Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 FASB

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 68

-Subparagraph l

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-Number 141R

-Paragraph 34

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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-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.

+ Details

Goodwill (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2010
Goodwill [Line Items]
Goodwill	$ 6,448,000	$ 5,575,000	$ 5,575,000
CEI [Member]
Goodwill [Line Items]
Percentage Decrease In Fair Value Required To Indicate Potential Impairment	20.00%
Goodwill	1,688,521	1,688,521
TE [Member]
Goodwill [Line Items]
Percentage Decrease In Fair Value Required To Indicate Potential Impairment	16.00%
Goodwill	500,576	500,576
Jcp And L [Member]
Goodwill [Line Items]
Percentage Decrease In Fair Value Required To Indicate Potential Impairment	38.00%
Goodwill	1,811,000	1,811,000
Met-Ed [Member]
Goodwill [Line Items]
Percentage Decrease In Fair Value Required To Indicate Potential Impairment	62.00%
Goodwill	416,499	416,499
FES [Member]
Goodwill [Line Items]
Percentage Decrease In Fair Value Required To Indicate Potential Impairment	62.00%
Goodwill	24,000	24,000
Penelec [Member]
Goodwill [Line Items]
Percentage Decrease In Fair Value Required To Indicate Potential Impairment	58.00%
Goodwill	768,628	768,628
Competitive Energy Services [Member]
Goodwill [Line Items]
Percentage Decrease In Fair Value Required To Indicate Potential Impairment	53.00%
Goodwill	897,000	24,000	24,000
Competitive Energy Services [Member] \| Allegheny Energy Inc [Member]
Goodwill [Line Items]
Goodwill	873,000
Regulated Distribution [Member]
Goodwill [Line Items]
Percentage Decrease In Fair Value Required To Indicate Potential Impairment	44.00%
Goodwill	5,551,000	5,551,000	5,551,000
Regulated Independent Transmission [Member]
Goodwill [Line Items]
Goodwill	$ 0	$ 0	$ 0