Schedule of Reclassifications Out of Accumualted Other Comprehensive Income (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Tax (expense)/benefit		$ (1,085)	$ 193	$ 417
EARNINGS (LOSS) FROM CONTINUING OPERATIONS		(2,110)	(800)	(832)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(478)	(535)	(268)
Prior-service costs
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[1]	(33)	(37)	(33)
Actuarial gains/(losses)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[1]	(733)	(851)	(449)
Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		(766)	(888)	(482)
Tax (expense)/benefit		280	343	186
EARNINGS (LOSS) FROM CONTINUING OPERATIONS		(486)	(545)	(296)
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		1	3	40
Tax (expense)/benefit		0	0	0
EARNINGS (LOSS) FROM CONTINUING OPERATIONS		1	3	40
Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		9	10	(20)
Tax (expense)/benefit		(2)	(3)	8
Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] | Foreign Exchange Contract [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[2]	9	10	(20)
Net Gains and Losses on Cash Flow Hedging Derivatives
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
EARNINGS (LOSS) FROM CONTINUING OPERATIONS		7	7	(12)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		$ (7)	$ (7)	$ 12

[1] These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see Note 16 for additional details).

[2] This accumulated other comprehensive income component is included in our derivatives and hedging activities (see Note 14 for additional details).