Investments (excluding Consolidated Investment Entities) - Fixed Maturities (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Available-for-sale Securities, Including Securities Pledged [Line Items]
Fixed maturities, amortized cost	$ 30,966	$ 37,531
Fixed maturities, available-for-sale, at fair value	34,320	43,569
Securities pledged, amortized costs	1,171	355
U.S. Treasuries
Available-for-sale Securities, Including Securities Pledged [Line Items]
Fixed maturities, amortized cost	775	1,033
Gross Unrealized Capital Gains	237	438
Gross Unrealized Capital Losses	0	0
Embedded Derivatives	0	0
Fixed maturities, available-for-sale, at fair value	1,012	1,471
OTTI	0	0
U.S. Government agencies and authorities
Available-for-sale Securities, Including Securities Pledged [Line Items]
Fixed maturities, amortized cost	69	74
Gross Unrealized Capital Gains	12	28
Gross Unrealized Capital Losses	0	0
Embedded Derivatives	0	0
Fixed maturities, available-for-sale, at fair value	81	102
OTTI	0	0
State, municipalities and political subdivisions
Available-for-sale Securities, Including Securities Pledged [Line Items]
Fixed maturities, amortized cost	962	1,166
Gross Unrealized Capital Gains	114	180
Gross Unrealized Capital Losses	1	0
Embedded Derivatives	0	0
Fixed maturities, available-for-sale, at fair value	1,075	1,346
OTTI	0	0
U.S. corporate public securities
Available-for-sale Securities, Including Securities Pledged [Line Items]
Fixed maturities, amortized cost	10,767	13,366
Gross Unrealized Capital Gains	1,675	3,028
Gross Unrealized Capital Losses	43	7
Embedded Derivatives	0	0
Fixed maturities, available-for-sale, at fair value	12,399	16,387
OTTI	0	0
U.S. corporate private securities
Available-for-sale Securities, Including Securities Pledged [Line Items]
Fixed maturities, amortized cost	4,802	5,653
Gross Unrealized Capital Gains	510	828
Gross Unrealized Capital Losses	22	35
Embedded Derivatives	0	0
Fixed maturities, available-for-sale, at fair value	5,290	6,446
OTTI	0	0
Foreign corporate public securities and foreign governments
Available-for-sale Securities, Including Securities Pledged [Line Items]
Fixed maturities, amortized cost	3,395	4,023
Gross Unrealized Capital Gains	407	714
Gross Unrealized Capital Losses	17	1
Embedded Derivatives	0	0
Fixed maturities, available-for-sale, at fair value	3,785	4,736
OTTI	0	0
Foreign corporate private securities
Available-for-sale Securities, Including Securities Pledged [Line Items]
Fixed maturities, amortized cost	3,383	4,220
Gross Unrealized Capital Gains	294	470
Gross Unrealized Capital Losses	3	29
Embedded Derivatives	0	0
Fixed maturities, available-for-sale, at fair value	3,643	4,646
OTTI	31	15
Residential mortgage-backed
Available-for-sale Securities, Including Securities Pledged [Line Items]
Fixed maturities, amortized cost	4,488	5,370
Gross Unrealized Capital Gains	165	255
Gross Unrealized Capital Losses	24	17
Embedded Derivatives	14	20
Fixed maturities, available-for-sale, at fair value	4,642	5,626
OTTI	1	2
Commercial mortgage-backed securities
Available-for-sale Securities, Including Securities Pledged [Line Items]
Fixed maturities, amortized cost	3,901	3,882
Gross Unrealized Capital Gains	208	290
Gross Unrealized Capital Losses	17	40
Embedded Derivatives	0	0
Fixed maturities, available-for-sale, at fair value	4,092	4,131
OTTI	0	1
Other asset-backed securities
Available-for-sale Securities, Including Securities Pledged [Line Items]
Fixed maturities, amortized cost	2,123	2,110
Gross Unrealized Capital Gains	33	46
Gross Unrealized Capital Losses	6	10
Embedded Derivatives	0	0
Fixed maturities, available-for-sale, at fair value	2,149	2,138
OTTI	1	8
Fixed maturities
Available-for-sale Securities, Including Securities Pledged [Line Items]
Fixed maturities, amortized cost	34,665	40,897
Gross Unrealized Capital Gains	3,655	6,277
Gross Unrealized Capital Losses	133	139
Embedded Derivatives	14	20
Fixed maturities, available-for-sale, at fair value	38,168	47,029
OTTI	33	26
Total fixed maturities, less securities pledged, Amortized Cost	33,494	40,542
Total fixed maturities, less securities pledged, Gross Unrealized Capital Gains	3,505	6,182
Total fixed maturities, less securities pledged, Gross Unrealized Capital Losses	132	138
Total fixed maturities, less securities pledged, Fair Value	36,848	46,580
Collateral Pledged
Available-for-sale Securities, Including Securities Pledged [Line Items]
Securities pledged	1,320	449
Collateral Pledged | Fixed maturities
Available-for-sale Securities, Including Securities Pledged [Line Items]
Embedded Derivatives	0	0
OTTI	0	0
Securities pledged, amortized costs	1,171	355
Securities pledged, Gross Unrealized Capital Gains	150	95
Securities pledged, Gross Unrealized Capital Losses	1	1
Securities pledged	$ 1,320	$ 449