Fair Value (Recurring Fair Value Measurements) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Assets [Abstract]
Fixed maturity securities	$ 77,909	$ 81,299
Equity securities	101	133
Short-term investments	312	1,885
Derivative assets: (1)	2,288	3,852
Embedded derivatives within asset host contracts (2)	197	283
Separate account assets	104,173	103,986
Liabilities [Abstract]
Derivative liabilities: (1)	9,037	9,608
Embedded derivatives within liability host contracts (2)	6,971	7,584
Recurring
Assets [Abstract]
Fixed maturity securities	77,909	81,299
Equity securities	101	133
Short-term investments	312	1,885
Derivative assets: (1)	2,091	3,569
Embedded derivatives within asset host contracts (2)	197	283
Separate account assets	104,173	103,986
Total assets	184,783	191,155
Liabilities [Abstract]
Derivative liabilities: (1)	2,066	2,024
Embedded derivatives within liability host contracts (2)	6,971	7,584
Total liabilities	9,037	9,608
Recurring | Interest rate
Assets [Abstract]
Derivative assets: (1)	622	2,094
Liabilities [Abstract]
Derivative liabilities: (1)	751	200
Recurring | Foreign currency exchange rate
Assets [Abstract]
Derivative assets: (1)	167	207
Liabilities [Abstract]
Derivative liabilities: (1)	136	144
Recurring | Credit
Assets [Abstract]
Derivative assets: (1)	38	41
Liabilities [Abstract]
Derivative liabilities: (1)	2
Recurring | Equity market
Assets [Abstract]
Derivative assets: (1)	1,264	1,227
Liabilities [Abstract]
Derivative liabilities: (1)	1,177	1,680
Recurring | U.S. corporate
Assets [Abstract]
Fixed maturity securities	35,448	37,276
Recurring | Foreign corporate
Assets [Abstract]
Fixed maturity securities	11,110	11,375
Recurring | U.S. government and agency
Assets [Abstract]
Fixed maturity securities	7,663	8,464
Recurring | RMBS
Assets [Abstract]
Fixed maturity securities	7,783	8,219
Recurring | CMBS
Assets [Abstract]
Fixed maturity securities	6,577	6,697
Recurring | State and political subdivision
Assets [Abstract]
Fixed maturity securities	4,521	4,555
Recurring | ABS
Assets [Abstract]
Fixed maturity securities	3,044	2,881
Recurring | Foreign government
Assets [Abstract]
Fixed maturity securities	1,763	1,832
Recurring | Level 1
Assets [Abstract]
Fixed maturity securities	2,175	2,108
Equity securities	35	31
Short-term investments	216	1,669
Derivative assets: (1)	0	0
Embedded derivatives within asset host contracts (2)	0	0
Separate account assets	81	86
Total assets	2,507	3,894
Liabilities [Abstract]
Derivative liabilities: (1)	0	0
Embedded derivatives within liability host contracts (2)	0	0
Total liabilities	0	0
Recurring | Level 1 | Interest rate
Assets [Abstract]
Derivative assets: (1)	0	0
Liabilities [Abstract]
Derivative liabilities: (1)	0	0
Recurring | Level 1 | Foreign currency exchange rate
Assets [Abstract]
Derivative assets: (1)	0	0
Liabilities [Abstract]
Derivative liabilities: (1)	0	0
Recurring | Level 1 | Credit
Assets [Abstract]
Derivative assets: (1)	0	0
Liabilities [Abstract]
Derivative liabilities: (1)	0
Recurring | Level 1 | Equity market
Assets [Abstract]
Derivative assets: (1)	0	0
Liabilities [Abstract]
Derivative liabilities: (1)	0	0
Recurring | Level 1 | U.S. corporate
Assets [Abstract]
Fixed maturity securities	0	0
Recurring | Level 1 | Foreign corporate
Assets [Abstract]
Fixed maturity securities	0	0
Recurring | Level 1 | U.S. government and agency
Assets [Abstract]
Fixed maturity securities	2,175	2,108
Recurring | Level 1 | RMBS
Assets [Abstract]
Fixed maturity securities	0	0
Recurring | Level 1 | CMBS
Assets [Abstract]
Fixed maturity securities	0	0
Recurring | Level 1 | State and political subdivision
Assets [Abstract]
Fixed maturity securities	0	0
Recurring | Level 1 | ABS
Assets [Abstract]
Fixed maturity securities	0	0
Recurring | Level 1 | Foreign government
Assets [Abstract]
Fixed maturity securities	0	0
Recurring | Level 2
Assets [Abstract]
Fixed maturity securities	74,941	78,440
Equity securities	63	99
Short-term investments	96	216
Derivative assets: (1)	2,061	3,540
Embedded derivatives within asset host contracts (2)	0	0
Separate account assets	104,090	103,897
Total assets	181,251	186,192
Liabilities [Abstract]
Derivative liabilities: (1)	2,044	1,997
Embedded derivatives within liability host contracts (2)	0	0
Total liabilities	2,044	1,997
Recurring | Level 2 | Interest rate
Assets [Abstract]
Derivative assets: (1)	622	2,094
Liabilities [Abstract]
Derivative liabilities: (1)	751	200
Recurring | Level 2 | Foreign currency exchange rate
Assets [Abstract]
Derivative assets: (1)	166	206
Liabilities [Abstract]
Derivative liabilities: (1)	129	137
Recurring | Level 2 | Credit
Assets [Abstract]
Derivative assets: (1)	24	27
Liabilities [Abstract]
Derivative liabilities: (1)	0
Recurring | Level 2 | Equity market
Assets [Abstract]
Derivative assets: (1)	1,249	1,213
Liabilities [Abstract]
Derivative liabilities: (1)	1,164	1,660
Recurring | Level 2 | U.S. corporate
Assets [Abstract]
Fixed maturity securities	34,976	36,789
Recurring | Level 2 | Foreign corporate
Assets [Abstract]
Fixed maturity securities	10,915	11,178
Recurring | Level 2 | U.S. government and agency
Assets [Abstract]
Fixed maturity securities	5,488	6,356
Recurring | Level 2 | RMBS
Assets [Abstract]
Fixed maturity securities	7,743	8,197
Recurring | Level 2 | CMBS
Assets [Abstract]
Fixed maturity securities	6,577	6,692
Recurring | Level 2 | State and political subdivision
Assets [Abstract]
Fixed maturity securities	4,521	4,555
Recurring | Level 2 | ABS
Assets [Abstract]
Fixed maturity securities	2,958	2,841
Recurring | Level 2 | Foreign government
Assets [Abstract]
Fixed maturity securities	1,763	1,832
Recurring | Level 3
Assets [Abstract]
Fixed maturity securities	793	751
Equity securities	3	3
Short-term investments	0	0
Derivative assets: (1)	30	29
Embedded derivatives within asset host contracts (2)	197	283
Separate account assets	2	3
Total assets	1,025	1,069
Liabilities [Abstract]
Derivative liabilities: (1)	22	27
Embedded derivatives within liability host contracts (2)	6,971	7,584
Total liabilities	6,993	7,611
Recurring | Level 3 | Interest rate
Assets [Abstract]
Derivative assets: (1)	0	0
Liabilities [Abstract]
Derivative liabilities: (1)	0	0
Recurring | Level 3 | Foreign currency exchange rate
Assets [Abstract]
Derivative assets: (1)	1	1
Liabilities [Abstract]
Derivative liabilities: (1)	7	7
Recurring | Level 3 | Credit
Assets [Abstract]
Derivative assets: (1)	14	14
Liabilities [Abstract]
Derivative liabilities: (1)	2
Recurring | Level 3 | Equity market
Assets [Abstract]
Derivative assets: (1)	15	14
Liabilities [Abstract]
Derivative liabilities: (1)	13	20
Recurring | Level 3 | U.S. corporate
Assets [Abstract]
Fixed maturity securities	472	487
Recurring | Level 3 | Foreign corporate
Assets [Abstract]
Fixed maturity securities	195	197
Recurring | Level 3 | U.S. government and agency
Assets [Abstract]
Fixed maturity securities	0	0
Recurring | Level 3 | RMBS
Assets [Abstract]
Fixed maturity securities	40	22
Recurring | Level 3 | CMBS
Assets [Abstract]
Fixed maturity securities	0	5
Recurring | Level 3 | State and political subdivision
Assets [Abstract]
Fixed maturity securities	0	0
Recurring | Level 3 | ABS
Assets [Abstract]
Fixed maturity securities	86	40
Recurring | Level 3 | Foreign government
Assets [Abstract]
Fixed maturity securities	$ 0	$ 0