Acquisitions (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Jun. 29, 2012 MW
Acquisitions (Textual) [Abstract]
Percent of interest owned indirectly by Southern Power		90.00%
Apex Nevada Solar LLC [Member] \| Southern Power [Member]
Acquisitions (Textual) [Abstract]
Power of solar polycrystalline silicon facility		20
Beginning year of output of constructed plant		2012
Ending year of output of constructed plant		2037
Cash Consideration for acquisition of the interests in Apex		$ 102
Cash Consideration paid at closing	86.5
Cash Consideration will be paid under MIPA	$ 15.5

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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