Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated other comprehensive loss	$ (2,332)	$ (1,181)	$ (2,116)	$ (1,260)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	(387)	14
Other Comprehensive Income (Loss), Before Reclassifications, Tax	102	32
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	69	33
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(216)	79
Translation Adjustments Other Than Translation Of Balance Sheet Tax Benefit Expense	20	(39)
Pension and other postretirement benefit adjustments, tax cost	31	15
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	1
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated other comprehensive loss	(922)	16	(628)	(38)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	(387)	14
Other Comprehensive Income (Loss), Before Reclassifications, Tax	93	40
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(294)	54
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated other comprehensive loss	(1,418)	(1,132)	(1,492)	(1,157)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	0	0
Other Comprehensive Income (Loss), Before Reclassifications, Tax	32	(1)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	42	26
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	74	25
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated other comprehensive loss	8	(65)	$ 4	$ (65)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	0	0
Other Comprehensive Income (Loss), Before Reclassifications, Tax	(23)	(7)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	27	7
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	$ 4	$ 0