Segment Information - Total Assets (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019
Assets
Total assets:	$ 9,579	$ 9,610	$ 10,723
Reportable Segment Totals
Assets
Total assets:	8,937	9,403	10,381
Americas
Assets
Total assets:	4,707	5,264	5,994
Europe
Assets
Total assets:	3,315	3,127	3,342
Asia Pacific
Assets
Total assets:	915	1,012	1,045
Other
Assets
Total assets:	$ 642	$ 207	$ 342