Overview and Summary of Signficant Accounting Policies (Accounting for Taxes Collected from Customers and Remitted to Governmental Authorities) (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	11 Months Ended	12 Months Ended
	Dec. 31, 2011	Nov. 27, 2011	Dec. 31, 2012	Dec. 31, 2010	Dec. 31, 2012 DP&L [Member]	Dec. 31, 2011 DP&L [Member]	Dec. 31, 2010 DP&L [Member]
Excise Taxes Collected	$ 4.3	$ 49.4	$ 50.5	$ 51.7	$ 50.5	$ 53.7	$ 51.7