Short-Term Debt and Credit Facilities (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011
Short-term Debt [Line Items]
Advances From Parent	$ 22.2	$ 0
Advances to parent	0	97.2
Og and E [Member]
Short-term Debt [Line Items]
Advances From Parent	22.2
Advances to parent		97.2
Intercomany Borrowings, Maximum Borrowing Capacity	400.0
Intercompany Borrowings Termination Date	Dec. 13, 2016
Outstanding Intercompany Borrowings	13.5
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
Period For Which Regulatory Approval Has Been Given to Acquire Short Term Debt	2 years
Short Term Borrowing Capacity That Has Regulatory Approval	800
Maximum [Member]
Short-term Debt [Line Items]
Cash	$ 0.1