Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Net income tax payments/(refunds)	$ 1,490	$ 355	$ 209
U.S. deferred income taxes and foreign withholding tax	35
Undistributed Earnings of Foreign Subsidiaries	700
Unrecognized tax benefits that would affect the effective tax rate, if recognized	1,479	1,180	1,018
Unrecognized tax benefits	1,617	$ 1,312	$ 1,141	$ 1,055
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities	$ 115