Supplemental Equity and Comprehensive Income Information - Reclass AOCI (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Amount Reclassified from Accumulated Other Comprehensive Income
Net of tax	$ (143)	$ (82)	$ (421)	$ (228)
Gains (losses) associated with defined benefit pension and postretirement plans amortization
Amount Reclassified from Accumulated Other Comprehensive Income
Prior service benefit	20	21	58	65
Net actuarial loss	(170)	(140)	(510)	(422)
Total before tax	(150)	(119)	(452)	(357)
Tax effect	36	39	108	116
Net of tax	(114)	(80)	(344)	(241)
Cash flow hedging instruments gains (losses)
Amount Reclassified from Accumulated Other Comprehensive Income
Total before tax	(37)	(2)	(99)	21
Tax effect	8		22	(8)
Net of tax	(29)	(2)	(77)	13
Cash flow hedging instruments gains (losses) \| Foreign currency forward/option contracts
Amount Reclassified from Accumulated Other Comprehensive Income
Cost of sales	$ (37)	$ (2)	$ (99)	$ 21

The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities.

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