Ownership of Coal-fired Facilities (Narrative) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2013
Construction work in process		$ 24.0
Number Of Generating Facilities		7
Supplemental Eviromental Project		0.2
DP&L [Member]
Undivided ownership interests		7.00%
Construction work in process		24.0
Impairment of Long-Lived Assets Held-for-use	80.8
Supplemental Eviromental Project		0.2
Hutchings Plant [Member]
Number of Coal Fired Units		6
Supplemental Eviromental Project		0.2
Hutchings Plant [Member] | DP&L [Member]
Undivided ownership interests		100.00%
Supplemental Eviromental Project		$ 0.2
Beckjord Unit 6 [Member] | DP&L [Member]
Undivided ownership interests		50.00%