Investments - Scheduled maturities of available for sale fixed maturities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Fiscal Year Maturity [Abstract]
Available for sale (AFS) fixed maturities	$ 10,371	$ 10,377
Fair Value Percent, Fiscal Year Maturity [Abstract]
Average life of ABS	3 years
Average life of MBS	6 years 6 months
Fixed maturities:
Amortized Cost Basis, Fiscal Year Maturity [Abstract]
One year or less	$ 462
After one year through five years	2,409
After five years through ten years	1,279
After ten years	631
Fixed maturities amortized cost, Subtotal	4,781
Amortized Cost	10,723
Fair Value, Fiscal Year Maturity [Abstract]
One year or less	457
After one year through five years	2,344
After five years through ten years	1,264
After ten years	593
Fixed maturities fair value, Subtotal	4,658
Available for sale (AFS) fixed maturities	$ 10,371	$ 10,377
Fair Value Percent, Fiscal Year Maturity [Abstract]
One year or less	4.00%
After one year through five years	23.00%
After five years through ten years	12.00%
After ten years	6.00%
Fixed maturities fair value, Subtotal, Percent	45.00%
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	$ 4,065
Fair Value, Fiscal Year Maturity [Abstract]
Fixed maturities without single maturity date	$ 3,967
Fair Value Percent, Fiscal Year Maturity [Abstract]
Fixed maturities without single maturity date	38.00%
Mortgage-backed securities
Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Fixed maturities without single maturity date	$ 1,877
Fair Value, Fiscal Year Maturity [Abstract]
Fixed maturities without single maturity date	$ 1,746
Fair Value Percent, Fiscal Year Maturity [Abstract]
Fixed maturities without single maturity date	17.00%