Income Taxes Schedule of Unrecognized Tax Benefits Roll Forward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits	$ 208	$ 195	$ 235	$ 289
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions	30	28	23
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	1	9	35
Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions	20	5	2
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities	19	46	24
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations	12	7	9
Unrecognized Tax Benefits, Increase (Decrease) Resulting from Foreign Currency Translation	$ (5)	$ (11)	$ (11)