Income Taxes (Interest and Penalties related to unrecognized tax benefits in Income Tax Expense) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended		11 Months Ended	12 Months Ended
Dec. 31, 2012 DP&L [Member]	Dec. 31, 2011 DP&L [Member]	Dec. 31, 2010 DP&L [Member]	Dec. 31, 2012 Successor [Member]	Dec. 31, 2011 Successor [Member]	Nov. 27, 2011 Predecessor [Member]	Dec. 31, 2010 Predecessor [Member]
Expense	$ (0.1)	$ 0.6	$ 0.4	$ (0.1)		$ 0.6	$ 0.2
Liability	$ 0.8	$ 0.9	$ 0.3	$ 0.8	$ 0.9

This element represents the amount of statutory penalties accrued as of the date of the statement of financial position for a tax position claimed or expected to be claimed by the entity, in its tax return, that does not meet the minimum statutory threshold to avoid payment of penalties.

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This element represents the recognized expense for the amount of statutory penalties in the period in which the entity claims or expects to claim a tax position, in its tax return, that does not meet the minimum statutory threshold to avoid payment of penalties or, if not recognizing the expense in the period in which the tax return was initially filed, the expense is generally recognized in the period in which the enterprise's judgment about meeting the minimum statutory threshold changes.

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