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.

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- 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.

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Property, Plant and Equipment, Net (Details) (USD $) In Millions, unless otherwise specified							6 Months Ended				6 Months Ended						6 Months Ended				6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2012 Regulated assets [Member]	Dec. 31, 2011 Regulated assets [Member]	Jun. 30, 2012 Regulated assets [Member] Utility generation, distribution and transmission system [Member]	Dec. 31, 2011 Regulated assets [Member] Utility generation, distribution and transmission system [Member]	Jun. 30, 2012 Regulated assets [Member] Utility generation, distribution and transmission system [Member] Minimum [Member]	Jun. 30, 2012 Regulated assets [Member] Utility generation, distribution and transmission system [Member] Maximum [Member]	Jun. 30, 2012 Regulated assets [Member] Interstate pipeline assets [Member]	Dec. 31, 2011 Regulated assets [Member] Interstate pipeline assets [Member]	Jun. 30, 2012 Regulated assets [Member] Interstate pipeline assets [Member] Minimum [Member]	Jun. 30, 2012 Regulated assets [Member] Interstate pipeline assets [Member] Maximum [Member]	Jun. 30, 2012 Nonregulated assets [Member]	Dec. 31, 2011 Nonregulated assets [Member]	Jun. 30, 2012 Nonregulated assets [Member] Independent power plants [Member]	Dec. 31, 2011 Nonregulated assets [Member] Independent power plants [Member]	Jun. 30, 2012 Nonregulated assets [Member] Independent power plants [Member] Minimum [Member]	Jun. 30, 2012 Nonregulated assets [Member] Independent power plants [Member] Maximum [Member]	Jun. 30, 2012 Nonregulated assets [Member] Other assets [Member]	Dec. 31, 2011 Nonregulated assets [Member] Other assets [Member]	Jun. 30, 2012 Nonregulated assets [Member] Other assets [Member] Minimum [Member]	Jun. 30, 2012 Nonregulated assets [Member] Other assets [Member] Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment			$ 47,361	$ 46,425	$ 41,083	$ 40,180			$ 6,278	$ 6,245			$ 1,115	$ 1,106	$ 677	$ 677			$ 438	$ 429
Accumulated depreciation and amortization			(14,844)	(14,390)									(557)	(533)
Property, plant and equipment in service, net	33,075	32,608	32,517	32,035									558	573
Construction work-in-progress	2,265	1,559	1,800	1,600
Property, plant and equipment, net	$ 35,340	$ 34,167
Depreciable Life							5 years	80 years			3 years	80 years					5 years	30 years			3 years	30 years