Income Taxes - Effective Tax Rates (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Abstract]
Consolidated effective tax rate	38.10%	37.60%
Accumulated undistributed foreign earnings	$ 2,500
Cumulative unrecognized deferred tax liabilities	$ 325