Equity, Income Tax Effects on Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other Comprehensive Income (Loss), before Tax
Other comprehensive loss before income tax expense (benefit)		$ (513)	$ (549)	$ (881)
Other Comprehensive Income (Loss), Tax
Income tax expense (benefit) related to items of other comprehensive loss		(37)	17	(164)
Other Comprehensive Income (Loss), Net of Tax
Reclassification from accumulated other comprehensive income (loss), current period, net of tax		7	19	0
Other comprehensive loss		(476)	(566)	(717)
Accumulated Foreign Currency Translation Adjustment [Member]
Other Comprehensive Income (Loss), before Tax
Other comprehensive income (loss), before reclassifications, before tax		(415)	(606)	(407)
Other Comprehensive Income (Loss), Tax
Other comprehensive income (loss), before reclassifications, tax expense (benefit)		0	0	0
Other Comprehensive Income (Loss), Net of Tax
Other comprehensive income (loss), before reclassifications, net of tax		(415)	(606)	(407)
Accumulated Defined Benefit Plans Adjustment, Net Actuarial (Gain) Loss Component [Member]
Other Comprehensive Income (Loss), before Tax
Other comprehensive income (loss), before reclassifications, before tax		(110)	50	(471)
Reclassification from accumulated other comprehensive income (loss), current period, before tax	[1]	48	62	34
Other Comprehensive Income (Loss), Tax
Other comprehensive income (loss), before reclassifications, tax expense (benefit)		(34)	15	(162)
Reclassification from accumulated other comprehensive income (loss), current period, tax expense (benefit)		18	22	12
Other Comprehensive Income (Loss), Net of Tax
Other comprehensive income (loss), before reclassifications, net of tax		(76)	35	(309)
Reclassification from accumulated other comprehensive income (loss), current period, net of tax		30	40	22
Accumulated Defined Benefit Plans Adjustment, Miscellaneous Gain [Member]
Other Comprehensive Income (Loss), before Tax
Other comprehensive income (loss), before reclassifications, before tax		0
Other Comprehensive Income (Loss), Tax
Other comprehensive income (loss), before reclassifications, tax expense (benefit)		(8)
Other Comprehensive Income (Loss), Net of Tax
Other comprehensive income (loss), before reclassifications, net of tax		8
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Cost (Credit) Component [Member]
Other Comprehensive Income (Loss), before Tax
Other comprehensive income (loss), before reclassifications, before tax			(22)	(1)
Reclassification from accumulated other comprehensive income (loss), current period, before tax	[1]	(36)	(40)	(40)
Other Comprehensive Income (Loss), Tax
Other comprehensive income (loss), before reclassifications, tax expense (benefit)			(8)	(1)
Reclassification from accumulated other comprehensive income (loss), current period, tax expense (benefit)		(13)	(14)	(14)
Other Comprehensive Income (Loss), Net of Tax
Other comprehensive income (loss), before reclassifications, net of tax			(14)	0
Reclassification from accumulated other comprehensive income (loss), current period, net of tax		(23)	(26)	(26)
Accumulated Defined Benefit Plans Adjustment, Curtailment and Settlement Component [Member]
Other Comprehensive Income (Loss), before Tax
Reclassification from accumulated other comprehensive income (loss), current period, before tax	[1]	0	7	3
Other Comprehensive Income (Loss), Tax
Reclassification from accumulated other comprehensive income (loss), current period, tax expense (benefit)			2	0
Other Comprehensive Income (Loss), Net of Tax
Reclassification from accumulated other comprehensive income (loss), current period, net of tax			5	3
Accumulated Defined Benefit Plans Adjustment [Member]
Other Comprehensive Income (Loss), before Tax
Reclassification from accumulated other comprehensive income (loss), current period, before tax		12	29	(3)
Other comprehensive loss before income tax expense (benefit)		(98)	57	(475)
Other Comprehensive Income (Loss), Tax
Reclassification from accumulated other comprehensive income (loss), current period, tax expense (benefit)		5	10	(2)
Income tax expense (benefit) related to items of other comprehensive loss		(37)	17	(165)
Other Comprehensive Income (Loss), Net of Tax
Reclassification from accumulated other comprehensive income (loss), current period, net of tax		7	19	(1)
Other comprehensive loss		$ (61)	$ 40	(310)
Accumulated Net Gain (Loss) from Cash Flow Hedges [Member]
Other Comprehensive Income (Loss), before Tax
Other comprehensive income (loss), before reclassifications, before tax				(1)
Reclassification from accumulated other comprehensive income (loss), current period, before tax				2
Other comprehensive loss before income tax expense (benefit)				1
Other Comprehensive Income (Loss), Tax
Other comprehensive income (loss), before reclassifications, tax expense (benefit)				0
Reclassification from accumulated other comprehensive income (loss), current period, tax expense (benefit)				1
Income tax expense (benefit) related to items of other comprehensive loss				1
Other Comprehensive Income (Loss), Net of Tax
Other comprehensive income (loss), before reclassifications, net of tax				(1)
Reclassification from accumulated other comprehensive income (loss), current period, net of tax				1
Other comprehensive loss				$ 0

[1] These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost, as further discussed in Note 12. Net periodic benefit cost is reflected in operating expenses and general and administrative expenses.