Derivatives (Primary Risks) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 318,306		$ 318,306		$ 328,116
Estimated Fair Value Assets	9,466		9,466		11,411
Estimated Fair Value Liabilities	7,406		7,406		$ 6,975
Derivative, Gain (Loss) on Derivative, Net	230	$ 258	802	$ 746
Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net	1	19	$ 28	21
Maximum Length of Time Hedged in Cash Flow Hedge			6 years		6 years
Accumulated Other Comprehensive Income Loss	762		$ 762		$ 2,000
Fair Value Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Not Designated as Hedging Instrument, Economic Hedge | Derivative Contract [Domain]
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net			(740)	(318)
Derivatives Designated as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	63,504		63,504		63,923
Estimated Fair Value Assets	4,594		4,594		5,244
Estimated Fair Value Liabilities	3,785		3,785		3,909
Derivatives Designated as Hedging Instruments: | Fair Value Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	6,633		6,633		6,081
Estimated Fair Value Assets	1,177		1,177		1,445
Estimated Fair Value Liabilities	772		772		556
Derivatives Designated as Hedging Instruments: | Fair Value Hedges [Member] | Interest rate swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	4,551		4,551		4,143
Estimated Fair Value Assets	1,107		1,107		1,353
Estimated Fair Value Liabilities	655		655		467
Derivatives Designated as Hedging Instruments: | Fair Value Hedges [Member] | Foreign currency swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,496		1,496		602
Estimated Fair Value Assets	70		70		82
Estimated Fair Value Liabilities	15		15		0
Derivatives Designated as Hedging Instruments: | Fair Value Hedges [Member] | Foreign currency forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	586		586		1,336
Estimated Fair Value Assets	0		0		10
Estimated Fair Value Liabilities	102		102		89
Derivatives Designated as Hedging Instruments: | Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	53,182		53,182		54,162
Estimated Fair Value Assets	2,935		2,935		3,563
Estimated Fair Value Liabilities	3,013		3,013		3,315
Derivatives Designated as Hedging Instruments: | Cash Flow Hedges [Member] | Interest rate swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	4,306		4,306		4,107
Estimated Fair Value Assets	6		6		8
Estimated Fair Value Liabilities	356		356		262
Derivatives Designated as Hedging Instruments: | Cash Flow Hedges [Member] | Interest rate forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	6,261		6,261		7,447
Estimated Fair Value Assets	0		0		1
Estimated Fair Value Liabilities	1,143		1,143		1,354
Derivatives Designated as Hedging Instruments: | Cash Flow Hedges [Member] | Foreign currency swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	42,615		42,615		42,608
Estimated Fair Value Assets	2,929		2,929		3,554
Estimated Fair Value Liabilities	1,514		1,514		1,699
Derivatives Designated as Hedging Instruments: | Foreign Operations Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	3,689		3,689		3,680
Estimated Fair Value Assets	482		482		236
Estimated Fair Value Liabilities	0		0		38
Derivatives Designated as Hedging Instruments: | Foreign Operations Hedges [Member] | Foreign currency forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	689		689		680
Estimated Fair Value Assets	66		66		0
Estimated Fair Value Liabilities	0		0		38
Derivatives Designated as Hedging Instruments: | Foreign Operations Hedges [Member] | Currency options
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	3,000		3,000		3,000
Estimated Fair Value Assets	416		416		236
Estimated Fair Value Liabilities	0		0		0
Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	254,802		254,802		264,193
Estimated Fair Value Assets	4,872		4,872		6,167
Estimated Fair Value Liabilities	3,621		3,621		3,066
Derivative, Gain (Loss) on Derivative, Net	(1,538)	$ (476)	(3,198)	$ (2,942)
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Interest rate swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	28,544		28,544		31,661
Estimated Fair Value Assets	1,374		1,374		1,660
Estimated Fair Value Liabilities	1,376		1,376		1,354
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Interest rate forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,878		1,878		381
Estimated Fair Value Assets	0		0		0
Estimated Fair Value Liabilities	121		121		32
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Interest rate floors
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	19,645		19,645		25,270
Estimated Fair Value Assets	30		30		125
Estimated Fair Value Liabilities	0		0		0
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Interest rate caps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	42,165		42,165		48,290
Estimated Fair Value Assets	680		680		950
Estimated Fair Value Liabilities	0		0		0
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Interest rate futures
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	903		903		1,453
Estimated Fair Value Assets	3		3		2
Estimated Fair Value Liabilities	1		1		1
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Interest rate options
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	42,910		42,910		44,391
Estimated Fair Value Assets	418		418		473
Estimated Fair Value Liabilities	272		272		88
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Synthetic GICs
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	49,003		49,003		46,316
Estimated Fair Value Assets	0		0		0
Estimated Fair Value Liabilities	0		0		0
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Foreign currency swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	11,992		11,992		12,815
Estimated Fair Value Assets	1,409		1,409		1,454
Estimated Fair Value Liabilities	370		370		383
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Foreign currency forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	15,648		15,648		16,195
Estimated Fair Value Assets	105		105		544
Estimated Fair Value Liabilities	1,136		1,136		661
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Currency futures
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	311		311		333
Estimated Fair Value Assets	0		0		8
Estimated Fair Value Liabilities	0		0		0
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Currency options
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	15		15		0
Estimated Fair Value Assets	1		1		0
Estimated Fair Value Liabilities	0		0		0
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Credit default swaps — purchased
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,890		2,890		2,925
Estimated Fair Value Assets	10		10		18
Estimated Fair Value Liabilities	73		73		79
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Credit default swaps — written
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	13,012		13,012		11,512
Estimated Fair Value Assets	167		167		133
Estimated Fair Value Liabilities	21		21		28
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Equity futures
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,648		2,648		2,988
Estimated Fair Value Assets	9		9		8
Estimated Fair Value Liabilities	4		4		4
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Equity index options
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	21,165		21,165		16,701
Estimated Fair Value Assets	542		542		765
Estimated Fair Value Liabilities	246		246		323
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Equity variance swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	141		141		163
Estimated Fair Value Assets	4		4		4
Estimated Fair Value Liabilities	1		1		1
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Equity total return swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,932		1,932		2,799
Estimated Fair Value Assets	120		120		23
Estimated Fair Value Liabilities	0		0		112
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Derivatives hedging MRBs
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	15,129		15,129		18,814
Estimated Fair Value Assets	238		238		300
Estimated Fair Value Liabilities	1,092		1,092		1,147
Not Designated as Hedging Instrument, Economic Hedge | Interest Rate Contract
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	7,912		7,912		9,098
Estimated Fair Value Assets	9		9		41
Estimated Fair Value Liabilities	902		902		764
Not Designated as Hedging Instrument, Economic Hedge | Foreign currency exchange rate
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	770		770		887
Estimated Fair Value Assets	3		3		26
Estimated Fair Value Liabilities	23		23		2
Not Designated as Hedging Instrument, Economic Hedge | Equity
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	6,447		6,447		8,829
Estimated Fair Value Assets	226		226		233
Estimated Fair Value Liabilities	$ 167		$ 167		$ 381