Investments - Amortized Cost and Fair Values of Fixed Maturity Securities (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost, Fixed maturities available-for-sale	$ 45,010	$ 44,617
Cost or Amortized Cost, Fixed maturities trading	390	633
Cost or Amortized Cost, Total fixed maturity securities	45,400	45,250
Gross Unrealized Gains	813	1,089
Gross Unrealized Losses	2,568	2,286
Allowance for Credit Losses	75	69
Estimated Fair Value, Fixed maturities available-for-sale	43,180	43,351
Estimated Fair Value, Fixed maturities trading	390	633
Total fixed maturities	43,570	43,984
Corporate and other bonds
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost, Fixed maturities available-for-sale	25,624	25,484
Gross Unrealized Gains	482	682
Gross Unrealized Losses	1,074	881
Allowance for Credit Losses	31	28
Estimated Fair Value, Fixed maturities available-for-sale	25,001	25,257
States, municipalities and political subdivisions
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost, Fixed maturities available-for-sale	9,110	8,870
Gross Unrealized Gains	255	303
Gross Unrealized Losses	793	742
Allowance for Credit Losses
Estimated Fair Value, Fixed maturities available-for-sale	8,572	8,431
Residential mortgage-backed
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost, Fixed maturities available-for-sale	4,035	4,011
Gross Unrealized Gains	37	50
Gross Unrealized Losses	372	366
Allowance for Credit Losses
Estimated Fair Value, Fixed maturities available-for-sale	3,700	3,695
Commercial mortgage-backed
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost, Fixed maturities available-for-sale	1,498	1,515
Gross Unrealized Gains	13	18
Gross Unrealized Losses	81	80
Allowance for Credit Losses	21	21
Estimated Fair Value, Fixed maturities available-for-sale	1,409	1,432
Other asset-backed
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost, Fixed maturities available-for-sale	3,722	3,729
Gross Unrealized Gains	19	28
Gross Unrealized Losses	219	194
Allowance for Credit Losses	23	20
Estimated Fair Value, Fixed maturities available-for-sale	3,499	3,543
Asset-backed
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost, Fixed maturities available-for-sale	9,255	9,255
Gross Unrealized Gains	69	96
Gross Unrealized Losses	672	640
Allowance for Credit Losses	44	41
Estimated Fair Value, Fixed maturities available-for-sale	8,608	8,670
U.S. Treasury and obligations of government-sponsored enterprises
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost, Fixed maturities available-for-sale	244	236
Gross Unrealized Gains	1	1
Gross Unrealized Losses	3	3
Allowance for Credit Losses
Estimated Fair Value, Fixed maturities available-for-sale	242	234
Foreign government
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost, Fixed maturities available-for-sale	769	764
Gross Unrealized Gains	6	7
Gross Unrealized Losses	26	20
Allowance for Credit Losses
Estimated Fair Value, Fixed maturities available-for-sale	749	751
Redeemable preferred stock
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost, Fixed maturities available-for-sale	8	8
Gross Unrealized Gains
Gross Unrealized Losses
Allowance for Credit Losses
Estimated Fair Value, Fixed maturities available-for-sale	8	8
Fixed maturities available-for-sale
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Cost or Amortized Cost, Fixed maturities available-for-sale	45,010	44,617
Estimated Fair Value, Fixed maturities available-for-sale	43,180	43,351
Fixed maturities trading
Amortized Cost and Fair Values of Fixed Maturity Securities [Abstract]
Estimated Fair Value, Fixed maturities trading	$ 390	$ 633

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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).

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Amount, after 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), investment in debt security measured at amortized cost (held-to-maturity), and investment in debt security measured at fair value with change in fair value recognized in net income (trading).

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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.

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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).

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