Future Policy Benefit Reserves - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Insurance [Abstract]
Liability for future policy benefit, expected future gross premium, discounted, before reinsurance	$ 3,550		$ 3,664
Liability for future policy benefit, weighted-average duration	11 years	11 years
Liability future policy benefit, losses recognized in current period	$ 14	$ 20
Liability future policy benefit, losses recognized in prior period	$ 6	$ 2