Derivative Instruments (Gross Notional Amount and Fair Value of Derivatives Contracts) (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Derivative [Line Items]
Notional Amount	$ 39,631	$ 35,830
Carrying Value / Fair Value of Assets	440	470
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	1,261	1,323
Derivative Fair Value Of Free Standing Derivative Asset	155	187
Derivative Liability, Fair Value, Gross Liability	527	550
Not Designated as Hedging Instrument
Derivative [Line Items]
Notional Amount	29,882	26,500
Carrying Value / Fair Value of Assets	357	364
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	822	855
Not Designated as Hedging Instrument | Interest Rate Swaps
Derivative [Line Items]
Notional Amount	1,886	1,848
Carrying Value / Fair Value of Assets	6	6
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	14	20
Not Designated as Hedging Instrument | Foreign Currency Forwards
Derivative [Line Items]
Notional Amount	1,101	1,148
Carrying Value / Fair Value of Assets	3	9
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	20	37
Not Designated as Hedging Instrument | Financial Futures
Derivative [Line Items]
Notional Amount	223	209
Carrying Value / Fair Value of Assets	0	0
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	0	0
Not Designated as Hedging Instrument | Consumer Price Index Swap [Member]
Derivative [Line Items]
Notional Amount	394	408
Carrying Value / Fair Value of Assets	4	6
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	5	2
Not Designated as Hedging Instrument | Credit Default Swaps
Derivative [Line Items]
Notional Amount	4,165	2,661
Carrying Value / Fair Value of Assets	2	4
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	21	6
Not Designated as Hedging Instrument | Synthetic Guaranteed Investment Contracts
Derivative [Line Items]
Notional Amount	16,176	15,362
Carrying Value / Fair Value of Assets	0	0
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	0	0
Not Designated as Hedging Instrument | Embedded Derivatives In Modified Coinsurance Or Funds Withheld Arrangements
Derivative [Line Items]
Notional Amount	0	0
Carrying Value / Fair Value of Assets	285	283
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	351	338
Not Designated as Hedging Instrument | Embedded Derivatives In Indexed Annuity [Member]
Derivative [Line Items]
Notional Amount	0	0
Carrying Value / Fair Value of Assets	0	0
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	383	435
Not Designated as Hedging Instrument | Currency Swap [Member]
Derivative [Line Items]
Notional Amount	150	150
Carrying Value / Fair Value of Assets	42	47
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	0	0
Not Designated as Hedging Instrument | Interest Rate Swaption
Derivative [Line Items]
Notional Amount	2,273	1,773
Carrying Value / Fair Value of Assets	3	1
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	0	0
Not Designated as Hedging Instrument | Total Return Swap
Derivative [Line Items]
Notional Amount	865	956
Carrying Value / Fair Value of Assets	0	0
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	25	14
Not Designated as Hedging Instrument | Equity Option
Derivative [Line Items]
Notional Amount	669	255
Carrying Value / Fair Value of Assets	11	5
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	2	1
Not Designated as Hedging Instrument | Foreign Exchange Option
Derivative [Line Items]
Notional Amount	430	430
Derivative Fair Value Of Free Standing Derivative Asset	0	1
Derivative Liability, Fair Value, Gross Liability	0	0
Not Designated as Hedging Instrument | Swap
Derivative [Line Items]
Notional Amount	1,300	1,300
Derivative Fair Value Of Free Standing Derivative Asset	1	2
Derivative Liability, Fair Value, Gross Liability	1	2
Not Designated as Hedging Instrument | Credit Default Option
Derivative [Line Items]
Notional Amount	250	0
Carrying Value / Fair Value of Assets	0	0
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	0	0
Designated As Hedging Instrument
Derivative [Line Items]
Notional Amount	9,749	9,330
Carrying Value / Fair Value of Assets	83	106
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	439	468
Designated As Hedging Instrument | Interest Rate Swaps
Derivative [Line Items]
Notional Amount	3,301	3,336
Carrying Value / Fair Value of Assets	27	5
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	72	103
Designated As Hedging Instrument | Foreign Currency Forwards
Derivative [Line Items]
Notional Amount	1,933	1,966
Carrying Value / Fair Value of Assets	47	94
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	5	0
Designated As Hedging Instrument | Currency Swap [Member]
Derivative [Line Items]
Notional Amount	2,008	2,008
Carrying Value / Fair Value of Assets	6	7
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	160	159
Designated As Hedging Instrument | Forward Contracts [Member]
Derivative [Line Items]
Notional Amount	2,507	2,020
Carrying Value / Fair Value of Assets	3	0
Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral	$ 202	$ 206