Income Taxes - Effective Tax Rate Reconciliation and Pretax Income (Loss) and Revenue by Tax Jurisdiction (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pre-tax Income Taxes and Revenue [Line Items]
Expected tax provision (benefit)	$ 23	$ 76	$ 83
Tax-exempt interest	(14)	(19)	(20)
Change in liability for uncertain tax positions	0	0	(17)
Return to provision adjustment	(20)	(4)	(7)
Noncontrolling interest	(3)	(8)	(1)
State taxes	12	7	4
Taxes on reinsurance	0	(2)	9
Foreign taxes	6	8	(3)
Stock based compensation	5	4	0
Other	2	(4)	(3)
Total provision (benefit) for income taxes	$ 11	$ 58	$ 45
Effective tax rate	7.20%	12.20%	10.90%
Total	$ 148	$ 477	$ 413
Total revenues	723	848	1,115
U.S.
Pre-tax Income Taxes and Revenue [Line Items]
Total	189	378	385
Total revenues	661	685	894
Bermuda
Pre-tax Income Taxes and Revenue [Line Items]
Total	44	115	16
Total revenues	84	123	151
U.K.
Pre-tax Income Taxes and Revenue [Line Items]
Total	(69)	(8)	13
Total revenues	(15)	41	60
France
Pre-tax Income Taxes and Revenue [Line Items]
Total	(16)	(8)	(1)
Total revenues	(8)	(3)	6
Other
Pre-tax Income Taxes and Revenue [Line Items]
Total revenues	$ 1	$ 2	$ 4