Contingencies and Regulatory Matters Retail Regulatory Matters (Details) (Alabama Power [Member], USD $)	Jun. 30, 2014	Dec. 31, 2013
Loss Contingencies [Line Items]
Under recovered rate CNP environmental balance	$ 32,000,000	$ 7,000,000
Under Recovered Rate Cnp Balance	33,000,000	18,000,000
Other Regulatory Liabilities, Current	33,000,000	37,000,000
Deferred Over Recovered Regulatory Clause Revenues	0	15,000,000
Accumulated reserve balance for future storms	87,000,000	96,000,000
Fuel Recovery Clause [Member]
Loss Contingencies [Line Items]
Other Regulatory Liabilities, Current	19,000,000	27,000,000
Deferred Over Recovered Regulatory Clause Revenues	$ 0	$ 15,000,000