Consolidated Statement of Changes in Stockholders' Equity (Parenthetical)	3 Months Ended
Mar. 31, 2012	Mar. 31, 2011
Consolidated Statement of Changes in Stockholders' Equity
Common shares issued from treasury stock for stock-based compensation (in shares)	4,804,576	5,629,306

The number of common shares issued from treasury stock for stock-based compensation during the period.

No definition available.

Name:	cat_CommonSharesIssuedSharesFromTreasuryStockForStockBasedCompensation
Namespace Prefix:	cat_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration