Provision for Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Income Taxes Information [Line Items]
Exchange gain associated with hedging program	$ 434	$ 607
Tax credit carryforward/back, net	946
Tax effect of net carryforwards/backs, net of valuation allowances, not subject to expiration	785
Unremitted earnings of subsidiaries outside the U.S.	16,053
Expires After 2015 but before 2020 [Member]
Income Taxes Information [Line Items]
Tax credit carryforward/back, net	$ 7
Expiration date of net carryforwards/backs	before the end of 2020
Expires After 2020 [Member]
Income Taxes Information [Line Items]
Tax credit carryforward/back, net	$ 154
Expiration date of net carryforwards/backs	after 2020
Minimum [Member]
Income Taxes Information [Line Items]
Minimum amount of net reductions to company's global unrecognized tax benefit	$ 225
Maximum [Member]
Income Taxes Information [Line Items]
Minimum amount of net reductions to company's global unrecognized tax benefit	$ 250