Goodwill Impairment (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Goodwill Impairment		$ 135.8		$ 135.8
Goodwill	317.0			317.0		452.8
Effective Income Tax Rate, Continuing Operations	(4.80%)		13.30%	(49.00%)	18.20%
Parent Company [Member]
Goodwill Impairment				135.8
DP&L [Member]
Effective Income Tax Rate, Continuing Operations	30.20%		17.40%	29.90%	20.90%
DPLER [Member]
Goodwill Impairment				$ 135.8