Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2015

Related Party Transactions [Member]

Schedule of Related Party Transactions [Table Text Block]

	Three months ended
	March 31,
$ in millions	2015		2014
Transactions with the Service Company
Charges for services provided	$	9.8	$	10.4

Related Party Balances [Member]

Schedule of Related Party Transactions [Table Text Block]

Transactions with the Service Company	At March 31, 2015		At December 31, 2014
Net advances / (payable) to the Service Company	$	3.0	$	(4.7)

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

Schedule of Related Party Transactions [Table Text Block]

	Three months ended
	March 31,
$ in millions	2015		2014
DP&L Revenues:
Sales to DPLER (including MC Squared) (a)	$	110.7	$	139.5
DP&L Operations and Maintenance Expenses:
Premiums paid for insurance services provided by MVIC (b)	$	(0.7)	$	(0.8)
Expense recoveries for services provided to DPLER (c)	$	0.8	$	-
Transactions with the Service Company
Charges for services provided	$	8.4	$	10.4

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

Schedule of Related Party Transactions [Table Text Block]

DP&L Customer security deposits:	At March 31, 2015		At December 31, 2014
Deposits received from DPLER (d)	$	2.4	$	20.1
Balances with the Service Company
Net advances / (payable) to the Service Company	$	3.0	$	(4.7)