Investments - Scheduled maturities of available for sale fixed maturities (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Fair Value, Fiscal Year Maturity [Abstract]
Available for sale (AFS) fixed maturities	$ 10,435	$ 10,377
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	$ 458
After one year through five years	2,866
After five years through ten years	1,278
After ten years	259
Fixed maturities amortized cost, Subtotal	4,861
Amortized cost	10,561
Fair Value, Fiscal Year Maturity [Abstract]
One year or less	449
After one year through five years	2,845
After five years through ten years	1,304
After ten years	252
Fixed maturities fair value, subtotal	4,850
Available for sale (AFS) fixed maturities	$ 10,435	$ 10,377
Fair Value Percent, Fiscal Year Maturity [Abstract]
One year or less	4.00%
After one year through five years	27.00%
After five years through ten years	12.00%
After ten years	3.00%
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	$ 3,757
Fair Value, Fiscal Year Maturity [Abstract]
Fixed maturities without single maturity date	$ 3,723
Fair Value Percent, Fiscal Year Maturity [Abstract]
Fixed maturities without single maturity date	36.00%
Mortgage-backed securities
Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Fixed maturities without single maturity date	$ 1,943
Fair Value, Fiscal Year Maturity [Abstract]
Fixed maturities without single maturity date	$ 1,862
Fair Value Percent, Fiscal Year Maturity [Abstract]
Fixed maturities without single maturity date	18.00%