Income Taxes - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Contingency [Line Items]
Unrecognized tax benefits, affect the effective tax rate	$ 13	$ 57	$ 61
Accrual for payment of interest and penalties associated with uncertain tax positions	9	14
Decrease in accruals for payment of interest and penalties associated with uncertain tax positions	7
Deferred income taxes, net	$ 2,897	$ 2,923