Goodwill Impairment (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Goodwill Impairment		$ 135,800,000
Goodwill	317,000,000		317,000,000
Effective Income Tax Rate, Continuing Operations	30.70%	(65.80%)
Parent Company [Member]
Goodwill Impairment		135,800,000
DP&L [Member]
Effective Income Tax Rate, Continuing Operations	29.00%	29.90%
DPLER [Member]
Goodwill Impairment		135,800,000
Goodwill		$ 135,800,000