Insurance and Contractholder Liabilities - Net Amount of Risk and Average Age of Contractholders (Details) - Variable Annuity position in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($) position	Dec. 31, 2023 USD ($) position
Net Amount at Risk by Product and Guarantee [Line Items]
Account value	$ 7,777	$ 7,736
Net amount at risk	$ 1,283	$ 1,609
Average attained age of contractholders (weighted by exposure)	77 years 8 months 12 days	77 years 3 months 18 days
Guaranteed Minimum Death Benefits Total Contractholders | position	130	140