Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Net income tax payments/(refunds)	$ 1,460	$ 1,490	$ 355
U.S. deferred income taxes and foreign withholding tax	32
Undistributed Earnings of Foreign Subsidiaries	850
Unrecognized tax benefits that would affect the effective tax rate, if recognized	1,402	1,479	1,180
Unrecognized tax benefits	$ 1,557	$ 1,617	$ 1,312	$ 1,141