Derivative Instruments (Gross Notional Amount and Fair Value of Derivatives Contracts) (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Derivative [Line Items]
Notional Amount	$ 49,059	$ 35,830
Carrying Value / Fair Value of Assets	611	187
Derivative Liability, Fair Value, Gross Liability	806	550
Derivative Asset, Subject to Master Netting Arrangement, after Offset	914	470
Derivative Liability, Subject to Master Netting Arrangement, after Offset	1,643	1,323
Not Designated as Hedging Instrument
Derivative [Line Items]
Notional Amount	38,223	26,500
Carrying Value / Fair Value of Assets	836	364
Derivative Liability, Fair Value, Gross Liability	1,159	855
Not Designated as Hedging Instrument | Interest Rate Swaps
Derivative [Line Items]
Notional Amount	1,940	1,848
Carrying Value / Fair Value of Assets	5	6
Derivative Liability, Fair Value, Gross Liability	12	20
Not Designated as Hedging Instrument | Foreign Currency Forwards
Derivative [Line Items]
Notional Amount	1,325	1,148
Derivative Asset, Subject to Master Netting Arrangement, after Offset	1	9
Derivative Liability, Subject to Master Netting Arrangement, after Offset	24	37
Not Designated as Hedging Instrument | Financial Futures
Derivative [Line Items]
Notional Amount	208	209
Carrying Value / Fair Value of Assets	0	0
Derivative Liability, Fair Value, Gross Liability	0	0
Not Designated as Hedging Instrument | Consumer Price Index Swap [Member]
Derivative [Line Items]
Notional Amount	408	408
Carrying Value / Fair Value of Assets	2	6
Derivative Liability, Fair Value, Gross Liability	5	2
Not Designated as Hedging Instrument | Synthetic Guaranteed Investment Contracts
Derivative [Line Items]
Notional Amount	17,117	15,362
Carrying Value / Fair Value of Assets	0	0
Derivative Liability, Fair Value, Gross Liability	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	303	283
Derivative Liability, Fair Value, Gross Liability	399	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, Fair Value, Gross Liability	438	435
Not Designated as Hedging Instrument | Currency Swap [Member]
Derivative [Line Items]
Notional Amount	150	150
Derivative Asset, Subject to Master Netting Arrangement, after Offset	43	47
Derivative Liability, Subject to Master Netting Arrangement, after Offset	0	0
Not Designated as Hedging Instrument | Interest Rate Swaption
Derivative [Line Items]
Notional Amount	750	1,773
Carrying Value / Fair Value of Assets	1	1
Derivative Liability, Fair Value, Gross Liability	0	0
Not Designated as Hedging Instrument | Total Return Swap
Derivative [Line Items]
Notional Amount	606	956
Carrying Value / Fair Value of Assets	5	0
Derivative Liability, Fair Value, Gross Liability	5	14
Not Designated as Hedging Instrument | Foreign Exchange Option
Derivative [Line Items]
Notional Amount	430	430
Derivative Asset, Subject to Master Netting Arrangement, after Offset	0	1
Derivative Liability, Subject to Master Netting Arrangement, after Offset	0	0
Not Designated as Hedging Instrument | Equity Option
Derivative [Line Items]
Notional Amount	5,576	255
Carrying Value / Fair Value of Assets	465	5
Derivative Liability, Fair Value, Gross Liability	258	1
Not Designated as Hedging Instrument | Credit Default Swaps
Derivative [Line Items]
Notional Amount	6,238	2,661
Carrying Value / Fair Value of Assets	7	4
Derivative Liability, Fair Value, Gross Liability	15	6
Not Designated as Hedging Instrument | Credit Default Option
Derivative [Line Items]
Notional Amount	2,200	0
Derivative Asset, Subject to Master Netting Arrangement, after Offset	0	0
Derivative Liability, Subject to Master Netting Arrangement, after Offset	0	0
Not Designated as Hedging Instrument | Swap
Derivative [Line Items]
Notional Amount	1,275	1,300
Carrying Value / Fair Value of Assets	4	2
Derivative Liability, Fair Value, Gross Liability	3	2
Designated As Hedging Instrument
Derivative [Line Items]
Notional Amount	10,836	9,330
Derivative Asset, Subject to Master Netting Arrangement, after Offset	78	106
Derivative Liability, Subject to Master Netting Arrangement, after Offset	484	468
Designated As Hedging Instrument | Interest Rate Swaps
Derivative [Line Items]
Notional Amount	3,374	3,336
Derivative Asset, Subject to Master Netting Arrangement, after Offset	39	5
Derivative Liability, Subject to Master Netting Arrangement, after Offset	55	103
Designated As Hedging Instrument | Foreign Currency Forwards
Derivative [Line Items]
Notional Amount	2,266	1,966
Derivative Asset, Subject to Master Netting Arrangement, after Offset	20	94
Derivative Liability, Subject to Master Netting Arrangement, after Offset	32	0
Designated As Hedging Instrument | Currency Swap [Member]
Derivative [Line Items]
Notional Amount	2,008	2,008
Derivative Asset, Subject to Master Netting Arrangement, after Offset	6	7
Derivative Liability, Subject to Master Netting Arrangement, after Offset	194	159
Designated As Hedging Instrument | Forward Contracts [Member]
Derivative [Line Items]
Notional Amount	3,188	2,020
Derivative Asset, Subject to Master Netting Arrangement, after Offset	13	0
Derivative Liability, Subject to Master Netting Arrangement, after Offset	$ 203	$ 206