Pension and Postretirement Benefits (Defined Benefits Plan Assets, Target Allocations) (Details)	12 Months Ended
	Dec. 31, 2014
Equity Securities [Member]
Defined Benefit Plan, Target Plan Asset Allocations	19.00%
Debt Securities [Member]
Defined Benefit Plan, Target Plan Asset Allocations	69.00%
Real Estate [Member]
Defined Benefit Plan, Target Plan Asset Allocations	6.00%
Other Investments [Member]
Defined Benefit Plan, Target Plan Asset Allocations	6.00%
DP&L [Member] | Equity Securities [Member]
Defined Benefit Plan, Target Plan Asset Allocations	19.00%
DP&L [Member] | Debt Securities [Member]
Defined Benefit Plan, Target Plan Asset Allocations	69.00%
DP&L [Member] | Real Estate [Member]
Defined Benefit Plan, Target Plan Asset Allocations	6.00%
DP&L [Member] | Other Investments [Member]
Defined Benefit Plan, Target Plan Asset Allocations	6.00%