Market Risk Benefits - Rollforward of market risk benefits (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Market Risk Benefit [Roll Forward]
Balance, beginning of year	$ 4,870	$ 4,034
Effect of changes in our own credit risk	(1,189)	(371)	$ (1,160)	$ (465)
Balance, beginning of year, before effect of changes in our own credit risk	3,710	3,569
Issuances	133	200
Interest accrual	48	42
Attributed fees	189	252
Expected claims	(18)	(26)
Effect of changes in interest rates	(512)	524
Effect of changes in interest rate volatility	(14)	(77)
Effect of changes in equity markets	(579)	(427)
Effect of changes in equity index volatility	(15)	13
Actual outcome different from model expected outcome	(60)	73
Effect of changes in future expected policyholder behavior	0
Effect of changes in other future expected assumptions	(6)	(112)
Other, including foreign exchange	(2)	1
Balance, end of period before effect of changes in our own credit risk	2,874	4,032
Balance, end of period	4,063	4,403
Less: Reinsured MRB, end of period	(68)	(89)
Net	3,995	4,314
Combined
Net amount at risk
Net amount at risk	589	1,757
GMDB only
Net amount at risk
Net amount at risk	759	1,573
GMWB only
Net amount at risk
Net amount at risk	140	68
Individual Retirement
Market Risk Benefit [Roll Forward]
Balance, beginning of year	4,562	3,738
Effect of changes in our own credit risk	(1,100)	(339)	(1,072)	(441)
Balance, beginning of year, before effect of changes in our own credit risk	3,490	3,297
Issuances	123	191
Interest accrual	45	38
Attributed fees	174	235
Expected claims	(18)	(25)
Effect of changes in interest rates	(474)	478
Effect of changes in interest rate volatility	(14)	(73)
Effect of changes in equity markets	(529)	(391)
Effect of changes in equity index volatility	(15)	16
Actual outcome different from model expected outcome	(63)	72
Effect of changes in future expected policyholder behavior	0
Effect of changes in other future expected assumptions	(5)	(94)
Other, including foreign exchange	0	1
Balance, end of period before effect of changes in our own credit risk	2,714	3,745
Balance, end of period	3,814	4,084
Less: Reinsured MRB, end of period	(68)	(89)
Net	$ 3,746	$ 3,995
Net amount at risk
Average attained age of contract holders	71 years	71 years
Individual Retirement | Combined
Net amount at risk
Net amount at risk	$ 576	$ 1,726
Individual Retirement | GMDB only
Net amount at risk
Net amount at risk	623	1,307
Individual Retirement | GMWB only
Net amount at risk
Net amount at risk	128	63
Group Retirement
Market Risk Benefit [Roll Forward]
Balance, beginning of year	308	296
Effect of changes in our own credit risk	(89)	(32)	$ (88)	$ (24)
Balance, beginning of year, before effect of changes in our own credit risk	220	272
Issuances	10	9
Interest accrual	3	4
Attributed fees	15	17
Expected claims	0	(1)
Effect of changes in interest rates	(38)	46
Effect of changes in interest rate volatility	0	(4)
Effect of changes in equity markets	(50)	(36)
Effect of changes in equity index volatility	0	(3)
Actual outcome different from model expected outcome	3	1
Effect of changes in future expected policyholder behavior	0
Effect of changes in other future expected assumptions	(1)	(18)
Other, including foreign exchange	(2)	0
Balance, end of period before effect of changes in our own credit risk	160	287
Balance, end of period	249	319
Less: Reinsured MRB, end of period	0	0
Net	$ 249	$ 319
Net amount at risk
Average attained age of contract holders	64 years	64 years
Group Retirement | Combined
Net amount at risk
Net amount at risk	$ 13	$ 31
Group Retirement | GMDB only
Net amount at risk
Net amount at risk	136	266
Group Retirement | GMWB only
Net amount at risk
Net amount at risk	$ 12	$ 5