Goodwill Impairment (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Goodwill Impairment	$ 135.8
Goodwill	317.0		452.8
Effective Income Tax Rate, Continuing Operations	(65.80%)	23.20%
Parent Company [Member]
Goodwill Impairment	135.8
DP&L [Member]
Effective Income Tax Rate, Continuing Operations	29.90%	24.10%
DPLER [Member]
Goodwill Impairment	$ 135.8