Accumulated other comprehensive income (loss) (Details 2) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Other income (expense)									$ 146		$ 161		$ 322
Interest expense excluding Financial Products									(505)		(507)		(484)
Interest expense of Financial Products									(596)		(587)		(624)
Consolidated profit before taxes									139		3,439		3,152
Tax (provision) benefit									(192)		(916)		(692)
Reclassifications net of tax	$ (1,171)	$ 283	$ 550	$ 271	$ (94)	$ 559	$ 802	$ 1,245	(67)	[1]	2,512	[1]	2,452	[1]
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Reclassifications net of tax									52		(17)		45
Reclassification out of Accumulated Other Comprehensive Income | Foreign currency translation
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Other income (expense)									(17)		0		0
Tax (provision) benefit									0		0		0
Reclassifications net of tax									(17)		0		0
Reclassification out of Accumulated Other Comprehensive Income | Pension and other postretirement benefits
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Amortization of prior service credit (cost)									56		53		38
Tax (provision) benefit									(21)		(18)		(13)
Reclassifications net of tax									35		35		25
Reclassification out of Accumulated Other Comprehensive Income | Derivative financial instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Consolidated profit before taxes									5		(139)		(6)
Tax (provision) benefit									(2)		51		2
Reclassifications net of tax									3		(88)		(4)
Reclassification out of Accumulated Other Comprehensive Income | Derivative financial instruments | Foreign exchange contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Other income (expense)									14		(127)		5
Reclassification out of Accumulated Other Comprehensive Income | Derivative financial instruments | Interest rate contracts | Machinery, Energy & Transportation
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Interest expense excluding Financial Products									(6)		(6)		(5)
Reclassification out of Accumulated Other Comprehensive Income | Derivative financial instruments | Interest rate contracts | Financial Products
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Interest expense of Financial Products									(3)		(6)		(6)
Reclassification out of Accumulated Other Comprehensive Income | Available-for-sale securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Other income (expense)									46		56		35
Tax (provision) benefit									(15)		(20)		(11)
Reclassifications net of tax									$ 31		$ 36		$ 24

[1] 1 Profit (loss) attributable to common stockholders.