Accumulated Other Comprehensive Income (Loss) (Income (Expense) Effect of Reclassifications) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Affected Line Item on the Statements of Income
Interest Expense	$ (1,001)	$ (994)	$ (963)
Other Income (Expense) - net	169	309	396
Total Pre-tax	1,971	2,155	2,285
Income Taxes	(502)	(409)	(458)
Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income
Total After-Tax	(232)	(102)	(115)
Qualifying Derivatives [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income
Total Pre-tax	(32)	(18)	35
Income Taxes	8	5	(6)
Total After-Tax	(24)	(13)	29
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	(10)	(9)	(8)
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	0	0	1
Other Income (Expense) - net	(22)	(9)	42
Defined Benefit Plans [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income
Total Pre-tax	(260)	(112)	(180)
Income Taxes	52	23	36
Total After-Tax	(208)	(89)	(144)
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	(4)	(3)	(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	$ (256)	$ (109)	$ (178)