Investments (Summary of fixed maturity and equity securities) (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	$ 44,668	$ 43,481
Gross Unrealized Gains	1,089	715
Gross Unrealized Losses	2,286	3,040
Allowance for Credit Losses	69	45	$ 16
Estimated Fair Value	43,402	41,111
Corporate and other bonds
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	25,484	25,839
Gross Unrealized Gains	682	423
Gross Unrealized Losses	881	1,305
Allowance for Credit Losses	28	13	4
Estimated Fair Value	25,257	24,944
States, municipalities and political subdivisions
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	8,870	7,396
Gross Unrealized Gains	303	243
Gross Unrealized Losses	742	835
Allowance for Credit Losses	0	0
Estimated Fair Value	8,431	6,804
Residential mortgage-backed
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	4,011	3,725
Gross Unrealized Gains	50	7
Gross Unrealized Losses	366	488
Allowance for Credit Losses	0	0
Estimated Fair Value	3,695	3,244
Commercial mortgage-backed
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	1,566	1,830
Gross Unrealized Gains	18	11
Gross Unrealized Losses	80	142
Allowance for Credit Losses	21	18
Estimated Fair Value	1,483	1,681
Other asset-backed
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	3,729	3,770
Gross Unrealized Gains	28	24
Gross Unrealized Losses	194	239
Allowance for Credit Losses	20	14
Estimated Fair Value	3,543	3,541
Asset-backed
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	9,306	9,325
Gross Unrealized Gains	96	42
Gross Unrealized Losses	640	869
Allowance for Credit Losses	41	32	$ 12
Estimated Fair Value	8,721	8,466
U.S. Treasury and obligations of government-sponsored enterprises
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	236	220
Gross Unrealized Gains	1	1
Gross Unrealized Losses	3	1
Allowance for Credit Losses	0	0
Estimated Fair Value	234	220
Foreign government
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	764	701
Gross Unrealized Gains	7	6
Gross Unrealized Losses	20	30
Allowance for Credit Losses	0	0
Estimated Fair Value	751	677
Redeemable preferred stock
Fixed maturity securities available-for-sale:
Cost or Amortized Cost	8	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Allowance for Credit Losses	0	0
Estimated Fair Value	$ 8	$ 0

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

+ Details

Name:	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

+ Details

Name:	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount excluding accrued interest, of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479130/326-30-45-1

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amortized cost excluding accrued interest, before allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479130/326-30-45-1

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_DebtSecuritiesUnrealizedGainLossAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ResidentialMortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CommercialMortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USTreasuryAndGovernmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ForeignGovernmentDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_RedeemablePreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: