Accumulated Other Comprehensive Income (Loss) - Income (Expense) Effect of Reclassifications (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Affected Line Item on the Statements of Income [Line Items]
Other Income (Expense) - net	$ (47)	$ 61
Interest Expense	(217)	(224)
Income Taxes	(129)	(179)
Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Total After-tax	(31)	47
Qualifying Derivatives [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Total Pre-tax	1	97
Income Taxes	0	(19)
Total After-tax	1	78
Qualifying Derivatives [Member] | Interest Rate Swaps [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Interest Expense	(3)	(1)
Qualifying Derivatives [Member] | Cross Currency Swaps [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Other Income (Expense) - net	3	97
Interest Expense	1	1
Defined Benefit Plans [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Total Pre-tax	(41)	(40)
Income Taxes	9	9
Total After-tax	(32)	(31)
Defined Benefit Plans [Member] | Net Actuarial Loss [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Total Pre-tax	$ (41)	$ (40)