Number Of Customers.

No definition available.

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- Definition

Number of existing utility operating companies.

+ References

No definition available.

+ Details

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- Definition

Number of facilities of which the company owns, operates and controls electric generation capacity.

+ References

No definition available.

+ Details

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- Definition

Number of generation facilities from which the company purchases entire output.

+ References

No definition available.

+ Details

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- Definition

Plant Capacity

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Reportable Operating Segments.

+ References

No definition available.

+ Details

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- Definition

Service Area.

+ References

No definition available.

+ Details

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 159

-Paragraph 18

-Subparagraph f

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 18

-Paragraph 20

-Subparagraph a (1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

+ Details

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- Definition

The proportionate share of interest (percent) in a jointly owned utility plant.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 10

-Section C

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 980

-SubTopic 360

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 10.C)

-URI http://asc.fasb.org/extlink&oid=6500719&loc=d3e659983-123033

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- Definition

Revenue derived from energy-related services such supplying various forms of energy (such as steam, electricity and chilled water from the operation of on-site facilities or cogeneration plants), procurement services provided to energy purchasers, and the marketing and trading of energy commodities and derivatives.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 5

-Section 03

-Paragraph 1

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

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Balance Type:	credit
Period Type:	duration

- Details

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Segment Information (Details Textuals) (USD $) In Millions, unless otherwise specified	2 Months Ended	10 Months Ended	12 Months Ended
	Feb. 24, 2011 Segments	Dec. 31, 2011 Segments	Dec. 31, 2011 Companies	Dec. 31, 2010	Dec. 31, 2009
Segment Reporting Information [Line Items]
Reportable Operating Segments	2	3
Number of utility distribution companies			10
Electricity sales			$ 15,117	$ 12,523	$ 12,032
Bath County, Virginia
Segment Reporting Information [Line Items]
Generation capacity		2,773	2,773
Regulated Distribution
Segment Reporting Information [Line Items]
Number of customers served by utility distribution companies			6,000,000
Number of square miles in service area		67,000	67,000
Competitive Energy Services
Segment Reporting Information [Line Items]
Number of generation facilities from which the company purchases entire output			18
Number of facilities of which the company owns, operates and controls electric generation capacity			18
Generation capacity		17,000	17,000
Competitive Energy Services \| Unregulated Plants
Segment Reporting Information [Line Items]
Generation capacity		2,700	2,700
Competitive Energy Services \| AGC \| Bath County, Virginia
Segment Reporting Information [Line Items]
Pumped storage hydroelectric station, Ownership percentage		40.00%	40.00%
Generation capacity		1,109	1,109
Competitive Energy Services \| AE Supply \| AGC
Segment Reporting Information [Line Items]
Ownership interest		59.00%	59.00%
Competitive Energy Services \| MP \| AGC
Segment Reporting Information [Line Items]
Ownership interest		41.00%	41.00%