Fair Value (Tables)

6 Months Ended

Jun. 30, 2017

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Fair Value and Cost Of Non-Derivative Instruments

The following table presents the fair value, carrying value and cost of our non-derivative instruments at June 30, 2017 and December 31, 2016. Information about the fair value of our derivative instruments can be found in Note 6 – Derivative Instruments and Hedging Activities.

	June 30, 2017				December 31, 2016
$ in millions	Cost		Fair Value		Cost		Fair Value
Assets
Money market funds	$	0.4	$	0.4	$	0.4	$	0.4
Equity securities	2.6		3.9		2.4		3.4
Debt securities	4.2		4.3		4.4		4.4
Hedge funds	0.1		0.1		—		0.1
Real estate	—		—		0.3		0.3
Tangible assets	0.1		0.1		0.1		0.1
Total Assets	$	7.4	$	8.8	$	7.6	$	8.7
	Carrying Value		Fair Value		Carrying Value		Fair Value
Liabilities
Long-term debt (a)	$	1,837.3	$	1,926.2	$	1,858.0	$	1,907.7

Fair Value of Assets and Liabilities Measured on Recurring Basis

The fair value of assets and liabilities at June 30, 2017 and December 31, 2016 and the respective category within the fair value hierarchy for DPL was determined as follows:

Assets and Liabilities at Fair Value
			Level 1		Level 2		Level 3
$ in millions	Fair value at June 30, 2017		Based on Quoted Prices in Active Markets		Other Observable Inputs		Unobservable Inputs
Assets
Master Trust assets
Money market funds	$	0.4	$	0.4	$	—	$	—
Equity securities	3.9		—		3.9		—
Debt securities	4.3		—		4.3		—
Hedge funds	0.1		—		0.1		—
Tangible assets	0.1		—		0.1		—
Total Master Trust assets	8.8		0.4		8.4		—
Derivative Assets
Forward power contracts	16.4		—		16.4		—
Interest rate hedges	0.9		—		0.9		—
Natural gas	0.3		0.3		—		—
Total Derivative assets	17.6		0.3		17.3		—
Total Assets	$	26.4	$	0.7	$	25.7	$	—
Liabilities
Derivative Liabilities
Interest rate hedges	$	0.2	$	—	$	0.2	$	—
FTRs	0.6		—		—		0.6
Natural gas futures	1.0		1.0		—		—
Forward power contracts	9.8		—		9.8		—
Total Derivative liabilities	11.6		1.0		10.0		0.6
Long-term debt	1,926.3		—		1,908.4		17.9
Total Liabilities	$	1,937.9	$	1.0	$	1,918.4	$	18.5

Assets and Liabilities at Fair Value
			Level 1		Level 2		Level 3
$ in millions	Fair value at December 31, 2016		Based on Quoted Prices in Active Markets		Other Observable Inputs		Unobservable Inputs
Assets
Master Trust assets
Money market funds	$	0.4	$	0.4	$	—	$	—
Equity securities	3.4		—		3.4		—
Debt securities	4.4		—		4.4		—
Hedge funds	0.1		—		0.1		—
Real estate	0.3		—		0.3		—
Tangible assets	0.1		—		0.1		—
Total Master Trust assets	8.7		0.4		8.3		—
Derivative assets
Forward power contracts	19.5		—		19.5		—
Interest rate hedges	1.2		—		1.2		—
FTRs	0.1		—		—		0.1
Total Derivative assets	20.8		—		20.7		0.1
Total Assets	$	29.5	$	0.4	$	29.0	$	0.1
Liabilities
Derivative liabilities
Interest rate hedges	$	0.7	$	—	$	0.7	$	—
Forward power contracts	28.5		—		26.0		2.5
Total Derivative liabilities	29.2		—		26.7		2.5
Long-term debt	1,907.7		—		1,889.7		18.0
Total Liabilities	$	1,936.9	$	—	$	1,916.4	$	20.5

Fair Value Measurements, Nonrecurring [Table Text Block]

When evaluating impairment of long-lived assets, we measure fair value using the applicable fair value measurement guidance. Impairment expense is measured by comparing the fair value at the evaluation date to the carrying amount. The following table summarizes Long-lived assets measured at fair value on a non-recurring basis during the periods and their level within the fair value hierarchy:

$ in millions	Carrying		Fair Value						Gross
	Amount (b)		Level 1		Level 2		Level 3		Loss
	Six months ended June 30, 2017
Assets
Long-lived assets (a)
Stuart	$	42.4	$	—	$	—	$	3.3	$	39.1
Killen	$	35.2	$	—	$	—	$	7.9	$	27.3
	Six months ended June 30, 2016
Assets
Long-lived assets (a)
Killen	$	315.1	$	—	$	—	$	84.3	$	230.8
DP&L peaking facilities	$	9.9	$	—	$	—	$	5.2	$	4.7

(a)See Note 14 – Fixed-asset Impairments for further information

(b)Carrying amount at date of valuation

Fair Value Inputs, Assets, Quantitative Information [Table Text Block]

The following summarizes the significant unobservable inputs used in the Level 3 measurement on a non-recurring basis during the six months ended June 30, 2017:

$ in millions	Fair value		Valuation technique	Unobservable input	Weighted average
Long-lived assets held and used:
Stuart	$	3.3	Discounted cash flow	Pre-tax operating margin (through remaining life)	10	%
				Weighted-average cost of capital	7	%
Killen	$	7.9	Discounted cash flow	Pre-tax operating margin (through remaining life)	22	%
				Weighted-average cost of capital	7	%

THE DAYTON POWER AND LIGHT COMPANY [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Fair Value and Cost Of Non-Derivative Instruments

The following table presents the fair value, carrying value and cost of our non-derivative instruments at June 30, 2017 and December 31, 2016. Information about the fair value of our derivative instruments can be found in Note 6 – Derivative Instruments and Hedging Activities.

	June 30, 2017				December 31, 2016
$ in millions	Cost		Fair Value		Cost		Fair Value
Assets
Money market funds	$	0.4	$	0.4	$	0.4	$	0.4
Equity securities	2.6		3.9		2.4		3.4
Debt securities	4.2		4.3		4.4		4.4
Hedge funds	0.1		0.1		—		0.1
Real estate	—		—		0.3		0.3
Tangible assets	0.1		0.1		0.1		0.1
Total assets	$	7.4	$	8.8	$	7.6	$	8.7
	Carrying Value		Fair Value		Carrying Value		Fair Value
Liabilities
Long-term debt (a)	$	739.6	$	753.0	$	749.0	$	763.5

Fair Value of Assets and Liabilities Measured on Recurring Basis

The fair value of assets and liabilities at June 30, 2017 and December 31, 2016 and the respective category within the fair value hierarchy for DP&L was determined as follows:

Assets and Liabilities at Fair Value
			Level 1		Level 2		Level 3
$ in millions	Fair value at June 30, 2017		Based on Quoted Prices in Active Markets		Other Observable Inputs		Unobservable Inputs
Assets
Master Trust assets
Money market funds	$	0.4	$	0.4	$	—	$	—
Equity securities	3.9		—		3.9		—
Debt securities	4.3		—		4.3		—
Hedge funds	0.1		—		0.1		—
Tangible assets	0.1		—		0.1		—
Total Master Trust assets	8.8		0.4		8.4		—
Derivative assets
Natural gas futures	0.3		0.3		—		—
Interest rate hedges	0.9		—		0.9		—
Forward power contracts	16.4		—		16.4		—
Total derivative assets	17.6		0.3		17.3		—
Total assets	$	26.4	$	0.7	$	25.7	$	—
Liabilities
Derivative liabilities
FTRs	$	0.6	$	—	$	—	$	0.6
Interest rate hedges	0.2		—		0.2		—
Natural gas futures	1.0		1.0		—		—
Forward power contracts	9.8		—		9.8		—
Total derivative liabilities	11.6		1.0		10.0		0.6
Long-term debt (a)	753.0		—		735.1		17.9
Total liabilities	$	764.6	$	1.0	$	745.1	$	18.5

(a) Amounts exclude immaterial capital lease obligations

Assets and Liabilities at Fair Value
			Level 1		Level 2		Level 3
$ in millions	Fair value at December 31, 2016		Based on Quoted Prices in Active Markets		Other Observable Inputs		Unobservable Inputs
Assets
Master Trust assets
Money market funds	$	0.4	$	0.4	$	—	$	—
Equity securities	3.4		—		3.4		—
Debt securities	4.4		—		4.4		—
Hedge funds	0.1		—		0.1		—
Real estate	0.3		—		0.3		—
Tangible assets	0.1		—		0.1		—
Total Master Trust assets	8.7		0.4		8.3		—
Derivative assets
FTRs	0.1		—		—		0.1
Interest rate hedges	1.2		—		1.2		—
Forward power contracts	19.5		—		19.5		—
Total Derivative assets	20.8		—		20.7		0.1
Total assets	$	29.5	$	0.4	$	29.0	$	0.1
Liabilities
Derivative liabilities
Interest rate hedges	$	0.7	$	—	$	0.7	$	—
Forward power contracts	28.5		—		26.0		2.5
Total Derivative liabilities	29.2		—		26.7		2.5
Long-term debt (a)	763.5		—		745.5		18.0
Total liabilities	$	792.7	$	—	$	772.2	$	20.5

Fair Value Measurements, Nonrecurring [Table Text Block]

When evaluating impairment of long-lived assets, we measure fair value using the applicable fair value measurement guidance. Impairment expense is measured by comparing the fair value at the evaluation date to the carrying amount. The following table summarizes Long-lived assets measured at fair value on a non-recurring basis during the periods and their level within the fair value hierarchy:

$ in millions
	Carrying		Fair Value						Gross
	Amount (b)		Level 1		Level 2		Level 3		Loss
	Six months ended June 30, 2017
Assets
Long-lived assets (a)
Stuart	$	42.3	$	—	$	—	$	3.3	$	39.0
Killen	$	35.2	$	—	$	—	$	7.9	$	27.3
	Six months ended June 30, 2016
Assets
Long-lived assets (a)
Stuart	$	456.4	$	—	$	—	$	164.4	$	292.0
Killen	$	330.5	$	—	$	—	$	84.3	$	246.2
Zimmer	$	429.9	$	—	$	—	$	111.0	$	318.9

(a)See Note 14 – Fixed-asset Impairments for further information

(b)Carrying amount at date of valuation

Fair Value Inputs, Assets, Quantitative Information [Table Text Block]

The following summarizes the significant unobservable inputs used in the Level 3 measurement on a non-recurring basis during the six months ended June 30, 2017:

$ in millions	Fair value		Valuation technique	Unobservable input	Weighted average
Long-lived assets held and used:
Stuart	$	3.3	Discounted cash flow	Pre-tax operating margin (through remaining life)	10	%
				Weighted-average cost of capital	7	%
Killen	$	7.9	Discounted cash flow	Pre-tax operating margin (through remaining life)	22	%
				Weighted-average cost of capital	7	%

The following summarizes the significant unobservable inputs used in the Level 3 measurement on a non-recurring basis during the six months ended June 30, 2016:

$ in millions	Fair value		Valuation technique	Unobservable input	Weighted average
Long-lived assets held and used:
Stuart	$	164.4	Discounted cash flow	Annual revenue growth	-9% to 10% (2%)
				Annual pre-tax operating margin	-29% to 52% (5%)
				Weighted-average cost of capital	9%
Killen	$	84.3	Discounted cash flow	Annual revenue growth	-11% to 13% (2%)
				Annual pre-tax operating margin	-50% to 67% (6%)
				Weighted-average cost of capital	11%
Zimmer	$	111.0	Discounted cash flow	Annual revenue growth	-14% to 13% (1%)
				Annual pre-tax operating margin	-46% to 80% (4%)
				Weighted-average cost of capital	9%