Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Jan. 01, 2016
Income Tax Disclosure [Abstract]
Tax expense	$ 93	$ 120	$ 171	$ 243
Income before income taxes	301	328	568	687
(Favorable) unfavorable impact on income tax expense, discrete tax adjustments	3		(2)
(Favorable) unfavorable impact on income tax expense, certain items			(9)
(Favorable) unfavorable impact on income tax expense, release of valuation allowance			(7)
Unfavorable impact on income tax expense, EMEA		$ 3		$ 8
Possible valuation allowance reduction	$ 255		$ 255
Unrecognized tax benefits					$ 54
Favorable impact of unrecognized tax benefits if recognized					40
Accrued interest					5
Unsettled unrecognized tax benefits that would require cash					$ 9