Property and Equipment - Depreciation Expense and Other Amortization Expense (Details) - Property, Plant and Equipment - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 949	$ 1,074	$ 555
Other amortization expense	$ 1	$ 3	$ 4