Commitments and Contingencies (Details) (USD $)	9 Months Ended		1 Months Ended	12 Months Ended	36 Months Ended	58 Months Ended	85 Months Ended	9 Months Ended
	Sep. 30, 2012 day stations spaces complexes	Mar. 31, 2012	Feb. 28, 2002 California Department of Water Resources	Dec. 31, 2006 California Department of Water Resources	Dec. 31, 2011 Louisiana Generating, LLC	Jan. 12, 2009 Louisiana Generating, LLC	Mar. 15, 2004 Louisiana Generating, LLC	Sep. 30, 2012 Agreement To Acquire All Outstanding Shares of GenOn [Member] Lawsuits
California Department of Water Resources
Damages alleged			$ 940,000,000
Percentage of ownership acquired by the company from another party (as a percent)				50.00%
Loss Contingency, Settlement Agreement, Consideration		20,000,000
Loss Contingency, Number of Days After Approval, Payment Due	30
Loss Contingency, Number of Fast Charge Stations to Be Installed in California	200
Loss Contingency, Number of Parking Spaces Required	10,000
Loss Contingency, Number of Multi-Family Complexes Able to Charge	1,000
Long-term Purchase Commitment, Amount	100,000,000
Louisiana Generating, LLC
Civil penalties, CAA violations (in dollars per day)					37,500	32,500	27,500
Civil Penalties	3,500,000
Loss Contingency, Mitigation Projects	$ 10,500,000
Loss Contingency, Years to Resolve	5
Loss Contingency, Estimated Days to enter Consent Decree	90
Loss Contingency, Number of Plaintiffs								8
Loss Contingency, Pending Claims, Number								1