Income taxes (Details 4) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Deferred income tax assets:
Pension	$ 1,513	$ 903	$ 2,100
Postemployment benefits other than pensions	1,514	1,435	1,678
Tax carryforwards	826	760	663
Warranty reserves	346	313	358
Stock based compensation	327	320	281
Inventory	123us-gaap_DeferredTaxAssetsInventory	112us-gaap_DeferredTaxAssetsInventory	195us-gaap_DeferredTaxAssetsInventory
Allowance for credit losses	198	184	170
Post sale discounts	175cat_DeferredTaxAssetsPostSaleDiscounts	146cat_DeferredTaxAssetsPostSaleDiscounts	141cat_DeferredTaxAssetsPostSaleDiscounts
Deferred compensation	132	126	110
Other-net	549us-gaap_DeferredTaxAssetsOther	524us-gaap_DeferredTaxAssetsOther	491us-gaap_DeferredTaxAssetsOther
Deferred income tax assets, Total	5,703us-gaap_DeferredTaxAssetsGross	4,823us-gaap_DeferredTaxAssetsGross	6,187us-gaap_DeferredTaxAssetsGross
Deferred income tax liabilities:
Capital and intangible assets	(2,625)	(2,815)	(2,759)
Bond discount	(233)	(240)	(249)
Translation	(252)	(133)	(173)
Undistributed profits of non-U.S. subsidiaries	(69)	(90)	(128)
Deferred income tax liabilities, Total	(3,179)us-gaap_DeferredTaxLiabilities	(3,278)us-gaap_DeferredTaxLiabilities	(3,309)us-gaap_DeferredTaxLiabilities
Valuation allowance for deferred tax assets	(741)	(745)	(586)
Deferred income taxes-net	$ 1,783us-gaap_DeferredTaxAssetsLiabilitiesNet	$ 800us-gaap_DeferredTaxAssetsLiabilitiesNet	$ 2,292us-gaap_DeferredTaxAssetsLiabilitiesNet

The tax effect, as of the balance sheet date, of the amount of the estimated future tax deductions arising from post sale discounts, which can only be deducted for tax purposes when actual discount is granted, and which can only be realized if sufficient tax-basis income is generated in future periods to enable the deductions to be taken.

No definition available.