Fair Value Measurements (Tables)

3 Months Ended

12 Months Ended

Mar. 31, 2015

Mar. 31, 2014

Dec. 31, 2014

Fair Value and Cost of Non-Derivative Instruments

	March 31, 2015				December 31, 2014
$ in millions	Carrying Value		Fair Value		Carrying Value		Fair Value
Assets
Money market funds	$	0.1	$	0.1	$	0.1	$	0.1
Equity securities		2.7		3.8		2.7		3.7
Debt securities		4.6		4.6		4.7		4.7
Hedge funds		0.7		0.7		0.8		0.8
Real estate		0.3		0.4		0.4		0.4
Total Assets	$	8.4	$	9.6	$	8.7	$	9.7
Liabilities
Debt	$	2,159.7	$	2,238.5	$	2,159.7	$	2,204.8

Fair Value of Assets and Liabilities Measured on Recurring Basis

Assets and Liabilities at Fair Value
			Level 1		Level 2		Level 3
$ in millions	Fair Value at March 31, 2015		Based on Quoted Prices in Active Markets		Other Observable Inputs		Unobservable Inputs
Assets
Master Trust assets
Money market funds	$	0.1	$	0.1	$	-	$	-
Equity securities		3.8		-		3.8		-
Debt securities		4.6		-		4.6		-
Hedge funds		0.7		-		0.7		-
Real estate		0.4		-		0.4		-
Total Master Trust assets		9.6		0.1		9.5		-
Derivative Assets
FTRs		0.3		-		-		0.3
Forward power contracts		20.3		-		18.8		1.5
Total Derivative assets		20.6		-		18.8		1.8
Total Assets	$	30.2	$	0.1	$	28.3	$	1.8
Liabilities
Derivative Liabilities
Heating oil		0.3		0.3		-		-
Forward power contracts		20.4		-		19.0		1.4
Total Derivative liabilities		20.7		0.3		19.0		1.4
Long-term debt		2,238.5		-		2,220.3		18.2
Total Liabilities	$	2,259.2	$	0.3	$	2,239.3	$	19.6

Assets and Liabilities at Fair Value
			Level 1		Level 2		Level 3
$ in millions	Fair Value at December 31, 2014		Based on Quoted Prices in Active Markets		Other Observable Inputs		Unobservable Inputs
Assets
Master Trust assets
Money market funds	$	0.1	$	0.1	$	-	$	-
Equity securities		3.7		-		3.7		-
Debt securities		4.7		-		4.7		-
Hedge funds		0.8		-		0.8		-
Real estate		0.4		-		0.4		-
Total Master Trust assets		9.7		0.1		9.6		-
Derivative assets
Forward power contracts		14.9		-		13.7		1.2
Total Derivative assets		14.9		-		13.7		1.2
Total Assets	$	24.6	$	0.1	$	23.3	$	1.2
Liabilities
Derivative liabilities
FTRs	$	0.6	$	-	$	-	$	0.6
Heating oil futures		0.4		0.4		-		-
Natural gas futures		0.1		0.1		-		-
Forward power contracts		11.1		-		11.1		-
Total Derivative liabilities		12.2		0.5		11.1		0.6
Long-term debt		2,204.8		-		2,186.6		18.2
Total Liabilities	$	2,217.0	$	0.5	$	2,197.7	$	18.8

Fair Value Measurements, Nonrecurring [Table Text Block]

$ in millions	Three months ended March 31, 2014
		Carrying	Fair Value							Gross
		Amount (c)		Level 1		Level 2		Level 3		Loss
Assets
Long-lived assets (a)
DP&L (East Bend)	$	14.2	$	-	$	-	$	2.7	$	11.5
Goodwill (b)
DPLER Reporting unit	$	135.8	$	-	$	-	$	-	$	135.8

DP&L [Member]

Fair Value and Cost of Non-Derivative Instruments

	March 31, 2015				December 31, 2014
$ in millions	Carrying Value		Fair Value		Carrying Value		Fair Value
Assets
Money market funds	$	0.1	$	0.1	$	0.1	$	0.1
Equity securities		2.7		3.8		2.7		3.7
Debt securities		4.6		4.6		4.7		4.7
Hedge funds		0.7		0.7		0.8		0.8
Real estate		0.3		0.4		0.4		0.4
Total assets	$	8.4	$	9.6	$	8.7	$	9.7
Liabilities
Debt	$	877.2	$	885.2	$	877.1	$	882.5

Fair Value of Assets and Liabilities Measured on Recurring Basis

Assets and Liabilities at Fair Value
			Level 1		Level 2		Level 3
$ in millions	Fair Value at March 31, 2015		Based on Quoted Prices in Active Markets		Other Observable Inputs		Unobservable Inputs
Assets
Master Trust assets
Money market funds	$	0.1	$	0.1	$	-	$	-
Equity securities		3.8		-		3.8		-
Debt securities		4.6		-		4.6		-
Hedge funds		0.7		-		0.7		-
Real estate		0.4		-		0.4		-
Total Master Trust assets		9.6		0.1		9.5		-
Derivative assets
FTRs		0.3		-		-		0.3
Forward power contracts		20.5		-		19.0		1.5
Total derivative assets		20.8		-		19.0		1.8
Total assets	$	30.4	$	0.1	$	28.5	$	1.8
Liabilities
Derivative liabilities
Heating oil	$	0.3	$	0.3	$	-	$	-
Forward power contracts		20.6		-		19.2		1.4
Total derivative liabilities		20.9		0.3		19.2		1.4
Long-term debt		885.2		-		867.0		18.2
Total liabilities	$	906.1	$	0.3	$	886.2	$	19.6

Assets and Liabilities at Fair Value
			Level 1		Level 2		Level 3
$ in millions	Fair Value at December 31, 2014		Based on Quoted Prices in Active Markets		Other Observable Inputs		Unobservable Inputs
Assets
Master Trust assets
Money market funds	$	0.1	$	0.1	$	-	$	-
Equity securities		3.7		-		3.7		-
Debt securities		4.7		-		4.7		-
Hedge funds		0.8		-		0.8		-
Real estate		0.4		-		0.4		-
Total Master Trust assets		9.7		0.1		9.6		-
Derivative assets
Forward power contracts		15.1		-		13.9		1.2
Total Derivative assets		15.1		-		13.9		1.2
Total assets	$	24.8	$	0.1	$	23.5	$	1.2
Liabilities
Derivative liabilities
FTRs	$	0.6	$	-	$	-	$	0.6
Heating oil futures		0.4		0.4		-		-
Natural gas futures		0.1		0.1		-		-
Forward power contracts		11.2		-		11.2		-
Total Derivative liabilities		12.3		0.5		11.2		0.6
Long-term debt		882.5		-		864.3		18.2
Total liabilities	$	894.8	$	0.5	$	875.5	$	18.8