Short-Term Debt and Credit Facilities (Details) (USD $) In Millions, unless otherwise specified			9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Og and E [Member]	Sep. 30, 2012 Maximum [Member]
Short-term Debt [Line Items]
Advances to parent	$ 40.7	$ 97.2
Intercomany Borrowings, Maximum Borrowing Capacity			400.0
Line of Credit Facility, Expiration Date			Dec. 13, 2016
Outstanding Intercompany Borrowings			0
Aggregate Commitment - Revolving Credit Facility			400.0
Letters of Credit Outstanding			2.2
Weighted Average Interest Rate			0.53%
Outstanding borrowings under revolving credit agreement			0
Commercial paper borrowings			0
Cash				0.1
Period For Which Regulatory Approval Has Been Given to Acquire Short Term Debt			2 years
Short Term Borrowing Capacity That Has Regulatory Approval			$ 800