Other Comprehensive Income (Schedule of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	[1]	$ (4,646)	$ (2,759)	$ (3,840)
Other Comprehensive Income (Loss), Before Reclassifications, Net of Tax	[1]	(1,336)	(2,124)	741
Reclassification from Accumulated Other Comprehensive Income, Current Period, net of tax	[1]	268	225	317
Other Comprehensive Income (Loss), Net of Tax	[1]	(1,068)	(1,899)	1,058
Comprehensive (Income) Loss, Net of Tax, Attributable to Noncontrolling Interest	[1]	6	12	23
Accumulated other comprehensive loss	[1]	(5,708)	(4,646)	(2,759)
Accumulated Defined Benefit Pension Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	[1]	(3,134)	(2,105)	(3,596)
Other Comprehensive Income (Loss), Before Reclassifications, Net of Tax	[1]	(331)	(1,271)	1,184
Reclassification from Accumulated Other Comprehensive Income, Current Period, net of tax	[1]	296	242	307
Other Comprehensive Income (Loss), Net of Tax	[1]	(35)	(1,029)	1,491
Comprehensive (Income) Loss, Net of Tax, Attributable to Noncontrolling Interest	[1]	0	0	0
Accumulated other comprehensive loss	[1]	(3,169)	(3,134)	(2,105)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	[1]	(1,513)	(649)	(246)
Other Comprehensive Income (Loss), Before Reclassifications, Net of Tax	[1]	(1,002)	(863)	(443)
Reclassification from Accumulated Other Comprehensive Income, Current Period, net of tax	[1]	(40)	(13)	17
Other Comprehensive Income (Loss), Net of Tax	[1]	(1,042)	(876)	(426)
Comprehensive (Income) Loss, Net of Tax, Attributable to Noncontrolling Interest	[1]	6	12	23
Accumulated other comprehensive loss	[1]	(2,549)	(1,513)	(649)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	[1]	1	(5)	2
Other Comprehensive Income (Loss), Before Reclassifications, Net of Tax	[1]	(3)	10	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, net of tax	[1]	12	(4)	(7)
Other Comprehensive Income (Loss), Net of Tax	[1]	9	6	(7)
Comprehensive (Income) Loss, Net of Tax, Attributable to Noncontrolling Interest	[1]	0	0	0
Accumulated other comprehensive loss	[1]	$ 10	$ 1	$ (5)

[1] All amounts are net of tax. Amounts in parentheses indicate debits to AOCI.