Segment Information Segment Information - Revenue by Country of Domicile (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Total revenues	$ 190	$ 234
United States [Member]
Segment Reporting Information [Line Items]
Total revenues	150	182
Bermuda [Member]
Segment Reporting Information [Line Items]
Total revenues	34	44
United Kingdom and Other [Member]
Segment Reporting Information [Line Items]
Total revenues	$ 6	$ 8