Derivatives (Primary Risks) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 328,116	$ 308,215
Estimated Fair Value Assets	11,411	10,466
Estimated Fair Value Liabilities	6,975	3,852
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	63,923	61,088
Estimated Fair Value Assets	5,244	4,009
Estimated Fair Value Liabilities	3,909	1,764
Derivatives Designated as Hedging Instruments [Member] | Fair Value Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	6,081	5,987
Estimated Fair Value Assets	1,445	2,175
Estimated Fair Value Liabilities	556	87
Derivatives Designated as Hedging Instruments [Member] | Fair Value Hedges [Member] | Interest rate swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	4,143	3,550
Estimated Fair Value Assets	1,353	2,164
Estimated Fair Value Liabilities	467	6
Derivatives Designated as Hedging Instruments [Member] | Fair Value Hedges [Member] | Foreign currency swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	602	801
Estimated Fair Value Assets	82	11
Estimated Fair Value Liabilities	0	23
Derivatives Designated as Hedging Instruments [Member] | Fair Value Hedges [Member] | Foreign currency forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,336	1,636
Estimated Fair Value Assets	10	0
Estimated Fair Value Liabilities	89	58
Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	54,162	52,101
Estimated Fair Value Assets	3,563	1,695
Estimated Fair Value Liabilities	3,315	1,677
Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedges [Member] | Interest rate swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	4,107	4,117
Estimated Fair Value Assets	8	6
Estimated Fair Value Liabilities	262	1
Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedges [Member] | Interest rate forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	7,447	6,889
Estimated Fair Value Assets	1	89
Estimated Fair Value Liabilities	1,354	119
Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedges [Member] | Foreign currency swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	42,608	41,095
Estimated Fair Value Assets	3,554	1,600
Estimated Fair Value Liabilities	1,699	1,557
Derivatives Designated as Hedging Instruments [Member] | Foreign Operations Hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	3,680	3,000
Estimated Fair Value Assets	236	139
Estimated Fair Value Liabilities	38	0
Derivatives Designated as Hedging Instruments [Member] | Foreign Operations Hedges [Member] | Foreign currency forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	680	0
Estimated Fair Value Assets	0	0
Estimated Fair Value Liabilities	38	0
Derivatives Designated as Hedging Instruments [Member] | Foreign Operations Hedges [Member] | Currency options
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	3,000	3,000
Estimated Fair Value Assets	236	139
Estimated Fair Value Liabilities	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	264,193	247,127
Estimated Fair Value Assets	6,167	6,457
Estimated Fair Value Liabilities	3,066	2,088
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Interest rate swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	31,661	38,860
Estimated Fair Value Assets	1,660	3,644
Estimated Fair Value Liabilities	1,354	115
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Interest rate forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	381	374
Estimated Fair Value Assets	0	0
Estimated Fair Value Liabilities	32	26
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Interest rate floors
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	25,270	7,701
Estimated Fair Value Assets	125	145
Estimated Fair Value Liabilities	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Interest rate caps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	48,290	65,559
Estimated Fair Value Assets	950	124
Estimated Fair Value Liabilities	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Interest rate futures
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,453	1,615
Estimated Fair Value Assets	2	4
Estimated Fair Value Liabilities	1	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Interest rate options
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	44,391	11,754
Estimated Fair Value Assets	473	493
Estimated Fair Value Liabilities	88	10
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Synthetic GICs
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	46,316	40,121
Estimated Fair Value Assets	0	0
Estimated Fair Value Liabilities	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Foreign currency swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	12,815	12,787
Estimated Fair Value Assets	1,454	768
Estimated Fair Value Liabilities	383	614
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Foreign currency forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	16,195	16,230
Estimated Fair Value Assets	544	36
Estimated Fair Value Liabilities	661	666
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Currency futures
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	333	839
Estimated Fair Value Assets	8	0
Estimated Fair Value Liabilities	0	2
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Currency options
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	0	900
Estimated Fair Value Assets	0	0
Estimated Fair Value Liabilities	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Credit default swaps — purchased
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,925	3,042
Estimated Fair Value Assets	18	13
Estimated Fair Value Liabilities	79	113
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Credit default swaps — written
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	11,512	8,626
Estimated Fair Value Assets	133	177
Estimated Fair Value Liabilities	28	12
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Equity futures
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,988	4,204
Estimated Fair Value Assets	8	12
Estimated Fair Value Liabilities	4	5
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Equity index options
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	16,701	29,743
Estimated Fair Value Assets	765	1,004
Estimated Fair Value Liabilities	323	458
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Equity variance swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	163	699
Estimated Fair Value Assets	4	17
Estimated Fair Value Liabilities	1	13
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Total rate of return swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	0	1,048
Estimated Fair Value Assets	0	9
Estimated Fair Value Liabilities	0	4
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Equity Total Return Swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,799	3,025
Estimated Fair Value Assets	23	11
Estimated Fair Value Liabilities	$ 112	$ 50