Future Policy Benefit Reserves - Earned Premiums and Interest Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Insurance [Abstract]
Earned premiums	$ 112	$ 118	$ 340	$ 356
Interest expense	$ 191	$ 192	$ 570	$ 569