Pension and Postretirement Benefits (Tables)

3 Months Ended

12 Months Ended

Mar. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Schedule of Amounts Recognized in Balance Sheet [Table Text Block]

$ in millions	Pension				Postretirement
	December 31,				December 31,
	2014		2013		2014		2013
Amounts recognized in the Balance sheets
Current liabilities	$	(0.4)	$	(0.4)	$	(0.5)	$	(0.5)
Non-current liabilities		(71.7)		(21.0)		(15.8)		(15.5)
Net liability at Year ended December 31,	$	(72.1)	$	(21.4)	$	(16.3)	$	(16.0)
Amounts recognized in Accumulated Other Comprehensive Income, Regulatory Assets and Regulatory Liabilities, pre-tax
Components:
Prior service cost	$	14.1	$	8.8	$	0.4	$	0.5
Net actuarial loss / (gain)		103.4		63.0		(5.0)		(6.0)
Accumulated Other Comprehensive Income, Regulatory Assets and Regulatory Liabilities, pre-tax	$	117.5	$	71.8	$	(4.6)	$	(5.5)
Recorded as:
Regulatory asset	$	99.0	$	76.3	$	0.4	$	0.4
Regulatory liability		-		-		(4.8)		(5.6)
Accumulated other comprehensive income		18.5		(4.5)		(0.2)		(0.3)
Accumulated Other Comprehensive Income, Regulatory Assets and Regulatory Liabilities, pre-tax	$	117.5	$	71.8	$	(4.6)	$	(5.5)

Net Periodic Benefit Cost / (Income)

Net Periodic Benefit Cost / (Income)	Pension				Postretirement
	Three months ended				Three months ended
	March 31,				March 31,
$ in millions	2015		2014		2015		2014
Service cost	$	1.8	$	1.5	$	-	$	0.1
Interest cost		4.3		4.4		0.2		0.2
Expected return on plan assets		(5.7)		(5.8)		-		(0.1)
Amortization of unrecognized:
Prior service cost		0.5		0.4		-		-
Actuarial loss / (gain)		1.5		0.9		(0.1)		(0.1)
Net periodic benefit cost	$	2.4	$	1.4	$	0.1	$	0.1

Estimated Amounts that will be Amortized from Accumulated Other Comprehensive Income, Regulatory Assets And Regulatory Liabilities

$ in millions	Pension		Postretirement
Net actuarial gain / (loss)	$	5.8	$	(0.5)
Prior service cost	$	2.0	$	-

Weighted Average Assumptions Used to Determine Benefit Obligations

Benefit Obligation Assumptions	Pension			Postretirement
	2014	2013	2012	2014	2013	2012
Discount rate for obligations	4.02%	4.86%	4.04%	3.71%	4.58%	3.75%
Rate of compensation increases	3.94%	3.94%	3.94%	N/A	N/A	N/A

Weighted Average Assumptions Used to Determine Net Periodic Benefit Cost (Income)

Net Periodic Benefit Cost / (Income) Assumptions	Pension			Postretirement
	2014	2013	2012	2014	2013	2012
Discount rate	4.86%	4.04%	4.88%	4.51%	4.58%	4.62%
Expected rate of return on plan assets	6.75%	6.75%	7.00%	6.00%	6.00%	6.00%
Rate of compensation increases	3.94%	3.94%	3.94%	N/A	N/A	N/A

Assumed Health Care Cost Trend Rates

Health Care Cost Assumptions	Expense			Benefit Obligation
	2014	2013	2012	2014	2013	2012
Pre - age 65
Current health care cost trend rate	7.75%	8.00%	8.50%	6.97%	7.75%	8.00%
Year trend reaches ultimate	2023	2019	2019	2029	2023	2019
Post - age 65
Current health care cost trend rate	6.75%	7.50%	8.00%	6.97%	6.75%	7.50%
Year trend reaches ultimate	2021	2018	2018	2029	2021	2018
Ultimate health care cost trend rate	5.00%	5.00%	5.00%	4.50%	5.00%	5.00%

Effect of Change in Health Care Cost Trend Rate

Effect of change in health care cost trend rate
$ in millions	One-percent increase		One-percent decrease
Service cost plus interest cost	$	0.1	$	-
Benefit obligation	$	1.0	$	(0.9)

Estimated Future Benefit Payments and Medicare Part D Reimbursements

Benefit payments and Medicare Part D reimbursements, which reflect future service, are estimated to be paid as follows:
$ in millions	Pension		Postretirement
2015	$	18.6	$	1.4
2016		25.2		1.8
2017		25.7		1.7
2018		26.3		1.6
2019		26.7		1.5
2020 - 2024		137.0		6.1

Estimated future benefit payments and Medicare Part D reimbursements
$ in millions due within the following years:	Pension		Postretirement
2015	$	24.8	$	1.9
2016	$	25.2	$	1.8
2017	$	25.7	$	1.7
2018	$	26.3	$	1.6
2019	$	26.7	$	1.5
2020 - 2024	$	137.0	$	6.1

Fair Value Measurements of Pension Assets Using Significant Unobservable Inputs

$ in millions		Fair Value	Valuation Technique	Unobservable input	Range (Weighted Average)
Long-lived assets held and used:
DP&L  (East Bend)	$	-	Discounted cash flows	Annual revenue growth	-31% to 18% (0%)
				Annual pretax operating margin	3% to 34% (15%)

Schedule of Allocation of Plan Assets [Table Text Block]

	Target
	Allocation
Equity Securities		19%
Debt Securities		69%
Real Estate		6%
Other		6%

Pension [Member]

Pension And Postretirement Benefit Plans' Obligations And Assets

$ in millions	Pension
	Year ended December 31, 2014		Year ended December 31, 2013
Change in benefit obligation
Benefit obligation at beginning of period	$	370.5	$	395.6
Service cost		5.9		7.2
Interest cost		17.5		15.6
Plan amendments		6.8		-
Actuarial (gain) / loss		67.3		(26.5)
Benefits paid		(24.2)		(21.4)
Benefit obligation at end of period		443.8		370.5
Change in plan assets
Fair value of plan assets at beginning of period		349.1		361.4
Actual return on plan assets		46.4		8.7
Contributions to plan assets		0.4		0.4
Benefits paid		(24.2)		(21.4)
Fair value of plan assets at end of period		371.7		349.1
Funded status of plan	$	(72.1)	$	(21.4)

Net Periodic Benefit Cost / (Income)

Net Periodic Benefit Cost - Pension
$ in millions	Year ended December 31, 2014		Year ended December 31, 2013		Year ended December 31, 2012
Service cost	$	5.9	$	7.2	$	6.2
Interest cost		17.5		15.6		17.3
Expected return on assets (a)		(22.9)		(23.3)		(22.7)
Amortization of unrecognized:
Actuarial gain		3.4		4.9		5.0
Prior service cost		1.5		1.5		1.5
Net periodic benefit cost	$	5.4	$	5.9	$	7.3

Other Changes in Plan Assets and Benefit Obligation Recognized in Accumulated Other Comprehensive Income, Regulatory Assets And Regulatory Liabilities

Pension
$ in millions	Year ended December 31, 2014		Year ended December 31, 2013		Year ended December 31, 2012
Net actuarial loss / (gain)	$	43.8	$	(12.0)	$	5.5
Prior service cost		6.8		-		-
Reversal of amortization item:
Net actuarial loss		(3.4)		(4.9)		(5.0)
Prior service cost		(1.5)		(1.5)		(1.5)
Total recognized in Accumulated Other Comprehensive Income, Regulatory Assets and Regulatory Liabilities	$	45.7	$	(18.4)	$	(1.0)
Total recognized in net periodic benefit cost and Accumulated Other Comprehensive Income, Regulatory Assets and Regulatory Liabilities	$	51.1	$	(12.5)	$	6.3

Fair Value Measurements for Plan Assets

Fair Value Measurements for Pension Plan Assets at December 31, 2014
Asset Category $ in millions	Market Value at December 31, 2014		Quoted prices in active markets for identical assets		Significant observable inputs		Significant unobservable inputs
				(Level 1)		(Level 2)		(Level 3)
Equity securities (a)
Small/Mid cap equity	$	10.6	$	10.6	$	-	$	-
Large cap equity		22.2		22.2		-		-
International equity		18.2		18.2		-		-
Emerging markets equity		2.8		2.8		-		-
SIIT dynamic equity		11.6		11.6		-		-
Total equity securities		65.4		65.4		-		-
Debt securities (b)
Emerging markets debt		6.0		6.0		-		-
High yield bond		6.5		6.5		-		-
Long duration fund		242.7		242.7		-		-
Total debt securities		255.2		255.2		-		-
Cash and cash equivalents (c)
Cash		1.6		1.6		-		-
Other investments (d)
Core property collective fund		26.3		-		26.3		-
Common collective fund		23.2		-		23.2		-
Total other investments		49.5		-		49.5		-
Total pension plan assets	$	371.7	$	322.2	$	49.5	$	-

Fair Value Measurements for Pension Plan Assets at December 31, 2013
Asset Category $ in millions	Market Value at December 31, 2013		Quoted prices in active markets for identical assets		Significant observable inputs		Significant unobservable inputs
				(Level 1)		(Level 2)		(Level 3)
Equity securities (a)
Small/Mid cap equity	$	10.5	$	10.5	$	-	$	-
Large cap equity		20.8		20.8		-		-
International equity		20.3		20.3		-		-
Emerging markets equity		3.2		3.2		-		-
SIIT dynamic equity		10.5		10.5		-		-
Total equity securities		65.3		65.3		-		-
Debt securities (b)
Emerging markets debt		6.6		6.6		-		-
High yield bond		6.9		6.9		-		-
Long duration fund		223.3		223.3		-		-
Total debt securities		236.8		236.8		-		-
Cash and cash equivalents (c)
Cash		0.9		0.9		-		-
Other investments (d)
Core property collective fund		23.5		-		23.5		-
Common collective fund		22.6		-		22.6		-
Total other investments		46.1		-		46.1		-
Total pension plan assets	$	349.1	$	303.0	$	46.1	$	-

Postretirement [Member]

Pension And Postretirement Benefit Plans' Obligations And Assets

$ in millions	Postretirement
	Year ended December 31, 2014		Year ended December 31, 2013
Change in benefit obligation
Benefit obligation at beginning of period	$	19.7	$	22.4
Service cost		0.2		0.2
Interest cost		0.8		0.8
Actuarial (gain) / loss		0.2		(2.2)
Benefits paid		(1.3)		(1.5)
Benefit obligation at end of period		19.6		19.7
Change in plan assets
Fair value of plan assets at beginning of period		3.7		4.2
Contributions to plan assets		0.9		1.0
Benefits paid		(1.3)		(1.5)
Fair value of plan assets at end of period		3.3		3.7
Funded status of plan	$	(16.3)	$	(16.0)

Net Periodic Benefit Cost / (Income)

Net Periodic Benefit Cost - Postretirement
$ in millions	Year ended December 31, 2014		Year ended December 31, 2013		Year ended December 31, 2012
Service cost	$	0.2	$	0.2	$	0.1
Interest cost		0.8		0.8		0.9
Expected return on assets (a)		(0.2)		(0.1)		(0.3)
Amortization of unrecognized:
Actuarial loss		(0.6)		(0.5)		(0.6)
Net periodic benefit cost	$	0.2	$	0.4	$	0.1

Other Changes in Plan Assets and Benefit Obligation Recognized in Accumulated Other Comprehensive Income, Regulatory Assets And Regulatory Liabilities

Postretirement
$ in millions	Year ended December 31, 2014		Year ended December 31, 2013		Year ended December 31, 2012
Net actuarial loss / (gain)	$	0.4	$	(2.0)	$	1.0
Reversal of amortization item:
Net actuarial gain		0.6		0.5		0.7
Total recognized in Accumulated Other Comprehensive Income, Regulatory Assets and Regulatory Liabilities	$	1.0	$	(1.5)	$	1.7
Total recognized in net periodic benefit cost and Accumulated Other Comprehensive Income, Regulatory Assets and Regulatory Liabilities	$	1.2	$	(1.1)	$	-

Fair Value Measurements for Plan Assets

Fair Value Measurements for Postemployment Benefit Plan Assets at December 31, 2014
Asset Category $ in millions	Market Value at December 31, 2014		Quoted prices in active markets for identical assets		Significant observable inputs		Significant unobservable inputs
				(Level 1)		(Level 2)		(Level 3)
JP Morgan Core Bond Fund (a)	$	3.2	$	3.2	$	-	$	-

Fair Value Measurements for Postemployment Benefit Plan Assets at December 31, 2013
Asset Category $ in millions	Market Value at December 31, 2013		Quoted prices in active markets for identical assets		Significant observable inputs		Significant unobservable inputs
				(Level 1)		(Level 2)		(Level 3)
JP Morgan Core Bond Fund (a)	$	3.7	$	3.7	$	-	$	-