Segment and Geographic Area Information - Long-lived Assets by Geographic Region (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets
Total long-lived assets	$ 2,962	$ 2,883
United States and Puerto Rico
Revenues from External Customers and Long-Lived Assets
Total long-lived assets	2,026	1,993
Europe
Revenues from External Customers and Long-Lived Assets
Total long-lived assets	646	599
All other
Revenues from External Customers and Long-Lived Assets
Total long-lived assets	$ 290	$ 291