Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Income tax expense	$ 12	$ 5
Effective income tax rate	13.00%	(500.00%)
Uncertain income tax liabilities	$ 237
Maximum
Income Tax Contingency [Line Items]
Decrease in liability for unrecognized tax benefits reasonably possible	$ 122