Investments - Scheduled maturities of available for sale fixed maturities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Dec. 31, 2024
Fair Value, Fiscal Year Maturity [Abstract]
Available for sale (AFS) fixed maturities	$ 10,568	$ 10,398
Fair Value Percent, Fiscal Year Maturity [Abstract]
Average life of ABS	3 years
Average life of MBS	6 years
Fixed maturities
Amortized Cost Basis, Fiscal Year Maturity [Abstract]
One year or less	$ 715
After one year through five years	2,547
After five years through ten years	1,331
After ten years	231
Fixed maturities amortized cost, Subtotal	4,824
Amortized cost	10,747
Fair Value, Fiscal Year Maturity [Abstract]
One year or less	700
After one year through five years	2,533
After five years through ten years	1,337
After ten years	217
Fixed maturities fair value, subtotal	4,787
Available for sale (AFS) fixed maturities	$ 10,568	$ 10,398
Fair Value Percent, Fiscal Year Maturity [Abstract]
One year or less	7.00%
After one year through five years	24.00%
After five years through ten years	13.00%
After ten years	2.00%
Fixed maturities fair value, subtotal, percent	46.00%
Fair value, total, percent	100.00%
Collateralized loan obligations and other asset backed securities
Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Fixed maturities without single maturity date	$ 3,660
Fair Value, Fiscal Year Maturity [Abstract]
Fixed maturities without single maturity date	$ 3,622
Fair Value Percent, Fiscal Year Maturity [Abstract]
Fixed maturities without single maturity date	34.00%
Mortgage-backed securities
Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Fixed maturities without single maturity date	$ 2,263
Fair Value, Fiscal Year Maturity [Abstract]
Fixed maturities without single maturity date	$ 2,159
Fair Value Percent, Fiscal Year Maturity [Abstract]
Fixed maturities without single maturity date	20.00%