Segment and Related Information - Financial Data for Business Segments (Details) (USD $)	3 Months Ended				6 Months Ended					3 Months Ended				6 Months Ended					3 Months Ended				6 Months Ended					3 Months Ended		6 Months Ended		3 Months Ended				6 Months Ended					3 Months Ended				6 Months Ended					3 Months Ended				6 Months Ended					3 Months Ended				6 Months Ended					3 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2014 state		Jun. 30, 2013		Jun. 30, 2014 state		Jun. 30, 2013		Dec. 31, 2013	Jun. 30, 2014 Electric Utilities [Member]		Jun. 30, 2013 Electric Utilities [Member]		Jun. 30, 2014 Electric Utilities [Member]		Jun. 30, 2013 Electric Utilities [Member]		Dec. 31, 2013 Electric Utilities [Member]	Jun. 30, 2014 Traditional Operating Companies [Member] Electric Utilities [Member]		Jun. 30, 2013 Traditional Operating Companies [Member] Electric Utilities [Member]		Jun. 30, 2014 Traditional Operating Companies [Member] Electric Utilities [Member]		Jun. 30, 2013 Traditional Operating Companies [Member] Electric Utilities [Member]		Dec. 31, 2013 Traditional Operating Companies [Member] Electric Utilities [Member]	Jun. 30, 2014 Southern Power [Member]	Jun. 30, 2013 Southern Power [Member]	Jun. 30, 2014 Southern Power [Member]	Jun. 30, 2013 Southern Power [Member]	Jun. 30, 2014 Southern Power [Member] Electric Utilities [Member]		Jun. 30, 2013 Southern Power [Member] Electric Utilities [Member]		Jun. 30, 2014 Southern Power [Member] Electric Utilities [Member]		Jun. 30, 2013 Southern Power [Member] Electric Utilities [Member]		Dec. 31, 2013 Southern Power [Member] Electric Utilities [Member]	Jun. 30, 2014 Eliminations [Member]		Jun. 30, 2013 Eliminations [Member]		Jun. 30, 2014 Eliminations [Member]		Jun. 30, 2013 Eliminations [Member]		Dec. 31, 2013 Eliminations [Member]	Jun. 30, 2014 Eliminations [Member] Electric Utilities [Member]		Jun. 30, 2013 Eliminations [Member] Electric Utilities [Member]		Jun. 30, 2014 Eliminations [Member] Electric Utilities [Member]		Jun. 30, 2013 Eliminations [Member] Electric Utilities [Member]		Dec. 31, 2013 Eliminations [Member] Electric Utilities [Member]	Jun. 30, 2014 All Other [Member]		Jun. 30, 2013 All Other [Member]		Jun. 30, 2014 All Other [Member]		Jun. 30, 2013 All Other [Member]		Dec. 31, 2013 All Other [Member]	Jun. 30, 2013 Kemper Igcc [Member]	Jun. 30, 2014 Kemper Igcc [Member]	Jun. 30, 2013 Kemper Igcc [Member]	Dec. 31, 2013 Kemper Igcc [Member]
Segment Reporting Information [Line Items]
Number of States in which Entity Operates	4				4
Segment and Related Information (Textual) [Abstract]
Electric Utilities' Revenues	$ 4,467,000,000		$ 4,246,000,000		$ 9,111,000,000		$ 8,143,000,000			$ 4,454,000,000		$ 4,230,000,000		$ 9,081,000,000		$ 8,116,000,000			$ 4,209,000,000		$ 4,018,000,000		$ 8,587,000,000		$ 7,687,000,000			$ 68,000,000	$ 89,000,000	$ 140,000,000	$ 167,000,000	$ 329,000,000		$ 307,000,000		$ 680,000,000		$ 610,000,000			$ (26,000,000)		$ (22,000,000)		$ (50,000,000)		$ (46,000,000)			$ (84,000,000)		$ (95,000,000)		$ (186,000,000)		$ (181,000,000)			$ 39,000,000		$ 38,000,000		$ 80,000,000		$ 73,000,000
Financial data for business segments
Electric Utilities' Revenues	4,467,000,000		4,246,000,000		9,111,000,000		8,143,000,000			4,454,000,000		4,230,000,000		9,081,000,000		8,116,000,000			4,209,000,000		4,018,000,000		8,587,000,000		7,687,000,000			68,000,000	89,000,000	140,000,000	167,000,000	329,000,000		307,000,000		680,000,000		610,000,000			(26,000,000)		(22,000,000)		(50,000,000)		(46,000,000)			(84,000,000)		(95,000,000)		(186,000,000)		(181,000,000)			39,000,000		38,000,000		80,000,000		73,000,000
Segment net income (loss)	611,000,000	[1],[2]	297,000,000	[1],[2]	962,000,000	[1],[3]	378,000,000	[1],[3]		611,000,000	[1],[2]	296,000,000	[1],[2]	963,000,000	[1],[3]	391,000,000	[1],[3]		580,000,000	[1],[2]	268,000,000	[1],[2]	899,000,000	[1],[3]	334,000,000	[1],[3]						31,000,000	[1],[2]	28,000,000	[1],[2]	64,000,000	[1],[3]	57,000,000	[1],[3]		(2,000,000)	[1],[2]	(3,000,000)	[1],[2]	(3,000,000)	[1],[3]	(1,000,000)	[1],[3]		0	[1],[2]	0	[1],[2]	0	[1],[3]	0	[1],[3]		2,000,000	[1],[2]	4,000,000	[1],[2]	2,000,000	[1],[3]	(12,000,000)	[1],[3]
Total assets	66,400,000,000				66,400,000,000				64,546,000,000	65,683,000,000				65,683,000,000				63,775,000,000	61,210,000,000				61,210,000,000				59,447,000,000					4,605,000,000				4,605,000,000				4,429,000,000	(639,000,000)				(639,000,000)				(306,000,000)	(132,000,000)				(132,000,000)				(101,000,000)	1,356,000,000				1,356,000,000				1,077,000,000
Pre-tax charge to income																																																																				450,000,000	380,000,000	990,000,000	1,180,000,000
After tax charge to income																																																																				$ 277,900,000	$ 234,700,000	$ 611,300,000	$ 728,700,000

[1] After dividends on preferred and preference stock of subsidiaries.

[2] Segment net income (loss) for the traditional operating companies for the three months ended June 30, 2013 includes a $450.0 million pre-tax charge ($277.9 million after tax) for an estimated probable loss on the Kemper IGCC. See Note (B) under "Integrated Coal Gasification Combined Cycle – Kemper IGCC Schedule and Cost Estimate" herein for additional information.

[3] Segment net income (loss) for the traditional operating companies for the six months ended June 30, 2014 and June 30, 2013 includes $380.0 million in pre-tax charges ($234.7 million after tax) and $990.0 million in pre-tax charges ($611.3 million after tax), respectively, for estimated probable losses on the Kemper IGCC. See Note (B) under "Integrated Coal Gasification Combined Cycle – Kemper IGCC Schedule and Cost Estimate" herein for additional information.