Future Policy Benefit Reserves - Earned Premiums and Interest Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Insurance [Abstract]
Earned premiums	$ 451	$ 473	$ 491
Interest expense	$ 760	$ 763	$ 754