The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

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Gross amount of long-lived physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References+ Details

- Definition

Amount, net of accumulated depreciation, depletion and amortization, of long-lived physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References+ Details

Property, plant and equipment (Detail) (USD $) In Millions, unless otherwise specified																															36 Months Ended				3 Months Ended					36 Months Ended				3 Months Ended
	Mar. 31, 2013 Insurance and Other [Member]	Dec. 31, 2012 Insurance and Other [Member]	Mar. 31, 2013 Insurance and Other [Member] Buildings and improvements [Member]	Dec. 31, 2012 Insurance and Other [Member] Buildings and improvements [Member]	Mar. 31, 2013 Insurance and Other [Member] Machinery and equipment [Member]	Dec. 31, 2012 Insurance and Other [Member] Machinery and equipment [Member]	Mar. 31, 2013 Insurance and Other [Member] Furniture, fixtures and other [Member]	Dec. 31, 2012 Insurance and Other [Member] Furniture, fixtures and other [Member]	Mar. 31, 2013 Insurance and Other [Member] Assets held for lease [Member]	Dec. 31, 2012 Insurance and Other [Member] Assets held for lease [Member]	Mar. 31, 2013 Insurance and Other [Member] Land [Member]	Dec. 31, 2012 Insurance and Other [Member] Land [Member]	Mar. 31, 2013 Railroad [Member] Land [Member]	Dec. 31, 2012 Railroad [Member] Land [Member]	Mar. 31, 2013 Railroad [Member] Track structure and other roadway [Member]	Dec. 31, 2012 Railroad [Member] Track structure and other roadway [Member]	Mar. 31, 2013 Railroad [Member] Locomotives, freight cars and other equipment [Member]	Dec. 31, 2012 Railroad [Member] Locomotives, freight cars and other equipment [Member]	Mar. 31, 2013 Railroad [Member] Construction in progress [Member]	Dec. 31, 2012 Railroad [Member] Construction in progress [Member]	Mar. 31, 2013 Utilities and Energy [Member] Utility generation, distribution and transmission system [Member]	Dec. 31, 2012 Utilities and Energy [Member] Utility generation, distribution and transmission system [Member]	Mar. 31, 2013 Utilities and Energy [Member] Interstate pipeline assets [Member]	Dec. 31, 2012 Utilities and Energy [Member] Interstate pipeline assets [Member]	Mar. 31, 2013 Utilities and Energy [Member] Independent power plants and other assets [Member]	Dec. 31, 2012 Utilities and Energy [Member] Independent power plants and other assets [Member]	Mar. 31, 2013 Utilities and Energy [Member] Construction in progress [Member]	Dec. 31, 2012 Utilities and Energy [Member] Construction in progress [Member]	Mar. 31, 2013 Railroad, Utilities and Energy [Member]	Dec. 31, 2012 Railroad, Utilities and Energy [Member]	Mar. 31, 2013 Minimum [Member] Insurance and Other [Member] Buildings and improvements [Member]	Mar. 31, 2013 Minimum [Member] Insurance and Other [Member] Machinery and equipment [Member]	Mar. 31, 2013 Minimum [Member] Insurance and Other [Member] Furniture, fixtures and other [Member]	Mar. 31, 2013 Minimum [Member] Insurance and Other [Member] Assets held for lease [Member]	Mar. 31, 2013 Minimum [Member] Railroad [Member] Track structure and other roadway [Member]	Mar. 31, 2013 Minimum [Member] Railroad [Member] Locomotives, freight cars and other equipment [Member]	Mar. 31, 2013 Minimum [Member] Utilities and Energy [Member] Utility generation, distribution and transmission system [Member]	Mar. 31, 2013 Minimum [Member] Utilities and Energy [Member] Interstate pipeline assets [Member]	Mar. 31, 2013 Minimum [Member] Utilities and Energy [Member] Independent power plants and other assets [Member]	Mar. 31, 2013 Maximum [Member] Insurance and Other [Member] Buildings and improvements [Member]	Mar. 31, 2013 Maximum [Member] Insurance and Other [Member] Machinery and equipment [Member]	Mar. 31, 2013 Maximum [Member] Insurance and Other [Member] Furniture, fixtures and other [Member]	Mar. 31, 2013 Maximum [Member] Insurance and Other [Member] Assets held for lease [Member]	Mar. 31, 2013 Maximum [Member] Railroad [Member] Track structure and other roadway [Member]	Mar. 31, 2013 Maximum [Member] Railroad [Member] Locomotives, freight cars and other equipment [Member]	Mar. 31, 2013 Maximum [Member] Utilities and Energy [Member] Utility generation, distribution and transmission system [Member]	Mar. 31, 2013 Maximum [Member] Utilities and Energy [Member] Interstate pipeline assets [Member]	Mar. 31, 2013 Maximum [Member] Utilities and Energy [Member] Independent power plants and other assets [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 32,348	$ 32,025	$ 6,074	$ 6,074	$ 15,509	$ 15,436	$ 2,863	$ 2,736	$ 6,844	$ 6,731	$ 1,058	$ 1,048	$ 5,957	$ 5,950	$ 38,488	$ 38,255	$ 6,657	$ 6,528	$ 1,014	$ 963	$ 42,490	$ 42,682	$ 6,371	$ 6,354	$ 2,110	$ 1,860	$ 2,859	$ 2,647	$ 105,946	$ 105,239
Accumulated depreciation	(13,200)	(12,837)																											(17,827)	(17,555)
Total Property, plant and equipment, net	$ 19,148	$ 19,188																											$ 88,119	$ 87,684
Estimated useful life (in years)																															2 years	3 years	2 years	12 years	5 years	5 years	5 years	3 years	3 years	40 years	20 years	20 years	30 years	100 years	37 years	80 years	80 years	30 years