Investments - Net Realized Capital Gains (Losses) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Available-for-sale Securities Including Securities Pledged [Line Items]
Realized capital gains (losses)	$ (50,000,000)	$ (11,000,000)	$ (69,000,000)	$ 4,000,000
Embedded derivatives within fixed maturities
Available-for-sale Securities Including Securities Pledged [Line Items]
Realized capital gains (losses)	2,000,000	0	6,000,000	(1,000,000)
Other derivatives, net
Available-for-sale Securities Including Securities Pledged [Line Items]
Realized capital gains (losses)	2,000,000	0	1,000,000	1,000,000
Managed Custody Guarantees
Available-for-sale Securities Including Securities Pledged [Line Items]
Realized capital gains (losses)	2,000,000	(1,000,000)	1,000,000	0
Stabilizer
Available-for-sale Securities Including Securities Pledged [Line Items]
Realized capital gains (losses)	1,000,000	(1,000,000)	5,000,000	(1,000,000)
Derivatives
Available-for-sale Securities Including Securities Pledged [Line Items]
Realized capital gains (losses)	(33,000,000)	20,000,000	(70,000,000)	110,000,000
Mortgages [Member]
Available-for-sale Securities Including Securities Pledged [Line Items]
Realized capital gains (losses)	1,000,000	2,000,000	(3,000,000)	3,000,000
Other investments
Available-for-sale Securities Including Securities Pledged [Line Items]
Realized capital gains (losses)	0	0	(1,000,000)	0
Fixed Maturities, Available-for-sale, Including Securities Pledged
Available-for-sale Securities Including Securities Pledged [Line Items]
Realized capital gains (losses)	(22,000,000)	(9,000,000)	(18,000,000)	(25,000,000)
Fixed Maturities, at Fair Value Using the Fair Value Option
Available-for-sale Securities Including Securities Pledged [Line Items]
Realized capital gains (losses)	(3,000,000)	(22,000,000)	9,000,000	(85,000,000)
Equity securities
Available-for-sale Securities Including Securities Pledged [Line Items]
Realized capital gains (losses)	$ 0	$ 0	$ 1,000,000	$ 2,000,000