Intangible Assets and Goodwill (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended			3 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012 Y	Jun. 30, 2011	Dec. 31, 2011 Y	Jun. 30, 2012 ERA Mining Machinery Limited	Mar. 31, 2012 Caterpillar Tohoku Limited	Jun. 30, 2012 Customer Relationships	Jun. 30, 2012 Customer Relationships Y	Dec. 31, 2011 Customer Relationships Y	Jun. 30, 2012 Intellectual Property Y	Dec. 31, 2011 Intellectual Property Y	Jun. 30, 2012 Other Y	Dec. 31, 2011 Other Y
Intangible assets
Weighted Amortizable Life (in years)			14		13				15	15	11	11	10	11
Gross Carrying Amount	$ 4,925		$ 4,925		$ 4,904			$ 2,822	$ 2,822	$ 2,811	$ 1,787	$ 1,794	$ 316	$ 299
Accumulated Amortization	(707)		(707)		(554)			(272)	(272)	(213)	(317)	(244)	(118)	(97)
Net	4,218		4,218		4,350			2,550	2,550	2,598	1,470	1,550	198	202
Indefinite-lived intangible assets in process research & development	18		18		18
Total intangible assets, net	4,236		4,236		4,368
Total intangible assets, gross carrying amount	4,943		4,943		4,922
Finite-lived intangible assets acquired						194	8
Assets classified to held for sale, intangible assets									100
Accumulated amortization on held for sale intangible assets									4
Impaired finite-lived intangible assets, gross								51	51
Imparied finite-lived intangible assets, accumulated amortization								29	29
Impairment of Intangible Assets, Finite-lived								22
Amortization expense	99	22	193	44
2012			393
2013			393
2014			386
2015			380
2016			371
Thereafter			$ 2,506