Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2014

Related Party Transactions [Member]

Schedule of Related Party Transactions [Table Text Block]

	Three months ended				Nine months ended
	September 30,				September 30,
$ in millions	2014		2013		2014		2013
Transactions with the Service Company
Charges for services provided	$	5.5	$	-	$	27.8	$	-
Charges to the Service Company		0.2		-		0.2		-

Related Party Balances [Member]

Schedule of Related Party Transactions [Table Text Block]

Transactions with the Service Company	At September 30, 2014		At December 31, 2013
Net prepaid / (payable) to the Service Company	$	9.4	$	-

DP&L [Member] | Related Party Transactions [Member]

Schedule of Related Party Transactions [Table Text Block]

	Three months ended				Nine months ended
	September 30,				September 30,
$ in millions	2014		2013		2014		2013
DP&L Revenues:
Sales to DPLER (including MC Squared) (a)	$	125.6	$	123.8	$	376.6	$	336.0
DP&L Operations and Maintenance Expenses:
Premiums paid for insurance services provided by MVIC (b)	$	(0.7)	$	(0.7)	$	(2.1)	$	(2.2)
Expense recoveries for services provided to DPLER (c)	$	0.5	$	1.3	$	1.6	$	3.8
Transactions with the Service Company
Charges for services provided	$	9.0	$	-	$	28.1	$	-

DP&L [Member] | Related Party Balances [Member]

Schedule of Related Party Transactions [Table Text Block]

DP&L Customer security deposits:	At September 30, 2014		At December 31, 2013
Deposits received from DPLER (d)	$	20.1	$	19.2
Balances with the Service Company
Net prepaid / (payable) to the Service Company	$	9.4	$	-