The charge against earnings resulting from the aggregate write down of all assets from their carrying value to their fair value.

+ References+ Details

The charge against earnings in the period, comprised of costs associated with restructuring activities not otherwise specified in the taxonomy pursuant to a duly authorized plan, excluding a discontinued operation as defined by generally accepted accounting principles. Costs of such activities include those for one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, and relocating employees, but excludes costs associated with the retirement of a long-lived asset and severance costs associated with established compensation plans.

+ References+ Details

- Definition

The charge against earnings in the period for known and estimated costs of termination benefits provided to current employees that are involuntarily terminated under a benefit arrangement associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan, excluding costs or losses pertaining to an entity newly acquired in a business combination or a discontinued operation as defined by generally accepted accounting principles and costs associated with one-time termination benefits.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 420

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-Section S99

-Paragraph 1

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS146-1

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 715

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-Section 50

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-Paragraph 5-8

-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

-Name Accounting Standards Codification

-Topic 420

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 5

-Section P

-Subsection 3, 4

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-Paragraph 8-13, 20

-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 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 112

-Paragraph 7

-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 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

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-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

+ Details

Impairment of Long-Lived Assets (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended						3 Months Ended			12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 FES	Dec. 31, 2010 FES	Dec. 31, 2009 FES	Mar. 31, 2011 Fremont Energy Center	Mar. 31, 2011 Fremont Energy Center Excessive or Obsolete Inventory MW	Mar. 31, 2011 Fremont Energy Center Write-down of carrying value MW	Dec. 31, 2011 Peaking Facilities	Dec. 31, 2011 Competitive Energy Services employees	Dec. 31, 2011 Competitive Energy Services Maximum	Dec. 31, 2011 Competitive Energy Services FGCO	Dec. 31, 2011 Competitive Energy Services FGCO Maximum	Dec. 31, 2011 Competitive Energy Services AE Supply	Dec. 31, 2011 Competitive Energy Services AE Supply Maximum	Dec. 31, 2011 Competitive Energy Services MP	Dec. 31, 2011 Competitive Energy Services MP Maximum	Dec. 31, 2011 Competitive Energy Services Excessive or Obsolete Inventory	Dec. 31, 2011 Competitive Energy Services Write-down of carrying value	Dec. 31, 2011 Competitive Energy Services Mono-Nitrogen Oxide Emission Allowances	Dec. 31, 2011 Competitive Energy Services Mono-Nitrogen Oxide Emission Allowances FES	Dec. 31, 2011 Competitive Energy Services Mono-Nitrogen Oxide Emission Allowances AE Supply	Dec. 31, 2011 Competitive Energy Services Sulfur Dioxide Emission Allowances	Dec. 31, 2011 Competitive Energy Services Sulfur Dioxide Emission Allowances FES	Dec. 31, 2011 Competitive Energy Services Sulfur Dioxide Emission Allowances AE Supply
Impairment of Long-Lived Assets [Line Items]
Load following capacity									544
Peaking capacity								163
Asset impairments	$ 413	$ 388	$ 6	$ 294	$ 388	$ 6	$ 11			$ 23											$ 6	$ 1	$ 5	$ 21	$ 18	$ 3
Impairment of assets related to retirement											334								18	311				5
Other asset impairment charges related to emission allowances																								16	13	3
Employees affected by plant retirement											634
Estimated total severance benfits												25		15		5		5
Additional costs to prepare plants for closing											$ 9		$ 4		$ 3		$ 2