Fair Value (Recurring Fair Value Measurements) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	$ 326,685	$ 327,820
Equity securities	1,050	1,342
Unit-linked and FVO Securities (1)	11,145	13,102
Short-term investments	5,930	3,850
Residential mortgage loans - FVO	81,344	80,529
Derivative assets	18,869	10,084
Separate account assets	168,454	188,445
Liabilities [Abstract]
Derivative liabilities	4,849	3,737
Embedded derivatives within liability host contracts	2,308	802
Separate account liabilities	168,454	188,445
Residential mortgage loans - FVO
Assets [Abstract]
Residential mortgage loans - FVO	180	188
Recurring
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	326,685	327,820
Equity securities	1,050	1,342
Unit-linked and FVO Securities (1)	11,145	13,102
Short-term investments	5,435	3,182
Other investments	697	689
Derivative assets	18,869	10,084
Embedded derivatives within asset host contracts	76	60
Separate account assets	168,454	188,445
Total assets (6)	532,591	544,912
Liabilities [Abstract]
Derivative liabilities	4,849	3,737
Embedded derivatives within liability host contracts	2,308	802
Total liabilities	7,222	4,561
Recurring | Interest rate contracts
Assets [Abstract]
Derivative assets	11,636	6,707
Liabilities [Abstract]
Derivative liabilities	755	418
Recurring | Foreign currency exchange rate contracts
Assets [Abstract]
Derivative assets	5,673	2,378
Liabilities [Abstract]
Derivative liabilities	3,603	2,442
Recurring | Credit contracts
Assets [Abstract]
Derivative assets	73	276
Liabilities [Abstract]
Derivative liabilities	158	103
Recurring | Equity market contracts
Assets [Abstract]
Derivative assets	1,487	723
Liabilities [Abstract]
Derivative liabilities	333	774
Recurring | Derivative Liabilities Within Separate Accounts
Liabilities [Abstract]
Separate account liabilities	65	22
Recurring | Residential mortgage loans - FVO
Assets [Abstract]
Residential mortgage loans - FVO	180	188
Recurring | U.S. corporate
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	85,071	87,753
Recurring | Foreign government
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	64,844	67,229
Recurring | Foreign corporate
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	59,195	64,165
Recurring | U.S. government and agency
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	47,959	42,084
Recurring | RMBS
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	30,469	28,547
Recurring | ABS
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	14,838	14,542
Recurring | Municipals
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	13,871	13,053
Recurring | CMBS
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	10,438	10,447
Recurring | Level 1
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	21,221	21,061
Equity securities	547	794
Unit-linked and FVO Securities (1)	8,812	10,598
Short-term investments	2,917	2,042
Other investments	65	74
Derivative assets	34	15
Embedded derivatives within asset host contracts	0	0
Separate account assets	73,366	86,790
Total assets (6)	106,962	121,374
Liabilities [Abstract]
Derivative liabilities	24	11
Embedded derivatives within liability host contracts	0	0
Total liabilities	28	12
Recurring | Level 1 | Interest rate contracts
Assets [Abstract]
Derivative assets	1	2
Liabilities [Abstract]
Derivative liabilities	5	3
Recurring | Level 1 | Foreign currency exchange rate contracts
Assets [Abstract]
Derivative assets	5	7
Liabilities [Abstract]
Derivative liabilities	0	0
Recurring | Level 1 | Credit contracts
Assets [Abstract]
Derivative assets	0	0
Liabilities [Abstract]
Derivative liabilities	0	0
Recurring | Level 1 | Equity market contracts
Assets [Abstract]
Derivative assets	28	6
Liabilities [Abstract]
Derivative liabilities	19	8
Recurring | Level 1 | Derivative Liabilities Within Separate Accounts
Liabilities [Abstract]
Separate account liabilities	4	1
Recurring | Level 1 | Residential mortgage loans - FVO
Assets [Abstract]
Residential mortgage loans - FVO	0	0
Recurring | Level 1 | U.S. corporate
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	0	0
Recurring | Level 1 | Foreign government
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	0	0
Recurring | Level 1 | Foreign corporate
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	0	0
Recurring | Level 1 | U.S. government and agency
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	21,060	21,058
Recurring | Level 1 | RMBS
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	161	3
Recurring | Level 1 | ABS
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	0	0
Recurring | Level 1 | Municipals
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	0	0
Recurring | Level 1 | CMBS
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	0	0
Recurring | Level 2
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	281,537	287,948
Equity securities	131	118
Unit-linked and FVO Securities (1)	1,816	1,879
Short-term investments	2,150	1,108
Other investments	157	160
Derivative assets	17,513	9,882
Embedded derivatives within asset host contracts	0	0
Separate account assets	94,027	100,668
Total assets (6)	397,331	401,763
Liabilities [Abstract]
Derivative liabilities	4,542	3,393
Embedded derivatives within liability host contracts	0	0
Total liabilities	4,588	3,407
Recurring | Level 2 | Interest rate contracts
Assets [Abstract]
Derivative assets	10,417	6,616
Liabilities [Abstract]
Derivative liabilities	748	220
Recurring | Level 2 | Foreign currency exchange rate contracts
Assets [Abstract]
Derivative assets	5,651	2,336
Liabilities [Abstract]
Derivative liabilities	3,354	2,324
Recurring | Level 2 | Credit contracts
Assets [Abstract]
Derivative assets	53	244
Liabilities [Abstract]
Derivative liabilities	137	102
Recurring | Level 2 | Equity market contracts
Assets [Abstract]
Derivative assets	1,392	686
Liabilities [Abstract]
Derivative liabilities	303	747
Recurring | Level 2 | Derivative Liabilities Within Separate Accounts
Liabilities [Abstract]
Separate account liabilities	46	14
Recurring | Level 2 | Residential mortgage loans - FVO
Assets [Abstract]
Residential mortgage loans - FVO	0	0
Recurring | Level 2 | U.S. corporate
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	75,876	81,501
Recurring | Level 2 | Foreign government
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	64,740	67,112
Recurring | Level 2 | Foreign corporate
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	48,581	56,188
Recurring | Level 2 | U.S. government and agency
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	26,899	21,026
Recurring | Level 2 | RMBS
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	27,676	25,682
Recurring | Level 2 | ABS
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	13,878	13,326
Recurring | Level 2 | Municipals
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	13,871	13,046
Recurring | Level 2 | CMBS
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	10,016	10,067
Recurring | Level 3
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	23,927	18,811
Equity securities	372	430
Unit-linked and FVO Securities (1)	517	625
Short-term investments	368	32
Other investments	475	455
Derivative assets	1,322	187
Embedded derivatives within asset host contracts	76	60
Separate account assets	1,061	987
Total assets (6)	28,298	21,775
Liabilities [Abstract]
Derivative liabilities	283	333
Embedded derivatives within liability host contracts	2,308	802
Total liabilities	2,606	1,142
Recurring | Level 3 | Interest rate contracts
Assets [Abstract]
Derivative assets	1,218	89
Liabilities [Abstract]
Derivative liabilities	2	195
Recurring | Level 3 | Foreign currency exchange rate contracts
Assets [Abstract]
Derivative assets	17	35
Liabilities [Abstract]
Derivative liabilities	249	118
Recurring | Level 3 | Credit contracts
Assets [Abstract]
Derivative assets	20	32
Liabilities [Abstract]
Derivative liabilities	21	1
Recurring | Level 3 | Equity market contracts
Assets [Abstract]
Derivative assets	67	31
Liabilities [Abstract]
Derivative liabilities	11	19
Recurring | Level 3 | Derivative Liabilities Within Separate Accounts
Liabilities [Abstract]
Separate account liabilities	15	7
Recurring | Level 3 | Residential mortgage loans - FVO
Assets [Abstract]
Residential mortgage loans - FVO	180	188
Recurring | Level 3 | U.S. corporate
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	9,195	6,252
Recurring | Level 3 | Foreign government
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	104	117
Recurring | Level 3 | Foreign corporate
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	10,614	7,977
Recurring | Level 3 | U.S. government and agency
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	0	0
Recurring | Level 3 | RMBS
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	2,632	2,862
Recurring | Level 3 | ABS
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	960	1,216
Recurring | Level 3 | Municipals
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	0	7
Recurring | Level 3 | CMBS
Assets [Abstract]
Estimated Fair Value of Fixed Maturity Securities AFS	422	380
Other limited partnership interests | Recurring
Assets [Abstract]
Investments, Fair Value Disclosure	$ 92	$ 95