Segment and Related Information - Financial Data for Business Segments and Products and Services (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013 entities	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013 entities		Dec. 31, 2012		Dec. 31, 2011
Segment Reporting Information [Line Items]
Number of traditional operating companies	4								4
Revenues	$ 3,927,000,000	$ 5,017,000,000	$ 4,246,000,000	$ 3,897,000,000	$ 3,703,000,000	$ 5,049,000,000	$ 4,181,000,000	$ 3,604,000,000	$ 17,087,000,000		$ 16,537,000,000		$ 17,657,000,000
Financial data for business segments
Operating revenues	3,927,000,000	5,017,000,000	4,246,000,000	3,897,000,000	3,703,000,000	5,049,000,000	4,181,000,000	3,604,000,000	17,087,000,000		16,537,000,000		17,657,000,000
Depreciation and amortization									1,901,000,000		1,787,000,000		1,717,000,000
Interest income									19,000,000		40,000,000		21,000,000
Interest expense									824,000,000		859,000,000		857,000,000
Income taxes									849,000,000		1,334,000,000		1,219,000,000
Segment net income (loss)	414,000,000	852,000,000	297,000,000	81,000,000	383,000,000	976,000,000	623,000,000	368,000,000	1,644,000,000	[1],[2]	2,350,000,000	[1]	2,203,000,000	[1]
Total assets	64,546,000,000				63,149,000,000				64,546,000,000		63,149,000,000		59,267,000,000
Gross property additions									5,868,000,000		5,059,000,000		4,853,000,000
Kemper IGCC [Member]
Segment and Related Information (Textual) [Abstract]
Pre-Tax Charge To Income				1,200,000,000					1,200,000,000
After Tax Charge To Income									729,000,000
Electric Utilities [Member]
Segment Reporting Information [Line Items]
Revenues									17,035,000,000		16,478,000,000		17,587,000,000
Financial data for business segments
Operating revenues									17,035,000,000		16,478,000,000		17,587,000,000
Depreciation and amortization									1,886,000,000		1,772,000,000		1,700,000,000
Interest income									18,000,000		22,000,000		19,000,000
Interest expense									788,000,000		820,000,000		803,000,000
Income taxes									935,000,000		1,400,000,000		1,293,000,000
Segment net income (loss)									1,652,000,000	[1],[2]	2,321,000,000	[1]	2,214,000,000	[1]
Total assets	63,775,000,000				62,251,000,000				63,775,000,000		62,251,000,000		58,076,000,000
Gross property additions									5,859,000,000		5,054,000,000		4,844,000,000
Traditional Operating Companies [Member] | Electric Utilities [Member]
Segment Reporting Information [Line Items]
Revenues									16,136,000,000		15,730,000,000		16,763,000,000
Financial data for business segments
Operating revenues									16,136,000,000		15,730,000,000		16,763,000,000
Depreciation and amortization									1,711,000,000		1,629,000,000		1,576,000,000
Interest income									17,000,000		21,000,000		18,000,000
Interest expense									714,000,000		757,000,000		726,000,000
Income taxes									889,000,000		1,307,000,000		1,217,000,000
Segment net income (loss)									1,486,000,000	[1],[2]	2,145,000,000	[1]	2,052,000,000	[1]
Total assets	59,447,000,000				58,600,000,000				59,447,000,000		58,600,000,000		54,622,000,000
Gross property additions									5,226,000,000		4,813,000,000		4,589,000,000
Southern Power [Member]
Segment Reporting Information [Line Items]
Revenues									346,000,000		425,000,000		359,000,000
Financial data for business segments
Operating revenues									346,000,000		425,000,000		359,000,000
Southern Power [Member] | Electric Utilities [Member]
Segment Reporting Information [Line Items]
Revenues									1,275,000,000		1,186,000,000		1,236,000,000
Financial data for business segments
Operating revenues									1,275,000,000		1,186,000,000		1,236,000,000
Depreciation and amortization									175,000,000		143,000,000		124,000,000
Interest income									1,000,000		1,000,000		1,000,000
Interest expense									74,000,000		63,000,000		77,000,000
Income taxes									46,000,000		93,000,000		76,000,000
Segment net income (loss)									166,000,000	[1],[2]	175,000,000	[1]	162,000,000	[1]
Total assets	4,429,000,000				3,780,000,000				4,429,000,000		3,780,000,000		3,581,000,000
Gross property additions									633,000,000		241,000,000		255,000,000
All Other [Member]
Segment Reporting Information [Line Items]
Revenues									139,000,000		141,000,000		149,000,000
Financial data for business segments
Operating revenues									139,000,000		141,000,000		149,000,000
Depreciation and amortization									15,000,000		15,000,000		16,000,000
Interest income									2,000,000		19,000,000		3,000,000
Interest expense									36,000,000		39,000,000		54,000,000
Income taxes									(85,000,000)		(66,000,000)		(74,000,000)
Segment net income (loss)									(10,000,000)	[1],[2]	33,000,000	[1]	(8,000,000)	[1]
Total assets	1,077,000,000				1,116,000,000				1,077,000,000		1,116,000,000		1,592,000,000
Gross property additions									9,000,000		5,000,000		9,000,000
Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues									(87,000,000)		(82,000,000)		(79,000,000)
Financial data for business segments
Operating revenues									(87,000,000)		(82,000,000)		(79,000,000)
Depreciation and amortization									0		0		1,000,000
Interest income									(1,000,000)		(1,000,000)		(1,000,000)
Interest expense									0		0		0
Income taxes									(1,000,000)		0		0
Segment net income (loss)									2,000,000	[1],[2]	(4,000,000)	[1]	(3,000,000)	[1]
Total assets	(306,000,000)				(218,000,000)				(306,000,000)		(218,000,000)		(401,000,000)
Gross property additions									0		0		0
Eliminations [Member] | Electric Utilities [Member]
Segment Reporting Information [Line Items]
Revenues									(376,000,000)		(438,000,000)		(412,000,000)
Financial data for business segments
Operating revenues									(376,000,000)		(438,000,000)		(412,000,000)
Depreciation and amortization									0		0		0
Interest income									0		0		0
Interest expense									0		0		0
Income taxes									0		0		0
Segment net income (loss)									0	[1],[2]	1,000,000	[1]	0	[1]
Total assets	(101,000,000)				(129,000,000)				(101,000,000)		(129,000,000)		(127,000,000)
Gross property additions									$ 0		$ 0		$ 0

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

[2] (b) Segment net income (loss) in 2013 includes $1.2 billion in pre-tax charges ($729 million after tax) for estimated probable losses on the Kemper IGCC. See Note (3) under "Integrated Coal Gasification Combined Cycle – Kemper IGCC Construction Schedule and Cost Estimate" for additional information.