Benefit Plans (Defined Benefits Plan Assets, Target Allocations) (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Equity Securities [Member]
Target Allocation	28.00%
Percentage of plan assets	17.00%	18.00%
Debt Securities [Member]
Target Allocation	72.00%
Percentage of plan assets	67.00%	69.00%
Real Estate [Member]
Target Allocation	0.00%
Percentage of plan assets	9.00%	7.00%
Other Investments [Member]
Target Allocation	0.00%
Percentage of plan assets	7.00%	6.00%
THE DAYTON POWER AND LIGHT COMPANY [Member] | Equity Securities [Member]
Target Allocation	28.00%
Percentage of plan assets	17.00%	18.00%
THE DAYTON POWER AND LIGHT COMPANY [Member] | Debt Securities [Member]
Target Allocation	72.00%
Percentage of plan assets	67.00%	69.00%
THE DAYTON POWER AND LIGHT COMPANY [Member] | Real Estate [Member]
Target Allocation	0.00%
Percentage of plan assets	9.00%	7.00%
THE DAYTON POWER AND LIGHT COMPANY [Member] | Other Investments [Member]
Target Allocation	0.00%
Percentage of plan assets	7.00%	6.00%