Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Prepaid expenses and other current assets:
Prepaid expenses	$ 64	$ 50	$ 52
Value added taxes	49	46	192
Other	99	103	115
Prepaid expenses and other current assets	$ 212	$ 199	$ 359