Acquisitions (Details) (Campo Verde Solar LLC [Member], Southern Power [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Apr. 23, 2013 Subsequent Event [Member] MW
Acquisitions (Textual) [Abstract]
Percent of interest owned indirectly by Southern Power	90.00%
Power of solar polycrystalline silicon facility		139
Beginning year of output of constructed plant		2013
Life Output Of Plant	20 years
Cash Consideration for acquisition of the interests in Apex		$ 136.6
Cash Consideration will be paid under MIPA		$ 357.3

Amount of cash paid to acquire the entity.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 68

-Subparagraph f(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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant