Accumulated Other Comprehensive Income (Loss) (Income (Expense) Effect of Reclassifications) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Affected Line Item on the Statements of Income [Line Items]
Depreciation	$ (226)	$ (233)	$ (658)	$ (688)
Other Income (Expense) - net	75	136	61	33
Interest Expense	(221)	(213)	(645)	(637)
Total Pre-tax	540	611	1,630	1,563
Income Taxes	(144)	(201)	(432)	(534)
Total After-Tax	396	410	1,198	1,029
Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Total After-Tax	(45)	(15)	(128)	(84)
Available For Sale Securities [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Other Income (Expense) - net	0	7	4	11
Total Pre-tax	0	7	4	11
Income Taxes	0	(4)	(2)	(6)
Total After-Tax	0	3	2	5
Qualifying Derivatives [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Total Pre-tax	(13)	15	(43)	2
Income Taxes	3	(3)	23	(4)
Total After-Tax	(10)	12	(20)	(2)
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	(2)	(5)	(9)	(12)
Discontinued operations	0	0	(77)	0
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	(10)	12	22	(17)
Interest Expense	(1)	0	1	1
Qualifying Derivatives [Member] | Energy Commodities [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Discontinued operations	0	8	20	30
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	(45)	(40)	(146)	(116)
Income Taxes	10	10	35	29
Total After-Tax	(35)	(30)	(111)	(87)
Defined Benefit Plans [Member] | Prior Service Costs [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Total Pre-tax	0	(2)	0	(6)
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	(45)	(38)	(146)	(110)
Equity Investees Accumulated Other Comprehensive Income [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Affected Line Item on the Statements of Income [Line Items]
Other Income (Expense) - net	0	0	2	0
Total Pre-tax	0	0	2	0
Income Taxes	0	0	(1)	0
Total After-Tax	$ 0	$ 0	$ 1	$ 0