Market Risk Benefits - Balances of and Changes in Market Risk Benefits (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Market Risk Benefit [Roll Forward]
Beginning balance	$ 335	$ 1,103	$ 1,103
Issuances	5	4	17
Interest accrual and time decay	(10)	(26)	(53)
Reserve increase from attributed fees collected	184	189	788
Reserve release for benefit payments and derecognition	(4)	(9)	(35)
Effect of changes in interest rates and bond markets	(527)	504	(367)
Effect of changes in equity markets and subaccount performance	(730)	(392)	(1,267)
Effect of changes in equity index volatility	39	(43)	(67)
Actual policyholder behavior different from expected behavior	31	7	5
Effect of changes in other future expected assumptions			128
Effect of changes in the instrument-specific credit risk on market risk benefits	48	(204)	83
Ending balance	(629)	1,133	335
Reconciliation of the gross balances in an asset or liability position:
Asset position	1,964	990	1,427
Liability position	(1,335)	(2,123)	(1,762)
Net asset (liability) position	$ 629	$ (1,133)	$ (335)
Weighted average attained age of contractholders	69 years	68 years	69 years
Changes in unrealized (gains) losses in net income relating to liabilities held at end of period	$ (1,202)	$ 59	$ (1,551)
Changes in unrealized (gains) losses in other comprehensive income relating to liabilities held at end of period	48	(204)	84
Death benefits
Reconciliation of the gross balances in an asset or liability position:
Guaranteed benefit amount in excess of current account balances (net amount at risk)	578	1,956	913
Living benefits
Reconciliation of the gross balances in an asset or liability position:
Guaranteed benefit amount in excess of current account balances (net amount at risk)	2,233	2,836	2,513
Composite (greater of)
Reconciliation of the gross balances in an asset or liability position:
Guaranteed benefit amount in excess of current account balances (net amount at risk)	$ 2,735	$ 4,596	$ 3,308