Property, plant and equipment and assets held for lease (Detail) (USD $) In Millions, unless otherwise specified																																					3 Months Ended
	Mar. 31, 2014 Insurance and Other [Member]	Dec. 31, 2013 Insurance and Other [Member]	Mar. 31, 2014 Insurance and Other [Member] Buildings and improvements [Member]	Dec. 31, 2013 Insurance and Other [Member] Buildings and improvements [Member]	Mar. 31, 2014 Insurance and Other [Member] Machinery and equipment [Member]	Dec. 31, 2013 Insurance and Other [Member] Machinery and equipment [Member]	Mar. 31, 2014 Insurance and Other [Member] Furniture, fixtures and other [Member]	Dec. 31, 2013 Insurance and Other [Member] Furniture, fixtures and other [Member]	Mar. 31, 2014 Insurance and Other [Member] Land [Member]	Dec. 31, 2013 Insurance and Other [Member] Land [Member]	Mar. 31, 2014 Railroad [Member] Land [Member]	Dec. 31, 2013 Railroad [Member] Land [Member]	Mar. 31, 2014 Railroad [Member] Track structure and other roadway [Member]	Dec. 31, 2013 Railroad [Member] Track structure and other roadway [Member]	Mar. 31, 2014 Railroad [Member] Locomotives, freight cars and other equipment [Member]	Dec. 31, 2013 Railroad [Member] Locomotives, freight cars and other equipment [Member]	Mar. 31, 2014 Railroad [Member] Construction in progress [Member]	Dec. 31, 2013 Railroad [Member] Construction in progress [Member]	Mar. 31, 2014 Utilities and Energy [Member] Utility generation, distribution and transmission system [Member]	Dec. 31, 2013 Utilities and Energy [Member] Utility generation, distribution and transmission system [Member]	Mar. 31, 2014 Utilities and Energy [Member] Interstate pipeline assets [Member]	Dec. 31, 2013 Utilities and Energy [Member] Interstate pipeline assets [Member]	Mar. 31, 2014 Utilities and Energy [Member] Independent power plants and other assets [Member]	Dec. 31, 2013 Utilities and Energy [Member] Independent power plants and other assets [Member]	Mar. 31, 2014 Utilities and Energy [Member] Construction in progress [Member]	Dec. 31, 2013 Utilities and Energy [Member] Construction in progress [Member]	Mar. 31, 2014 Railroad, Utilities and Energy [Member]	Dec. 31, 2013 Railroad, Utilities and Energy [Member]	Mar. 31, 2014 Finance and Financial Products [Member]	Dec. 31, 2013 Finance and Financial Products [Member]	Mar. 31, 2014 Finance and Financial Products [Member] Land [Member]	Dec. 31, 2013 Finance and Financial Products [Member] Land [Member]	Mar. 31, 2014 Finance and Financial Products [Member] Assets held for lease [Member]	Dec. 31, 2013 Finance and Financial Products [Member] Assets held for lease [Member]	Mar. 31, 2014 Finance and Financial Products [Member] Buildings, machinery and other [Member]	Dec. 31, 2013 Finance and Financial Products [Member] Buildings, machinery and other [Member]	Mar. 31, 2014 Minimum [Member] Insurance and Other [Member] Buildings and improvements [Member]	Mar. 31, 2014 Minimum [Member] Insurance and Other [Member] Machinery and equipment [Member]	Mar. 31, 2014 Minimum [Member] Insurance and Other [Member] Furniture, fixtures and other [Member]	Mar. 31, 2014 Minimum [Member] Railroad [Member] Track structure and other roadway [Member]	Mar. 31, 2014 Minimum [Member] Railroad [Member] Locomotives, freight cars and other equipment [Member]	Mar. 31, 2014 Minimum [Member] Utilities and Energy [Member] Utility generation, distribution and transmission system [Member]	Mar. 31, 2014 Minimum [Member] Utilities and Energy [Member] Interstate pipeline assets [Member]	Mar. 31, 2014 Minimum [Member] Utilities and Energy [Member] Independent power plants and other assets [Member]	Mar. 31, 2014 Minimum [Member] Finance and Financial Products [Member] Assets held for lease [Member]	Mar. 31, 2014 Minimum [Member] Finance and Financial Products [Member] Buildings, machinery and other [Member]	Mar. 31, 2014 Maximum [Member] Insurance and Other [Member] Buildings and improvements [Member]	Mar. 31, 2014 Maximum [Member] Insurance and Other [Member] Machinery and equipment [Member]	Mar. 31, 2014 Maximum [Member] Insurance and Other [Member] Furniture, fixtures and other [Member]	Mar. 31, 2014 Maximum [Member] Railroad [Member] Track structure and other roadway [Member]	Mar. 31, 2014 Maximum [Member] Railroad [Member] Locomotives, freight cars and other equipment [Member]	Mar. 31, 2014 Maximum [Member] Utilities and Energy [Member] Utility generation, distribution and transmission system [Member]	Mar. 31, 2014 Maximum [Member] Utilities and Energy [Member] Interstate pipeline assets [Member]	Mar. 31, 2014 Maximum [Member] Utilities and Energy [Member] Independent power plants and other assets [Member]	Mar. 31, 2014 Maximum [Member] Finance and Financial Products [Member] Assets held for lease [Member]	Mar. 31, 2014 Maximum [Member] Finance and Financial Products [Member] Buildings, machinery and other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 26,472	$ 26,074	$ 6,308	$ 6,244	$ 16,136	$ 15,984	$ 2,924	$ 2,748	$ 1,104	$ 1,098	$ 5,973	$ 5,973	$ 40,525	$ 40,098	$ 7,996	$ 7,551	$ 971	$ 973	$ 57,903	$ 57,490	$ 6,498	$ 6,448	$ 2,999	$ 2,516	$ 4,247	$ 4,217	$ 127,112	$ 125,266
Property, plant and equipment, accumulated depreciation	(12,674)	(12,451)																									(23,604)	(22,784)
Total property, plant and equipment, net	13,798	13,623																									103,508	102,482
Estimated useful life (in years)																																					2 years	3 years	2 years	5 years	5 years	5 years	3 years	3 years	6 years	3 years	40 years	25 years	15 years	100 years	40 years	80 years	80 years	30 years	30 years	50 years
Property, plant and equipment and assets held for lease, gross																													11,042	10,888	232	233	9,651	9,509	1,159	1,146
Property, plant and equipment and assets held for lease, accumulated depreciation																													(3,268)	(3,188)
Total property, plant and equipment and assets held for lease, net																													$ 7,774	$ 7,700