Segment and Geographic Information Schedule of Revenue by Geographic Area (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets
Revenue	$ 11,628,830	$ 12,506,109	$ 11,876,674
UNITED STATES
Revenues from External Customers and Long-Lived Assets
Revenue	5,755,437	6,220,267	6,192,636
UNITED KINGDOM
Revenues from External Customers and Long-Lived Assets
Revenue	1,460,600	1,599,074	1,665,317
GERMANY
Revenues from External Customers and Long-Lived Assets
Revenue	1,522,529	1,578,543	974,514
Other countries
Revenues from External Customers and Long-Lived Assets
Revenue	$ 2,890,264	$ 3,108,225	$ 3,044,207