Derivative, Notional Amount, Purchase (Sales), Net

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- Definition

Gain on sale of Derivative Instruments Interest Rate Swap

+ References

No definition available.

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- Definition

Sale of Derivative Instruments Interest Rate Swap

+ References

No definition available.

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- Definition

Amount of obligation to return cash collateral under master netting arrangements that have not been offset against derivative assets.

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- Definition

Amount of obligation to return securities collateral under master netting arrangements that have not been offset against derivative assets.

+ References

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- Definition

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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- Definition

Fair value, after effects of master netting arrangements, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset offset against an obligation to return collateral. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Derivative Instruments and Hedging Activities (Outstanding Derivative Instruments) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2019	Dec. 31, 2018	Mar. 29, 2018
Sale of Derivative Instruments Interest Rate Swap				$ (60.0)
Gain on sale of Derivative Instruments Interest Rate Swap	$ 0.8
THE DAYTON POWER AND LIGHT COMPANY [Member]
Sale of Derivative Instruments Interest Rate Swap				$ (60.0)
Gain on sale of Derivative Instruments Interest Rate Swap	$ 0.8
Designated as Hedging Instrument [Member] \| Interest Rate Swap [Member]
Derivative, Notional Amount, Purchase (Sales), Net		$ 140.0
Designated as Hedging Instrument [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member] \| Interest Rate Swap [Member]
Derivative, Notional Amount, Purchase (Sales), Net		140.0
Derivative Financial Instruments, Assets [Member]
Derivative Asset, Fair Value, Gross Asset		1.1	$ 1.5
Derivative, Collateral, Obligation to Return Securities		0.0	0.0
Derivative, Collateral, Obligation to Return Cash		0.0	0.0
Derivative Asset, Fair Value, Amount Offset Against Collateral		1.1	1.5
Derivative Financial Instruments, Assets [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Asset, Fair Value, Gross Asset		1.1	1.5
Derivative, Collateral, Obligation to Return Securities		0.0	0.0
Derivative, Collateral, Obligation to Return Cash		0.0	0.0
Derivative Asset, Fair Value, Amount Offset Against Collateral		1.1	1.5
Cash Flow Hedging [Member] \| Other Prepayments and Current Assets [Member] \| Short-term Derivative Positions [Member] \| Forward Contract Power [Member]
Derivative Asset, Fair Value, Gross Asset			0.9
Derivative, Collateral, Obligation to Return Securities			0.0
Derivative, Collateral, Obligation to Return Cash			0.0
Derivative Asset, Fair Value, Amount Offset Against Collateral			0.9
Cash Flow Hedging [Member] \| Other Prepayments and Current Assets [Member] \| Short-term Derivative Positions [Member] \| Interest Rate Swap [Member]
Derivative Asset, Fair Value, Gross Asset		0.8
Derivative, Collateral, Obligation to Return Securities		0.0
Derivative, Collateral, Obligation to Return Cash		0.0
Derivative Asset, Fair Value, Amount Offset Against Collateral		0.8
Cash Flow Hedging [Member] \| Other Prepayments and Current Assets [Member] \| Short-term Derivative Positions [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member] \| Interest Rate Swap [Member]
Derivative Asset, Fair Value, Gross Asset		0.8	0.9
Derivative, Collateral, Obligation to Return Securities		0.0	0.0
Derivative, Collateral, Obligation to Return Cash		0.0	0.0
Derivative Asset, Fair Value, Amount Offset Against Collateral		0.8	0.9
Cash Flow Hedging [Member] \| Other Deferred Asset [Member] \| Long-term Derivative Positions [Member] \| Interest Rate Swap [Member]
Derivative Asset, Fair Value, Gross Asset		0.3	0.6
Derivative, Collateral, Obligation to Return Securities		0.0	0.0
Derivative, Collateral, Obligation to Return Cash		0.0	0.0
Derivative Asset, Fair Value, Amount Offset Against Collateral		0.3	0.6
Cash Flow Hedging [Member] \| Other Deferred Asset [Member] \| Long-term Derivative Positions [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member] \| Interest Rate Swap [Member]
Derivative Asset, Fair Value, Gross Asset		0.3	0.6
Derivative, Collateral, Obligation to Return Securities			0.0
Derivative, Collateral, Obligation to Return Cash			0.0
Derivative Asset, Fair Value, Amount Offset Against Collateral		$ 0.3	$ 0.6