Contingencies and Regulatory Matters Current And Actual Cost Estimate (Details) (Kemper Igcc [Member], Mississippi Power [Member], USD $) In Billions, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2014		Dec. 31, 2012
Loss Contingencies [Line Items]
Estimated Cost	$ 3.81	[1]	$ 2.88
Cost Of Lignite Mine And Equipment	0.23
Cost Of CO2 Pipeline Facilities	0.10
Cost Of AFUDC	0.37	[2],[3]
Plant General Exceptions	0.07
Plant Regulatory Asset	0.09	[3],[4]
Maximum Cap Construction Cost	4.67	[1],[3]
Project Estimate [Member]
Loss Contingencies [Line Items]
Estimated Cost	2.40	[1]
Cost Of Lignite Mine And Equipment	0.21
Cost Of CO2 Pipeline Facilities	0.14
Cost Of AFUDC	0.17	[2],[3]
Plant General Exceptions	0.05
Plant Regulatory Asset	0	[3],[4]
Maximum Cap Construction Cost	2.97	[1],[3]
Current Estimate [Member]
Loss Contingencies [Line Items]
Estimated Cost	4.44	[1]
Cost Of Lignite Mine And Equipment	0.24
Cost Of CO2 Pipeline Facilities	0.11
Cost Of AFUDC	0.55	[2],[3]
Plant General Exceptions	0.10
Plant Regulatory Asset	0.12	[3],[4]
Maximum Cap Construction Cost	$ 5.56	[1],[3]

[1] The 2012 MPSC CPCN Order approved a construction cost cap of up to $2.88 billion, net of the DOE Grants and excluding the Cost Cap Exceptions.

[2] Mississippi Power's original estimate included recovery of financing costs during construction rather than the accrual of AFUDC. This approach was not approved by the Mississippi PSC in 2012 as described in "Rate Recovery of Kemper IGCC Costs."

[3] Amounts in the Current Estimate reflect costs through May 31, 2015, but do not reflect any adjustments as a result of the expected placement of the combined cycle and the associated common facilities portion of the Kemper IGCC in service in the summer of 2014.

[4] The 2012 MPSC CPCN Order approved deferral of non-capital Kemper IGCC-related costs during construction as described in "Rate Recovery of Kemper IGCC Costs – Regulatory Assets."