Debt Covenant, Debt to EBITDA Ratio, Maximum

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- Definition

Debt Covenant, Interest Coverage Ratio, Minimum

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- Definition

Debt Covenant, Leverage Ratio, Maximum

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- Definition

Debt Covenant, Total Debt to Total Capitalization Ratio, Maximum

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- Definition

Debt Instrument, Debt Covenant, Debt to EBITDA Ratio, Number of Quarters

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Debt Instrument, Debt Covenant, EBITDA to Interest Calculation, Number of Quarters

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- Definition

Debt Instrument, Number of Financial Covenants

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- Definition

Debt to EBITDA Ratio

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

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Interest Coverage Ratio

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- Definition

Letter Of Credit Sublimit

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- Definition

Leverage Ratio

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Line of Credit Facility, Additional Borrowing Capacity

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After separation required compliance with the financial covenant, shall be suspended from 1/1/17 to 12/31/17 if during such time DP&L's LT indebtedness (as determined by the PUCO) is less than or equal to $750.0 million.

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Make Whole Premium

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Standard Repayment Rate - Repayment rate after July 31, 2018

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Total Debt to Total Capitalization Ratio

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Total Long-term Debt At Subsidiary With Purchase Accounting Adjustments

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Unamortized adjustments to market value from purchase accounting

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Unamortized Deferred Financing Costs

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Unamortized Deferred Financing Costs (Subsidiary)

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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.

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Face (par) amount of debt instrument at time of issuance.

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

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

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

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Gross amount of debt extinguished.

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Amount of long-term debt and capital lease obligations including current maturities.

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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 of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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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 (Narrative) (Details) $ in Millions	6 Months Ended		12 Months Ended
Debt (Narrative) (Details) $ in Millions	Dec. 31, 2018 USD ($)	Jul. 03, 2018	Dec. 31, 2019 USD ($) fiscal_quarter debt_covenant	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	May 07, 2019 USD ($)	Apr. 30, 2018 USD ($)	Mar. 30, 2018 USD ($)	Jan. 03, 2018	Aug. 03, 2015 USD ($)
Debt Instrument [Line Items]
Current portion - long-term debt			$ 140.2
Unamortized adjustments to market value from purchase accounting			3.7
Letter Of Credit Sublimit			75.0
Line of Credit Facility, Additional Borrowing Capacity			50.0
Issuance of long-term debt			821.7	$ 0.0	$ 0.0
Unamortized Deferred Financing Costs	$ (4.3)		(5.9)	(4.3)
Current portion - long-term debt	103.6		$ 139.8	103.6
Debt Covenant, Leverage Ratio, Maximum			0.67
Debt Covenant, Interest Coverage Ratio, Minimum			2.25
Interest Coverage Ratio			3.20
Leverage Ratio			1.32
Debt Covenant, Total Debt to Total Capitalization Ratio, Maximum			0.65
Long Term Indebtedness, Less than or Equal to			$ 750.0
Total Debt to Total Capitalization Ratio			0.57
Debt Instrument, Unamortized Discount (Premium), Net	0.5		$ 1.0	0.5
Total Long-term Debt At Subsidiary With Purchase Accounting Adjustments	586.1		574.4	586.1
Long-term Debt, Excluding Current Maturities	1,372.3		1,223.3	1,372.3
Long-term Debt, Maturities, Repayments of Principal in Year Two			$ 380.2
Debt Covenant, Debt to EBITDA Ratio, Maximum			7.00
Debt to EBITDA Ratio			5.83
THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Letter Of Credit Sublimit			$ 75.0
Line of Credit Facility, Additional Borrowing Capacity			100.0
Unamortized Deferred Financing Costs (Subsidiary)	(6.3)		(5.4)	(6.3)
Debt Instrument, Unamortized Discount (Premium), Net	$ 1.4		$ 2.7	1.4
3.95% Senior Notes due 2049 [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, End			Jan. 01, 2049
Issuance of long-term debt			$ 425.0
Long-term Debt, Gross			425.0
Extinguishment of Debt, Amount			$ 435.0
Debt instrument interest percentage			3.95%
Senior Unsecured Notes At 6.80 Maturing On October 2019 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross								$ 200.0
Make Whole Premium			$ 1.5				$ 5.1
Extinguishment of Debt, Amount			$ 99.0	$ 101.0
Debt instrument interest percentage	6.75%		6.75%	6.75%
Term Loan Maturing 2022 (DPL) [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, End			Aug. 24, 2022
Long-term Debt, Gross	$ 436.1		$ 0.0	$ 436.1
Eurodollar rate Term Loan B [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage	3.25%			3.25%					2.00%
Base Rate Term Loan B [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage	2.25%			2.25%					1.00%
Revolving Credit Agreement and Standby Letters of Credit [Member]
Debt Instrument [Line Items]
Number of financial covenants \| debt_covenant			2
Revolving Credit Agreement and Standby Letters of Credit [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Number of prior quarters included in debt to EBITDA ratio \| fiscal_quarter			4
Debt Covenant, Interest Coverage Ratio, Minimum			2.50
Interest Coverage Ratio			8.51
Debt Covenant, Total Debt to Total Capitalization Ratio, Maximum			0.67
U.S. Government note maturing in 2061 - 4.20% [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, End			Feb. 01, 2061
Long-term Debt, Gross	$ 17.7		$ 17.5	$ 17.7
Debt instrument interest percentage			4.20%
Term Loan Maturing 2022 [Member]
Debt Instrument [Line Items]
Early prepayment rate		101.00%
Standard Repayment Rate	100.00%
Bank Term Loan maturing in May 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, End			Jul. 31, 2020
Bank Term Loan Maturing July 2020 [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount				70.0
Five Year Senior Unsecured Notes At6.75 Maturing October152019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, End			Oct. 01, 2019
Long-term Debt, Gross	$ 99.0			99.0
Debt instrument interest percentage			6.75%
DPL Revolving Credit Agreement and Term Loan Maturing July 2020 [Member]
Debt Instrument [Line Items]
Number of financial covenants \| debt_covenant			2
Debt Instrument, Debt Covenant, Debt to EBITDA Ratio, Number of Quarters \| fiscal_quarter			4
Debt Covenant, Interest Coverage Ratio, Minimum			2.50
Senior Unsecured Bonds at 7.25% maturing in 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, End			Oct. 01, 2021
Long-term Debt, Gross	780.0		$ 380.0	780.0		$ 780.0
Make Whole Premium			41.4
Extinguishment of Debt, Amount			$ 400.0
Debt instrument interest percentage			7.25%
Note to DPL Capital Trust II Maturing in 2031 - 8.125% [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, End			Sep. 01, 2031
Long-term Debt, Gross	15.6		$ 15.6	15.6
Debt instrument interest percentage			8.125%
Variable Rate Notes Backed by Term Loan and First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount				60.0
Variable Rate Notes Backed by Term Loan and First Mortgage Bonds [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount										$ 200.0
One Point One Three To One Point One Seven Bonds Maturing In August Two Thousand Twenty [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, End			Aug. 01, 2020
Long-term Debt, Gross			$ 140.0
Debt [Member]
Debt Instrument [Line Items]
Long-term Debt and Capital Lease Obligations, Including Current Maturities	$ 1,475.9		$ 1,363.1	$ 1,475.9
Minimum [Member] \| Bank Term Loan maturing in May 2018 [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage	2.67%		3.02%	2.67%
Minimum [Member] \| One Point One Three To One Point One Seven Bonds Maturing In August Two Thousand Twenty [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage	1.29%		2.49%	1.29%