Deferred Finance Costs, Net, Including Acquisition Adjustments

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Early prepayment rate - prepayments prior to July 3, 2018 must be at this rate

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- Definition

Long Term Debt Range Adjusted To Fair Value At Merger End

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Long Term Debt Range Adjusted To Fair Value at Merger Start

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- Definition

Standard Repayment Rate - Repayment rate after July 31, 2018

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- Definition

Total Long-term Debt At Subsidiary With Purchase Accounting Adjustments

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

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- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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- Definition

Latest date the outstanding debt instruments are required to be repaid, in CCYY-MM-DD format.

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- Definition

Amount, after accumulated amortization, of debt discount.

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- Definition

Amount, after accumulated amortization, of debt discount (premium).

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- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Debt (Long-term Debt) (Details) - USD ($) $ in Millions	6 Months Ended		9 Months Ended
Debt (Long-term Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Jul. 03, 2018	Sep. 30, 2018	Mar. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Unamortized deferred finance costs			$ (6.7)		$ (9.8)
Unamortized deferred finance costs			(4.8)		(6.9)
Unamortized long-term debt discounts and premiums, net			(0.5)		(0.5)
Total long-term debt at subsidiary			586.7		646.6
Total long-term debt			1,476.0		1,704.8
Less: current portion			(4.6)		(4.6)
Long-term debt			$ 1,471.4		1,700.2
Long-term debt, earliest maturities			2019
Long-term debt, latest maturities			2061
THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 594.9
Unamortized deferred finance costs			(6.7)		(9.8)
Unamortized long-term debt discounts and premiums, net			(1.5)		(2.0)
Unamortized long-term debt discounts			(1.5)		(2.0)
Total long-term debt			586.7		646.6
Less: current portion			(4.6)		(4.6)
Long-term debt			$ 582.1		642.0
Long-term debt, earliest maturities			2020
Long-term debt, latest maturities			2061
Term Loan Maturing 2022 [Domain]
Debt Instrument [Line Items]
Debt instrument maturity year			Aug. 24, 2022
Term Loan Maturing 2022 [Domain] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Debt instrument maturity year			Aug. 24, 2022
Term Loan Maturing 2022 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 437.2		440.6
Early prepayment rate		101.00%
Term Loan Maturing 2022 [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 437.2		440.6
Early prepayment rate		101.00%
Pollution Control Series Maturing in August 2020 - 1.13% - 1.14% [Member]
Debt Instrument [Line Items]
Debt instrument maturity year			Aug. 01, 2020
Pollution Control Series Maturing in August 2020 - 1.13% - 1.14% [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 140.0		200.0
Debt instrument maturity year			Aug. 01, 2020
U.S. Government note maturing in February 2061 - 4.20% [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 17.7		17.8
Debt instrument maturity year			Feb. 01, 2061
Debt instrument interest percentage			4.20%
U.S. Government note maturing in February 2061 - 4.20% [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 17.7		17.8
Debt instrument maturity year			Feb. 01, 2061
Debt instrument interest percentage			4.20%
Bank term loan due in July 2020 - rates from: 2.44% - 2.45% [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross					70.0
Debt instrument maturity year			Jul. 31, 2020
Senior unsecured due in October 2019 - 6.75% [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 99.0	$ 200.0	200.0
Debt instrument maturity year			Oct. 01, 2019
Debt instrument interest percentage			6.75%
Senior unsecured due in October 2021 - 7.25% [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 780.0		780.0
Debt instrument maturity year			Oct. 01, 2021
Debt instrument interest percentage			7.25%
Note to DPL Capital Trust II Maturing in September 2031 - 8.125% [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 15.6		$ 15.6
Debt instrument maturity year			Sep. 01, 2031
Debt instrument interest percentage			8.125%
Subsequent Event [Member] \| Term Loan Maturing 2022 [Member]
Debt Instrument [Line Items]
Standard Repayment Rate	100.00%
Subsequent Event [Member] \| Term Loan Maturing 2022 [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Standard Repayment Rate	100.00%
Maximum [Member] \| Term Loan Maturing 2022 [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage			4.82%
Debt Instrument, Interest Rate, Effective Percentage					4.60%
Maximum [Member] \| Term Loan Maturing 2022 [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage			4.82%
Debt Instrument, Interest Rate, Effective Percentage					4.60%
Maximum [Member] \| Pollution Control Series Maturing in August 2020 - 1.13% - 1.14% [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage					1.92%
Maximum [Member] \| Zero Point Two Three To Zero Point Two Nine And Zero Point One Six To Zero Point Three Six Percentage Of Bonds Maturing In November Two Thousand Forty [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage			2.722%
Maximum [Member] \| Zero Point Two Three To Zero Point Two Nine And Zero Point One Six To Zero Point Three Six Percentage Of Bonds Maturing In November Two Thousand Forty [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage			2.72%		1.92%
Maximum [Member] \| Bank term loan due in July 2020 - rates from: 2.44% - 2.45% [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage			3.898%		4.10%
Minimum [Member] \| Term Loan Maturing 2022 [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage					4.01%
Debt Instrument, Interest Rate, Effective Percentage			3.57%
Minimum [Member] \| Term Loan Maturing 2022 [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage					4.01%
Debt Instrument, Interest Rate, Effective Percentage			3.57%
Minimum [Member] \| Pollution Control Series Maturing in August 2020 - 1.13% - 1.14% [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage					1.52%
Minimum [Member] \| Zero Point Two Three To Zero Point Two Nine And Zero Point One Six To Zero Point Three Six Percentage Of Bonds Maturing In November Two Thousand Forty [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage			2.498%
Minimum [Member] \| Zero Point Two Three To Zero Point Two Nine And Zero Point One Six To Zero Point Three Six Percentage Of Bonds Maturing In November Two Thousand Forty [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage			2.50%		1.52%
Minimum [Member] \| Bank term loan due in July 2020 - rates from: 2.44% - 2.45% [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage			3.817%		3.02%