Income Taxes (Narrative) (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 DP&L [Member]	Dec. 31, 2012 DP&L [Member]	Dec. 31, 2011 DP&L [Member]
Estimated annual effective income tax rate			35.00%	35.00%
Tax Refund		$ 19.9		$ 19.9
Decrease in income tax expense		1.2		1.2
Additional tax increase / decrease				1.1	7.6	2.4
Effective income tax rates		(11.20%)	(2.80%)
Deferred tax assets related to state and local tax net operating loss carryforwards, net of related valuation allowances			20.4
Deferred Tax Assets Operating Loss Carryforwards State And Local Valuation Allowances		16.6	16.2
Tax expense (benefit) interest and penalties recorded in the statements of results of operations	$ 2.3	$ 0	$ 0