Introduction - Asset Retirement Obligations (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015
Minimum [Member]
Property, Plant and Equipment [Line Items]
Asset Retirement Obligation	$ 525
Minimum [Member] | Alabama Power [Member]
Property, Plant and Equipment [Line Items]
Asset Retirement Obligation	330
Minimum [Member] | Georgia Power [Member]
Property, Plant and Equipment [Line Items]
Asset Retirement Obligation	10
Minimum [Member] | Gulf Power [Member]
Property, Plant and Equipment [Line Items]
Asset Retirement Obligation	70
Minimum [Member] | Mississippi Power [Member]
Property, Plant and Equipment [Line Items]
Asset Retirement Obligation	75
Maximum [Member]
Property, Plant and Equipment [Line Items]
Asset Retirement Obligation	575
Maximum [Member] | Alabama Power [Member]
Property, Plant and Equipment [Line Items]
Asset Retirement Obligation	350
Maximum [Member] | Georgia Power [Member]
Property, Plant and Equipment [Line Items]
Asset Retirement Obligation	20
Maximum [Member] | Gulf Power [Member]
Property, Plant and Equipment [Line Items]
Asset Retirement Obligation	80
Maximum [Member] | Mississippi Power [Member]
Property, Plant and Equipment [Line Items]
Asset Retirement Obligation	$ 85