                  
Cumulative Number of Claims | claim 6,152                  
2020                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 67 81 119 $ 128            
IBNR $ 34                  
Cumulative Number of Claims | claim 4,678                  
2021                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 110 129 $ 137              
IBNR $ 68                  
Cumulative Number of Claims | claim 4,645                  
2022                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 158 $ 155                
IBNR $ 116                  
Cumulative Number of Claims | claim 4,350                  
2023                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 175                  
IBNR $ 167                  
Cumulative Number of Claims | claim 2,750                  
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Specialty - Surety - Net Cumulative Paid Claim and Claim Adjustment Expenses) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Total net liability for unpaid claim and claim adjustment expenses $ 18,163 $ 16,929 $ 16,300 $ 15,857            
Specialty                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Total net liability for unpaid claim and claim adjustment expenses 5,916 5,563                
Surety | Specialty                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 405                  
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented 434                  
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014 13                  
Liability for unallocated claim adjustment expenses for accident years presented 21                  
Total net liability for unpaid claim and claim adjustment expenses 468                  
Surety | Specialty | 2014                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 38 38 39 39 $ 38 $ 38 $ 36 $ 38 $ 30 $ 7
Surety | Specialty | 2015                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 43 42 42 44 42 40 38 26 $ 7  
Surety | Specialty | 2016                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 40 41 43 43 45 45 37 $ 5    
Surety | Specialty | 2017                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 62 62 49 46 41 37 $ 23      
Surety | Specialty | 2018                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 41 40 39 34 25 $ 5        
Surety | Specialty | 2019                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 70 59 44 34 $ 12          
Surety | Specialty | 2020                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 33 28 20 $ 4            
Surety | Specialty | 2021                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 35 20 $ 5              
Surety | Specialty | 2022                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 35 $ 12                
Surety | Specialty | 2023                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net $ 8                  
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Specialty - Surety - Net Strengthening or Releasing of Prior Accident Year Reserves) (Details) - Specialty - USD ($)
$ in Millions
 12 Months Ended 24 Months Ended 36 Months Ended 48 Months Ended 60 Months Ended 72 Months Ended 84 Months Ended 96 Months Ended 108 Months Ended 120 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2022
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Claims Development [Line Items]                                    
Total $ (43) $ (83) $ (73)                              
Surety                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims (55) (83) (75)                              
Total net development for accident years prior to 2014 12 0 2                              
Total unallocated claim adjustment expense development 0 0 0                              
Total (43) (83) (73)                              
Surety | 2014                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims (1) (1) (2) $ 0 $ (15) $ (9) $ (25) $ (30) $ 1                 $ (82)
Surety | 2015                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims 0 (8) (5) (5) (16) (25) (27) $ 0                 $ (86)  
Surety | 2016                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims (15) (6) (3) (17) (25) (15) $ 0                 $ (81)    
Surety | 2017                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims 1 (5) (13) (19) (12) $ (5)                 $ (53)      
Surety | 2018                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims (5) (6) (29) (17) $ (6)                 $ (63)        
Surety | 2019                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims (5) (11) (14) $ (7)                 $ (37)          
Surety | 2020                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims (14) (38) $ (9)                 $ (61)            
Surety | 2022                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims 3                 $ 3                
Surety | 2021                                    
Claims Development [Line Items]                                    
Cumulative Number of Claims $ (19) $ (8)                 $ (27)              
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Commercial - Net Prior Year Claim and Allocated Claim Adjustment Expense Reserve Development) (Details) - Commercial - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Liability for Claims and Claims Adjustment Expense [Line Items]      
Commercial $ 33 $ 49 $ 53
General Liability 149 67 15
Workers' Compensation (203) (152) (82)
Property and Other (1) (7) 8
Total pretax (favorable) unfavorable development $ (22) $ (43) $ (6)
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Commercial - Commercial Auto - Short Duration Contracts) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Total net liability for unpaid claim and claim adjustment expenses $ 18,163 $ 16,929 $ 16,300 $ 15,857
Commercial        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Total net liability for unpaid claim and claim adjustment expenses 9,021 $ 8,430    
Commercial Auto | Commercial        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Total net liability for unpaid claim and claim adjustment expenses 926      
General Liability | Commercial        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Total net liability for unpaid claim and claim adjustment expenses 3,780      
Workers' Compensation | Commercial        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Total net liability for unpaid claim and claim adjustment expenses 3,645      
Property and Other | Commercial        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Total net liability for unpaid claim and claim adjustment expenses $ 670      
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Commercial - Commercial Auto - Net Incurred Claims and Allocated Claim Adjustment Expenses) (Details) - Commercial Auto - Commercial
$ in Millions
Dec. 31, 2023
USD ($)
claim
Dec. 31, 2022
USD ($)
Dec. 31, 2021
USD ($)
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 3,110                  
IBNR 622                  
2014                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net 201 $ 201 $ 202 $ 201 $ 201 $ 205 $ 205 $ 212 $ 223 $ 234
IBNR $ 1                  
Cumulative Number of Claims | claim 33,633                  
2015                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 184 182 183 181 183 190 190 199 $ 201  
IBNR $ 4                  
Cumulative Number of Claims | claim 30,430                  
2016                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 197 200 195 190 186 186 186 $ 198    
IBNR $ 4                  
Cumulative Number of Claims | claim 30,455                  
2017                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 241 239 232 221 200 198 $ 199      
IBNR $ 4                  
Cumulative Number of Claims | claim 30,947                  
2018                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 255 254 245 227 227 $ 229        
IBNR $ 1                  
Cumulative Number of Claims | claim 34,333                  
2019                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 325 323 289 266 $ 257          
IBNR $ 10                  
Cumulative Number of Claims | claim 37,258                  
2020                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 298 304 303 $ 310            
IBNR $ 21                  
Cumulative Number of Claims | claim 29,142                  
2021                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 390 388 $ 397              
IBNR $ 93                  
Cumulative Number of Claims | claim 32,918                  
2022                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 465 $ 437                
IBNR $ 137                  
Cumulative Number of Claims | claim 36,777                  
2023                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 554                  
IBNR $ 347                  
Cumulative Number of Claims | claim 34,211                  
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Commercial - Commercial Auto - Net Cumulative Paid Claim and Claim Adjustment Expenses) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Total net liability for unpaid claim and claim adjustment expenses $ 18,163 $ 16,929 $ 16,300 $ 15,857            
Commercial                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Total net liability for unpaid claim and claim adjustment expenses 9,021 8,430                
Commercial Auto | Commercial                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 2,197                  
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented 913                  
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014 4                  
Liability for unallocated claim adjustment expenses for accident years presented 9                  
Total net liability for unpaid claim and claim adjustment expenses 926                  
Commercial Auto | Commercial | 2014                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 200 199 199 198 $ 196 $ 187 $ 166 $ 137 $ 102 $ 64
Commercial Auto | Commercial | 2015                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 180 179 178 175 172 153 130 96 $ 52  
Commercial Auto | Commercial | 2016                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 192 190 185 175 154 126 93 $ 52    
Commercial Auto | Commercial | 2017                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 232 225 203 178 150 107 $ 58      
Commercial Auto | Commercial | 2018                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 249 238 212 175 128 $ 66        
Commercial Auto | Commercial | 2019                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 295 257 203 147 $ 77          
Commercial Auto | Commercial | 2020                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 246 197 134 $ 71            
Commercial Auto | Commercial | 2021                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 240 168 $ 83              
Commercial Auto | Commercial | 2022                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 236 $ 112                
Commercial Auto | Commercial | 2023                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net $ 127                  
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Commercial - Commercial Auto - Net Strengthening or Releasing of Prior Accident Year Reserves) (Details) - Commercial - USD ($)
$ in Millions
 12 Months Ended 24 Months Ended 36 Months Ended 48 Months Ended 60 Months Ended 72 Months Ended 84 Months Ended 96 Months Ended 108 Months Ended 120 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2022
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Total $ 33 $ 49 $ 53                              
Commercial Auto                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 28 45 53                              
Total net development for accident years prior to 2014 2 4 0                              
Total unallocated claim adjustment expense development 3 0 0                              
Total 33 49 53                              
2014 | Commercial Auto                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 0 (1) 1 $ 0 $ (4) $ 0 $ (7) $ (11) $ (11)                 $ (33)
2015 | Commercial Auto                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 2 (1) 2 (2) (7) 0 (9) $ (2)                 $ (17)  
2016 | Commercial Auto                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (3) 5 5 4 0 0 $ (12)                 $ (1)    
2017 | Commercial Auto                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 2 7 11 21 2 $ (1)                 $ 42      
2018 | Commercial Auto                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 1 9 18 0 $ (2)                 $ 26        
2019 | Commercial Auto                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 2 34 23 $ 9                 $ 68          
2020 | Commercial Auto                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (6) 1 $ (7)                 $ (12)            
2021 | Commercial Auto                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 2 $ (9)                 $ (7)              
2022 | Commercial Auto                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims $ 28                 $ 28                
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Commercial - General Liability - Net Incurred Claims and Allocated Claim Adjustment Expenses) (Details) - General Liability - Commercial
$ in Millions
Dec. 31, 2023
USD ($)
claim
Dec. 31, 2022
USD ($)
Dec. 31, 2021
USD ($)
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 7,639                  
IBNR 2,821                  
2014                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net 679 $ 676 $ 659 $ 659 $ 658 $ 635 $ 631 $ 654 $ 658 $ 653
IBNR $ 28                  
Cumulative Number of Claims | claim 28,196                  
2015                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 639 625 617 602 600 589 574 576 $ 581  
IBNR $ 28                  
Cumulative Number of Claims | claim 24,261                  
2016                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 704 684 683 673 671 667 659 $ 623    
IBNR $ 39                  
Cumulative Number of Claims | claim 24,803                  
2017                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 690 652 630 634 632 632 $ 632      
IBNR $ 36                  
Cumulative Number of Claims | claim 22,471                  
2018                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 679 650 639 646 644 $ 653        
IBNR $ 129                  
Cumulative Number of Claims | claim 20,425                  
2019                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 720 691 682 682 $ 680          
IBNR $ 174                  
Cumulative Number of Claims | claim 19,647                  
2020                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 736 726 722 $ 723            
IBNR $ 347                  
Cumulative Number of Claims | claim 14,593                  
2021                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 793 784 $ 782              
IBNR $ 401                  
Cumulative Number of Claims | claim 15,121                  
2022                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 928 $ 929                
IBNR $ 676                  
Cumulative Number of Claims | claim 15,754                  
2023                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 1,071                  
IBNR $ 963                  
Cumulative Number of Claims | claim 11,633                  
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Commercial - General Liability - Net Cumulative Paid Claim and Claim Adjustment Expenses) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Total net liability for unpaid claim and claim adjustment expenses $ 18,163 $ 16,929 $ 16,300 $ 15,857            
Commercial                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Total net liability for unpaid claim and claim adjustment expenses 9,021 8,430                
General Liability | Commercial                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 4,085                  
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented 3,554                  
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014 162                  
Liability for unallocated claim adjustment expenses for accident years presented 64                  
Total net liability for unpaid claim and claim adjustment expenses 3,780                  
General Liability | Commercial | 2014                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 642 624 607 569 $ 547 $ 481 $ 376 $ 247 $ 119 $ 31
General Liability | Commercial | 2015                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 573 561 530 501 446 357 230 110 $ 19  
General Liability | Commercial | 2016                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 620 582 524 481 407 279 163 $ 32    
General Liability | Commercial | 2017                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 606 553 471 399 250 118 $ 23      
General Liability | Commercial | 2018                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 491 428 307 228 107 $ 33        
General Liability | Commercial | 2019                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 455 322 181 98 $ 25          
General Liability | Commercial | 2020                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 280 192 99 $ 23            
General Liability | Commercial | 2021                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 262 140 $ 26              
General Liability | Commercial | 2022                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 123 $ 29                
General Liability | Commercial | 2023                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net $ 33                  
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Commercial - General Liability - Net Strengthening or Releasing of Prior Accident Year Reserves) (Details) - Commercial - USD ($)
$ in Millions
 12 Months Ended 24 Months Ended 36 Months Ended 48 Months Ended 60 Months Ended 72 Months Ended 84 Months Ended 96 Months Ended 108 Months Ended 120 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Total $ 149 $ 67 $ 15                              
General Liability                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 151 74 13                              
Total net development for accident years prior to 2014 (2) (7) 0                              
Total unallocated claim adjustment expense development 0 0 2                              
Total 149 67 15                              
General Liability | 2014                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 3 17 0 $ 1 $ 23 $ 4 $ (23) $ (4) $ 5                 $ 26
General Liability | 2015                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 14 8 15 2 11 15 (2) $ (5)                 $ 58  
General Liability | 2016                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 20 1 10 2 4 8 $ 36                 $ 81    
General Liability | 2017                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 38 22 (4) 2 0 $ 0                 $ 58      
General Liability | 2018                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 29 11 (7) 2 $ (9)                 $ 26        
General Liability | 2019                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 29 9 0 $ 2                 $ 40          
General Liability | 2020                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 10 4 $ (1)                 $ 13            
General Liability | 2021                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 9 $ 2                 $ 11              
General Liability | 2022                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims $ (1)                 $ (1)                
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Commercial - Workers' Compensation - Net Incurred Claims and Allocated Claim Adjustment Expenses) (Details) - Workers' Compensation - Commercial
$ in Millions
Dec. 31, 2023
USD ($)
claim
Dec. 31, 2022
USD ($)
Dec. 31, 2021
USD ($)
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 4,172                  
IBNR 1,238                  
2014                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net 419 $ 430 $ 448 $ 439 $ 446 $ 450 $ 452 $ 479 $ 480 $ 467
IBNR $ 70                  
Cumulative Number of Claims | claim 33,550                  
2015                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 334 353 372 382 394 408 406 431 $ 422  
IBNR $ 59                  
Cumulative Number of Claims | claim 31,904                  
2016                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 308 331 355 366 382 396 405 $ 426    
IBNR $ 56                  
Cumulative Number of Claims | claim 31,994                  
2017                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 398 399 402 400 421 432 $ 440      
IBNR $ 78                  
Cumulative Number of Claims | claim 33,142                  
2018                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 404 415 415 428 440 $ 450        
IBNR $ 74                  
Cumulative Number of Claims | claim 34,886                  
2019                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 419 436 437 449 $ 452          
IBNR $ 78                  
Cumulative Number of Claims | claim 34,349                  
2020                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 414 446 466 $ 477            
IBNR $ 135                  
Cumulative Number of Claims | claim 29,454                  
2021                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 432 454 $ 468              
IBNR $ 146                  
Cumulative Number of Claims | claim 30,066                  
2022                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 489 $ 497                
IBNR $ 198                  
Cumulative Number of Claims | claim 33,229                  
2023                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 555                  
IBNR $ 344                  
Cumulative Number of Claims | claim 31,549                  
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Commercial - Workers' Compensation - Net Cumulative Paid Claim and Claim Adjustment Expenses) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Total net liability for unpaid claim and claim adjustment expenses $ 18,163 $ 16,929 $ 16,300 $ 15,857            
Commercial                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Total net liability for unpaid claim and claim adjustment expenses 9,021 8,430                
Workers' Compensation | Commercial                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 2,418                  
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented 1,754                  
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014 1,842                  
Other (23)                  
Liability for unallocated claim adjustment expenses for accident years presented 72                  
Total net liability for unpaid claim and claim adjustment expenses 3,645                  
Workers' Compensation | 2014 | Commercial                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 319 312 306 297 $ 290 $ 282 $ 258 $ 215 $ 159 $ 61
Workers' Compensation | 2015 | Commercial                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 259 256 251 243 231 212 180 131 $ 51  
Workers' Compensation | 2016 | Commercial                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 235 234 227 219 198 169 129 $ 53    
Workers' Compensation | 2017 | Commercial                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 287 279 265 243 207 151 $ 63      
Workers' Compensation | 2018 | Commercial                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 298 280 259 229 163 $ 68        
Workers' Compensation | 2019 | Commercial                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 291 262 223 169 $ 71          
Workers' Compensation | 2020 | Commercial                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 228 200 147 $ 65            
Workers' Compensation | 2021 | Commercial                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 222 164 $ 67              
Workers' Compensation | 2022 | Commercial                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 192 $ 79                
Workers' Compensation | 2023 | Commercial                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net $ 87                  
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Commercial - Workers' Compensation - Net Strengthening or Releasing of Prior Accident Year Reserves) (Details) - Commercial - USD ($)
$ in Millions
 12 Months Ended 24 Months Ended 36 Months Ended 48 Months Ended 60 Months Ended 72 Months Ended 84 Months Ended 96 Months Ended 108 Months Ended 120 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Total $ (203) $ (152) $ (82)                              
Workers' Compensation                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (144) (99) (46)                              
Adjustment for development on a discounted basis (2) (3) 2                              
Total net development for accident years prior to 2014 (63) (60) (38)                              
Total unallocated claim adjustment expense development 6 10 0                              
Total (203) (152) (82)                              
Workers' Compensation | 2014                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (11) (18) 9 $ (7) $ (4) $ (2) $ (27) $ (1) $ 13                 $ (48)
Workers' Compensation | 2015                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (19) (19) (10) (12) (14) 2 (25) $ 9                 $ (88)  
Workers' Compensation | 2016                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (23) (24) (11) (16) (14) (9) $ (21)                 $ (118)    
Workers' Compensation | 2017                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (1) (3) 2 (21) (11) $ (8)                 $ (42)      
Workers' Compensation | 2018                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (11) 0 (13) (12) $ (10)                 $ (46)        
Workers' Compensation | 2019                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (17) (1) (12) $ (3)                 $ (33)          
Workers' Compensation | 2020                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (32) (20) $ (11)                 $ (63)            
Workers' Compensation | 2021                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (22) $ (14)                 $ (36)              
Workers' Compensation | 2022                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims $ (8)                 $ (8)                
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (International - Net prior year claim and allocated claim adjustment expense reserve development) (Details) - International - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Liability for Claims and Claims Adjustment Expense [Line Items]      
Commercial $ (18) $ (10) $ (35)
Specialty 35 (4) 36
Other (4) 1 1
Total pretax (favorable) unfavorable development $ 13 $ (13) $ 2
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (International - Short Duration Contracts) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Total net liability for unpaid claim and claim adjustment expenses $ 18,163 $ 16,929 $ 16,300 $ 15,857
International        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Total net liability for unpaid claim and claim adjustment expenses 2,276 $ 2,003    
Excluding Hardy | International        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Total net liability for unpaid claim and claim adjustment expenses 1,655      
Hardy | International        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Total net liability for unpaid claim and claim adjustment expenses $ 621      
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (International - Excluding Hardy - Net Incurred Claims and Allocated Claim Adjustment Expenses) (Details) - Excluding Hardy - International
$ in Millions
Dec. 31, 2023
USD ($)
claim
Dec. 31, 2022
USD ($)
Dec. 31, 2021
USD ($)
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 3,682                  
IBNR 1,073                  
2014                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net 288 $ 286 $ 283 $ 290 $ 289 $ 272 $ 279 $ 291 $ 291 $ 276
IBNR $ 15                  
Cumulative Number of Claims | claim 25,130                  
2015                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 281 285 285 283 280 286 303 304 $ 289  
IBNR $ 19                  
Cumulative Number of Claims | claim 23,608                  
2016                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 309 292 290 276 285 288 302 $ 284    
IBNR $ 36                  
Cumulative Number of Claims | claim 18,079                  
2017                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 393 360 371 376 383 363 $ 299      
IBNR $ 39                  
Cumulative Number of Claims | claim 18,841                  
2018                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 411 401 388 389 385 $ 367        
IBNR $ 48                  
Cumulative Number of Claims | claim 21,327                  
2019                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 362 360 352 355 $ 342          
IBNR $ 61                  
Cumulative Number of Claims | claim 18,993                  
2020                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 347 362 372 $ 381            
IBNR $ 107                  
Cumulative Number of Claims | claim 15,744                  
2021                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 375 397 $ 408              
IBNR $ 162                  
Cumulative Number of Claims | claim 15,136                  
2022                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 438 $ 428                
IBNR $ 227                  
Cumulative Number of Claims | claim 11,899                  
2023                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 478                  
IBNR $ 359                  
Cumulative Number of Claims | claim 7,869                  
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (International - Excluding Hardy - Net Cumulative Paid Claim and Claim Adjustment Expenses) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Total net liability for unpaid claim and claim adjustment expenses $ 18,163 $ 16,929 $ 16,300 $ 15,857            
International                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Total net liability for unpaid claim and claim adjustment expenses 2,276 2,003                
Excluding Hardy | International                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 2,128                  
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented 1,554                  
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014 64                  
Liability for unallocated claim adjustment expenses for accident years presented 37                  
Total net liability for unpaid claim and claim adjustment expenses 1,655                  
Excluding Hardy | 2014 | International                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 253 248 241 236 $ 203 $ 182 $ 166 $ 149 $ 121 $ 51
Excluding Hardy | 2015 | International                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 246 237 230 219 204 182 162 132 $ 56  
Excluding Hardy | 2016 | International                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 237 226 214 192 180 158 131 $ 66    
Excluding Hardy | 2017 | International                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 321 264 237 214 186 146 $ 64      
Excluding Hardy | 2018 | International                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 308 266 242 212 166 $ 89        
Excluding Hardy | 2019 | International                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 247 224 201 164 $ 73          
Excluding Hardy | 2020 | International                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 178 162 128 $ 60            
Excluding Hardy | 2021 | International                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 154 124 $ 56              
Excluding Hardy | 2022 | International                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 138 $ 46                
Excluding Hardy | 2023 | International                    
Short-Duration Insurance Contracts, Net Cumulative Paid Claim and Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net $ 46                  
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (International - Excluding Hardy - Net Strengthening or Releasing of Prior Accident Year Reserves) (Details) - Excluding Hardy - International - USD ($)
$ in Millions
 12 Months Ended 24 Months Ended 36 Months Ended 48 Months Ended 60 Months Ended 72 Months Ended 84 Months Ended 96 Months Ended 108 Months Ended 120 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
2014                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims $ 2 $ 3 $ (7) $ 1 $ 17 $ (7) $ (12) $ 0 $ 15                 $ 12
2015                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (4) 0 2 3 (6) (17) (1) $ 15                 $ (8)  
2016                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 17 2 14 (9) (3) (14) $ 18                 $ 25    
2017                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 33 (11) (5) (7) 20 $ 64                 $ 94      
2018                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 10 13 (1) 4 $ 18                 $ 44        
2019                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 2 8 (3) $ 13                 $ 20          
2020                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (15) (10) $ (9)                 $ (34)            
2021                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (22) $ (11)                 $ (33)              
2022                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims $ 10                 $ 10                
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (International - Hardy - Net Incurred Claims and Allocated Claim Adjustment Expenses) (Details) - International
$ in Millions
Dec. 31, 2023
USD ($)
claim
Dec. 31, 2022
USD ($)
Dec. 31, 2021
USD ($)
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Hardy                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 2,082                  
IBNR 420                  
Hardy | 2014                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net 167 $ 166 $ 167 $ 169 $ 170 $ 170 $ 169 $ 175 $ 182 $ 183
IBNR $ (1)                  
Cumulative Number of Claims | claim 8,534,000,000                  
Hardy | 2015                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 177 178 176 175 173 175 175 177 187  
IBNR $ (3)                  
Cumulative Number of Claims | claim 9,741,000,000                  
Hardy | 2016                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 223 219 218 224 223 233 244 227    
IBNR $ 6                  
Cumulative Number of Claims | claim 10,895,000,000                  
Hardy | 2017                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 239 251 251 243 242 252 243      
IBNR $ (5)                  
Cumulative Number of Claims | claim 13,294,000,000                  
Hardy | 2018                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 324 307 307 302 298 268        
IBNR $ 36                  
Cumulative Number of Claims | claim 15,366,000,000                  
Hardy | 2019                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 220 224 217 223 219          
IBNR $ 25                  
Cumulative Number of Claims | claim 11,670,000,000                  
Hardy | 2020                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 192 195 201 210            
IBNR $ 55                  
Cumulative Number of Claims | claim 7,036,000,000                  
Hardy | 2021                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 154 168 177              
IBNR $ 59                  
Cumulative Number of Claims | claim 3,831,000,000                  
Hardy | 2022                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 186 190                
IBNR $ 96                  
Cumulative Number of Claims | claim 2,371,000,000                  
Hardy | 2023                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 200                  
IBNR $ 152                  
Cumulative Number of Claims | claim 1,388,000,000                  
Excluding Hardy                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 3,682                  
IBNR 1,073                  
Excluding Hardy | 2014                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net 288 286 283 290 289 272 279 291 291 $ 276
IBNR $ 15                  
Cumulative Number of Claims | claim 25,130                  
Excluding Hardy | 2015                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 281 285 285 283 280 286 303 304 $ 289  
IBNR $ 19                  
Cumulative Number of Claims | claim 23,608                  
Excluding Hardy | 2016                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 309 292 290 276 285 288 302 $ 284    
IBNR $ 36                  
Cumulative Number of Claims | claim 18,079                  
Excluding Hardy | 2017                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 393 360 371 376 383 363 $ 299      
IBNR $ 39                  
Cumulative Number of Claims | claim 18,841                  
Excluding Hardy | 2018                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 411 401 388 389 385 $ 367        
IBNR $ 48                  
Cumulative Number of Claims | claim 21,327                  
Excluding Hardy | 2019                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 362 360 352 355 $ 342          
IBNR $ 61                  
Cumulative Number of Claims | claim 18,993                  
Excluding Hardy | 2020                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 347 362 372 $ 381            
IBNR $ 107                  
Cumulative Number of Claims | claim 15,744                  
Excluding Hardy | 2021                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 375 397 $ 408              
IBNR $ 162                  
Cumulative Number of Claims | claim 15,136                  
Excluding Hardy | 2022                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 438 $ 428                
IBNR $ 227                  
Cumulative Number of Claims | claim 11,899                  
Excluding Hardy | 2023                    
Short-duration Insurance Contracts, Net Incurred Claim and Claim Adjustment Expenses [Line Items]                    
Incurred claims and allocated claim adjustment expense, net $ 478                  
IBNR $ 359                  
Cumulative Number of Claims | claim 7,869                  
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (International - Hardy - Net Cumulative Paid Claim and Claim Adjustment Expenses) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Total net liability for unpaid claim and claim adjustment expenses $ 18,163 $ 16,929 $ 16,300 $ 15,857            
International                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Total net liability for unpaid claim and claim adjustment expenses 2,276 2,003                
Hardy | International                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 1,462                  
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented 620                  
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2014 (8)                  
Liability for unallocated claim adjustment expenses for accident years presented 9                  
Total net liability for unpaid claim and claim adjustment expenses 621                  
Hardy | International | 2014                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 164 164 163 162 $ 161 $ 155 $ 150 $ 140 $ 122 $ 56
Hardy | International | 2015                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 163 169 160 162 154 143 128 97 $ 29  
Hardy | International | 2016                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 208 205 204 193 180 171 144 $ 63    
Hardy | International | 2017                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 229 224 212 205 183 150 $ 53      
Hardy | International | 2018                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 270 249 231 200 170 $ 55        
Hardy | International | 2019                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 167 157 140 102 $ 43          
Hardy | International | 2020                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 118 103 77 $ 27            
Hardy | International | 2021                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 68 44 $ 13              
Hardy | International | 2022                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net 58 $ 23                
Hardy | International | 2023                    
Short Duration Contracts Net Cumulative Paid Claim Adjustment Expenses [Line Items]                    
Cumulative paid claims and allocated claim adjustment expense, net $ 17                  
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (International - Hardy - Net Strengthening or Releasing of Prior Accident Year Reserves) (Details) - International - Hardy - USD ($)
$ in Millions
 12 Months Ended 24 Months Ended 36 Months Ended 48 Months Ended 60 Months Ended 72 Months Ended 84 Months Ended 96 Months Ended 108 Months Ended 120 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2023
2014                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims $ 1 $ (1) $ (2) $ (1) $ 0 $ 1 $ (6) $ (7) $ (1)                 $ (16)
2015                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (1) 2 1 2 (2) 0 (2) $ (10)                 $ (10)  
2016                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 4 1 (6) 1 (10) (11) $ 17                 $ (4)    
2017                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (12) 0 8 1 (10) $ 9                 $ (4)      
2018                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims 17 0 5 4 $ 30                 $ 56        
2019                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (4) 7 (6) $ 4                 $ 1          
2020                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (3) (6) $ (9)                 $ (18)            
2021                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims (14) $ (9)                 $ (23)              
2023                                    
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]                                    
Cumulative Number of Claims $ (4)                 $ (4)                
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Historical Claims Duration) (Details)
Dec. 31, 2023
Medical Professional Liability | Specialty  
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]  
Year 1 3.70%
Year 2 16.40%
Year 3 22.10%
Year 4 17.20%
Year 5 12.40%
Year 6 9.10%
Year 7 4.80%
Year 8 2.90%
Year 9 1.20%
Year 10 1.10%
Other Professional Liability and Management Liability | Specialty  
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]  
Year 1 6.50%
Year 2 19.80%
Year 3 19.30%
Year 4 14.90%
Year 5 10.90%
Year 6 6.30%
Year 7 4.90%
Year 8 6.00%
Year 9 1.70%
Year 10 0.50%
Surety | Specialty  
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]  
Year 1 17.70%
Year 2 46.60%
Year 3 17.70%
Year 4 3.40%
Year 5 2.20%
Year 6 5.20%
Year 7 (1.70%)
Year 8 (0.80%)
Year 9 (0.10%)
Year 10 0.00%
Commercial Auto | Commercial  
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]  
Year 1 25.20%
Year 2 22.20%
Year 3 18.20%
Year 4 14.30%
Year 5 10.60%
Year 6 4.90%
Year 7 2.00%
Year 8 0.70%
Year 9 0.30%
Year 10 0.50%
General Liability | Commercial  
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]  
Year 1 3.60%
Year 2 12.80%
Year 3 16.30%
Year 4 17.40%
Year 5 14.40%
Year 6 9.10%
Year 7 5.90%
Year 8 5.30%
Year 9 2.20%
Year 10 2.70%
Workers' Compensation | Commercial  
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]  
Year 1 16.00%
Year 2 22.90%
Year 3 13.80%
Year 4 8.80%
Year 5 6.00%
Year 6 3.20%
Year 7 2.10%
Year 8 1.30%
Year 9 1.20%
Year 10 1.70%
Excluding Hardy | International  
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]  
Year 1 16.90%
Year 2 21.80%
Year 3 9.80%
Year 4 6.50%
Year 5 5.90%
Year 6 7.40%
Year 7 8.40%
Year 8 2.60%
Year 9 2.80%
Year 10 1.70%
Hardy | International  
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]  
Year 1 18.00%
Year 2 31.30%
Year 3 13.70%
Year 4 7.50%
Year 5 4.70%
Year 6 4.90%
Year 7 0.50%
Year 8 2.30%
Year 9 (1.40%)
Year 10 0.00%
v3.24.0.1
Claim and Claim Adjustment Expense Reserves (Impact of Loss Portfolio Transfer on the Consolidated Statement of Operations) (Details) - Asbestos and Environmental Reserves - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Liability for Claims and Claims Adjustment Expense [Line Items]      
Net A&EP adverse development before consideration of LPT $ 86 $ 92 $ 143
Provision for uncollectible third-party reinsurance on A&EP 0 (5) (5)
Total additional amounts ceded under LPT 86 87 138
Retroactive reinsurance benefit recognized (94) (91) (107)
Pretax impact of deferred retroactive reinsurance $ (8) $ (4) $ 31
v3.24.0.1
Future Policy Benefit Reserves - Narrative (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Sep. 30, 2023
Sep. 30, 2022
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Insurance [Abstract]          
Liability for unpaid claims and claims adjustment expense, long term care policies, period increase (decrease) $ 8 $ 186      
Insurance claims and policyholders benefits, including policyholders' dividends, remeasurement impact     $ (88) $ (214) $ (8)
Liability for future policy benefit, expected future gross premium, discounted, before reinsurance     $ 3,824 $ 4,070  
Liability for future policy benefit, weighted-average duration     11 years 12 years  
Liability future policy benefit, losses recognized in current period     $ 164 $ 178  
Liability future policy benefit, losses recognized in prior period     $ 42 $ 12  
v3.24.0.1
Future Policy Benefit Reserves - Summary of Balances and Changes (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Present value of future net premiums        
Balance, January 1 $ 3,991 $ 4,735 $ 5,086  
Effect of changes in discount rate (125) (74) (880) $ (1,140)
Balance, January 1, at original locked in discount rate 3,917 3,855 3,946  
Effect of changes in cash flow assumptions   28 352 173
Expect of actual variances from expected experience   (126) (49) (24)
Adjusted balance, January 1   3,819 4,158 4,095
Interest accrual 202 216 219  
Net premiums: earned during period (436) (457) (459)  
Balance, end of period at original locked in discount rate 3,585 3,917 3,855  
Effect of changes in discount rate 125 74 880 1,140
Balance, December 31 3,710 3,991 4,735  
Present value of future benefits & expenses        
Balance, January 1 17,471 22,745 23,955  
Effect of changes in discount rate (578) (125) (5,942) (7,395)
Balance, January 1, at original locked in discount rate 17,346 16,803 16,560  
Effect of change in cash flow assumptions   36 538 176
Effect of actual variances from expected experience   (46) (21) (19)
Adjusted balance, January 1   17,336 17,320 16,717
Interest accrual 962 979 973  
Benefit & expense payments (1,207) (953) (887)  
Balance, end of period at original locked in discount rate 17,091 17,346 16,803  
Effect of changes in discount rate 578 125 5,942 7,395
Balance, December 31 17,669 17,471 22,745  
Net LFPB 13,959 13,480 [1] 18,010 $ 19,132
Insurance claims and policyholders benefits, including policyholders' dividends, remeasurement impact $ (88) $ (214) $ (8)  
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Future Policy Benefit Reserves - Earned Premiums and Interest Expense (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Insurance [Abstract]      
Earned premiums $ 451 $ 473 $ 491
Interest expense $ 760 $ 763 $ 754
v3.24.0.1
Future Policy Benefit Reserves - Undiscounted Expected Future Benefit and Expense Payments and Undiscounted Expected Future Gross Premiums (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Insurance [Abstract]    
Expected future benefit and expense payments $ 32,851 $ 34,261
Expected future gross premiums $ 5,414 $ 5,910
v3.24.0.1
Future Policy Benefit Reserves - Weighted Average Interest Rates (Details)
Dec. 31, 2023
Dec. 31, 2022
Insurance [Abstract]    
Original locked in discount rate 5.22% 5.27%
Upper-medium grade fixed income instrument discount rate 4.94% 5.23%
v3.24.0.1
Legal Proceedings, Contingencies and Guarantees (Narrative) (Details)
$ in Billions
Dec. 31, 2023
USD ($)
Guarantee Obligations  
Legal Proceedings, Commitments and Contingencies, and Guarantees [Line Items]  
Guarantor obligations, maximum exposure, undiscounted $ 1.5
v3.24.0.1
Reinsurance (Components of Reinsurance Receivables) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Reinsurance receivables related to insurance reserves        
Ceded claim and claim adjustment expenses $ 5,141 $ 5,191 $ 4,969 $ 4,005
Reinsurance receivables related to paid losses 293 247    
Reinsurance receivables 5,434 5,438 $ 5,484  
Allowance for uncollectible reinsurance (22) (22)    
Reinsurance receivables, net of allowance for uncollectible reinsurance $ 5,412 $ 5,416 [1]    
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Reinsurance (Voluntary Reinsurance) (Details)
$ in Millions
Dec. 31, 2023
USD ($)
Effects of Reinsurance [Line Items]  
Total voluntary reinsurance outstanding balance $ 4,823
A- to A++  
Effects of Reinsurance [Line Items]  
Total voluntary reinsurance outstanding balance 4,047
B- to B++  
Effects of Reinsurance [Line Items]  
Total voluntary reinsurance outstanding balance 769
Insolvent  
Effects of Reinsurance [Line Items]  
Total voluntary reinsurance outstanding balance $ 7
v3.24.0.1
Reinsurance (Narrative) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Feb. 05, 2021
Ceded Credit Risk [Line Items]        
Funds held under reinsurance agreements, liability $ 3,600 $ 3,700   $ 690
Largest recoverable from single reinsurer 5,412 5,416 [1]    
Reinsurance recoveries reported in insurance claims and policyholders' benefits reported on the Consolidated Statement of Operations 2,772 2,631 $ 3,058  
Subsidiaries of Berkshire Hathaway Group        
Ceded Credit Risk [Line Items]        
Largest recoverable from single reinsurer 1,800      
Cavello Bay Reinsurance Limited        
Ceded Credit Risk [Line Items]        
Largest recoverable from single reinsurer 576      
Swiss Reinsurance Group        
Ceded Credit Risk [Line Items]        
Largest recoverable from single reinsurer 410      
Significant Captive Program        
Ceded Credit Risk [Line Items]        
Direct and ceded earned premiums 2,907 3,270 3,638  
Reinsurance recoveries reported in insurance claims and policyholders' benefits reported on the Consolidated Statement of Operations $ 1,512 $ 1,796 $ 2,003  
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Reinsurance (Components of Earned Premiums) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Premiums Earned, Net [Abstract]      
Direct $ 14,315 $ 13,524 $ 12,997
Assumed 267 277 288
Ceded 5,102 5,134 5,110
Net 9,480 8,667 [1] 8,175 [1]
Property and casualty      
Premiums Earned, Net [Abstract]      
Direct 13,908 13,097 12,554
Assumed 223 231 240
Ceded 5,102 5,134 5,110
Net 9,029 8,194 7,684
Long-term care      
Premiums Earned, Net [Abstract]      
Direct 407 427 443
Assumed 44 46 48
Ceded 0 0 0
Net $ 451 $ 473 $ 491
Percentage of assumed premiums earned to net premiums earned      
Premiums Earned, Net [Abstract]      
Assumed/ Net % 2.80% 3.20% 3.50%
Percentage of assumed premiums earned to net premiums earned | Property and casualty      
Premiums Earned, Net [Abstract]      
Assumed/ Net % 2.50% 2.80% 3.10%
Percentage of assumed premiums earned to net premiums earned | Long-term care      
Premiums Earned, Net [Abstract]      
Assumed/ Net % 9.80% 9.70% 9.80%
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Reinsurance (Components of Written Premiums) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Premiums Written, Net [Abstract]      
Direct $ 14,902 $ 14,264 $ 13,587
Assumed 262 281 303
Ceded 5,272 5,417 5,485
Net 9,892 9,128 8,405
Property and casualty      
Premiums Written, Net [Abstract]      
Direct 14,498 13,843 13,150
Assumed 219 235 255
Ceded 5,272 5,417 5,485
Net 9,445 8,661 7,920
Long-term care      
Premiums Written, Net [Abstract]      
Direct 404 421 437
Assumed 43 46 48
Ceded 0 0 0
Net $ 447 $ 467 $ 485
Percentage of assumed premiums written to net premiums written      
Premiums Written, Net [Abstract]      
Assumed/ Net % 2.60% 3.10% 3.60%
Percentage of assumed premiums written to net premiums written | Property and casualty      
Premiums Written, Net [Abstract]      
Assumed/ Net % 2.30% 2.70% 3.20%
Percentage of assumed premiums written to net premiums written | Long-term care      
Premiums Written, Net [Abstract]      
Assumed/ Net % 9.60% 9.90% 9.90%
v3.24.0.1
Debt (Schedule of debt instruments) (Details) - USD ($)
Dec. 31, 2023
Dec. 31, 2022
Debt Instrument [Line Items]    
Short-term debt $ 550,000,000 $ 243,000,000 [1]
Long-term debt 2,481,000,000 2,538,000,000 [1]
Total debt $ 3,031,000,000 2,781,000,000
3.950%, face amount of $550, due May 15, 2024    
Debt Instrument [Line Items]    
Stated interest rate 3.95%  
Face amount $ 550,000,000  
Long-term debt $ 0 549,000,000
4.500%, face amount of $500, due March 1, 2026    
Debt Instrument [Line Items]    
Stated interest rate 4.50%  
Face amount $ 500,000,000  
Long-term debt $ 500,000,000 499,000,000
3.450%, face amount of $500, due August 15, 2027    
Debt Instrument [Line Items]    
Stated interest rate 3.45%  
Face amount $ 500,000,000  
Long-term debt $ 498,000,000 497,000,000
3.900%, face amount of $500, due May 1, 2029    
Debt Instrument [Line Items]    
Stated interest rate 3.90%  
Face amount $ 500,000,000  
Long-term debt $ 497,000,000 497,000,000
2.050%, face amount of $500, due August 15, 2030    
Debt Instrument [Line Items]    
Stated interest rate 2.05%  
Face amount $ 500,000,000  
Long-term debt $ 496,000,000 496,000,000
5.500%, face amount of $500, due June 15, 2033    
Debt Instrument [Line Items]    
Stated interest rate 5.50%  
Face amount $ 500,000,000  
Long-term debt $ 490,000,000 0
Debenture of CNAF, 7.250%, face amount of $243, due November 15, 2023    
Debt Instrument [Line Items]    
Stated interest rate 7.25%  
Face amount $ 243,000,000  
Short-term debt 0 243,000,000
3.950%, face amount of $550, due May 15, 2024    
Debt Instrument [Line Items]    
Short-term debt $ 550,000,000 $ 0
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Debt (Narrative) (Details)
 12 Months Ended
Dec. 31, 2023
USD ($)
extensionTerm
Dec. 31, 2022
USD ($)
Debt Disclosure [Abstract]    
Federal Home Loan Bank stock $ 5,000,000  
Federal Home Loan Bank, advances, general debt obligations, maximum amount available 106,000,000  
Federal Home Loan Bank, advances, branch of FHLB Bank, amount of advances $ 0 $ 0
Debt instrument, term 5 years  
Line of credit, current borrowing capacity $ 250,000,000  
Additional borrowing capacity available $ 100,000,000  
Number of extension options | extensionTerm 2  
Extension term 1 year  
Line of credit, minimum net worth required for compliance $ 8,700,000,000  
Line of credit, amount outstanding $ 0 $ 0
v3.24.0.1
Debt (Maturity of debt) (Details)
$ in Millions
Dec. 31, 2023
USD ($)
Debt Disclosure [Abstract]  
2024 $ 550
2025 0
2026 500
2027 500
2028 0
Thereafter 1,500
Less: discount (19)
Total $ 3,031
v3.24.0.1
Benefit Plans (Funded Status) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Changes in benefit obligation:      
Actuarial (gain) loss $ 27 $ (514)  
Pension Benefits      
Changes in benefit obligation:      
Balance at beginning of period 1,931 2,561  
Interest cost 98 67 $ 62
Participants' contributions 0 0  
Actuarial (gain) loss 27 (514)  
Benefits paid (168) (171)  
Foreign currency translation and other 5 (12)  
Settlement through group annuity purchase (86) 0  
Balance at end of period 1,807 1,931 2,561
Change in plan assets:      
Balance beginning of period 2,025 2,577  
Actual return on plan assets 194 (374)  
Company contributions 8 7  
Participants' contributions 0 0  
Benefits paid (168) (171)  
Foreign currency translation and other 5 (14)  
Settlement through group annuity purchase (80) 0  
Balance end of period 1,984 2,025 2,577
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]      
Funded status 177 94  
Amounts recognized on the Consolidated Balance Sheets as of December 31:      
Other assets 223 143  
Other liabilities (46) (49)  
Net amount recognized 177 94  
Amounts recognized in Accumulated other comprehensive income, not yet recognized in net periodic cost (benefit):      
Net actuarial (gain) loss 658 743  
Net amount recognized 658 743  
Postretirement Benefits      
Changes in benefit obligation:      
Balance at beginning of period 4 6  
Interest cost 0 0  
Participants' contributions 1 2  
Actuarial (gain) loss 4 0  
Benefits paid (4) (4)  
Foreign currency translation and other 0 0  
Settlement through group annuity purchase 0 0  
Balance at end of period 5 4 6
Change in plan assets:      
Balance beginning of period 0 0  
Actual return on plan assets 0 0  
Company contributions 3 2  
Participants' contributions 1 2  
Benefits paid (4) (4)  
Foreign currency translation and other 0 0  
Settlement through group annuity purchase 0 0  
Balance end of period 0 0 $ 0
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]      
Funded status (5) (4)  
Amounts recognized on the Consolidated Balance Sheets as of December 31:      
Other assets 0 0  
Other liabilities (5) (4)  
Net amount recognized (5) (4)  
Amounts recognized in Accumulated other comprehensive income, not yet recognized in net periodic cost (benefit):      
Net actuarial (gain) loss 3 1  
Net amount recognized $ 3 $ 1  
v3.24.0.1
Benefit Plans (Narrative) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Actuarial gain (loss) $ (27) $ 514  
Defined benefit plan, plan with accumulated benefit obligation in excess of plan assets, accumulated benefit obligation 46 $ 49  
Defined benefit plan, plan with accumulated benefit obligation in excess of plan assets, plan assets $ 0    
Assumptions used in calculating assumed health care cost trend rate 4.00%    
Future capital call commitments for limited partnership investments $ 100    
Percentage of limited partnerships employing hedge fund strategies focused on fixed income and equity investments 15.00% 24.00%  
Defined contribution plan, maximum annual contributions per employee, percent 50.00%    
Defined contribution plan, employer matching contribution, percent of match 100.00%    
Defined contribution plan, employer matching contribution, percent of employees' gross pay 6.00%    
Company contribution of eligible compensation, depending on age, percent 5.00%    
Defined contribution plan, employers matching contribution, vesting period in years 5 years    
Benefit expense for the Company's savings plan $ 82 $ 71 $ 65
Pension Benefits      
Settlement through group annuity purchase 80    
Settlement through group annuity purchase 86    
Defined benefit plan, accumulated benefit obligation 1,807 1,931  
Actuarial gain (loss) $ (27) $ 514  
Percentage of limited partnerships invested in private debt and equity 9400.00% 62.00%  
Percentage of limited partnerships employing hedge fund strategies focused on fixed income and equity investments 600.00% 38.00%  
Defined benefit plan, expected future employer contributions, next fiscal year $ 6    
Postretirement Benefits      
Actuarial gain (loss) $ (4) $ 0  
Defined benefit plan, health care cost trend rate assumed for next fiscal year 4.00% 4.00% 4.00%
Defined benefit plan, expected future employer contributions, next fiscal year $ 1    
Minimum      
Defined benefit plan, plan assets, target allocation, percentage 0.00%    
Maximum      
Defined benefit plan, plan assets, target allocation, percentage 40.00%    
v3.24.0.1
Benefit Plans (Components of Net Periodic Cost (Benefit)) (Details) - Pension Benefits - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]      
Interest cost on projected benefit obligation $ 98 $ 67 $ 62
Expected return on plan assets (119) (152) (154)
Amortization of net actuarial loss (gain) 33 30 46
Settlement loss 0 0 1
Total net periodic pension cost (benefit) $ 12 $ (55) $ (45)
v3.24.0.1
Benefit Plans (Schedule of Non-Service Cost (Benefit) Presented in the Consolidated Statement of Operations) (Details) - Pension Benefits - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Net periodic defined benefits expense (reversal of expense), excluding service cost component $ 12 $ (55) $ (45)
Insurance claims and policyholder's benefits      
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Net periodic defined benefits expense (reversal of expense), excluding service cost component 3 (15) (13)
Other operating expenses      
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Net periodic defined benefits expense (reversal of expense), excluding service cost component $ 9 $ (40) $ (32)
v3.24.0.1
Benefit Plans (Schedule of Amounts Recognized in Other Comprehensive Income) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Retirement Benefits [Abstract]      
Amounts arising during the period $ 50 $ (12) $ 262
Settlement 0 0 1
Reclassification adjustment relating to prior service credit 0 0 0
Reclassification adjustment relating to actuarial loss 34 30 46
Total increase (decrease) in Other comprehensive income $ 84 $ 18 $ 309
v3.24.0.1
Benefit Plans (Actuarial Assumptions for Benefit Obligations) (Details)
Dec. 31, 2023
Dec. 31, 2022
Pension Benefits    
Defined Benefit Plan Disclosure [Line Items]    
Discount rate 5.10% 5.35%
Interest crediting rate 4.50% 3.50%
Postretirement Benefits    
Defined Benefit Plan Disclosure [Line Items]    
Discount rate 5.10% 5.25%
v3.24.0.1
Benefit Plans (Actuarial Assumptions for Net Cost or Benefit) (Details)
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate 5.35% 2.75% 2.35%
Expected long-term rate of return 6.25% 6.25% 6.75%
Interest crediting rate 3.50% 3.00% 3.00%
Postretirement Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate 5.25% 2.25% 1.60%
v3.24.0.1
Benefit Plans (Fair Value of Plan Assets Measured on a Recurring Basis) (Details) - Pension Benefits - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets $ 1,984 $ 2,025 $ 2,577
Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 1,984 2,025  
Total | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 1,584 1,470  
Level 1 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 225 363  
Level 2 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 1,345 1,091  
Level 3 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 14 16  
Fair Value Measured at Net Asset Value Per Share | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 375 534  
Fair Value Measured at Net Asset Value Per Share | Fair Value, Recurring | Equity Securities [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 25 21  
Total fixed maturity securities | Total | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 1,348 1,081  
Total fixed maturity securities | Level 1 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 10 0  
Total fixed maturity securities | Level 2 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 1,324 1,065  
Total fixed maturity securities | Level 3 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 14 16  
Corporate and other bonds | Total | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 1,057 866  
Corporate and other bonds | Level 1 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 10 0  
Corporate and other bonds | Level 2 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 1,041 859  
Corporate and other bonds | Level 3 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 6 7  
States, municipalities and political subdivisions | Total | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 50 49  
States, municipalities and political subdivisions | Level 1 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
States, municipalities and political subdivisions | Level 2 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 50 49  
States, municipalities and political subdivisions | Level 3 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Asset-backed | Total | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 241 166  
Asset-backed | Level 1 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Asset-backed | Level 2 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 233 157  
Asset-backed | Level 3 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 8 9  
Equity securities | Total | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 125 231  
Equity securities | Level 1 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 119 218  
Equity securities | Level 2 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 6 13  
Equity securities | Level 3 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Short-term investments | Total | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 96 146  
Short-term investments | Level 1 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 96 145  
Short-term investments | Level 2 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 1  
Short-term investments | Level 3 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Other assets | Total | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 15 12  
Other assets | Level 1 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Other assets | Level 2 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 15 12  
Other assets | Level 3 | Fair Value, Recurring      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets $ 0 $ 0  
v3.24.0.1
Benefit Plans (Estimated Future Minimum Benefit Payments to Participants) (Details)
$ in Millions
Dec. 31, 2023
USD ($)
Pension Benefits  
Defined Benefit Plan Disclosure [Line Items]  
2024 $ 164
2025 163
2026 161
2027 158
2028 154
2029-2033 692
Postretirement Benefits  
Defined Benefit Plan Disclosure [Line Items]  
2024 1
2025 1
2026 1
2027 0
2028 0
2029-2033 $ 1
v3.24.0.1
Stock-Based Compensation (Narrative) (Details) - USD ($)
$ / shares in Units, $ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of shares authorized (in shares) 16,000,000    
Number of shares available for grant (in shares) 3,600,000    
Measurement period of specific annual performance goals, in years 1 year    
Cliff vesting period following date of grant 2 years    
Allocated share-based compensation expense $ 38 $ 36 $ 32
Tax benefit from compensation expense 8 8 6
Compensation cost not yet recognized $ 44    
Compensation cost not yet recognized, period for recognition 1 year 9 months 18 days    
Share-based compensation arrangement by share-based payment award, equity instruments other than options, vested in period, fair value $ 34 $ 35 $ 36
Weighted average grant date fair value of awards granted (in usd per share) $ 37.06 $ 46.78 $ 45.82
Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based compensation arrangement by share-based payment award, award vesting rights, percentage 0.00%    
Award vesting period 1 year    
Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based compensation arrangement by share-based payment award, award vesting rights, percentage 200.00%    
Award vesting period 3 years    
v3.24.0.1
Stock-Based Compensation (Restricted shares, performance-based restricted share units and performance share unit activity) (Details) - $ / shares
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Number of Awards      
Balance as of beginning of period (in shares) 2,465,752    
Awards granted (in shares) 1,437,605    
Awards vested (in shares) (950,620)    
Awards forfeited, canceled or expired (in shares) (478,823)    
Performance-based adjustment (in shares) 152,399    
Balance as of end of period (in shares) 2,626,313 2,465,752  
Weighted Average Grant Date Fair Value      
Balance at beginning of period (in dollars per share) $ 43.10    
Awards granted (in dollars per share) 37.06 $ 46.78 $ 45.82
Awards vested (in dollars per share) 38.06    
Awards forfeited, canceled or expired (in dollars per share) 42.28    
Performance-based adjustment (in dollars per share) 36.87    
Balance at end of period (in dollars per share) $ 41.40 $ 43.10  
v3.24.0.1
Other Intangible Assets (Summary of Other Intangible Assets) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Schedule of Other Intangible Assets [Abstract]    
Indefinite-lived intangible assets: $ 76 $ 68
Total other intangible assets 86 78
Accumulated Amortization 8 7
Syndicate capacity    
Schedule of Other Intangible Assets [Abstract]    
Indefinite-lived intangible assets: 45 42
Agency force    
Schedule of Other Intangible Assets [Abstract]    
Indefinite-lived intangible assets: 16 16
Insurance licenses    
Schedule of Other Intangible Assets [Abstract]    
Indefinite-lived intangible assets: $ 15 10
Distribution channel    
Schedule of Other Intangible Assets [Abstract]    
Economic Useful Life 15 years  
Finite-lived intangible assets: $ 10 10
Accumulated Amortization $ 8 $ 7
v3.24.0.1
Leases (Narrative) (Detail) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2023
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Lessee, Lease, Description [Line Items]        
Lease expense   $ 55 $ 59 $ 57
Operating lease, cost   34 36 38
Variable lease, cost   21 23 19
Operating lease, payments   38 42 44
Right-of-use asset obtained in exchange for operating lease liability   28 $ 20 $ 11
Assets disposed of by method other than sale, in period of disposition, gain (loss) on disposition $ 24      
Lessee, operating lease, lease not yet commenced, liability $ 12 $ 12    
Maximum        
Lessee, Lease, Description [Line Items]        
Lessee, operating lease, lease not yet commenced, term of contract 10 years 10 years    
Minimum        
Lessee, Lease, Description [Line Items]        
Lessee, operating lease, lease not yet commenced, term of contract 3 years 3 years    
v3.24.0.1
Leases (Assets and Liabilities) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Leases [Abstract]    
Operating lease ROU assets $ 140 $ 155
Operating lease liabilities $ 215 $ 220
v3.24.0.1
Leases (Maturities) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Leases [Abstract]    
2024 $ 36  
2025 32  
2026 30  
2027 28  
2028 25  
Thereafter 103  
Total lease payments 254  
Less: Discount (39)  
Total operating lease liabilities $ 215 $ 220
v3.24.0.1
Leases (Lease Term and Discount Rate) (Details)
Dec. 31, 2023
Dec. 31, 2022
Leases [Abstract]    
Weighted average remaining lease term 8 years 4 months 24 days 9 years 2 months 12 days
Weighted average discount rate 3.70% 3.40%
v3.24.0.1
Stockholders' Equity and Statutory Accounting Practices (Narrative) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Stockholders' Equity and Statutory Accounting Practices [Abstract]    
Increase in statutory capital and surplus due to prescribed practice $ 92 $ 74
Statutory amount available for dividend payment before consideration of statutory dividends paid in the preceding twelve months 1,105  
Dividends paid in the preceding twelve months $ 1,055  
Statutory accounting practices, statutory capital and surplus, percentage of action level risk based capital 225.00% 238.00%
v3.24.0.1
Stockholders' Equity and Statutory Accounting Practices (Combined statutory capital and surplus and net income (loss)) (Details) - Combined Continental Casualty Companies - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Statutory Accounting Practices [Line Items]      
Statutory Capital and Surplus $ 10,946 $ 10,572  
Statutory Net Income (Loss) $ 1,172 $ 1,072 $ 1,253
v3.24.0.1
Accumulated Other Comprehensive Income (Loss) by Component (Schedule of Accumulated Other Comprehensive Income (Loss) by Component) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period [1] $ 8,548 $ 11,105    
Other comprehensive income (loss) before reclassifications 827 (2,383) $ 216  
Amounts reclassified from accumulated other comprehensive income (loss) net of tax (99) (145) 39  
Other comprehensive income (loss) after tax (expense) benefit 926 (2,238) 177  
Total stockholder's equity at end of period 9,893 8,548 [1] 11,105 [1]  
Cumulative effect adjustments from changes in accounting guidance, tax   11 446 $ 622
Reclassification from AOCI, tax 26 26 (10)  
Tax (expense) benefit on other comprehensive income (loss) (235) 568 (51)  
Prior to Adoption        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period 8,825      
Total stockholder's equity at end of period   8,825    
Effect of Adoption        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period (277)      
Total stockholder's equity at end of period   (277)    
Accumulated other comprehensive income (loss)        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period [1] (3,598) (1,360) (1,537)  
Total stockholder's equity at end of period (2,672) (3,598) [1] (1,360) [1] (1,537) [1]
Accumulated other comprehensive income (loss) | Prior to Adoption        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period (3,557) 320 [1] 803 [1]  
Total stockholder's equity at end of period   (3,557) 320 [1] 803 [1]
Accumulated other comprehensive income (loss) | Effect of Adoption        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period (41) (1,680) [1] (2,340) [1]  
Total stockholder's equity at end of period   (41) (1,680) [1] (2,340) [1]
Net unrealized gains (losses) on investments | Net unrealized gains (losses) on investments with an allowance for credit losses        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period (7) (2) 0  
Other comprehensive income (loss) before reclassifications (24) 0 (7)  
Amounts reclassified from accumulated other comprehensive income (loss) net of tax (19) 5 (5)  
Other comprehensive income (loss) after tax (expense) benefit (5) (5) (2)  
Total stockholder's equity at end of period (12) (7) (2) 0
Cumulative effect adjustments from changes in accounting guidance, tax   0 0 0
Reclassification from AOCI, tax 5 (1) 1  
Tax (expense) benefit on other comprehensive income (loss) 1 1 1  
Net unrealized gains (losses) on investments | Net unrealized gains (losses) on investments with an allowance for credit losses | Prior to Adoption        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period (7) (2) 0  
Total stockholder's equity at end of period   (7) (2) 0
Net unrealized gains (losses) on investments | Net unrealized gains (losses) on investments with an allowance for credit losses | Effect of Adoption        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period 0 0 0  
Total stockholder's equity at end of period   0 0 0
Net unrealized gains (losses) on investments | Net unrealized gains and losses on other investments        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period (2,738) 3,359 4,346  
Other comprehensive income (loss) before reclassifications 1,072 (6,223) (906)  
Amounts reclassified from accumulated other comprehensive income (loss) net of tax (53) (126) 81  
Other comprehensive income (loss) after tax (expense) benefit 1,125 (6,097) (987)  
Total stockholder's equity at end of period (1,613) (2,738) 3,359 4,346
Cumulative effect adjustments from changes in accounting guidance, tax   0 (617) (691)
Reclassification from AOCI, tax 14 21 (21)  
Tax (expense) benefit on other comprehensive income (loss) (304) 1,622 263  
Net unrealized gains (losses) on investments | Net unrealized gains and losses on other investments | Prior to Adoption        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period (2,738) 1,039 1,745  
Total stockholder's equity at end of period   (2,738) 1,039 1,745
Net unrealized gains (losses) on investments | Net unrealized gains and losses on other investments | Effect of Adoption        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period 0 2,320 2,601  
Total stockholder's equity at end of period   0 2,320 2,601
Pension and postretirement benefits        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period (591) (604) (848)  
Other comprehensive income (loss) before reclassifications 39 (11) 207  
Amounts reclassified from accumulated other comprehensive income (loss) net of tax (27) (24) (37)  
Other comprehensive income (loss) after tax (expense) benefit 66 13 244  
Total stockholder's equity at end of period (525) (591) (604) (848)
Cumulative effect adjustments from changes in accounting guidance, tax   0 0 0
Reclassification from AOCI, tax 7 6 10  
Tax (expense) benefit on other comprehensive income (loss) (17) (3) (65)  
Pension and postretirement benefits | Prior to Adoption        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period (591) (604) (848)  
Total stockholder's equity at end of period   (591) (604) (848)
Pension and postretirement benefits | Effect of Adoption        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period 0 0 0  
Total stockholder's equity at end of period   0 0 0
Cumulative impact of changes in discount rates used to measure long duration contracts        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period (41) (4,000) (4,941)  
Other comprehensive income (loss) before reclassifications (318) 3,959 941  
Amounts reclassified from accumulated other comprehensive income (loss) net of tax 0 0 0  
Other comprehensive income (loss) after tax (expense) benefit (318) 3,959 941  
Total stockholder's equity at end of period (359) (41) (4,000) (4,941)
Cumulative effect adjustments from changes in accounting guidance, tax   11 1,063 1,313
Reclassification from AOCI, tax     0  
Tax (expense) benefit on other comprehensive income (loss) 85 (1,052) (250)  
Cumulative impact of changes in discount rates used to measure long duration contracts | Prior to Adoption        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period 0 0 0  
Total stockholder's equity at end of period   0 0 0
Cumulative impact of changes in discount rates used to measure long duration contracts | Effect of Adoption        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period (41) (4,000) (4,941)  
Total stockholder's equity at end of period   (41) (4,000) (4,941)
Cumulative foreign currency translation adjustment        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period (221) (113) (94)  
Other comprehensive income (loss) before reclassifications 58 (108) (19)  
Amounts reclassified from accumulated other comprehensive income (loss) net of tax 0 0 0  
Other comprehensive income (loss) after tax (expense) benefit 58 (108) (19)  
Total stockholder's equity at end of period (163) (221) (113) (94)
Cumulative effect adjustments from changes in accounting guidance, tax   0 0 0
Reclassification from AOCI, tax 0 0 0  
Tax (expense) benefit on other comprehensive income (loss) 0 0 0  
Cumulative foreign currency translation adjustment | Prior to Adoption        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period (221) (113) (94)  
Total stockholder's equity at end of period   (221) (113) (94)
Cumulative foreign currency translation adjustment | Effect of Adoption        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Total stockholder's equity at beginning of period $ 0 0 0  
Total stockholder's equity at end of period   $ 0 $ 0 $ 0
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Business Segments (Narrative) (Details) - segment
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Segment Reporting Information [Line Items]      
Percentage of direct foreign written premiums 11.00% 10.00% 10.00%
Core Segments - Specialty, Commercial and International      
Segment Reporting Information [Line Items]      
Number of operating segments 3    
Non-Core Segments - Life & Group and Corporate & Other      
Segment Reporting Information [Line Items]      
Number of operating segments 2    
v3.24.0.1
Business Segments (Income Statement Information) (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2022
Sep. 30, 2022
Jun. 30, 2022
Mar. 31, 2022
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Segment Reporting Information [Line Items]              
Net written premiums         $ 9,892 $ 9,128 $ 8,405
Operating revenues              
Net earned premiums         9,480 8,667 [1] 8,175 [1]
Net investment income         2,264 1,805 [1] 2,159 [1]
Non-insurance warranty revenue         1,624 1,574 [1] 1,430 [1]
Other revenues         30 32 [1] 24 [1]
Total operating revenues         13,398 12,078 11,788
Claims, Benefits and Expenses              
Net incurred claims and benefits         7,039 6,628 6,349
Policyholders’ dividends         29 25 22
Amortization of deferred acquisition costs         1,644 1,490 [1] 1,443 [1]
Non-insurance warranty expense         1,544 1,471 [1] 1,328 [1]
Other insurance related expenses         1,251 1,160 1,062
Other expenses         274 291 242
Total claims, benefits and expenses         11,781 11,065 [1] 10,446 [1]
Core income (loss) before income tax         1,617 1,013 1,342
Income tax (expense) benefit on core income (loss)         (333) (177) (254)
Core income (loss)  $ 265 $ 43 $ 230 $ 298 1,284 836 1,088
Net investment gains (losses)         (99) (199) 120
Income tax (expense) benefit on net investment gains (losses)         20 45 (24)
Net investment gains (losses), after tax         (79) (154) 96
Net income (loss)         1,205 682 1,184
Operating Segments | Specialty              
Segment Reporting Information [Line Items]              
Net written premiums         3,329 3,306 3,225
Operating revenues              
Net earned premiums         3,307 3,203 3,076
Net investment income         558 431 497
Non-insurance warranty revenue         1,624 1,574 1,430
Other revenues         1 1 1
Total operating revenues         5,490 5,209 5,004
Claims, Benefits and Expenses              
Net incurred claims and benefits         1,923 1,839 1,787
Policyholders’ dividends         8 6 3
Amortization of deferred acquisition costs         686 656 643
Non-insurance warranty expense         1,544 1,471 1,328
Other insurance related expenses         373 336 296
Other expenses         53 51 47
Total claims, benefits and expenses         4,587 4,359 4,104
Core income (loss) before income tax         903 850 900
Income tax (expense) benefit on core income (loss)         (195) (182) (196)
Core income (loss)          708 668 704
Operating Segments | Commercial              
Segment Reporting Information [Line Items]              
Net written premiums         4,880 4,193 3,595
Operating revenues              
Net earned premiums         4,547 3,923 3,552
Net investment income         645 488 624
Non-insurance warranty revenue         0 0 0
Other revenues         29 30 23
Total operating revenues         5,221 4,441 4,199
Claims, Benefits and Expenses              
Net incurred claims and benefits         2,995 2,607 2,540
Policyholders’ dividends         21 19 19
Amortization of deferred acquisition costs         729 634 594
Non-insurance warranty expense         0 0 0
Other insurance related expenses         620 557 511
Other expenses         30 36 38
Total claims, benefits and expenses         4,395 3,853 3,702
Core income (loss) before income tax         826 588 497
Income tax (expense) benefit on core income (loss)         (174) (122) (103)
Core income (loss)          652 466 394
Operating Segments | International              
Segment Reporting Information [Line Items]              
Net written premiums         1,237 1,164 1,101
Operating revenues              
Net earned premiums         1,176 1,070 1,057
Net investment income         103 63 57
Non-insurance warranty revenue         0 0 0
Other revenues         0 1 0
Total operating revenues         1,279 1,134 1,114
Claims, Benefits and Expenses              
Net incurred claims and benefits         722 637 652
Policyholders’ dividends         0 0 0
Amortization of deferred acquisition costs         229 200 206
Non-insurance warranty expense         0 0 0
Other insurance related expenses         139 146 144
Other expenses         (4) 26 (2)
Total claims, benefits and expenses         1,086 1,009 1,000
Core income (loss) before income tax         193 125 114
Income tax (expense) benefit on core income (loss)         (48) (19) (28)
Core income (loss)          145 106 86
Operating Segments | Life & Group              
Segment Reporting Information [Line Items]              
Net written premiums         447 467 485
Operating revenues              
Net earned premiums         451 473 491
Net investment income         896 804 966
Non-insurance warranty revenue         0 0 0
Other revenues         (1) (1) 0
Total operating revenues         1,346 1,276 1,457
Claims, Benefits and Expenses              
Net incurred claims and benefits         1,317 1,469 1,261
Policyholders’ dividends         0 0 0
Amortization of deferred acquisition costs         0 0 0
Non-insurance warranty expense         0 0 0
Other insurance related expenses         118 118 103
Other expenses         1 9 10
Total claims, benefits and expenses         1,436 1,596 1,374
Core income (loss) before income tax         (90) (320) 83
Income tax (expense) benefit on core income (loss)         42 99 25
Core income (loss)          (48) (221) 108
Operating Segments | Corporate & Other              
Segment Reporting Information [Line Items]              
Net written premiums         0 (1) 0
Operating revenues              
Net earned premiums         0 (1) 0
Net investment income         62 19 15
Non-insurance warranty revenue         0 0 0
Other revenues         11 6 6
Total operating revenues         73 24 21
Claims, Benefits and Expenses              
Net incurred claims and benefits         82 76 109
Policyholders’ dividends         0 0 0
Amortization of deferred acquisition costs         0 0 0
Non-insurance warranty expense         0 0 0
Other insurance related expenses         2 4 9
Other expenses         204 174 155
Total claims, benefits and expenses         288 254 273
Core income (loss) before income tax         (215) (230) (252)
Income tax (expense) benefit on core income (loss)         42 47 48
Core income (loss)          (173) (183) (204)
Eliminations              
Segment Reporting Information [Line Items]              
Net written premiums         (1) (1) (1)
Operating revenues              
Net earned premiums         (1) (1) (1)
Net investment income         0 0 0
Non-insurance warranty revenue         0 0 0
Other revenues         (10) (5) (6)
Total operating revenues         (11) (6) (7)
Claims, Benefits and Expenses              
Net incurred claims and benefits         0 0 0
Policyholders’ dividends         0 0 0
Amortization of deferred acquisition costs         0 0 0
Non-insurance warranty expense         0 0 0
Other insurance related expenses         (1) (1) (1)
Other expenses         (10) (5) (6)
Total claims, benefits and expenses         (11) (6) (7)
Core income (loss) before income tax         0 0 0
Income tax (expense) benefit on core income (loss)         0 0 0
Core income (loss)          $ 0 $ 0 $ 0
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Business Segments (Balance Sheet Information) (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Segment Reporting Information [Line Items]        
Reinsurance receivables $ 5,434 $ 5,438 $ 5,484  
Insurance receivables 3,470 3,187 2,974  
Deferred acquisition costs 896 806 [1] 737  
Goodwill 146 144 [1] 148  
Deferred non-insurance warranty acquisition expense 3,661 3,671 [1] 3,476  
Insurance reserves        
Claim and claim adjustment expenses 23,304 22,120 [1] 21,268  
Unearned premiums 6,933 6,374 [1] 5,761  
Future policy benefits     18,298  
Future policy benefits 13,959 13,480 [1] 18,010 $ 19,132
Deferred non-insurance warranty revenue 4,694 4,714 [1] 4,503  
Operating Segments | Specialty        
Segment Reporting Information [Line Items]        
Reinsurance receivables 1,281 1,384 1,200  
Insurance receivables 1,053 1,082 1,136  
Deferred acquisition costs 392 381 363  
Goodwill 117 117 117  
Deferred non-insurance warranty acquisition expense 3,661 3,671 3,476  
Insurance reserves        
Claim and claim adjustment expenses 7,131 6,878 6,433  
Unearned premiums 3,227 3,193 3,001  
Future policy benefits     0  
Future policy benefits 0 0    
Deferred non-insurance warranty revenue 4,694 4,714 4,503  
Operating Segments | Commercial        
Segment Reporting Information [Line Items]        
Reinsurance receivables 1,218 1,062 923  
Insurance receivables 2,024 1,728 1,488  
Deferred acquisition costs 371 321 278  
Goodwill 0 0 0  
Deferred non-insurance warranty acquisition expense 0 0 0  
Insurance reserves        
Claim and claim adjustment expenses 10,103 9,395 8,890  
Unearned premiums 2,858 2,425 2,066  
Future policy benefits     0  
Future policy benefits 0 0    
Deferred non-insurance warranty revenue 0 0 0  
Operating Segments | International        
Segment Reporting Information [Line Items]        
Reinsurance receivables 468 414 381  
Insurance receivables 388 369 340  
Deferred acquisition costs 133 104 96  
Goodwill 29 27 31  
Deferred non-insurance warranty acquisition expense 0 0 0  
Insurance reserves        
Claim and claim adjustment expenses 2,709 2,403 2,280  
Unearned premiums 749 653 585  
Future policy benefits     0  
Future policy benefits 0 0    
Deferred non-insurance warranty revenue 0 0 0  
Operating Segments | Life & Group        
Segment Reporting Information [Line Items]        
Reinsurance receivables 93 101 401  
Insurance receivables 5 8 6  
Deferred acquisition costs 0 0 0  
Goodwill 0 0 0  
Deferred non-insurance warranty acquisition expense 0 0 0  
Insurance reserves        
Claim and claim adjustment expenses 675 695 848  
Unearned premiums 99 103 109  
Future policy benefits     18,298  
Future policy benefits 13,959 13,480    
Deferred non-insurance warranty revenue 0 0 0  
Operating Segments | Corporate & Other        
Segment Reporting Information [Line Items]        
Reinsurance receivables 2,374 2,477 2,579  
Insurance receivables 0 0 4  
Deferred acquisition costs 0 0 0  
Goodwill 0 0 0  
Deferred non-insurance warranty acquisition expense 0 0 0  
Insurance reserves        
Claim and claim adjustment expenses 2,686 2,749 2,817  
Unearned premiums 0 0 0  
Future policy benefits     0  
Future policy benefits 0 0    
Deferred non-insurance warranty revenue 0 0 0  
Eliminations        
Segment Reporting Information [Line Items]        
Reinsurance receivables 0 0 0  
Insurance receivables 0 0 0  
Deferred acquisition costs 0 0 0  
Goodwill 0 0 0  
Deferred non-insurance warranty acquisition expense 0 0 0  
Insurance reserves        
Claim and claim adjustment expenses 0 0 0  
Unearned premiums 0 0 0  
Future policy benefits     0  
Future policy benefits 0 0    
Deferred non-insurance warranty revenue $ 0 $ 0 $ 0  
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Business Segments (Revenues by Line of Business) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Total revenues $ 13,299 $ 11,879 [1] $ 11,908 [1]
Total operating revenues 13,398 12,078 11,788
Net investment gains (losses) (99) (199) [1] 120 [1]
Operating Segments | Specialty      
Total revenues 5,490 5,209 5,004
Operating Segments | Commercial      
Total revenues 5,221 4,441 4,199
Operating Segments | International      
Total revenues 1,279 1,134 1,114
Operating Segments | Life & Group      
Total revenues 1,346 1,276 1,457
Operating Segments | Corporate & Other      
Total revenues 73 24 21
Eliminations      
Total revenues (11) (6) (7)
Management & Professional Liability | Operating Segments | Specialty      
Total revenues 2,931 2,771 2,776
Surety | Operating Segments | Specialty      
Total revenues 731 652 604
Warranty & Alternative Risks | Operating Segments | Specialty      
Total revenues 1,828 1,786 1,624
Middle Market | Operating Segments | Commercial      
Total revenues 1,696 1,532 1,508
Construction | Operating Segments | Commercial      
Total revenues 1,678 1,421 1,322
Small Business | Operating Segments | Commercial      
Total revenues 631 581 558
Other Commercial | Operating Segments | Commercial      
Total revenues 1,216 907 811
Canada | Operating Segments | International      
Total revenues 383 366 344
Europe | Operating Segments | International      
Total revenues 532 466 473
Hardy | Operating Segments | International      
Total revenues $ 364 $ 302 $ 297
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Quarterly Financial Data (Unaudited) (Details) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2022
Sep. 30, 2022
Jun. 30, 2022
Mar. 31, 2022
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Core income (loss) $ 265 $ 43 $ 230 $ 298 $ 1,284 $ 836 $ 1,088
Net income (loss) 239 (42) 190 295 1,205 682 [1] 1,184 [1]
Other comprehensive income (loss), net of tax $ 405 $ (840) $ (783) $ (1,020) $ 926 $ (2,238) [1] $ 177 [1]
Diluted earnings (loss) per share, Core income (loss) (in usd per share) $ 0.97 $ 0.16 $ 0.84 $ 1.09      
Diluted earnings (loss) per share (in usd per share) $ 0.87 $ (0.15) $ 0.69 $ 1.08 $ 4.43 $ 2.51 [1] $ 4.34 [1]
Liability for future policy benefits, gross premium valuation, pretax margin   $ 125          
Prior to Adoption              
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Core income (loss) $ 274 213 $ 245 $ 316   $ 1,048  
Net income (loss) 248 128 205 313   894 $ 1,202
Other comprehensive income (loss), net of tax $ 582 $ (1,426) $ (1,410) $ (1,623)   $ (3,877) $ (483)
Diluted earnings (loss) per share, Core income (loss) (in usd per share) $ 1.01 $ 0.78 $ 0.90 $ 1.16      
Diluted earnings (loss) per share (in usd per share) $ 0.91 $ 0.47 $ 0.75 $ 1.15   $ 3.28 $ 4.41
Effect of Adoption              
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Core income (loss) $ (9) $ (170) $ (15) $ (18)   $ (212)  
Net income (loss) (9) (170) (15) (18)   (212) $ (18)
Other comprehensive income (loss), net of tax $ (177) $ 586 $ 627 $ 603   $ 1,639 $ 660
Diluted earnings (loss) per share, Core income (loss) (in usd per share) $ (0.04) $ (0.62) $ (0.06) $ (0.07)      
Diluted earnings (loss) per share (in usd per share) $ (0.04) $ (0.62) $ (0.06) $ (0.07)   $ (0.77) $ (0.07)
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Related Party Transactions Narrative (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Other liabilities $ 2,897 $ 2,983 [1]  
Other assets 2,534 2,274 [1]  
Net earned premiums 9,480 8,667 [1] $ 8,175 [1]
Related Party      
Other liabilities 28 26  
Other assets 23 18  
Related Party | Fees and expenses of investment facilities and services      
Related party transaction, amounts of transaction 55 51 47
Related Party | Corporate services and related travel expenses      
Related party transaction, amounts of transaction 1 1  
Related Party | Loews      
Net earned premiums $ 2 $ 3 $ 2
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Non-Insurance Revenues from Contracts with Customers (Narrative) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Revenue from External Customer [Line Items]      
Deferred non-insurance warranty revenue $ 4,694 $ 4,714 [1] $ 4,503
Contract with customer, liability, revenue recognized 1,400 1,300  
Deferred non-insurance warranty acquisition expense 3,661 3,671 [1] $ 3,476
Amortization of deferred sales commissions 1,200    
Capitalized Commission Costs      
Revenue from External Customer [Line Items]      
Deferred non-insurance warranty acquisition expense 3,600    
Capitalized Administrator Service Costs      
Revenue from External Customer [Line Items]      
Deferred non-insurance warranty acquisition expense $ 62 $ 53  
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Non-Insurance Revenues from Contracts with Customers (Performance obligation) (Details)
$ in Billions
Dec. 31, 2023
USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Remaining performance obligation, amount $ 1.4
Remaining performance obligation, expected timing of satisfaction, period 12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Remaining performance obligation, amount $ 1.1
Remaining performance obligation, expected timing of satisfaction, period 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Remaining performance obligation, amount $ 0.8
Remaining performance obligation, expected timing of satisfaction, period 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Remaining performance obligation, amount $ 1.4
Remaining performance obligation, expected timing of satisfaction, period
v3.24.0.1
Schedule II. Condensed Financial Information of Registrant (Parent Company) (Schedule of Condensed Financial Information of Registrant, Statements of Operations and Comprehensive Income (Loss)) (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2022
Sep. 30, 2022
Jun. 30, 2022
Mar. 31, 2022
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Revenues              
Net investment income         $ 2,264 $ 1,805 [1] $ 2,159 [1]
Total revenues         13,299 11,879 [1] 11,908 [1]
Expenses              
Interest         127 112 [1] 113 [1]
Income tax benefit         (313) (132) [1] (278) [1]
Net income $ 239 $ (42) $ 190 $ 295 1,205 682 [1] 1,184 [1]
Other comprehensive income (loss) $ 405 $ (840) $ (783) $ (1,020) 926 (2,238) [1] 177 [1]
Total comprehensive income (loss)         2,131 (1,556) [1] 1,361 [1]
Parent Company              
Revenues              
Net investment income         41 8 0
Total revenues         41 8 0
Expenses              
Administrative and general         2 1 1
Interest         126 112 112
Total expenses         128 113 113
Loss from operations before income taxes and equity in net income of subsidiaries         (87) (105) (113)
Income tax benefit         4 6 11
Loss before equity in net income of subsidiaries         (83) (99) (102)
Equity in net income of subsidiaries         1,288 781 1,286
Net income         1,205 682 1,184
Total comprehensive income (loss)         $ 2,131 $ (1,556) $ 1,361
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Schedule II. Condensed Financial Information of Registrant (Parent Company) (Schedule of Condensed Financial Information of Registrant, Balance Sheets) (Details) - USD ($)
$ / shares in Units, $ in Millions
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
 [1]
Assets      
Cash $ 345 $ 475 [1]  
Other assets 2,534 2,274 [1]  
Total assets 64,711 61,000 [1]  
Liabilities      
Short-term debt 550 243 [1]  
Long-term debt 2,481 2,538 [1]  
Other liabilities 2,897 2,983 [1]  
Total liabilities 54,818 52,452 [1]  
Stockholders' Equity      
Common stock ($2.50 par value; 500,000,000 shares authorized; 273,040,243 shares issued; 270,881,457 and 270,895,902 shares outstanding) 683 683 [1]  
Additional paid-in capital 2,221 2,220 [1]  
Retained earnings 9,755 9,336 [1]  
Accumulated other comprehensive loss (2,672) (3,598) [1]  
Treasury stock (2,158,786 and 2,144,341 shares), at cost (94) (93) [1]  
Total stockholders’ equity 9,893 8,548 [1] $ 11,105
Total liabilities and stockholders' equity $ 64,711 $ 61,000 [1]  
Balance Sheet Parenthetical      
Common stock, par value (in usd per share) $ 2.50 $ 2.50  
Common stock, shares authorized (in shares 500,000,000 500,000,000  
Common stock, shares issued (in shares) 273,040,243 273,040,243  
Common stock, shares outstanding (in shares) 270,881,457 270,895,902  
Treasury stock, shares (in shares) 2,158,786 2,144,341  
Related Party      
Assets      
Other assets $ 23 $ 18  
Liabilities      
Other liabilities 28 26  
Parent Company      
Assets      
Investment in subsidiaries 11,948 10,786  
Cash 1 2  
Short-term investments 1,009 578  
Total assets 12,963 11,370  
Liabilities      
Short-term debt 550 243  
Long-term debt 2,481 2,538  
Other liabilities 39 41  
Total liabilities 3,070 2,822  
Stockholders' Equity      
Common stock ($2.50 par value; 500,000,000 shares authorized; 273,040,243 shares issued; 270,881,457 and 270,895,902 shares outstanding) 683 683  
Additional paid-in capital 2,221 2,220  
Retained earnings 9,755 9,336  
Accumulated other comprehensive loss (2,672) (3,598)  
Treasury stock (2,158,786 and 2,144,341 shares), at cost (94) (93)  
Total stockholders’ equity 9,893 8,548  
Total liabilities and stockholders' equity 12,963 11,370  
Parent Company | Related Party      
Assets      
Other assets 4 4  
Parent Company | Nonrelated Party      
Assets      
Other assets $ 1 $ 0  
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Schedule II. Condensed Financial Information of Registrant (Parent Company) (Schedule of Condensed Financial Information of Registrant, Statements of Cash Flows) (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2022
Sep. 30, 2022
Jun. 30, 2022
Mar. 31, 2022
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Cash Flows from Operating Activities              
Net income $ 239 $ (42) $ 190 $ 295 $ 1,205 $ 682 [1] $ 1,184 [1]
Adjustments to reconcile net income to net cash flows provided by operating activities:              
Net investment losses         99 199 [1] (120) [1]
Other, net         (192) (192) [1] (76) [1]
Net cash flows provided by operating activities         2,285 2,502 [1] 1,997 [1]
Cash Flows from Investing Activities              
Change in short-term investments         (274) 155 [1] (83) [1]
Other, net         (5) (10) [1] 1 [1]
Net cash flows used by investing activities         (1,843) (1,512) [1] (1,228) [1]
Cash Flows from Financing Activities              
Dividends paid to common stockholders         (787) (982) [1] (621) [1]
Proceeds from the issuance of debt         491 0 [1] 0 [1]
Repayment of debt         (243) 0 [1] 0 [1]
Purchase of treasury stock         (24) (39) [1] (18) [1]
Other, net         (14) (11) [1] (9) [1]
Net cash flows used by financing activities         (577) (1,032) [1] (648) [1]
Net change in cash         (130) (61) [1] 117 [1]
Cash, beginning of year [1]       536 475 536 419
Cash, end of year 475 [1]       345 475 [1] 536 [1]
Parent Company              
Cash Flows from Operating Activities              
Net income         1,205 682 1,184
Adjustments to reconcile net income to net cash flows provided by operating activities:              
Equity in net income of subsidiaries         (1,288) (781) (1,286)
Dividends received from subsidiaries         1,055 990 880
Other, net         2 28 33
Net cash flows provided by operating activities         974 919 811
Cash Flows from Investing Activities              
Change in short-term investments         (395) 114 (163)
Capital contributions to subsidiaries         (3) 0 0
Net cash flows used by investing activities         (398) 114 (163)
Cash Flows from Financing Activities              
Dividends paid to common stockholders         (787) (982) (621)
Proceeds from the issuance of debt         491 0 0
Repayment of debt         (243) 0 0
Purchase of treasury stock         (24) (39) (18)
Other, net         (14) (11) (8)
Net cash flows used by financing activities         (577) (1,032) (647)
Net change in cash         (1) 1 1
Cash, beginning of year       $ 1 2 1 0
Cash, end of year $ 2       $ 1 $ 2 $ 1
[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.
v3.24.0.1
Schedule II. Condensed Financial Information of Registrant (Parent Company) (Narrative) (Details)
Dec. 31, 2023
CNAF Consolidated | Loews  
Condensed Financial Statements, Captions [Line Items]  
Noncontrolling interest, ownership percentage by parent 92.00%
v3.24.0.1
Schedule V. Valuation and Qualifying Accounts (Schedule of valuation and qualifying accounts) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Mortgage loan receivables      
Movement in valuation allowances and reserves [Roll Forward]      
Balance Beginning of Period $ 24 $ 16 $ 26
Charged to Costs and Expenses 0 0 0
Charged to Other Accounts 11 8 (10)
Deductions 0 0 0
Balance at End of Period 35 24 16
Insurance and reinsurance receivables      
Movement in valuation allowances and reserves [Roll Forward]      
Balance Beginning of Period 51 50 54
Charged to Costs and Expenses 11 8 4
Charged to Other Accounts 0 0 0
Deductions (12) (7) (8)
Balance at End of Period 50 51 50
Fixed maturity securities      
Movement in valuation allowances and reserves [Roll Forward]      
Balance Beginning of Period 1 18 40
Charged to Costs and Expenses 0 0 0
Charged to Other Accounts 44 4 30
Deductions (29) (21) (52)
Balance at End of Period $ 16 $ 1 $ 18
v3.24.0.1
Schedule VI. Supplemental Information Concerning Property and Casualty Insurance Operations (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Incurred claim and claim adjustment expenses related to current year $ 5,667 $ 5,181 $ 5,021
Incurred claim and claim adjustment expenses related to prior years 48 (32) 15
Consolidated Property and Casualty Insurance Entity      
Deferred acquisition costs   806  
Reserves for unpaid claim and claim adjustment expenses 23,304 22,120  
Discount deducted from claim and claim adjustment expense reserves above (based on interest rates ranging from 3.5% to 6.4%) 647 683  
Unearned premiums 6,933 6,374  
Net written premiums 9,892 9,128 8,405
Net earned premiums 9,480 8,667 8,175
Net investment income 2,163 1,751 2,111
Incurred claim and claim adjustment expenses related to current year   5,181 5,021
Incurred claim and claim adjustment expenses related to prior years   (32) 15
Amortization of deferred acquisition costs 1,644 1,490 1,443
Paid claim and claim adjustment expenses $ 4,601 $ 4,302 $ 3,949
Consolidated Property and Casualty Insurance Entity | Minimum      
Supplemental Information Parenthetical      
SEC Schedule, 12-18, supplemental information, property-casualty insurance underwriters, interest rate at which discount computed 3.50% 3.50%  
Consolidated Property and Casualty Insurance Entity | Maximum      
Supplemental Information Parenthetical      
SEC Schedule, 12-18, supplemental information, property-casualty insurance underwriters, interest rate at which discount computed 6.40% 6.40%