Contractual Obligations, Commercial Commitments and Contingenciesl (Schedule Of Contractual Obligations And Commercial Commitments) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Contractual Obligations, Commercial Commitments And Contingencies [Line Items]
Long-term debt, Less than 1 year	$ 20.1
Long-term debt, More than 5 years	1,227.7
Total Purchase orders and other contractual obligations	72.4
Purchase orders and other contractual obligations, Less than 1 year	39.2
Purchase orders and other contractual obligations, 2 - 3 years	17.3
Purchase orders and other contractual obligations, 4 - 5 years	15.9
DP&L [Member]
Contractual Obligations, Commercial Commitments And Contingencies [Line Items]
Long-term debt, Less than 1 year	0.1
Long-term debt, More than 5 years	432.1
Coal Contracts [Member]
Contractual Obligations, Commercial Commitments And Contingencies [Line Items]
Total Coal Contracts	486.2
Coal Contracts, Less than 1 year	255.6
Coal Contracts, 2 - 3 years	161.2
Coal Contracts, 4 - 5 years	69.4
Coal Contracts [Member] | DP&L [Member]
Contractual Obligations, Commercial Commitments And Contingencies [Line Items]
Total long-term debt	486.2
Long-term debt, Less than 1 year	255.6
Long-term debt, 2 - 3 years	161.2
Long-term debt, 4 - 5 years	69.4
Limestone Contracts [Member]
Contractual Obligations, Commercial Commitments And Contingencies [Line Items]
Long-term debt, Less than 1 year	6.1
Total Limestone Contracts	18.3
Limestone Contracts, 2 - 3 years	12.2
Limestone Contracts [Member] | DP&L [Member]
Contractual Obligations, Commercial Commitments And Contingencies [Line Items]
Total long-term debt	18.3
Long-term debt, Less than 1 year	6.1
Long-term debt, 2 - 3 years	12.2
Other Intangible Assets [Member] | DP&L [Member]
Contractual Obligations, Commercial Commitments And Contingencies [Line Items]
Total long-term debt	72.4
Long-term debt, Less than 1 year	39.2
Long-term debt, 2 - 3 years	17.3
Long-term debt, 4 - 5 years	$ 15.9