Supplemental Cash Flow Information - Schedule of Activities Resulting from Management of Proceeds (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Net change in proceeds managed
Net change in fixed income securities	$ (99)	$ 45
Net change in short-term investments	282	(175)
Operating cash flow provided (used)	183	(130)
Net change in cash	(1)	0
Net change in proceeds managed	182	(130)
Net change in liabilities
Liabilities for collateral, beginning of period	(2,041)	(1,891)
Liabilities for collateral, end of period	(1,859)	(2,021)
Operating cash flow (used) provided	$ (182)	$ 130