Derivatives (Primary Risks) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 321,539		$ 328,116
Estimated Fair Value Assets	10,530		11,411
Estimated Fair Value Liabilities	5,545		$ 6,975
Derivative, Gain (Loss) on Derivative, Net	(90)	$ (951)
Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net	$ 1	(2)
Maximum Length of Time Hedged in Cash Flow Hedge	6 years		6 years
Accumulated Other Comprehensive Income Loss	$ 2,200		$ 2,000
Fair Value Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0
Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0
Not Designated as Hedging Instrument, Economic Hedge | Derivative Contract [Domain]
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net	153	185
Derivatives Designated as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	63,356		63,923
Estimated Fair Value Assets	5,199		5,244
Estimated Fair Value Liabilities	2,983		3,909
Derivatives Designated as Hedging Instruments: | Fair Value Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	5,531		6,081
Estimated Fair Value Assets	1,459		1,445
Estimated Fair Value Liabilities	461		556
Derivatives Designated as Hedging Instruments: | Fair Value Hedges [Member] | Interest rate swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	4,143		4,143
Estimated Fair Value Assets	1,394		1,353
Estimated Fair Value Liabilities	403		467
Derivatives Designated as Hedging Instruments: | Fair Value Hedges [Member] | Foreign currency swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	602		602
Estimated Fair Value Assets	65		82
Estimated Fair Value Liabilities	0		0
Derivatives Designated as Hedging Instruments: | Fair Value Hedges [Member] | Foreign currency forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	786		1,336
Estimated Fair Value Assets	0		10
Estimated Fair Value Liabilities	58		89
Derivatives Designated as Hedging Instruments: | Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	53,975		54,162
Estimated Fair Value Assets	3,463		3,563
Estimated Fair Value Liabilities	2,501		3,315
Derivatives Designated as Hedging Instruments: | Cash Flow Hedges [Member] | Interest rate swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	4,107		4,107
Estimated Fair Value Assets	42		8
Estimated Fair Value Liabilities	203		262
Derivatives Designated as Hedging Instruments: | Cash Flow Hedges [Member] | Interest rate forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	7,142		7,447
Estimated Fair Value Assets	8		1
Estimated Fair Value Liabilities	898		1,354
Derivatives Designated as Hedging Instruments: | Cash Flow Hedges [Member] | Foreign currency swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	42,726		42,608
Estimated Fair Value Assets	3,413		3,554
Estimated Fair Value Liabilities	1,400		1,699
Derivatives Designated as Hedging Instruments: | Foreign Operations Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	3,850		3,680
Estimated Fair Value Assets	277		236
Estimated Fair Value Liabilities	21		38
Derivatives Designated as Hedging Instruments: | Foreign Operations Hedges [Member] | Foreign currency forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	850		680
Estimated Fair Value Assets	15		0
Estimated Fair Value Liabilities	21		38
Derivatives Designated as Hedging Instruments: | Foreign Operations Hedges [Member] | Currency options
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	3,000		3,000
Estimated Fair Value Assets	262		236
Estimated Fair Value Liabilities	0		0
Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	258,183		264,193
Estimated Fair Value Assets	5,331		6,167
Estimated Fair Value Liabilities	2,562		3,066
Derivative, Gain (Loss) on Derivative, Net	(403)	$ (1,084)
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Interest rate swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	29,951		31,661
Estimated Fair Value Assets	1,668		1,660
Estimated Fair Value Liabilities	988		1,354
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Interest rate forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	830		381
Estimated Fair Value Assets	1		0
Estimated Fair Value Liabilities	21		32
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Interest rate floors
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	22,896		25,270
Estimated Fair Value Assets	140		125
Estimated Fair Value Liabilities	0		0
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Interest rate caps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	42,415		48,290
Estimated Fair Value Assets	733		950
Estimated Fair Value Liabilities	0		0
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Interest rate futures
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,344		1,453
Estimated Fair Value Assets	4		2
Estimated Fair Value Liabilities	2		1
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Interest rate options
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	44,404		44,391
Estimated Fair Value Assets	434		473
Estimated Fair Value Liabilities	52		88
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Synthetic GICs
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	47,850		46,316
Estimated Fair Value Assets	0		0
Estimated Fair Value Liabilities	0		0
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Foreign currency swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	12,317		12,815
Estimated Fair Value Assets	1,468		1,454
Estimated Fair Value Liabilities	339		383
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Foreign currency forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	16,743		16,195
Estimated Fair Value Assets	177		544
Estimated Fair Value Liabilities	723		661
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Currency futures
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	333		333
Estimated Fair Value Assets	0		8
Estimated Fair Value Liabilities	0		0
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Credit default swaps — purchased
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,880		2,925
Estimated Fair Value Assets	12		18
Estimated Fair Value Liabilities	79		79
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Credit default swaps — written
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	12,796		11,512
Estimated Fair Value Assets	126		133
Estimated Fair Value Liabilities	20		28
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Equity futures
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,785		2,988
Estimated Fair Value Assets	10		8
Estimated Fair Value Liabilities	47		4
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Equity index options
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	17,642		16,701
Estimated Fair Value Assets	527		765
Estimated Fair Value Liabilities	266		323
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Equity variance swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	141		163
Estimated Fair Value Assets	4		4
Estimated Fair Value Liabilities	1		1
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Equity total return swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,856		2,799
Estimated Fair Value Assets	27		23
Estimated Fair Value Liabilities	24		112
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Derivatives hedging MRBs
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	17,263		18,814
Estimated Fair Value Assets	141		300
Estimated Fair Value Liabilities	880		1,147
Not Designated as Hedging Instrument, Economic Hedge | Interest Rate Contract
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	8,401		9,098
Estimated Fair Value Assets	17		41
Estimated Fair Value Liabilities	600		764
Not Designated as Hedging Instrument, Economic Hedge | Foreign currency exchange rate
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,140		887
Estimated Fair Value Assets	7		26
Estimated Fair Value Liabilities	15		2
Not Designated as Hedging Instrument, Economic Hedge | Equity
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	7,722		8,829
Estimated Fair Value Assets	117		233
Estimated Fair Value Liabilities	$ 265		$ 381