Cat Financial Financing Activities (Details 4) (USD $) In Millions	Dec. 31, 2009	Dec. 31, 2010 Asset-backed securities
Finance receivables
Restricted assets of consolidated QSPE	$ 324	$ 136
Restricted liability of consolidated QSPE	$ 327	$ 73

Name:

cat_VariableInterestEntityConsolidatedCarryingAmountLiabilities

Namespace Prefix:

cat

Data Type:

xbrli:monetaryItemType

Balance Type:

credit

Period Type:

instant