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Business Combinations and Divestitures (Details 2) (USD $) In Millions, except Per Share data, unless otherwise specified	9 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended				1 Months Ended
	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2011 Customer relationships Bucyrus International, Inc. Y	Sep. 30, 2011 Intellectual property Bucyrus International, Inc. Y	Sep. 30, 2011 Other. Bucyrus International, Inc. Y	Sep. 30, 2011 Bucyrus International, Inc.	Sep. 30, 2010 Bucyrus International, Inc.	Sep. 30, 2011 Bucyrus International, Inc. Y	Sep. 30, 2010 Bucyrus International, Inc.	Jul. 08, 2011 Bucyrus International, Inc.	Sep. 30, 2011 Bucyrus International, Inc. Resource Industries	Aug. 31, 2011 Pyroban Group Limited Y
Acquired finite-lived intangible assets
Estimated fair value of asset /(liability)			$ 2,337	$ 1,489	$ 75	$ 3,901		$ 3,901		$ 3,901
Weighted-average useful life (in years)			15	12	4			14				15
Accumulated amortization	470	346	36	28	4	68		68
Estimated aggregate amortization expense
2011								75
2012	229							299
2013	376							299
2014	368							299
2015	365							290
2016	360							280
Thereafter	2,966							2,291
Goodwill acquired in business combination										5,263	5,263	23
Goodwill acquired in business combination, tax deductible											400
Pro forma results
Acquisition related cost								362
Nonrecurring expense related to fair value adjustment to acquisition-date inventory								160
Acceleration of stock compensation expense								25
Total Sales and revenues						15,811	12,071	45,038	32,194
Profit (loss)						1,290	825	3,751	1,340
Profit (loss) per common share (in dollars per share)						$ 1.99	$ 1.30	$ 5.82	$ 2.13
Profit (loss) per common share diluted (in dollars per share)						$ 1.94	$ 1.27	$ 5.63	$ 2.07
Percentage of equity acquired (as a percent)												100.00%
Purchase price of acquired entity										8,800		69
Net tangible assets acquired												6
Tangible assets acquired in business combination												$ 40