Income Taxes - Effective Tax Rates (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Taxes [Abstract]
Consolidated effective tax rate	33.40%	37.20%
Accumulated undistributed foreign earnings	$ 2,700
Cumulative unrecognized deferred tax liabilities	$ 362