Derivatives (Primary Risks Managed by Derivatives) (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 142,702	$ 116,742
Derivative assets	2,995	2,271
Derivative liabilities	3,887	3,911
Derivatives Designated as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	3,929	4,041
Derivative assets	499	584
Derivative liabilities	24	20
Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	138,773	112,701
Derivative assets	2,496	1,687
Derivative liabilities	3,863	3,891
Interest rate swaps | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	14,853	3,145
Derivative assets	90	98
Derivative liabilities	70	46
Interest rate floors | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	3,000	3,250
Derivative assets	4	12
Derivative liabilities	1	3
Interest rate caps | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	5,800	6,350
Derivative assets	94	137
Derivative liabilities	34	43
Interest rate options | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	31,680	28,688
Derivative assets	43	22
Derivative liabilities	208	232
Interest rate forwards | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	17,939	18,168
Derivative assets	47	35
Derivative liabilities	1,941	2,466
Interest rate forwards | Cash flow hedges: | Derivatives Designated as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	20	60
Derivative assets	0	0
Derivative liabilities	4	12
Foreign currency swaps | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	765	810
Derivative assets	126	147
Derivative liabilities	0	0
Foreign currency swaps | Cash flow hedges: | Derivatives Designated as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	3,909	3,981
Derivative assets	499	584
Derivative liabilities	20	8
Foreign currency forwards | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	309	295
Derivative assets	0	1
Derivative liabilities	0	1
Credit default swaps — written | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,530	1,757
Derivative assets	24	18
Derivative liabilities	1	2
Credit default swaptions | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	0	100
Derivative assets	0	0
Derivative liabilities	0	0
Equity index options | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	15,528	17,229
Derivative assets	626	697
Derivative liabilities	495	351
Equity total return swaps | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	46,739	32,909
Derivative assets	1,438	520
Derivative liabilities	1,113	747
Hybrid options | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	630	0
Derivative assets	4	0
Derivative liabilities	$ 0	$ 0