Supplemental Equity and Comprehensive Income Information - Reclass AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Amount Reclassified from Accumulated Other Comprehensive Income
Net of tax	$ (538)	$ (363)	$ (203)
Gains (losses) associated with defined benefit pension and postretirement plans amortization
Amount Reclassified from Accumulated Other Comprehensive Income
Transition asset			1
Prior service benefit	76	89	92
Net actuarial loss	(678)	(570)	(506)
Curtailments/Settlements	(4)	(2)	(8)
Total before tax	(606)	(483)	(421)
Tax effect	145	116	148
Net of tax	(461)	(367)	(273)
Cash flow hedging instruments gains (losses)
Amount Reclassified from Accumulated Other Comprehensive Income
Total before tax	(96)	7	109
Tax effect	19	(3)	(39)
Net of tax	(77)	4	70
Cash flow hedging instruments gains (losses) | Foreign currency forward/option contracts
Amount Reclassified from Accumulated Other Comprehensive Income
Cost of sales	(95)	8	110
Cash flow hedging instruments gains (losses) | Interest rate swap contracts
Amount Reclassified from Accumulated Other Comprehensive Income
Interest expense	$ (1)	$ (1)	$ (1)