Investments - Amortized Cost and Fair Values of Fixed Maturity Securities (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	$ 45,250	$ 44,196
Gross Unrealized Gains	1,089	715
Gross Unrealized Losses	2,286	3,039
Allowance for Credit Losses	69	45
Estimated Fair Value	43,984	41,827
Corporate bonds and other
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
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
Estimated Fair Value	25,257	24,944
States, municipalities and political subdivisions
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	8,870	7,396
Gross Unrealized Gains	303	243
Gross Unrealized Losses	742	835
Allowance for Credit Losses
Estimated Fair Value	8,431	6,804
Residential mortgage-backed
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	4,011	3,725
Gross Unrealized Gains	50	7
Gross Unrealized Losses	366	488
Allowance for Credit Losses
Estimated Fair Value	3,695	3,244
Commercial mortgage-backed
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	1,515	1,779
Gross Unrealized Gains	18	11
Gross Unrealized Losses	80	141
Allowance for Credit Losses	21	18
Estimated Fair Value	1,432	1,631
Other asset-backed
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
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
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	9,255	9,274
Gross Unrealized Gains	96	42
Gross Unrealized Losses	640	868
Allowance for Credit Losses	41	32
Estimated Fair Value	8,670	8,416
U.S. Treasury and obligations of government-sponsored enterprises
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	236	220
Gross Unrealized Gains	1	1
Gross Unrealized Losses	3	1
Allowance for Credit Losses
Estimated Fair Value	234	220
Foreign government
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	764	701
Gross Unrealized Gains	7	6
Gross Unrealized Losses	20	30
Allowance for Credit Losses
Estimated Fair Value	751	677
Redeemable preferred stock
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	8
Gross Unrealized Gains
Gross Unrealized Losses
Allowance for Credit Losses
Estimated Fair Value	8
Fixed maturities available-for-sale
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	44,617	43,430
Gross Unrealized Gains	1,089	715
Gross Unrealized Losses	2,286	3,039
Allowance for Credit Losses	69	45
Estimated Fair Value	43,351	41,061
Fixed maturities trading
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	633	766
Gross Unrealized Gains
Gross Unrealized Losses
Allowance for Credit Losses
Estimated Fair Value	$ 633	$ 766

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

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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

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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), classified as current.

+ 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

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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

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