Business Segments - Revenue and Long-Lived Assets by Geographic Segment (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Geographic Segments
Total revenue	$ 580	$ 539	$ 581	$ 453	$ 480	$ 432	$ 308	$ 479	$ 2,153	$ 1,699	$ 2,388
Property and equipment, net	213				242				213	242
U.S.
Geographic Segments
Total revenue									1,551	1,181	1,566
Property and equipment, net	147				143				147	143
Other
Geographic Segments
Total revenue									602	518	$ 822
Property and equipment, net	$ 66				$ 99				$ 66	$ 99