Investments - Amortized Cost and Fair Values of Fixed Maturity Securities (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	$ 42,037	$ 41,102
Gross Unrealized Gains	698	652
Gross Unrealized Losses	3,787	4,056
Allowance for Credit Losses	22	1
Estimated Fair Value	38,926	37,697
Corporate and other bonds
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	24,194	23,137
Gross Unrealized Gains	339	301
Gross Unrealized Losses	1,909	2,009
Allowance for Credit Losses	13
Estimated Fair Value	22,611	21,429
States, municipalities and political subdivisions
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	8,262	8,918
Gross Unrealized Gains	341	338
Gross Unrealized Losses	793	939
Allowance for Credit Losses
Estimated Fair Value	7,810	8,317
Residential mortgage-backed
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	3,133	3,073
Gross Unrealized Gains	4	5
Gross Unrealized Losses	444	447
Allowance for Credit Losses
Estimated Fair Value	2,693	2,631
Commercial mortgage-backed
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	1,843	1,886
Gross Unrealized Gains	4	4
Gross Unrealized Losses	257	255
Allowance for Credit Losses	7
Estimated Fair Value	1,583	1,635
Other asset-backed
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	3,571	3,287
Gross Unrealized Gains	9	2
Gross Unrealized Losses	330	361
Allowance for Credit Losses	2	1
Estimated Fair Value	3,248	2,927
Asset-backed
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	8,547	8,246
Gross Unrealized Gains	17	11
Gross Unrealized Losses	1,031	1,063
Allowance for Credit Losses	9	1
Estimated Fair Value	7,524	7,193
U.S. Treasury and obligations of government-sponsored enterprises
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	130	111
Gross Unrealized Gains		1
Gross Unrealized Losses	3	2
Allowance for Credit Losses
Estimated Fair Value	127	110
Foreign government
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	700	617
Gross Unrealized Gains	1	1
Gross Unrealized Losses	50	43
Allowance for Credit Losses
Estimated Fair Value	651	575
Redeemable preferred stock
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	5	3
Gross Unrealized Gains
Gross Unrealized Losses
Allowance for Credit Losses
Estimated Fair Value	5	3
Fixed maturities available-for-sale
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	41,838	41,032
Gross Unrealized Gains	698	652
Gross Unrealized Losses	3,786	4,056
Allowance for Credit Losses	22	1
Estimated Fair Value	38,728	37,627
Fixed maturities trading
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost	199	70
Gross Unrealized Gains
Gross Unrealized Losses	1
Allowance for Credit Losses
Estimated Fair Value	$ 198	$ 70

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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