Merger, Acquisitions, and Dispositions - Construction Projects (Details) - MW			1 Months Ended
	Jul. 01, 2016	Dec. 17, 2015	Dec. 31, 2016	Feb. 29, 2016	Oct. 26, 2016	Jul. 31, 2016	Mar. 31, 2016	Feb. 11, 2016	Aug. 31, 2015
Rutherford
Business Acquisition [Line Items]
Noncontrolling ownership percentage held by parent					90.10%
SOUTHERN POWER CO | Butler Solar LLC
Business Acquisition [Line Items]
Life output of plant			30 years
SOUTHERN POWER CO | Butler Solar Farm, LLC
Business Acquisition [Line Items]
Life output of plant				20 years
SOUTHERN POWER CO | Desert Stateline Holdings, LLC
Business Acquisition [Line Items]
Power of solar polycrystalline silicon facility						299			299
Noncontrolling ownership percentage held by parent							15.00%		51.00%
SOUTHERN POWER CO | RE Garland Holdings, LLC
Business Acquisition [Line Items]
Life output of plant		20 years
SOUTHERN POWER CO | RE Garland A Holdings, LLC
Business Acquisition [Line Items]
Life output of plant		15 years
SOUTHERN POWER CO | Rutherford
Business Acquisition [Line Items]
Power of solar polycrystalline silicon facility	74
Life output of plant	15 years
Noncontrolling ownership percentage held by parent	90.00%							100.00%
Turner Renewable Energy | Rutherford
Business Acquisition [Line Items]
Noncontrolling ownership percentage held by parent	10.00%