Segment Information - Segment Revenue by Country of Domicile (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Segment revenues	$ 960	$ 989	$ 964
U.S.
Segment Reporting Information [Line Items]
Segment revenues	762	788	761
Bermuda
Segment Reporting Information [Line Items]
Segment revenues	153	155	161
U.K.
Segment Reporting Information [Line Items]
Segment revenues	42	38	41
Other
Segment Reporting Information [Line Items]
Segment revenues	$ 3	$ 8	$ 1