Pension and Postretirement Benefits (Estimated Amounts that will be Amortized from Accumulated Other Comprehensive Income, Regulatory Assets And Regulatory Liabilities) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 Pension [Member]	Dec. 31, 2013 Pension [Member] DP&L [Member]	Dec. 31, 2012 Postretirement [Member]	Dec. 31, 2013 Postretirement [Member] DP&L [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial (gain) / loss	$ 3.4	$ 6.4	$ (0.5)	$ (0.8)
Prior service cost	$ 1.5	$ 2.8		$ 0.1