Future Policy Benefit Reserves - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Insurance [Abstract]
Liability for future policy benefit, expected future gross premium, discounted, before reinsurance	$ 3,664	$ 4,046
Liability for future policy benefit, weighted-average duration	11 years	12 years
Liability future policy benefit, losses recognized in current period	$ 20	$ 13
Liability future policy benefit, losses recognized in prior period	$ 2	$ 11