Supplemental Equity and Comprehensive Income Information - Reclass AOCI (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net of tax	$ (75)	$ (50)	$ (146)	$ (85)
Gains (losses) associated with defined benefit pension and postretirement plans amortization
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Transition asset		1		1
Prior service benefit	22	24	44	47
Net actuarial loss	(141)	(126)	(282)	(252)
Total before tax	(119)	(101)	(238)	(204)
Tax effect	41	34	77	68
Net of tax	(78)	(67)	(161)	(136)
Cash flow hedging instruments gains (losses)
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Total before tax	5	28	23	80
Tax effect	(2)	(11)	(8)	(29)
Net of tax	3	17	15	51
Cash flow hedging instruments gains (losses) | Foreign currency forward/option contracts
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Cost of sales	$ 5	$ 28	$ 23	81
Cash flow hedging instruments gains (losses) | Interest rate swap contracts
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Interest expense				$ (1)