Income taxes (Details 5) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deferred income tax assets:
Tax carryforwards	$ 1,312	$ 1,286
Pension	785	980
Postemployment benefits other than pensions	793	841
Warranty reserves	237	226
Stock-based compensation	121	135
Allowance for credit losses	155	149
Post sale discounts	158	160
Other employee compensation and benefits	186	203
Other-net	298	302
Deferred income tax assets, Total	4,045	4,282
Deferred income tax liabilities:
Capital and intangible assets	(1,381)	(1,360)
Bond discount	(127)	(133)
Translation	(190)	(165)
Other outside basis differences	(271)	(205)
Undistributed profits of non-U.S. subsidiaries	(129)	(138)
Deferred income tax liabilities, Total	(2,098)	(2,001)
Valuation allowance for deferred tax assets	(915)	(993)
Deferred income taxes-net	$ 1,032	$ 1,288