Goodwill Impairment (Narrative) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
Sep. 30, 2012	Dec. 31, 2012
Goodwill Allocated to DP&L Reporting Unit		$ 2,400
Goodwill Impairment	1,850.0	1,817.2
Effective Income Tax Rate, Continuing Operations		(2.80%)
DP&L [Member]
Goodwill Impairment		$ (1,817.2)

A ratio calculated by dividing the reported amount of income tax expense attributable to continuing operations for the period by GAAP-basis pretax income from continuing operations.

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Loss recognized during the period that results from the write-down of goodwill after comparing the implied fair value of reporting unit goodwill with the carrying amount of that goodwill. Goodwill is assessed at least annually for impairment.

+ References

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