Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated other comprehensive loss	$ (2,063)	$ (2,541)	$ (2,356)	$ (2,702)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	634	(157)
Other Comprehensive Income (Loss), Before Reclassifications, Tax	(368)	(346)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	27	664
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	293	161
Translation Adjustments Other Than Translation Of Balance Sheet Tax Benefit Expense	(157)	(53)
Pension and other postretirement benefit adjustments, tax cost	(27)	(252)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	(7)	(1)
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated other comprehensive loss	(1,426)	(1,562)	(1,798)	(1,332)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	634	(157)
Other Comprehensive Income (Loss), Before Reclassifications, Tax	(262)	(73)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	372	(230)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated other comprehensive loss	(634)	(988)	(571)	(1,379)
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	(93)	(267)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	30	658
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(63)	391
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated other comprehensive loss	(3)	9	$ 13	$ 9
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	(13)	(6)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(3)	6
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	$ (16)	$ 0