Segment Information - Total Assets (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020
Assets
Total assets:	$ 8,766	$ 8,882	$ 8,624
Reportable Segment Totals
Assets
Total assets:	8,382	8,434	7,970
Americas
Assets
Total assets:	4,925	4,927	4,663
Europe
Assets
Total assets:	3,457	3,507	3,307
Other
Assets
Total assets:	$ 384	$ 448	$ 654