Income Taxes (Components of Deferred Tax Assets and Liabilities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Depreciation / property basis	$ (548.2)		$ (531.5)
Income taxes recoverable	(14.8)		(11.4)
Regulatory assets	(18.0)		(15.6)
Investment tax credit	1.5		1.0
Intangibles	(7.0)		(2.0)
Compensation and employee benefits	3.2		(3.9)
Long-term debt	(1.5)		(1.7)
Other	(2.5)		0.8
Net noncurrent (liabilities)	(587.3)	[1]	(564.3)	[1]
Other	1.1	[2]	(2.6)	[2]
Net current assets	1.1		(2.6)
Deferred tax assets related to state and local tax net operating loss carryforwards, net of related valuation allowances	27.1		20.7
DP&L [Member]
Depreciation / property basis	(618.8)		(607.1)
Income taxes recoverable	(14.8)		(11.4)
Regulatory assets	(18.0)		(15.6)
Investment tax credit	8.6		8.8
Compensation and employee benefits	5.2		(0.2)
Other	(12.2)		(6.8)
Net noncurrent (liabilities)	(650.0)		(632.3)
Other	0.5		(5.0)
Net current assets	$ 0.5		$ (5.0)

[1] (c)The Other non-current liabilities caption includes deferred tax assets of $27.1 million in 2014 and $20.7 million in 2013 related to state and local tax net operating loss carryforwards, net of related valuation allowances of $21.9 million in 2014 and $16.6 million in 2013. These net operating loss carryforwards expire from 2014 to 2027.

[2] (d)Amounts are included within Other prepayments and current assets and Other current liabilities on the Consolidated Balance Sheets of DPL.