Accumulated Other Comprehensive Income (Loss) (Income (Expense) Effect of Reclassifications) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Affected Line Item on the Statements of Income
Interest Expense	$ (963)	$ (901)	$ (888)
Other Income (Expense) - net	396	(88)	502
Total Pre-tax	2,285	1,912	2,550
Income Taxes	(458)	(784)	(648)
Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income
Total After-Tax	(115)	(205)	(30)
Qualifying Derivatives [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income
Total Pre-tax	35	(91)	112
Income Taxes	(6)	18	(21)
Total After-Tax	29	(73)	91
Qualifying Derivatives [Member] | Interest Rate Swaps [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income
Interest Expense	(8)	(9)	(7)
Qualifying Derivatives [Member] | Cross Currency Swaps [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income
Interest Expense	1	0	3
Other Income (Expense) - net	42	(82)	116
Equity Investees AOCI [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income
Other Income (Expense) - net	0	(1)	1
Total Pre-tax	0	(1)	1
Income Taxes	0	0	0
Total After-Tax	0	(1)	1
Defined Benefit Plans [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income
Total Pre-tax	(180)	(169)	(158)
Income Taxes	36	38	36
Total After-Tax	(144)	(131)	(122)
Defined Benefit Plans [Member] | Prior Service Costs [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income
Total Pre-tax	(2)	(2)	(2)
Defined Benefit Plans [Member] | Net Actuarial Loss [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income
Total Pre-tax	$ (178)	$ (167)	$ (156)