2.2.0.25falsefalse4180 - Disclosure - Concentration of credit risk (Details)truefalseIn Millionsfalse1falsefalseUSDfalsefalse12/31/2010
USD ($)
USD ($) / shares
$I2010http://www.sec.gov/CIK0000018230instant2010-12-31T00:00:000001-01-01T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0SharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0PureStandardhttp://www.xbrl.org/2003/instancepurexbrli0USDUSD$2falsefalseUSDfalsefalse12/31/2009
USD ($)
USD ($) / shares
$I2009http://www.sec.gov/CIK0000018230instant2009-12-31T00:00:000001-01-01T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0SharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0PureStandardhttp://www.xbrl.org/2003/instancepurexbrli0USDUSD$3falsefalseUSDfalsefalse12/31/2008
USD ($)
USD ($) / shares
$I2008http://www.sec.gov/CIK0000018230instant2008-12-31T00:00:000001-01-01T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0SharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0PureStandardhttp://www.xbrl.org/2003/instancepurexbrli0USDUSD$2true0cat_ConcentrationOfCreditRiskDisclosureAbstractcatfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalse3false0cat_DerivativesMaximumExposureToCreditLosscatfalsecreditinstantThe maximum exposure to credit loss on derivative contracts before the application of any master netting agreements.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse576000000576falsetruefalsefalsefalse2truefalsefalse514000000514falsetruefalsefalsefalse3truefalsefalse10510000001051falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe maximum exposure to credit loss on derivative contracts before the application of any master netting agreements.No authoritative reference available.falsefalse32Concentration of credit risk (Details) (USD $)MillionsUnKnownUnKnownUnKnownfalsetrue
