Goodwill And Other Intangible Asset (Narrative) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill		$ 452.8	$ 759.1	$ 2,576.3
Goodwill, Impairment Loss	1,850.0	306.3	1,817.2
Reclassified From Finite-Lived To Indefinite-Lived Intangible Asset			1.1
DP&L [Member]
Goodwill		317.0	623.3	2,440.5
Goodwill, Impairment Loss		$ (306.3)	$ (1,817.2)