Derivatives (Primary Risks Managed by Derivatives) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 92,544	$ 113,375
Derivative assets	3,852	3,222
Derivative liabilities	9,608	7,119
Embedded Derivative, Fair Value of Embedded Derivative Asset	283	217
Embedded Derivative, Fair Value of Embedded Derivative Liability	7,584	4,582
Derivatives Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	3,040	3,121
Derivative assets	188	198
Derivative liabilities	112	27
Derivatives Not Designated or Not Qualifying as Hedging Instruments
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	89,504	110,254
Derivative assets	3,381	2,807
Derivative liabilities	1,912	2,510
Derivatives Not Designated or Not Qualifying as Hedging Instruments | Interest rate swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,295	7,559
Derivative assets	463	878
Derivative liabilities	0	29
Derivatives Not Designated or Not Qualifying as Hedging Instruments | Interest rate caps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,350	3,350
Derivative assets	2	2
Derivative liabilities	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments | Interest rate options
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	25,980	29,750
Derivative assets	712	782
Derivative liabilities	122	187
Derivatives Not Designated or Not Qualifying as Hedging Instruments | Interest rate forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	8,086	5,418
Derivative assets	851	94
Derivative liabilities	78	114
Derivatives Not Designated or Not Qualifying as Hedging Instruments | Foreign currency swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	989	1,040
Derivative assets	85	94
Derivative liabilities	32	15
Derivatives Not Designated or Not Qualifying as Hedging Instruments | Foreign currency forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	201	138
Derivative assets	0	0
Derivative liabilities	0	1
Derivatives Not Designated or Not Qualifying as Hedging Instruments | Credit default swaps — purchased
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	18	18
Derivative assets	0	0
Derivative liabilities	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments | Credit default swaps — written
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,755	1,613
Derivative assets	41	36
Derivative liabilities	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments | Credit Default Swaption
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	100	0
Derivative assets	0	0
Derivative liabilities	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments | Equity index options
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	31,576	51,509
Derivative assets	1,071	850
Derivative liabilities	838	1,728
Derivatives Not Designated or Not Qualifying as Hedging Instruments | Equity variance swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,098	2,136
Derivative assets	13	69
Derivative liabilities	20	69
Derivatives Not Designated or Not Qualifying as Hedging Instruments | Equity total return swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	15,056	7,723
Derivative assets	143	2
Derivative liabilities	822	367
Ceded guaranteed minimum income benefits
Derivatives, Fair Value [Line Items]
Embedded Derivative, Fair Value of Embedded Derivative Asset	283	217
Embedded Derivative, Fair Value of Embedded Derivative Liability	0	0
Direct guaranteed minimum benefits
Derivatives, Fair Value [Line Items]
Embedded Derivative, Fair Value of Embedded Derivative Asset	0	0
Embedded Derivative, Fair Value of Embedded Derivative Liability	2,751	1,548
Assumed guaranteed minimum benefits
Derivatives, Fair Value [Line Items]
Embedded Derivative, Fair Value of Embedded Derivative Asset	0	0
Embedded Derivative, Fair Value of Embedded Derivative Liability	596	442
Direct index-linked annuities
Derivatives, Fair Value [Line Items]
Embedded Derivative, Fair Value of Embedded Derivative Asset	0	0
Embedded Derivative, Fair Value of Embedded Derivative Liability	3,855	2,253
Direct index-linked annuities | Assumed index-linked annuities
Derivatives, Fair Value [Line Items]
Embedded Derivative, Fair Value of Embedded Derivative Asset	0	0
Embedded Derivative, Fair Value of Embedded Derivative Liability	382	339
Cash Flow Hedging | Derivatives Designated as Hedging Instruments | Interest rate forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	290	420
Derivative assets	66	22
Derivative liabilities	0	0
Cash Flow Hedging | Derivatives Designated as Hedging Instruments | Foreign currency swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,750	2,701
Derivative assets	122	176
Derivative liabilities	$ 112	$ 27