Policyholder Account Balances, Future Policy Benefits and Claims - Change in Unearned Income (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Deferred Income [Roll Forward]
Beginning balance	$ 489	$ 410
Deferral of revenue	29	112
Amortization	(9)	(33)
Ending balance	509	489
Universal Life Insurance
Deferred Income [Roll Forward]
Beginning balance	27	27
Deferral of revenue	0	1
Amortization	0	(1)
Ending balance	27	27
Variable Universal Life Insurance
Deferred Income [Roll Forward]
Beginning balance	196	150
Deferral of revenue	16	59
Amortization	(4)	(13)
Ending balance	208	196
Indexed Universal Life Insurance
Deferred Income [Roll Forward]
Beginning balance	266	233
Deferral of revenue	13	52
Amortization	(5)	(19)
Ending balance	$ 274	$ 266