ACQUISITION OF FOX ENERGY CENTER (Details) (Fox Energy Company, LLC, USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2013 MW
Fox Energy Company, LLC
Acquisitions
Capacity of Fox Energy Center (in megawatts)	593
Contracted capacity from variable interest entities under power purchase agreements (in megawatts)	500
Payment to be made for the acquisition of Fox Energy Company LLC	$ 391.6
Contract termination fee related to tolling arrangement	50.0
Assets acquired
Business Acquisition, Purchase Price Allocation, Current Assets, Prepaid Expense and Other Assets	0.4
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment	374.4
Business Acquisition, Purchase Price Allocation, Other Noncurrent Assets	15.6
Business Acquisition, Purchase Price Allocation, Assets Acquired	393.4
Inventories
Materials and supplies	3.0
Liabilities assumed
Business Acquisition, Purchase Price Allocation, Current Liabilities, Accounts Payable	1.8
Business Acquisition, Purchase Price Allocation, Liabilities Assumed	$ 1.8

The total cost of the acquired entity including the cash paid to shareholders of acquired entities, fair value of debt and equity securities issued to shareholders of acquired entities, the fair value of the liabilities assumed, and direct costs of the acquisition.

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The amount of acquisition cost of a business combination allocated to assets acquired.

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The amount of acquisition cost of a business combination allocated to prepaid expenses and other current assets. Does not include amounts allocated to cash and cash equivalents, marketable securities, receivables, inventory, and assets not to be used.

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The amount of acquisition cost of a business combination allocated to accounts payable of the acquired entity.

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Amount of acquisition cost of a business combination allocated to other noncurrent assets not separately disclosed.

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

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The amount of acquisition cost of a business combination allocated to property, plant and equipment to be used in ongoing operations.

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Represents the amount of acquisition cost of a business combination allocated to materials and supplies.

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Represents the capacity of an electric generating facility.

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