Dayton Power & Light 10-Q 7 May 20 2020 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information	3 Months Ended
	Mar. 31, 2020shares
Entity Registrant Name	DPL INC
Entity Central Index Key	0000787250
Document Type	10-Q
Document Period End Date	Mar. 31, 2020
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding	1
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
THE DAYTON POWER AND LIGHT COMPANY [Member]
Entity Registrant Name	DAYTON POWER & LIGHT CO
Entity Central Index Key	0000027430
Document Type	10-Q
Amendment Flag	false
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding	41,172,173
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenues	$ 174.7	$ 209
Operating costs and expenses
Net fuel cost	4	3.5
Utilities Operating Expense, Purchased Power	63.2	74.2
Operating expenses:
Operation and maintenance	48.7	51
Depreciation and amortization	17.8	18.4
Taxes other than income taxes	20.9	19.5
Other Operating Income (Expense), Net	(0.1)	0.9
Costs and Expenses	154.5	167.5
Operating income	20.2	41.5
Other income / (expense), net:
Interest expense	(18.9)	(23.7)
Other income / (expense)	(0.9)	1.4
Total other expense, net	(19.8)	(22.3)
Income from continuing operations before income tax	0.4	19.2
Income tax expense / (benefit) from continuing operations	(0.5)	2.7
Net income from continuing operations	0.9	16.5
Income from discontinued operations before income tax	1.3	29.8
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	0	0.1
Income tax expense from discontinued operations	0.3	4.3
Net income from discontinued operations	1	25.6
Net income	1.9	42.1
THE DAYTON POWER AND LIGHT COMPANY [Member]
Revenues	169	201.4
Operating costs and expenses
Net fuel cost	0.6	0.9
Utilities Operating Expense, Purchased Power	62.4	73.3
Operating expenses:
Operation and maintenance	47.1	48.2
Depreciation and amortization	17.3	18
Taxes other than income taxes	20.8	19.4
Gain (Loss) on Sale of Assets and Asset Impairment Charges, excluding Discontinued Operations	(0.1)	0
Costs and Expenses	148.1	159.8
Operating income	20.9	41.6
Other income / (expense), net:
Interest expense	(6.2)	(7.1)
Other income / (expense)	(1.8)	0.6
Total other expense, net	(8)	(6.5)
Income from continuing operations before income tax	12.9	35.1
Income tax expense / (benefit) from continuing operations	1.2	6.1
Net income	$ 11.7	$ 29

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net income	$ 1.9	$ 42.1
Derivative activity:
Change in derivative fair value, net of income tax	(0.3)	(0.3)
Reclassification of earnings, net of income tax	(0.3)	(0.2)
Total change in fair value of derivatives	(0.6)	(0.5)
Pension and postretirement activity:
Reclassification to earnings, net of income tax	0.3	0.1
Total change in unfunded pension obligation	0.3	0.1
Other comprehensive loss	(0.3)	(0.4)
Net comprehensive income	1.6	41.7
THE DAYTON POWER AND LIGHT COMPANY [Member]
Net income	11.7	29
Derivative activity:
Change in derivative fair value, net of income tax	(0.3)	(0.2)
Reclassification of earnings, net of income tax	(0.1)	(0.1)
Total change in fair value of derivatives	(0.4)	(0.3)
Pension and postretirement activity:
Reclassification to earnings, net of income tax	0.8	0.7
Total change in unfunded pension obligation	0.8	0.7
Other comprehensive loss	0.4	0.4
Net comprehensive income	$ 12.1	$ 29.4

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income tax (expense)/benefit on unrealized gains (losses) related to available-for-sale securities	$ 0	$ 0
Income tax (expense) benefit on reclassification to earnings	0	0
AOCI reclassed to Retained Earnings, income tax	0	0
Income tax (expense)/benefit on unrealized gains (losses) related to derivative activity	0	0.1
Income tax (expense)/benefit on reclassification of earnings related to derivative activity	0.1	0.1
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives Related to Discontinued Operations, Tax	0	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, Tax	0	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax	0	0
Income tax (expense)/benefit on reclassification of earnings related to pension and postretirement activity	0	0
THE DAYTON POWER AND LIGHT COMPANY [Member]
Income tax (expense)/benefit on unrealized gains (losses) related to available-for-sale securities	0	0
Income tax (expense) benefit on reclassification to earnings	0	0
AOCI reclassed to Retained Earnings, income tax	0	0
Income tax (expense)/benefit on unrealized gains (losses) related to derivative activity	0	0.1
Income tax (expense)/benefit on reclassification of earnings related to derivative activity	0	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives Related to Discontinued Operations, Tax	0	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, Tax	0	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax	0	0
Income tax (expense)/benefit on reclassification of earnings related to pension and postretirement activity	$ (0.2)	$ (0.2)

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 39.6	$ 36.5
Restricted cash	14.6	10.5
Accounts receivable, net	64.9	68.6
Inventories	10.7	14.1
Taxes applicable to subsequent years	60.8	77.8
Regulatory assets, current	17.6	19.7
Income Taxes Receivable, Current	29.4	23.6
Prepayments and other current assets	5.2	7.6
Assets Held-for-sale, Not Part of Disposal Group, Current	1.9	17.7
Total current assets	244.7	276.1
Property, plant & equipment:
Property, plant & equipment	1,749.5	1,701.9
Less: Accumulated depreciation and amortization	(375.9)	(362.6)
Property, plant and equipment, net of depreciation	1,373.6	1,339.3
Construction work in process	86.5	106.3
Total net property, plant & equipment	1,460.1	1,445.6
Other non-current assets:
Regulatory assets, non-current	175.8	173.8
Intangible assets, net of amortization	18.7	19.4
Other non-current assets	19.1	20.9
Total other non-current assets	213.6	214.1
Total assets	1,918.4	1,935.8
Current liabilities:
Current portion of long-term debt	318.9	283.8
Accounts payable	55.3	74.4
Accrued taxes	83	79.6
Accrued interest	26.5	11.4
Security deposits	20.2	20.7
Regulatory liabilities, current	22.5	27.9
Other current liabilities	16.5	21.2
Liabilities Held for Sale, Current	5.9	6.9
Total current liabilities	548.8	525.9
Non-current liabilities:
Long-term debt	1,223.7	1,223.3
Deferred taxes	133.3	127.2
Taxes payable	44.8	81.4
Regulatory liabilities, non-current	240.9	243.6
Pension, retiree and other benefits	71.7	79.9
Other deferred credits	19.3	20.2
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent	6.2	6.2
Total non-current liabilities	1,739.9	1,781.8
Commitments and contingencies
Common shareholder's equity:
Common stock	0	0
Other paid-in capital	2,370.7	2,370.7
Accumulated other comprehensive income	(3.9)	(3.6)
Retained Earnings (Accumulated Deficit)	(2,737.1)	(2,739)
Total common shareholder's equity	(370.3)	(371.9)
Total liabilities and shareholder's equity	1,918.4	1,935.8
THE DAYTON POWER AND LIGHT COMPANY [Member]
Current assets:
Cash and cash equivalents	7.3	10.8
Restricted cash	14.6	10.5
Accounts receivable, net	68.2	70.9
Inventories	9.1	10.4
Taxes applicable to subsequent years	60.4	77.4
Regulatory assets, current	17.6	19.7
Income Taxes Receivable, Current	39.7	35.7
Prepayments and other current assets	7.4	10.8
Total current assets	224.3	246.2
Property, plant & equipment:
Property, plant & equipment	2,374.1	2,333.6
Less: Accumulated depreciation and amortization	(1,019.1)	(1,012.7)
Property, plant and equipment, net of depreciation	1,355	1,320.9
Construction work in process	84.6	104.5
Total net property, plant & equipment	1,439.6	1,425.4
Other non-current assets:
Regulatory assets, non-current	175.8	173.8
Intangible assets, net of amortization	17.6	18.2
Other non-current assets	17.3	19.6
Total other non-current assets	210.7	211.6
Total assets	1,874.6	1,883.2
Current liabilities:
Current portion of long-term debt	224.9	179.8
Accounts payable	54.1	74.4
Accrued taxes	83.2	79.4
Accrued interest	5.5	1.4
Security deposits	20	20.6
Regulatory liabilities, current	22.5	27.9
Other current liabilities	11.7	16.3
Total current liabilities	421.9	399.8
Non-current liabilities:
Long-term debt	434.6	434.6
Deferred taxes	163.6	158.1
Taxes payable	45.8	82.3
Regulatory liabilities, non-current	240.9	243.6
Pension, retiree and other benefits	71.7	79.9
Other deferred credits	10.6	11.5
Total non-current liabilities	967.2	1,010
Commitments and contingencies
Common shareholder's equity:
Common stock	0.4	0.4
Other paid-in capital	617	617
Accumulated other comprehensive income	(36.5)	(36.9)
Retained Earnings (Accumulated Deficit)	(95.4)	(107.1)
Total common shareholder's equity	485.5	473.4
Total liabilities and shareholder's equity	$ 1,874.6	$ 1,883.2

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2020	Dec. 31, 2019
Common Stock, Shares Authorized	1,500	1,500
Common stock, shares issued	1	1
Common stock, shares outstanding	1	1
THE DAYTON POWER AND LIGHT COMPANY [Member]
Common Stock, Shares Authorized	50,000,000	50,000,000
Common stock, shares outstanding	41,172,173	41,172,173
Common stock, par value (in USD per share)	$ 0.01	$ 0.01

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net income	$ 1.9	$ 42.1
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	17.8	(3.1)
Deferred income taxes	3.4	5.2
Changes in certain assets and liabilities:
Accounts receivable, net	14.2	4.1
Inventories	3.4	(1.2)
Taxes applicable to subsequent years	17	18.7
Deferred regulatory costs, net	(5)	7.7
Accounts payable	(7.6)	(14)
Accrued taxes payable / receivable	(39.2)	(35.2)
Accrued interest	15.1	15.6
Increase (Decrease) in Obligation, Pension and Other Postretirement Benefits	(8.2)	(6.9)
Other	(0.4)	3.6
Net Cash Provided by (Used in) Operating Activities	12.4	36.6
Cash flows from investing activities:
Capital expenditures	(44.6)	(34.3)
Proceeds from Sale of Productive Assets	5.1	0
Other investing activities, net	(0.7)	0
Net cash used in investing activities	(40.2)	(34.3)
Cash flows from financing activities:
Repayments of Lines of Credit	(10)	0
Proceeds from Lines of Credit	45	0
Retirement of long-term debt, including early payment premium	0	(1.1)
Proceeds from (Payments for) Other Financing Activities	0	(0.1)
Net cash provided by / (used in) financing activities	35	(1.2)
Cash, cash equivalents, and restricted cash:
Restricted Cash and Cash Equivalents	54.2	112.8
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect	7.2	1.1
Supplemental cash flow information:
Interest paid, net of amounts capitalized	2.3	6.7
Non-cash financing and investing activities:
Accruals for capital expenditures	5	4.4
Non-cash capital contribution	0	1.5
THE DAYTON POWER AND LIGHT COMPANY [Member]
Cash flows from operating activities:
Net income	11.7	29
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	17.3	18
Deferred income taxes	3	(0.9)
Changes in certain assets and liabilities:
Accounts receivable, net	2.8	2.6
Inventories	1.3	(0.5)
Taxes applicable to subsequent years	17	18.1
Deferred regulatory costs, net	(5)	7.7
Accounts payable	(8.6)	(12.7)
Accrued taxes payable / receivable	(36.7)	(27.4)
Accrued interest	4.1	0.1
Increase (Decrease) in Obligation, Pension and Other Postretirement Benefits	(8.2)	(6.8)
Other	1.3	2.3
Net Cash Provided by (Used in) Operating Activities	0	29.5
Cash flows from investing activities:
Capital expenditures	(43.7)	(33.7)
Other investing activities, net	(0.7)	0
Net cash used in investing activities	(44.4)	(33.7)
Cash flows from financing activities:
Proceeds from Lines of Credit	45	0
Retirement of long-term debt, including early payment premium	0	(1.1)
Proceeds from (Payments for) Other Financing Activities	0	(0.1)
Net cash provided by / (used in) financing activities	45	(1.2)
Cash, cash equivalents, and restricted cash:
Restricted Cash and Cash Equivalents	21.9	60.8
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect	0.6	(5.4)
Supplemental cash flow information:
Interest paid, net of amounts capitalized	0.7	5.9
Non-cash financing and investing activities:
Accruals for capital expenditures	$ 4.8	$ 4.8

Statement of Equity Statement

Statement of Equity Statement - USD ($) $ in Millions	Total	Common Stock [Member]	Other Additional Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]	Subsidiaries [Member]	Subsidiaries [Member]Common Stock [Member]	Subsidiaries [Member]Other Additional Capital [Member]	Subsidiaries [Member]AOCI Attributable to Parent [Member]	Subsidiaries [Member]Retained Earnings [Member]	Subsidiaries [Member]Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Shares, Issued		1						41,172,173
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ (471.7)	$ 0	$ 2,370.5	$ 2.2	$ (2,844.4)		$ 445.3	$ 0.4	$ 711.8	$ (35.3)	$ (231.6)
Other Comprehensive Income (Loss), Net of Tax	(0.4)						0.4
Net income/ (loss)	42.1						29
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	41.7						29.4
Non-cash capital contribution	1.5		1.5
Stockholders' Equity, Other	$ 0.1		(0.1)				$ (0.3)				0.3
Common stock, par value (in USD per share)							$ 0.01
Common Stock, Shares Authorized	1,500						50,000,000
Shares, Issued		1						41,172,173
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ (428.4)	$ 0	2,372.1	1.8	(2,802.3)		$ 474.4	$ 0.4	711.8	(34.9)	(202.9)
Common stock, par value (in USD per share)							$ 0.01
Common Stock, Shares Authorized	1,500						50,000,000
Shares, Issued		1						41,172,173
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ (371.9)	$ 0	2,370.7	(3.6)	(2,739)		$ 473.4
Common Stock, Value, Issued	0						0.4
Additional Paid in Capital, Common Stock	2,370.7						617
Accumulated Other Comprehensive Income (Loss), Net of Tax	(3.6)					$ 14.5	(36.9)					$ (0.4)
Retained Earnings (Accumulated Deficit)	(2,739)						(107.1)
Other Comprehensive Income (Loss), Net of Tax	(0.3)					(0.6)	0.4					(0.4)
Net income/ (loss)	1.9						11.7
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	1.6						$ 12.1
Non-cash capital contribution	$ 0
Common stock, par value (in USD per share)							$ 0.01
Common Stock, Shares Authorized	1,500						50,000,000
Shares, Issued		1						41,172,173
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ (370.3)	$ 0	$ 2,370.7	$ (3.9)	$ (2,737.1)		$ 485.5	$ 0.4	$ 617	$ (36.5)	$ (95.4)
Common Stock, Value, Issued	0						0.4
Additional Paid in Capital, Common Stock	2,370.7						617
Accumulated Other Comprehensive Income (Loss), Net of Tax	(3.9)					$ 13.9	(36.5)					$ (0.8)
Retained Earnings (Accumulated Deficit)	$ (2,737.1)						$ (95.4)

Overview and Summary of Signifi

Overview and Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2020
Significant Accounting Policies [Line Items]
Overview and Summary of Significant Accounting Policies	Overview and Summary of Significant Accounting Policies Description of Business DPL is a regional energy company organized in 1985 under the laws of Ohio. DPL has one reportable segment: the Utility segment. See Note 11 – Business Segments for more information relating to this reportable segment. The terms “we,” “us,” “our” and “ours” are used to refer to DPL and its subsidiaries. DPL is an indirectly wholly-owned subsidiary of AES. DP&L , a wholly-owned subsidiary of DPL , is a public utility incorporated in 1911 under the laws of Ohio. Beginning in 2001, Ohio law gave Ohio consumers the right to choose the electric generation supplier from whom they purchase retail generation service; however, retail transmission and distribution services are still regulated. DP&L has the exclusive right to provide such transmission and distribution services to approximately 527,000 customers located in West Central Ohio. Additionally, DP&L provides retail SSO electric service to residential, commercial, industrial and governmental customers in a 6,000 - square mile area of West Central Ohio. Principal industries located in DP&L’s service territory include automotive, food processing, paper, plastic, health care, data management, manufacturing and defense. DP&L's sales typically reflect the seasonal weather patterns and the growth of energy efficiency initiatives. However, the impacts of weather, energy efficiency programs and economic changes in customer demand were almost entirely eliminated in 2019 by DP&L’s Decoupling Rider, which was in place from January 1, 2019 until December 18, 2019. See Note 3 – Regulatory Matters for more information. DP&L sells its proportional share of energy and capacity from its investment in OVEC into the wholesale market. DPL’s other primary subsidiaries include MVIC and AES Ohio Generation. MVIC is our captive insurance company that provides insurance services to DPL and our other subsidiaries. AES Ohio Generation's only operating asset is an undivided interest in Conesville. AES Ohio Generation sells all of its energy and capacity into the wholesale market. DPL's subsidiaries are all wholly-owned. DPL also has a wholly-owned business trust, DPL Capital Trust II, formed for the purpose of issuing trust capital securities to investors. DP&L’s electric transmission and distribution businesses are subject to rate regulation by federal and state regulators. Accordingly, DP&L applies the accounting standards for regulated operations to its electric transmission and distribution businesses and records regulatory assets when incurred costs are expected to be recovered in future customer rates, and regulatory liabilities when current cost recoveries in customer rates relate to expected future costs. DPL and its subsidiaries employed 625 people as of March 31, 2020 , of which 622 were employed by DP&L. Approximately 58% of all DPL employees are under a collective bargaining agreement, which expires October 31, 2020 . Financial Statement Presentation DPL’s Condensed Consolidated Financial Statements include the accounts of DPL and its wholly-owned subsidiaries except for DPL Capital Trust II, which is not consolidated, consistent with the provisions of GAAP. As of March 31, 2020 , AES Ohio Generation has an undivided ownership interest in one coal-fired generating facility, which is included in the financial statements at a carrying value of zero as it has been fully impaired. Operating revenues and expenses of this facility are included on a pro rata basis in the corresponding lines in the Condensed Consolidated Statements of Operations. Certain immaterial amounts from prior periods have been reclassified to conform to the current period presentation. All material intercompany accounts and transactions are eliminated in consolidation. We have evaluated subsequent events through the date this report is issued. These financial statements have been prepared in accordance with GAAP for interim financial statements, the instructions of Form 10-Q and Regulation S-X. Accordingly, certain information and footnote disclosures normally included in the annual financial statements prepared in accordance with GAAP have been omitted from this interim report. Therefore, our interim financial statements in this report should be read along with the annual financial statements included in our Form 10-K for the fiscal year ended December 31, 2019 . In the opinion of our management, the Condensed Consolidated Financial Statements presented in this report contain all adjustments necessary to fairly state our financial position as of March 31, 2020 ; our results of operations for the three months ended March 31, 2020 and 2019 , our cash flows for the three months ended March 31, 2020 and 2019 and the changes in our equity for the three months ended March 31, 2020 and 2019 . Unless otherwise noted, all adjustments are normal and recurring in nature. Due to various factors, interim results for the three months ended March 31, 2020 may not be indicative of our results that will be realized for the full year ending December 31, 2020 . The preparation of financial statements in conformity with GAAP requires us to make estimates and judgments that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities, and the revenues and expenses of the periods reported. Actual results could differ from these estimates. Significant items subject to such estimates and judgments include: recognition of revenue including unbilled revenues, the carrying value of property, plant and equipment; the valuation of derivative instruments; the valuation of insurance and claims liabilities; the valuation of allowances for credit losses and deferred income taxes; regulatory assets and liabilities; liabilities recorded for income tax exposures; litigation; contingencies; the valuation of AROs; and assets and liabilities related to employee benefits. Cash, Cash Equivalents, and Restricted Cash The following table provides a summary of cash, cash equivalents, and restricted cash amounts reported on the Condensed Consolidated Balance Sheet that reconcile to the total of such amounts as shown on the Condensed Consolidated Statements of Cash Flows: $ in millions March 31, 2020 December 31, 2019 Cash and cash equivalents $ 39.6 $ 36.5 Restricted cash 14.6 10.5 Cash, Cash Equivalents, and Restricted Cash, End of Period $ 54.2 $ 47.0 Accounting for Taxes Collected from Customers and Remitted to Governmental Authorities DP&L collects certain excise taxes levied by state or local governments from its customers. These taxes are accounted for on a net basis and not included in revenue. The amounts of such taxes collected for the three months ended March 31, 2020 and 2019 were $12.4 million and $13.9 million, respectively. New accounting pronouncements adopted in 2020 – The following table provides a brief description of recently adopted accounting pronouncements that had an impact on our consolidated financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or did not have a material impact on our consolidated financial statements. ASU Number and Name Description Date of Adoption Effect on the financial statements upon adoption 2016-13, 2018-19, 2019-04, 2019-05, 2019-10, 2019-11, 2020-02, 2020-03 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments See discussion of the ASU below. January 1, 2020 See impact upon adoption of the standard below. ASU 2016-13 and its subsequent corresponding updates revised the impairment model for financial assets measured at amortized cost, known as the Current Expected Credit Loss (CECL) model. For trade and other receivables, held-to-maturity debt securities, loans and other instruments, entities are required to use a new forward-looking "expected loss" model that generally will result in the earlier recognition of allowance for losses. For available-for-sale debt securities with unrealized losses, entities measure credit losses as it is done today, except that unrealized losses due to credit-related factors are recognized as an allowance on the balance sheet with a corresponding adjustment to earnings in the income statement. The new current expected credit loss model primarily impacts the calculation of expected credit losses on $61.6 million in gross trade accounts receivable. The application of CECL on our trade accounts receivable did not have a material impact on our condensed consolidated financial statements. New Accounting Pronouncements Issued But Not Yet Effective – The following table provides a brief description of recent accounting pronouncements that could have a material impact on our consolidated financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or are expected to have no material impact on our consolidated financial statements. ASU Number and Name Description Date of Adoption Effect on the financial statements upon adoption 2020-04, Reference Rate Form (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting The standard provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions that reference to LIBOR or another reference rate expected to be discontinued by reference rate reform. April 1, 2020 - December 31, 2022 We are currently evaluating the impact of adopting the standard on our condensed consolidated financial statements. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting For Income Taxes The standard removes certain exceptions for recognizing deferred taxes for investments, performing intraperiod allocation and calculating income taxes in interim periods. It also adds guidance to reduce complexity in certain areas, including recognizing deferred taxes for tax goodwill and allocating taxes to members of a consolidated group. January 1, 2021. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our condensed consolidated financial statements.
THE DAYTON POWER AND LIGHT COMPANY [Member]
Significant Accounting Policies [Line Items]
Overview and Summary of Significant Accounting Policies	Overview and Summary of Significant Accounting Policies Description of Business DP&L is a public utility incorporated in 1911 under the laws of Ohio. Beginning in 2001, Ohio law gave Ohio consumers the right to choose the electric generation supplier from whom they purchase retail generation service; however, retail transmission and distribution services are still regulated. DP&L has the exclusive right to provide such transmission and distribution services to approximately 527,000 customers located in West Central Ohio. Additionally, DP&L provides retail SSO electric service to residential, commercial, industrial and governmental customers in a 6,000 - square mile area of West Central Ohio. As a result of Generation Separation, DP&L now only has one reportable segment, the Utility segment. In addition to DP&L's electric transmission and distribution businesses, the Utility segment includes revenues and costs associated with DP&L's investment in OVEC and the historical results of DP&L’s Beckjord and Hutchings Coal generating facilities, which have either been sold or closed. Principal industries located in DP&L’s service territory include automotive, food processing, paper, plastic, health care, data management, manufacturing and defense. DP&L's sales typically reflect the seasonal weather patterns and the growth of energy efficiency initiatives. However, the impacts of weather, energy efficiency programs and economic changes in customer demand were almost entirely eliminated in 2019 by DP&L’s Decoupling Rider, which was in place from January 1, 2019 until December 18, 2019. See Note 3 – Regulatory Matters for more information. DP&L sells its proportional share of energy and capacity from its investment in OVEC into the wholesale market. DP&L is a subsidiary of DPL. The terms “we,” “us,” “our” and “ours” are used to refer to DP&L . DP&L’s electric transmission and distribution businesses are subject to rate regulation by federal and state regulators. Accordingly, DP&L applies the accounting standards for regulated operations to its electric transmission and distribution businesses and records regulatory assets when incurred costs are expected to be recovered in future customer rates, and regulatory liabilities when current cost recoveries in customer rates relate to expected future costs. DP&L employed 622 people as of March 31, 2020 . Approximately 58% of DP&L employees are under a collective bargaining agreement, which expires October 31, 2020 . Financial Statement Presentation DP&L does not have any subsidiaries. We have evaluated subsequent events through the date this report is issued. Certain immaterial amounts from prior periods have been reclassified to conform to the current period presentation. These financial statements have been prepared in accordance with GAAP for interim financial statements, the instructions of Form 10-Q and Regulation S-X. Accordingly, certain information and footnote disclosures normally included in the annual financial statements prepared in accordance with GAAP have been omitted from this interim report. Therefore, our interim financial statements in this report should be read along with the annual financial statements included in our Form 10-K for the fiscal year ended December 31, 2019 . In the opinion of our management, the Condensed Financial Statements presented in this report contain all adjustments necessary to fairly state our financial position as of March 31, 2020 ; our results of operations for the three months ended March 31, 2020 and 2019 , our cash flows for the three months ended March 31, 2020 and 2019 and the changes in our equity for the three months ended March 31, 2020 and 2019 . Unless otherwise noted, all adjustments are normal and recurring in nature. Due to various factors, interim results for the three months ended March 31, 2020 may not be indicative of our results that will be realized for the full year ending December 31, 2020 . The preparation of financial statements in conformity with GAAP requires us to make estimates and judgments that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities, and the revenues and expenses of the periods reported. Actual results could differ from these estimates. Significant items subject to such estimates and judgments include: recognition of revenue including unbilled revenues, the carrying value of property, plant and equipment; the valuation of derivative instruments; the valuation of insurance and claims liabilities; the valuation of allowances for credit losses and deferred income taxes; regulatory assets and liabilities; liabilities recorded for income tax exposures; litigation; contingencies; the valuation of AROs; and assets and liabilities related to employee benefits. Cash, Cash Equivalents, and Restricted Cash The following table provides a summary of cash, cash equivalents, and restricted cash amounts reported on the Condensed Balance Sheet that reconcile to the total of such amounts as shown on the Condensed Statements of Cash Flows: $ in millions March 31, 2020 December 31, 2019 Cash and cash equivalents $ 7.3 $ 10.8 Restricted cash 14.6 10.5 Cash, Cash Equivalents, and Restricted Cash, End of Period $ 21.9 $ 21.3 Accounting for Taxes Collected from Customers and Remitted to Governmental Authorities DP&L collects certain excise taxes levied by state or local governments from its customers. These taxes are accounted for on a net basis and not included in revenue. The amounts of such taxes collected for the three months ended March 31, 2020 and 2019 were $12.4 million and $13.9 million, respectively. New accounting pronouncements adopted in 2020 – The following table provides a brief description of recently adopted accounting pronouncements that had an impact on our financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or did not have a material impact on our financial statements. ASU Number and Name Description Date of Adoption Effect on the financial statements upon adoption 2016-13, 2018-19, 2019-04, 2019-05, 2019-10, 2019-11, 2020-02, 2020-03 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments See discussion of the ASU below. January 1, 2020 See impact upon adoption of the standard below. ASU 2016-13 and its subsequent corresponding updates revised the impairment model for financial assets measured at amortized cost, known as the Current Expected Credit Loss (CECL) model. For trade and other receivables, held-to-maturity debt securities, loans and other instruments, entities are required to use a new forward-looking "expected loss" model that generally will result in the earlier recognition of allowance for losses. For available-for-sale debt securities with unrealized losses, entities measure credit losses as it is done today, except that unrealized losses due to credit-related factors are recognized as an allowance on the balance sheet with a corresponding adjustment to earnings in the income statement. The new current expected credit loss model primarily impacts the calculation of expected credit losses on $60.4 million in gross trade accounts receivable. The application of CECL on our trade accounts receivable did not have a material impact on our condensed financial statements. New Accounting Pronouncements Issued But Not Yet Effective – The following table provides a brief description of recent accounting pronouncements that could have a material impact on our financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or are expected to have no material impact on our financial statements. ASU Number and Name Description Date of Adoption Effect on the financial statements upon adoption 2020-04, Reference Rate Form (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting The standard provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions that reference to LIBOR or another reference rate expected to be discontinued by reference rate reform. April 1, 2020 - December 31, 2022 We are currently evaluating the impact of adopting the standard on our condensed financial statements. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting For Income Taxes The standard removes certain exceptions for recognizing deferred taxes for investments, performing intraperiod allocation and calculating income taxes in interim periods. It also adds guidance to reduce complexity in certain areas, including recognizing deferred taxes for tax goodwill and allocating taxes to members of a consolidated group. January 1, 2021. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our condensed financial statements.

Supplemental Financial Informat

Supplemental Financial Information	3 Months Ended
	Mar. 31, 2020
Supplemental Financial Information [Line Items]
Supplemental Financial Information	Supplemental Financial Information Accounts receivable are as follows at March 31, 2020 and December 31, 2019 : March 31, December 31, $ in millions 2020 2019 Accounts receivable, net: Customer receivables $ 45.7 $ 46.3 Unbilled revenue 15.9 19.4 Amounts due from affiliates 0.2 0.3 Due from PJM transmission enhancement settlement 1.8 1.8 Other 2.0 1.2 Allowance for credit losses (0.7 ) (0.4 ) Total accounts receivable, net $ 64.9 $ 68.6 The following table is a rollforward of our allowance for credit losses related to the accounts receivable balances for the three months ended March 31, 2020 : $ in millions Beginning Allowance Balance at January 1, 2020 Current Period Provision Write-offs Charged Against Allowances Ending Allowance Balance at March 31, 2020 Allowance for credit losses $ 0.4 $ 0.4 $ (0.1 ) $ 0.7 The allowance for credit losses primarily relates to utility customer receivables, including unbilled amounts. Expected credit loss estimates are developed by disaggregating customers into those with similar credit risk characteristics and using historical credit loss experience. In addition, we also consider how current and future economic conditions would impact collectability, as applicable, including the economic impacts of the COVID-19 pandemic on our receivable balance as of March 31, 2020. Amounts are written off when reasonable collections efforts have been exhausted. Inventories are as follows at March 31, 2020 and December 31, 2019 : March 31, December 31, $ in millions 2020 2019 Inventories, at average cost: Fuel and limestone $ 1.3 $ 3.5 Materials and supplies 9.4 10.6 Total inventories, at average cost $ 10.7 $ 14.1 Accumulated Other Comprehensive Income / (Loss) The amounts reclassified out of Accumulated Other Comprehensive Income / (Loss) by component during the three months ended March 31, 2020 and 2019 are as follows: Details about Accumulated Other Comprehensive Income / (Loss) components Affected line item in the Condensed Consolidated Statements of Operations Three months ended March 31, $ in millions 2020 2019 Gains and losses on cash flow hedges (Note 5): Interest expense $ (0.4 ) $ (0.3 ) Income tax expense 0.1 0.1 Net of income taxes (0.3 ) (0.2 ) Amortization of defined benefit pension items (Note 8): Other expense 0.3 0.1 Income tax benefit — — Net of income taxes 0.3 0.1 Total reclassifications for the period, net of income taxes $ — $ (0.1 ) The changes in the components of Accumulated Other Comprehensive Income / (Loss) during the three months ended March 31, 2020 are as follows: $ in millions Gains / (losses) on cash flow hedges Change in unfunded pension and postretirement benefit obligation Total Balance at January 1, 2020 $ 14.5 $ (18.1 ) $ (3.6 ) Other comprehensive loss before reclassifications (0.3 ) — (0.3 ) Amounts reclassified from AOCI to earnings (0.3 ) 0.3 — Net current period other comprehensive income / (loss) (0.6 ) 0.3 (0.3 ) Balance at March 31, 2020 $ 13.9 $ (17.8 ) $ (3.9 )
THE DAYTON POWER AND LIGHT COMPANY [Member]
Supplemental Financial Information [Line Items]
Supplemental Financial Information	Supplemental Financial Information Accounts receivable are as follows at March 31, 2020 and December 31, 2019 : March 31, December 31, $ in millions 2020 2019 Accounts receivable, net: Customer receivables $ 44.5 $ 45.0 Unbilled revenue 15.9 19.4 Amounts due from affiliates 4.6 3.9 Due from PJM transmission enhancement settlement 1.8 1.8 Other 2.1 1.2 Allowance for credit losses (0.7 ) (0.4 ) Total accounts receivable, net $ 68.2 $ 70.9 The following table is a rollforward of our allowance for credit losses related to the accounts receivable balances for the three months ended March 31, 2020 : $ in millions Beginning Allowance Balance at January 1, 2020 Current Period Provision Write-offs Charged Against Allowances Ending Allowance Balance at March 31, 2020 Allowance for credit losses $ 0.4 $ 0.4 $ (0.1 ) $ 0.7 The allowance for credit losses primarily relates to utility customer receivables, including unbilled amounts. Expected credit loss estimates are developed by disaggregating customers into those with similar credit risk characteristics and using historical credit loss experience. In addition, we also consider how current and future economic conditions would impact collectability, as applicable, including the economic impacts of the COVID-19 pandemic on our receivable balance as of March 31, 2020. Amounts are written off when reasonable collections efforts have been exhausted. Inventories are made up of materials and supplies at March 31, 2020 and December 31, 2019 . Accumulated Other Comprehensive Income / (Loss) The amounts reclassified out of Accumulated Other Comprehensive Loss by component during the three months ended March 31, 2020 and 2019 are as follows: Details about Accumulated Other Comprehensive Income / (Loss) components Affected line item in the Condensed Statements of Operations Three months ended March 31, $ in millions 2020 2019 Gains and losses on cash flow hedges (Note 5): Interest expense $ (0.1 ) $ (0.1 ) Income tax expense — — Net of income taxes (0.1 ) (0.1 ) Amortization of defined benefit pension items (Note 8): Other expense 1.0 0.9 Income tax expense / (benefit) (0.2 ) (0.2 ) Net of income taxes 0.8 0.7 Total reclassifications for the period, net of income taxes $ 0.7 $ 0.6 The changes in the components of Accumulated Other Comprehensive Loss during the three months ended March 31, 2020 are as follows: $ in millions Gains / (losses) on cash flow hedges Change in unfunded pension and postretirement benefit obligation Total Balance at January 1, 2020 $ (0.4 ) $ (36.5 ) $ (36.9 ) Other comprehensive loss before reclassifications (0.3 ) — (0.3 ) Amounts reclassified from AOCI to earnings (0.1 ) 0.8 0.7 Net current period other comprehensive income / (loss) (0.4 ) 0.8 0.4 Balance at March 31, 2020 $ (0.8 ) $ (35.7 ) $ (36.5 )

Regulatory Matters (Notes)

Regulatory Matters (Notes)	3 Months Ended
	Mar. 31, 2020
Schedule of Regulatory Assets and Liabilities [Text Block]	Regulatory Matters DP&L ESP Orders Ohio law requires utilities to file either an ESP or MRO plan to establish SSO rates. From November 1, 2017 through December 18, 2019, DP&L operated pursuant to an approved ESP plan, which was initially filed on March 13, 2017 (ESP 3). On November 21, 2019, the PUCO issued a supplemental order modifying ESP 3, and as a result DP&L filed a Notice of Withdrawal of its ESP 3 Application and requested to revert to the ESP rates that were in effect prior to ESP 3. The Notice of Withdrawal was approved by the PUCO on December 18, 2019. The PUCO order required, among other things, DP&L to conduct both an ESP v. MRO Test to validate that the ESP is expected to be more favorable in the aggregate than what would be experienced under an MRO, and a prospective SEET, which were filed with the PUCO on April 1, 2020. A comment period is set for July 2020 and an evidentiary hearing regarding this matter is scheduled for October 2020 (if needed) with a final ruling expected in early 2021. DP&L is also subject to an annual retrospective SEET. The ultimate outcome of the ESP v. MRO and SEET proceedings could have a material adverse effect on DP&L’s results of operations, financial condition and cash flows. Certain parties which intervened in the ESP proceedings have filed petitions for rehearing of the recent PUCO ESP orders; some of which seek to eliminate DP&L’s RSC from the ESP 1 rates that are currently in place and others seek to re-implement the 2017 ESP, but without the DMR. We are unable to predict the outcomes of these petitions, but if these result in terms that are more adverse than DP&L's current ESP rate plan, it could have a material adverse effect on our results of operations, financial condition and cash flows. On January 23, 2020 DP&L filed with the PUCO requesting approval to defer its decoupling costs consistent with the methodology approved in its Distribution Rate Case. If approved, deferral would be effective December 18, 2019 and going forward would reduce impacts of weather, energy efficiency programs and economic changes in customer demand. In response to the PUCO’s COVID-19 emergency orders, DP&L filed an Application on March 23, 2020, requesting waivers of certain rule and tariff requirements and deferral of certain costs and revenues including those related to deposits and reconnection fees, late payment fees, credit card fees; and waived or uncollected amounts associated with putting customers on payment plans. On April 15, 2020, DP&L filed a Supplemental Application related to the COVID-19 emergency requesting certain tariff modifications for commercial and industrial customers, and deferral of the amounts associated with waiving minimum demand charges. See Note 14 – Risks and Uncertainties for additional information regarding the COVID-19 pandemic. FERC Proceedings On November 15, 2018 FERC issued a Notice of Proposed Rulemaking (NOPR) to address amortization of excess accumulated deferred income taxes resulting from the TCJA and their impact on transmission rates. Such notice requires all public utility transmission providers with stated transmission rates under an Open Access Transmission Tariff (OATT) to determine the amount of excess deferred income taxes caused by the TCJA. On March 3, 2020, DP&L filed an application before the FERC to change its transmission rate from a stated rate to a formula rate, which was accepted by the FERC and made effective as of May 3, 2020, subject to further proceeding and potential refunds. The formula rate includes adjustments to flow back over time the excess deferred income taxes caused by the TCJA. The NOPR, therefore, no longer applies to DP&L. The rate changes will increase revenues by approximately $4.1 million through the end of 2020, subject to refund based on final approved rates.
Subsidiaries [Member]
Schedule of Regulatory Assets and Liabilities [Text Block]	Regulatory Matters DP&L ESP Orders Ohio law requires utilities to file either an ESP or MRO plan to establish SSO rates. From November 1, 2017 through December 18, 2019, DP&L operated pursuant to an approved ESP plan, which was initially filed on March 13, 2017 (ESP 3). On November 21, 2019, the PUCO issued a supplemental order modifying ESP 3, and as a result DP&L filed a Notice of Withdrawal of its ESP 3 Application and requested to revert to the ESP rates that were in effect prior to ESP 3. The Notice of Withdrawal was approved by the PUCO on December 18, 2019. The PUCO order required, among other things, DP&L to conduct both an ESP v. MRO Test to validate that the ESP is expected to be more favorable in the aggregate than what would be experienced under an MRO, and a prospective SEET, which were filed with the PUCO on April 1, 2020. A comment period is set for July 2020 and an evidentiary hearing regarding this matter is scheduled for October 2020 (if needed) with a final ruling expected in early 2021. DP&L is also subject to an annual retrospective SEET. The ultimate outcome of the ESP v. MRO and SEET proceedings could have a material adverse effect on DP&L’s results of operations, financial condition and cash flows. Certain parties which intervened in the ESP proceedings have filed petitions for rehearing of the recent PUCO ESP orders; some of which seek to eliminate DP&L’s RSC from the ESP 1 rates that are currently in place and others seek to re-implement the 2017 ESP, but without the DMR. We are unable to predict the outcomes of these petitions, but if these result in terms that are more adverse than DP&L's current ESP rate plan, it could have a material adverse effect on our results of operations, financial condition and cash flows. On January 23, 2020 DP&L filed with the PUCO requesting approval to defer its decoupling costs consistent with the methodology approved in its Distribution Rate Case. If approved, deferral would be effective December 18, 2019 and going forward would reduce impacts of weather, energy efficiency programs and economic changes in customer demand. In response to the PUCO’s COVID-19 emergency orders, DP&L filed an Application on March 23, 2020, requesting waivers of certain rule and tariff requirements and deferral of certain costs and revenues including those related to deposits and reconnection fees, late payment fees, credit card fees; and waived or uncollected amounts associated with putting customers on payment plans. On April 15, 2020, DP&L filed a Supplemental Application related to the COVID-19 emergency requesting certain tariff modifications for commercial and industrial customers, and deferral of the amounts associated with waiving minimum demand charges. See Note 11 – Risks and Uncertainties for additional information regarding the COVID-19 pandemic. FERC Proceedings On November 15, 2018 FERC issued a Notice of Proposed Rulemaking (NOPR) to address amortization of excess accumulated deferred income taxes resulting from the TCJA and their impact on transmission rates. Such notice requires all public utility transmission providers with stated transmission rates under an Open Access Transmission Tariff (OATT) to determine the amount of excess deferred income taxes caused by the TCJA. On March 3, 2020, DP&L filed an application before the FERC to change its transmission rate from a stated rate to a formula rate, which was accepted by the FERC and made effective as of May 3, 2020, subject to further proceeding and potential refunds. The formula rate includes adjustments to flow back over time the excess deferred income taxes caused by the TCJA. The NOPR, therefore, no longer applies to DP&L. The rate changes will increase revenues by approximately $4.1 million through the end of 2020, subject to refund based on final approved rates.

Fair Value

Fair Value	3 Months Ended
	Mar. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	Fair Value The fair value of current financial assets and liabilities, debt service reserves and other deposits approximate their reported carrying amounts. The estimated fair values of our assets and liabilities have been determined using available market information. By virtue of these amounts being estimates and based on hypothetical transactions to sell assets or transfer liabilities, the use of different market assumptions and/or estimation methodologies may have a material effect on the estimated fair value amounts. For further information on our valuation techniques and policies, see Note 5— Fair Value in Item 8. — Financial Statements and Supplementary Data of our Form 10-K. The following table presents the fair value, carrying value and cost of our non-derivative instruments at March 31, 2020 and December 31, 2019 . Further information about the fair value of our derivative instruments can be found in Note 5 – Derivative Instruments and Hedging Activities . March 31, 2020 December 31, 2019 $ in millions Cost Fair Value Cost Fair Value Assets Money market funds $ 0.2 $ 0.2 $ 0.3 $ 0.3 Equity securities 2.1 3.1 2.3 4.2 Debt securities 4.1 4.0 4.0 4.1 Hedge funds — — 0.1 0.1 Tangible assets — — 0.1 0.1 Total Assets $ 6.4 $ 7.3 $ 6.8 $ 8.8 Carrying Value Fair Value Carrying Value Fair Value Liabilities Long-term debt $ 1,363.6 $ 1,376.6 $ 1,363.1 $ 1,404.0 These financial instruments are not subject to master netting agreements or collateral requirements and as such are presented in the Condensed Consolidated Balance Sheet at their gross fair value, except for Long-term debt, which is presented at amortized carrying value. We did not have any transfers of the fair values of our financial instruments between Level 1, Level 2 or Level 3 of the fair value hierarchy during the three months ended March 31, 2020 or 2019 . Master Trust Assets DP&L established a Master Trust to hold assets that could be used for the benefit of employees participating in employee benefit plans and these assets are not used for general operating purposes. These assets are primarily comprised of open-ended mutual funds, which are valued using the net asset value per unit. These investments are recorded at fair value within Other deferred assets on the Condensed Consolidated Balance Sheets and classified as equity investments. We recorded net unrealized gains / (losses) of $(1.1) million and $0.5 million during the during the three months ended March 31, 2020 and 2019, respectively. Long-term debt The fair value of debt is based on current public market prices for disclosure purposes only. Unrealized gains or losses are not recognized in the financial statements as long-term debt is presented at carrying value, net of unamortized premium or discount and unamortized deferred financing costs in the financial statements. The long-term debt amounts include the current portion payable in the next twelve months and have maturities that range from 2020 to 2061 . The fair value of assets and liabilities at March 31, 2020 and December 31, 2019 and the respective category within the fair value hierarchy for DPL is as follows: $ in millions Fair value at March 31, 2020 (a) Fair value at December 31, 2019 (a) Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets Master Trust assets Money market funds $ 0.2 $ — $ — $ 0.2 $ 0.3 $ — $ — $ 0.3 Equity securities — 3.1 — 3.1 — 4.2 — 4.2 Debt securities — 4.0 — 4.0 — 4.1 — 4.1 Hedge funds — — — — — 0.1 — 0.1 Tangible assets — — — — — 0.1 — 0.1 Total Master Trust assets 0.2 7.1 — 7.3 0.3 8.5 — 8.8 Derivative assets Interest rate hedges — — — — — 0.1 — 0.1 Total Derivative assets — — — — — 0.1 — 0.1 Total Assets $ 0.2 $ 7.1 $ — $ 7.3 $ 0.3 $ 8.6 $ — $ 8.9 Liabilities Derivative liabilities Interest rate hedges $ — $ 0.3 $ — $ 0.3 $ — $ — $ — $ — Long-term debt — 1,359.1 17.5 1,376.6 — 1,386.5 17.5 1,404.0 Total Liabilities $ — $ 1,359.4 $ 17.5 $ 1,376.9 $ — $ 1,386.5 $ 17.5 $ 1,404.0 (a) Includes credit valuation adjustment Our financial instruments are valued using the market approach in the following categories: • Level 1 inputs are used for money market accounts that are considered cash equivalents. The fair value is determined by reference to quoted market prices and other relevant information generated by market transactions. • Level 2 inputs are used to value derivatives such as interest rate hedge contracts which are valued using a benchmark interest rate. Other Level 2 assets include open-ended mutual funds in the Master Trust, which are valued using the end of day NAV per unit. • Level 3 inputs such as certain debt balances are considered a Level 3 input because the notes are not publicly traded. Our long-term debt is fair valued for disclosure purposes only. All of the inputs to the fair value of our derivative instruments are from quoted market prices. Our long-term debt is fair valued for disclosure purposes only and most of the fair values are determined using quoted market prices in inactive markets. These fair value inputs are considered Level 2 in the fair value hierarchy. As the Wright-Patterson Air Force Base note is not publicly traded, the fair value inputs are considered Level 3 in the fair value hierarchy as there are no observable inputs. Additional Level 3 disclosures are not presented since our long-term debt is not recorded at fair value.
THE DAYTON POWER AND LIGHT COMPANY [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	Fair Value The fair value of current financial assets and liabilities, debt service reserves and other deposits approximate their reported carrying amounts. The estimated fair values of our assets and liabilities have been determined using available market information. By virtue of these amounts being estimates and based on hypothetical transactions to sell assets or transfer liabilities, the use of different market assumptions and/or estimation methodologies may have a material effect on the estimated fair value amounts. For further information on our valuation techniques and policies, see Note 5— Fair Value in Item 8. — Financial Statements and Supplementary Data of our Form 10-K. The following table presents the fair value, carrying value and cost of our non-derivative instruments at March 31, 2020 and December 31, 2019 . Further information about the fair value of our derivative instruments can be found in Note 5 – Derivative Instruments and Hedging Activities . March 31, 2020 December 31, 2019 $ in millions Cost Fair Value Cost Fair Value Assets Money market funds $ 0.2 $ 0.2 $ 0.3 $ 0.3 Equity securities 2.1 3.1 2.3 4.2 Debt securities 4.1 4.0 4.0 4.1 Hedge funds — — 0.1 0.1 Tangible assets — — 0.1 0.1 Total assets $ 6.4 $ 7.3 $ 6.8 $ 8.8 Carrying Value Fair Value Carrying Value Fair Value Liabilities Long-term debt $ 574.5 $ 601.1 $ 574.4 $ 600.5 These financial instruments are not subject to master netting agreements or collateral requirements and as such are presented in the Condensed Balance Sheet at their gross fair value, except for Long-term debt, which is presented at amortized carrying value. We did not have any transfers of the fair values of our financial instruments between Level 1, Level 2 or Level 3 of the fair value hierarchy during the three months ended March 31, 2020 or 2019 . Master Trust Assets DP&L established a Master Trust to hold assets that could be used for the benefit of employees participating in employee benefit plans and these assets are not used for general operating purposes. These assets are primarily comprised of open-ended mutual funds, which are valued using the net asset value per unit. These investments are recorded at fair value within Other deferred assets on the Condensed Balance Sheets and classified as equity investments. We recorded net unrealized gains / (losses) of $(1.1) million and $0.5 million during the during the three months ended March 31, 2020 and 2019, respectively. Long-term debt The fair value of debt is based on current public market prices for disclosure purposes only. Unrealized gains or losses are not recognized in the financial statements as long-term debt is presented at carrying value, net of unamortized premium or discount and unamortized deferred financing costs in the financial statements. The long-term debt amounts include the current portion payable in the next twelve months and have maturities that range from 2020 to 2061 . The fair value of assets and liabilities at March 31, 2020 and December 31, 2019 and the respective category within the fair value hierarchy for DP&L is as follows: $ in millions Fair value at March 31, 2020 (a) Fair value at December 31, 2019 (a) Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets Master Trust assets Money market funds $ 0.2 $ — $ — $ 0.2 $ 0.3 $ — $ — $ 0.3 Equity securities — 3.1 — 3.1 — 4.2 — 4.2 Debt securities — 4.0 — 4.0 — 4.1 — 4.1 Hedge funds — — — — — 0.1 — 0.1 Tangible assets — — — — — 0.1 — 0.1 Total Master Trust assets 0.2 7.1 — 7.3 0.3 8.5 — 8.8 Derivative assets Interest rate hedges — — — — — 0.1 — 0.1 Total derivative assets — — — — — 0.1 — 0.1 Total assets $ 0.2 $ 7.1 $ — $ 7.3 $ 0.3 $ 8.6 $ — $ 8.9 Liabilities Derivative liabilities Interest rate hedges $ — $ 0.3 $ — $ 0.3 $ — $ — $ — $ — Long-term debt — 583.6 17.5 601.1 — 583.0 17.5 600.5 Total liabilities $ — $ 583.9 $ 17.5 $ 601.4 $ — $ 583.0 $ 17.5 $ 600.5 (a) Includes credit valuation adjustment Our financial instruments are valued using the market approach in the following categories: • Level 1 inputs are used for money market accounts that are considered cash equivalents. The fair value is determined by reference to quoted market prices and other relevant information generated by market transactions. • Level 2 inputs are used to value derivatives such as interest rate hedge contracts which are valued using a benchmark interest rate. Other Level 2 assets include open-ended mutual funds in the Master Trust, which are valued using the end of day NAV per unit. • Level 3 inputs such as certain debt balances are considered a Level 3 input because the notes are not publicly traded. Our long-term debt is fair valued for disclosure purposes only. All of the inputs to the fair value of our derivative instruments are from quoted market prices. Our long-term debt is fair valued for disclosure purposes only and most of the fair values are determined using quoted market prices in inactive markets. These fair value inputs are considered Level 2 in the fair value hierarchy. As the Wright-Patterson Air Force Base note is not publicly traded, the fair value inputs are considered Level 3 in the fair value hierarchy as there are no observable inputs. Additional Level 3 disclosures are not presented since our long-term debt is not recorded at fair value.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	3 Months Ended
	Mar. 31, 2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities In the normal course of business, DPL enters into various financial instruments, including derivative financial instruments. We use derivatives principally to manage the interest rate risk associated with our long-term debt. The derivatives that we use to economically hedge these risks are governed by our risk management policies for forward and futures contracts. Our net positions are continually assessed within our structured hedging programs to determine whether new or offsetting transactions are required. We monitor and value derivative positions monthly as part of our risk management processes. We use published sources for pricing, when possible, to mark positions to market. All of our derivative instruments are used for risk management purposes and are designated as cash flow hedges if they qualify under FASC 815 for accounting purposes. Cash Flow Hedges As part of our risk management processes, we identify the relationships between hedging instruments and hedged items, as well as the risk management objective and strategy for undertaking various hedge transactions. The fair values of cash flow hedges determined by current public market prices will continue to fluctuate with changes in market prices up to contract expiration. With the adoption of ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted improvements to Accounting for Hedging Activities effective January 1, 2019, we are no longer required to calculate effectiveness and thus the entire change in the fair value of a hedging instrument is recorded in other comprehensive income and amounts deferred will be reclassified to earnings in the same income statement line as the hedged item in the period in which it settles. As of March 31, 2020 , we have two interest rate swaps to hedge the variable interest on our $140.0 million variable interest rate tax-exempt First Mortgage Bonds. The interest rate swaps have a combined notional amount of $140.0 million and settle monthly based on a one-month LIBOR. The AOCI associated with the swaps will be amortized out of AOCI into interest expense over the remaining life of the underlying debt. We had previously entered into interest rate derivative contracts to manage interest rate exposure related to anticipated borrowings of fixed-rate debt. These interest rate derivative contracts were settled in 2013 and we continue to amortize amounts out of AOCI into interest expense. The following tables provide information concerning gains or losses recognized in AOCI for the cash flow hedges for the three months ended March 31, 2020 and 2019 : Three months ended March 31, 2020 March 31, 2019 Interest Interest $ in millions (net of tax) Rate Hedge Rate Hedge Power Beginning accumulated derivative gains in AOCI $ 14.5 $ 16.6 $ 0.4 Net losses associated with current period hedging transactions (0.3 ) (0.3 ) — Net gains reclassified to earnings Interest expense (0.3 ) (0.2 ) — Ending accumulated derivative gains in AOCI $ 13.9 $ 16.1 $ 0.4 Portion expected to be reclassified to earnings in the next twelve months $ (1.1 ) Maximum length of time that we are hedging our exposure to variability in future cash flows related to forecasted transactions (in months) 5 Financial Statement Effect DPL has elected not to offset derivative assets and liabilities and not to offset net derivative positions against the right to reclaim cash collateral pledged (an asset) or the obligation to return cash collateral received (a liability) under derivative agreements. The fair value derivative position of DPL's interest rate swaps are as follows: $ in millions (net of tax) Hedging Designation Balance sheet classification March 31, 2020 December 31, 2019 Interest rate swap Cash Flow Hedge Prepayments and other current assets $ — $ 0.1 Interest rate swap Cash Flow Hedge Accrued and other current liabilities $ (0.3 ) $ —
THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities In the normal course of business, DP&L enters into various financial instruments, including derivative financial instruments. We use derivatives principally to manage the interest rate risk associated with our long-term debt. The derivatives that we use to economically hedge these risks are governed by our risk management policies for forward and futures contracts. Our net positions are continually assessed within our structured hedging programs to determine whether new or offsetting transactions are required. We monitor and value derivative positions monthly as part of our risk management processes. We use published sources for pricing, when possible, to mark positions to market. All of our derivative instruments are used for risk management purposes and are designated as cash flow hedges if they qualify under FASC 815 for accounting purposes. Cash Flow Hedges As part of our risk management processes, we identify the relationships between hedging instruments and hedged items, as well as the risk management objective and strategy for undertaking various hedge transactions. The fair values of cash flow hedges determined by current public market prices will continue to fluctuate with changes in market prices up to contract expiration. With the adoption of ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted improvements to Accounting for Hedging Activities effective January 1, 2019, we are no longer required to calculate effectiveness and thus the entire change in the fair value of a hedging instrument is recorded in other comprehensive income and amounts deferred will be reclassified to earnings in the same income statement line as the hedged item in the period in which it settles. As of March 31, 2020 , we have two interest rate swaps to hedge the variable interest on our $140.0 million variable interest rate tax-exempt First Mortgage Bonds. The interest rate swaps have a combined notional amount of $140.0 million and settle monthly based on a one-month LIBOR. The AOCI associated with the swaps will be amortized out of AOCI into interest expense over the remaining life of the underlying debt. We had previously entered into interest rate derivative contracts to manage interest rate exposure related to anticipated borrowings of fixed-rate debt. These interest rate derivative contracts were settled in 2013 and we continue to amortize amounts out of AOCI into interest expense. The following tables provide information concerning gains or losses recognized in AOCI for the cash flow hedges for the three months ended March 31, 2020 and 2019 : Three months ended March 31, 2020 March 31, 2019 Interest Interest $ in millions (net of tax) Rate Hedge Rate Hedge Beginning accumulated derivative gains / (losses) in AOCI $ (0.4 ) $ 0.6 Net losses associated with current period hedging transactions (0.3 ) (0.2 ) Net gains reclassified to earnings Interest expense (0.1 ) (0.1 ) Ending accumulated derivative gains / (losses) in AOCI $ (0.8 ) $ 0.3 Portion expected to be reclassified to earnings in the next twelve months $ (0.1 ) Maximum length of time that we are hedging our exposure to variability in future cash flows related to forecasted transactions (in months) 5 Financial Statement Effect DP&L has elected not to offset derivative assets and liabilities and not to offset net derivative positions against the right to reclaim cash collateral pledged (an asset) or the obligation to return cash collateral received (a liability) under derivative agreements. The fair value derivative position of DP&L's interest rate swaps are as follows: $ in millions (net of tax) Hedging Designation Balance sheet classification March 31, 2020 December 31, 2019 Interest rate swap Cash Flow Hedge Prepayments and other current assets $ — $ 0.1 Interest rate swap Cash Flow Hedge Accrued and other current liabilities $ (0.3 ) $ —

Debt Obligations

Debt Obligations	3 Months Ended
	Mar. 31, 2020
Debt Instrument [Line Items]
Debt Obligations	Long-term Debt The following table summarizes DPL's long-term debt. Interest March 31, December 31, $ in millions Rate Maturity 2020 2019 First Mortgage Bonds 3.95% 2049 $ 425.0 $ 425.0 Tax-exempt First Mortgage Bonds - rates from 2.40% - 2.93% (a) and 1.29% - 1.42% (b) 2020 140.0 140.0 U.S. Government note 4.20% 2061 17.5 17.5 Unamortized deferred financing costs (5.3 ) (5.4 ) Unamortized debt discounts and premiums, net (2.7 ) (2.7 ) Total long-term debt at DP&L 574.5 574.4 Senior unsecured bonds 7.25% 2021 380.0 380.0 Senior unsecured bonds 4.35% 2029 400.0 400.0 Note to DPL Capital Trust II (c) 8.125% 2031 15.6 15.6 Unamortized deferred financing costs (5.5 ) (5.9 ) Unamortized debt discounts and premiums, net (1.0 ) (1.0 ) Total long-term debt 1,363.6 1,363.1 Less: current portion (139.9 ) (139.8 ) Long-term debt, net of current portion $ 1,223.7 $ 1,223.3 (a) Range of interest rates for the three months ended March 31, 2020 . (b) Range of interest rates for the year ended December 31, 2019 . (c) Note payable to related party. Lines of credit At March 31, 2020 and December 31, 2019 , DPL had outstanding borrowings on its line of credit of $94.0 million and $104.0 million, respectively. At March 31, 2020 and December 31, 2019 , DP&L had outstanding borrowings on its line of credit of $85.0 million and $40.0 million, respectively. Long-term debt covenants and restrictions DPL’s revolving credit agreement has two financial covenants. The first financial covenant, a Total Debt to EBITDA ratio, is calculated at the end of each fiscal quarter by dividing total debt at the end of the current quarter by consolidated EBITDA for the four prior fiscal quarters. The ratio in the agreement is not to exceed 7.00 to 1.00. As of March 31, 2020 , this financial covenant was met with a ratio of 6.75 to 1.00. The second financial covenant is an EBITDA to Interest Expense ratio that is calculated, at the end of each fiscal quarter, by dividing EBITDA for the four prior fiscal quarters by the consolidated interest charges for the same period. The ratio, per the agreement, is to be not less than 2.25 to 1.00. As of March 31, 2020 , this financial covenant was met with a ratio of 3.01 to 1.00. DPL’s secured revolving credit agreement also restricts dividend payments from DPL to AES, such that DPL cannot make dividend payments unless at the time of, and/or as a result of the distribution, (i) DPL’s leverage ratio does not exceed 0.67 to 1.00 and DPL’s interest coverage ratio is not less than 2.50 to 1.00 or, if such ratios are not within the parameters, (ii) DPL’s senior long-term debt rating from two of the three major credit rating agencies is at least investment grade. As a result, as of March 31, 2020, DPL was prohibited from making a distribution to its shareholder or making a loan to any of its affiliates (other than its subsidiaries). DP&L’s Bond Purchase and Covenants Agreement (financing document entered into in connection with the sale of our variable rate tax-exempt First Mortgage Bonds, dated as of August 1, 2015) has two financial covenants. The first measures Total Debt to Total Capitalization and is calculated, at the end of each fiscal quarter, by dividing total debt at the end of the quarter by total capitalization at the end of the quarter. DP&L’s Total Debt to Total Capitalization ratio shall not be greater than 0.65 to 1.00; except that the ratio is suspended as DP&L’s long-term indebtedness is less than or equal to $750.0 million . This financial covenant was met with a ratio of 0.58 to 1.00 as of March 31, 2020 . The second financial covenant measures EBITDA to Interest Expense. The Total Consolidated EBITDA to Consolidated Interest Charges ratio is calculated, at the end of each fiscal quarter, by dividing consolidated EBITDA for the four prior fiscal quarters by the consolidated interest charges for the same period. The ratio, per the agreement, is to be not less than 2.50 to 1.00. This financial covenant was met with a ratio of 7.83 to 1.00 as of March 31, 2020 . DP&L's unsecured revolving credit facility has one financial covenant. The covenant measures Total Debt to Total Capitalization and is calculated, at the end of each fiscal quarter, by dividing total debt at the end of the quarter by total capitalization at the end of the quarter. DP&L’s Total Debt to Total Capitalization ratio shall not be greater than 0.67 to 1.00. This financial covenant was met with a ratio of 0.58 to 1.00 as of March 31, 2020 . As of March 31, 2020 , DPL and DP&L were in compliance with all debt covenants, including the financial covenants described above. DP&L does not have any meaningful restrictions in its debt financing documents prohibiting dividends to its parent, DPL. Substantially all property, plant & equipment of DP&L is subject to the lien of the mortgage securing DP&L’s First and Refunding Mortgage.
THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Debt Obligations	Long-term Debt The following table summarizes DP&L's long-term debt. Interest March 31, December 31, $ in millions Rate Maturity 2020 2019 First Mortgage Bonds 3.95% 2049 $ 425.0 $ 425.0 Tax-exempt First Mortgage Bonds - rates from 2.40% - 2.93% (a) and 1.29% - 1.42% (b) 2020 140.0 140.0 U.S. Government note 4.20% 2061 17.5 17.5 Unamortized deferred financing costs (5.3 ) (5.4 ) Unamortized debt discounts and premiums, net (2.7 ) (2.7 ) Total long-term debt 574.5 574.4 Less: current portion (139.9 ) (139.8 ) Long-term debt, net of current portion $ 434.6 $ 434.6 (a) Range of interest rates for the three months ended March 31, 2020 . (b) Range of interest rates for the year ended December 31, 2019 . Line of credit At March 31, 2020 and December 31, 2019 , DP&L had outstanding borrowings on its line of credit of $85.0 million and $40.0 million, respectively. Long-term debt covenants and restrictions DP&L’s Bond Purchase and Covenants Agreement (financing document entered into in connection with the sale of our variable rate tax-exempt First Mortgage Bonds, dated as of August 1, 2015) has two financial covenants. The first measures Total Debt to Total Capitalization and is calculated, at the end of each fiscal quarter, by dividing total debt at the end of the quarter by total capitalization at the end of the quarter. DP&L’s Total Debt to Total Capitalization ratio shall not be greater than 0.65 to 1.00; except that the ratio is suspended as DP&L’s long-term indebtedness is less than or equal to $750.0 million . This financial covenant was met with a ratio of 0.58 to 1.00 as of March 31, 2020 . The second financial covenant measures EBITDA to Interest Expense. The Total EBITDA to Interest Charges ratio is calculated, at the end of each fiscal quarter, by dividing EBITDA for the four prior fiscal quarters by the interest charges for the same period. The ratio, per the agreement, is to be not less than 2.50 to 1.00. This financial covenant was met with a ratio of 7.83 to 1.00 as of March 31, 2020 . DP&L's unsecured revolving credit facility has one financial covenant. The covenant measures Total Debt to Total Capitalization and is calculated, at the end of each fiscal quarter, by dividing total debt at the end of the quarter by total capitalization at the end of the quarter. DP&L’s Total Debt to Total Capitalization ratio shall not be greater than 0.67 to 1.00. This financial covenant was met with a ratio of 0.58 to 1.00 as of March 31, 2020 . As of March 31, 2020 , DP&L was in compliance with all debt covenants, including the financial covenants described above. DP&L does not have any meaningful restrictions in its debt financing documents prohibiting dividends to its parent, DPL. Substantially all property, plant & equipment of DP&L is subject to the lien of the mortgage securing DP&L’s First and Refunding Mortgage.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2020
Entity Information [Line Items]
Income Taxes	Income Taxes The following table details the effective tax rates for the three months ended March 31, 2020 and 2019 . Three months ended March 31, 2020 2019 DPL (11.8)% 14.3% Income tax expense for the three months ended March 31, 2020 and 2019 was calculated using the estimated annual effective income tax rates for 2020 and 2019 of (14.9)% and 14.3% , respectively. Management estimates the annual effective tax rate based on its forecast of annual pre-tax income. To the extent that actual pre-tax results for the year differ from the forecasts applied to the most recent interim period, the estimated rates could be materially different from the actual effective tax rates. DPL’s effective combined state and federal income tax rate for all operations was (11.8)% for the three months ended March 31, 2020 . This rate is lower than the combined federal and state statutory rate of 22.3% primarily due to the flowthrough of the net tax benefit related to the reversal of excess deferred taxes of DP&L as a percentage of pre-tax book income. For the three months ended March 31, 2020 , DPL’s current period effective tax rate for all operations was not materially different than the estimated annual effective rate when applied to DPL's Income before income tax. AES files federal and state income tax returns which consolidate DPL and its subsidiaries. Under a tax sharing agreement with AES, DPL is responsible for the income taxes associated with its own taxable income and records the provision for income taxes using a separate return method. Effective with the approval of DP&L's 2017 ESP, through November 21, 2019, DPL was restricted from making tax sharing payments to AES throughout the term of the DMR and amounts that would otherwise have been tax sharing liabilities were converted to deemed capital contributions. With the November 21, 2019 order from the PUCO that removed the DMR, this requirement was eliminated.
THE DAYTON POWER AND LIGHT COMPANY [Member]
Entity Information [Line Items]
Income Taxes	Income Taxes The following table details the effective tax rates for the three months ended March 31, 2020 and 2019 . Three months ended March 31, 2020 2019 DP&L 9.3% 17.4% Income tax expense for the three months ended March 31, 2020 and 2019 was calculated using the estimated annual effective income tax rates for 2020 and 2019 of 9.1% and 17.3% , respectively. Management estimates the annual effective tax rate based on its forecast of annual pre-tax income. To the extent that actual pre-tax results for the year differ from the forecasts applied to the most recent interim period, the estimated rates could be materially different from the actual effective tax rates. DP&L’s effective combined state and federal income tax rate was 9.3% . This is lower than the combined federal and state statutory rate of 22.3% primarily due to the net tax benefit related to the reversal of excess deferred taxes as a percentage of pre-tax book income. For the three months ended March 31, 2020 , DP&L’s current period effective tax rate for all operations was not materially different than the estimated annual effective rate.

Benefit Plans

Benefit Plans	3 Months Ended
	Mar. 31, 2020
Entity Information [Line Items]
Pension and Postretirement Benefits	Benefit Plans DP&L sponsors a defined benefit pension plan for the majority of its employees. We generally fund pension plan benefits as accrued in accordance with the minimum funding requirements of ERISA and, in addition, make voluntary contributions from time to time. There were $7.5 million in employer contributions during each of the three-month periods ended March 31, 2020 and 2019. The amounts presented in the following tables for pension include the collective bargaining plan formula, the traditional management plan formula, the cash balance plan formula and the SERP, in the aggregate. The pension costs below have not been adjusted for amounts billed to the Service Company for former DP&L employees who are now employed by the Service Company that are still participants in the DP&L plan. The net periodic benefit cost of the pension benefit plans for the three months ended March 31, 2020 and 2019 was: Three months ended March 31, $ in millions 2020 2019 Service cost $ 0.9 $ 0.9 Interest cost 3.0 3.7 Expected return on plan assets (4.7 ) (5.0 ) Amortization of unrecognized: Prior service cost 0.3 0.3 Actuarial loss 1.5 1.1 Net periodic benefit cost $ 1.0 $ 1.0 In addition, DP&L provides postretirement health care and life insurance benefits to certain retired employees, their spouses and eligible dependents. We have funded a portion of the union-eligible benefits using a Voluntary Employee Beneficiary Association Trust. These postretirement health care benefits and the related unfunded obligation of $9.7 million at March 31, 2020 and $9.6 million at December 31, 2019 were not material to the financial statements in the periods covered by this report.
THE DAYTON POWER AND LIGHT COMPANY [Member]
Entity Information [Line Items]
Pension and Postretirement Benefits	Benefit Plans DP&L sponsors a defined benefit pension plan for the majority of its employees. We generally fund pension plan benefits as accrued in accordance with the minimum funding requirements of ERISA and, in addition, make voluntary contributions from time to time. There were $7.5 million in employer contributions during each of the three-month periods ended March 31, 2020 and 2019. The amounts presented in the following tables for pension include the collective bargaining plan formula, the traditional management plan formula, the cash balance plan formula and the SERP, in the aggregate. The pension costs below have not been adjusted for amounts billed to the Service Company for former DP&L employees who are now employed by the Service Company or for amounts billed to AES Ohio Generation for employees employed by AES Ohio Generation that are still participants in the DP&L plan. The net periodic benefit cost of the pension benefit plans for the three months ended March 31, 2020 and 2019 was: Three months ended March 31, $ in millions 2020 2019 Service cost $ 0.9 $ 0.9 Interest cost 3.0 3.7 Expected return on plan assets (4.7 ) (5.0 ) Amortization of unrecognized: Prior service cost 0.3 0.5 Actuarial loss 2.2 1.7 Net periodic benefit cost $ 1.7 $ 1.8 In addition, DP&L provides postretirement health care and life insurance benefits to certain retired employees, their spouses and eligible dependents. We have funded a portion of the union-eligible benefits using a Voluntary Employee Beneficiary Association Trust. These postretirement health care benefits and the related unfunded obligation of $9.7 million at March 31, 2020 and $9.6 million at December 31, 2019 were not material to the financial statements in the periods covered by this report.

Shareholder's Equity

Shareholder's Equity	3 Months Ended
	Mar. 31, 2020
Class of Stock [Line Items]
Shareholder's Equity	Shareholder's Defici t Capital Contributions from AES In DP&L's six-year 2017 ESP, the PUCO imposed restrictions on DPL making dividend payments to its parent company, AES, during the term of the ESP, as well as on making tax-sharing payments to AES during the term of the DMR. The PUCO also required that existing tax payments owed by DPL to AES, and similar tax payments that accrue during the term of the DMR, be converted into equity investments in DPL . With the November 21, 2019 order from the PUCO that removed the DMR and the subsequent approval of DP&L's ESP 1 rate plan, these requirements were eliminated. See Note 3 – Regulatory Matters in Item 8. — Financial Statements and Supplementary Data of our Form 10-K for additional information on changes to DP&L's ESP and the removal of the DMR. For the three months ended March 31, 2019, AES made capital contributions of $1.5 million by converting the amount owed to it by DPL related to tax-sharing payments for current tax liabilities.

Contractual Obligations, Commer

Contractual Obligations, Commercial Commitments and Contingencies	3 Months Ended
	Mar. 31, 2020
Entity Information [Line Items]
Contractual Obligations, Commercial Commitments and Contingencies	Contractual Obligations, Commercial Commitments and Contingencies Guarantees In the normal course of business, DPL enters into various agreements with its wholly-owned subsidiary, AES Ohio Generation , providing financial or performance assurance to third parties. These agreements are entered into primarily to support or enhance the creditworthiness otherwise attributed to this subsidiary on a stand-alone basis, thereby facilitating the extension of sufficient credit to accomplish this subsidiary's intended commercial purposes. At March 31, 2020 , DPL had $15.5 million of guarantees on behalf of AES Ohio Generation to third parties for future financial or performance assurance under such agreements. The guarantee arrangements entered into by DPL with these third parties cover select present and future obligations of AES Ohio Generation to such beneficiaries and are terminable by DPL upon written notice to the beneficiaries within a certain time. At March 31, 2020 and December 31, 2019 , we had no outstanding balance of obligations covered by these guarantees . To date, DPL has not incurred any losses related to the guarantees of AES Ohio Generation ’s obligations and we believe it is unlikely that DPL would be required to perform or incur any losses in the future associated with any of the above guarantees. Equity Ownership Interest DP&L has a 4.9% equity ownership interest in OVEC, which is recorded using the cost method of accounting under GAAP. DP&L , along with several non-affiliated energy companies party to an OVEC arrangement, receive and pay for OVEC capacity and energy and are responsible for OVEC debt obligations and other fixed costs in proportion to their power participation ratios under the arrangement which, for DP&L, is the same as its equity ownership interest. At March 31, 2020 , DP&L could be responsible for the repayment of 4.9% , or $65.8 million , of $1,343.2 million OVEC debt obligations if they came due, comprised of both fixed and variable rate securities with maturities from 2022 to 2040 . OVEC could also seek additional contributions from DP&L to avoid a default in the event that other OVEC members defaulted on their respective OVEC obligations. Contingencies In the normal course of business, we are subject to various lawsuits, actions, proceedings, claims and other matters asserted under various laws and regulations. We believe the amounts provided in our Condensed Consolidated Financial Statements, as prescribed by GAAP, are adequate considering the probable and estimable contingencies. However, there can be no assurances that the actual amounts required to satisfy alleged liabilities from various legal proceedings, claims, tax examinations and other matters discussed below, and to comply with applicable laws and regulations, will not exceed the amounts reflected in our Condensed Consolidated Financial Statements. As such, costs, if any, that may be incurred in excess of those amounts provided as of March 31, 2020 , cannot be reasonably determined. Environmental Matters DPL’s and DP&L’s facilities and operations are subject to a wide range of federal, state and local environmental regulations and laws. The environmental issues that may affect us include: • The federal CAA and state laws and regulations (including State Implementation Plans) which require compliance, obtaining permits and reporting as to air emissions; • Litigation with federal and certain state governments and certain special interest groups; • Rules and future rules issued by the USEPA, the Ohio EPA or other authorities associated with the federal Clean Water Act, which prohibits the discharge of pollutants into waters of the United States except pursuant to appropriate permits; and • Solid and hazardous waste laws and regulations, which govern the management and disposal of certain waste. The majority of solid waste created from the combustion of coal and fossil fuels consists of fly ash and other coal combustion by-products. In addition to imposing continuing compliance obligations, these laws and regulations authorize the imposition of substantial penalties for noncompliance, including fines, injunctive relief and other sanctions. In the normal course of business, we have investigatory and remedial activities underway at our facilities to comply, or to determine compliance, with such regulations. We record liabilities for loss contingencies related to environmental matters when a loss is probable of occurring and can be reasonably estimated in accordance with the provisions of GAAP. Accordingly, we have immaterial accruals for loss contingencies for environmental matters. We also have several environmental matters for which we have not accrued loss contingencies because the risk of loss is not probable, or a loss cannot be reasonably estimated. We evaluate the potential liability related to environmental matters quarterly and may revise our estimates. Such revisions in the estimates of the potential liabilities could have a material adverse effect on our results of operations, financial condition and cash flows. We have several pending environmental matters associated with our current and previously owned coal-fired generation units. Some of these matters could have a material adverse effect on our results of operations, financial condition and cash flows.
THE DAYTON POWER AND LIGHT COMPANY [Member]
Entity Information [Line Items]
Contractual Obligations, Commercial Commitments and Contingencies	Contractual Obligations, Commercial Commitments and Contingencies Equity Ownership Interest DP&L has a 4.9% equity ownership interest in OVEC, which is recorded using the cost method of accounting under GAAP. DP&L , along with several non-affiliated energy companies party to an OVEC arrangement, receive and pay for OVEC capacity and energy and are responsible for OVEC debt obligations and other fixed costs in proportion to their power participation ratios under the arrangement which, for DP&L, is the same as its equity ownership interest. At March 31, 2020 , DP&L could be responsible for the repayment of 4.9% , or $65.8 million , of $1,343.2 million OVEC debt obligations if they came due, comprised of both fixed and variable rate securities with maturities from 2022 to 2040 . OVEC could also seek additional contributions from DP&L to avoid a default in the event that other OVEC members defaulted on their respective OVEC obligations. Contingencies In the normal course of business, we are subject to various lawsuits, actions, proceedings, claims and other matters asserted under various laws and regulations. We believe the amounts provided in our Condensed Financial Statements, as prescribed by GAAP, are adequate considering the probable and estimable contingencies. However, there can be no assurances that the actual amounts required to satisfy alleged liabilities from various legal proceedings, claims, tax examinations and other matters discussed below, and to comply with applicable laws and regulations, will not exceed the amounts reflected in our Condensed Financial Statements. As such, costs, if any, that may be incurred in excess of those amounts provided as of March 31, 2020 , cannot be reasonably determined. Environmental Matters DP&L’s facilities and operations are subject to a wide range of federal, state and local environmental regulations and laws. The environmental issues that may affect us include: • The federal CAA and state laws and regulations (including State Implementation Plans) which require compliance, obtaining permits and reporting as to air emissions; • Litigation with federal and certain state governments and certain special interest groups; • Rules and future rules issued by the USEPA, the Ohio EPA or other authorities associated with the federal Clean Water Act, which prohibits the discharge of pollutants into waters of the United States except pursuant to appropriate permits; and • Solid and hazardous waste laws and regulations, which govern the management and disposal of certain waste. In addition to imposing continuing compliance obligations, these laws and regulations authorize the imposition of substantial penalties for noncompliance, including fines, injunctive relief and other sanctions. In the normal course of business, we have investigatory and remedial activities underway at our facilities to comply, or to determine compliance, with such regulations. We record liabilities for loss contingencies related to environmental matters when a loss is probable of occurring and can be reasonably estimated in accordance with the provisions of GAAP. Accordingly, we have immaterial accruals for loss contingencies for environmental matters. We also have several environmental matters for which we have not accrued loss contingencies because the risk of loss is not probable, or a loss cannot be reasonably estimated. We evaluate the potential liability related to environmental matters quarterly and may revise our estimates. Such revisions in the estimates of the potential liabilities could have a material adverse effect on our results of operations, financial condition and cash flows.

Business Segments

Business Segments	3 Months Ended
	Mar. 31, 2020
Segment Reporting Information [Line Items]
Business Segments	Business Segments DPL manages its business through one reportable operating segment, the Utility segment. The primary segment performance measure is income / (loss) from continuing operations before income tax as management has concluded that this measure best reflects the underlying business performance of DPL and is the most relevant measure considered in DPL’s internal evaluation of the financial performance of its segment. The Utility segment is discussed further below. Utility Segment The Utility segment is comprised of DP&L’s electric transmission and distribution businesses, which distribute electricity to residential, commercial, industrial and governmental customers. DP&L distributes electricity to more than 527,000 retail customers located in a 6,000 -square mile area of West Central Ohio. DP&L’s electric transmission and distribution businesses are subject to rate regulation by federal and state regulators. Accordingly, DP&L applies the accounting standards for regulated operations to its electric transmission and distribution businesses recording regulatory assets when incurred costs are expected to be recovered in future customer rates and regulatory liabilities when current cost recoveries in customer rates relate to expected future costs. The Utility segment includes revenues and costs associated with our investment in OVEC and DP&L’s Hutchings Coal generating facility, which was closed in 2013. This facility did not transfer to AES Ohio Generation as part of DP&L's Generation Separation on October 1, 2017. Thus, it is grouped within the Utility segment for segment reporting purposes. In addition, regulatory deferrals and collections, which include collections and amortization of fuel deferrals from historical periods, are included in the Utility segment. Included within the “Other” column are other businesses that do not meet the GAAP requirements for disclosure as reportable segments as well as certain corporate costs, which include interest expense and loss on early extinguishment of debt on DPL's long-term debt as well as adjustments related to purchase accounting from the Merger. DPL's undivided interest in Conesville is included within the "Other" column as it does not meet the requirement for disclosure as a reportable operating segment. The accounting policies of the reportable segment are the same as those described in Note 1 – Overview and Summary of Significant Accounting Policies of our 10-K. Intersegment sales, costs of sales and expenses are eliminated in consolidation. Certain shared and corporate costs are allocated between "Other" and the Utility reporting segment. The following tables present financial information for DPL’s Utility reportable business segment: $ in millions Utility Other Adjustments and Eliminations DPL Consolidated Three months ended March 31, 2020 Revenues from external customers $ 168.7 $ 6.0 $ — $ 174.7 Intersegment revenues 0.3 0.8 (1.1 ) — Total revenues $ 169.0 $ 6.8 $ (1.1 ) $ 174.7 Depreciation and amortization $ 17.3 $ 0.5 $ — $ 17.8 Interest expense $ 6.2 $ 12.7 $ — $ 18.9 Income / (loss) from continuing operations before income tax $ 12.9 $ (12.5 ) $ — $ 0.4 Cash capital expenditures $ 43.7 $ 0.9 $ — $ 44.6 $ in millions Utility Other Adjustments and Eliminations DPL Consolidated Three months ended March 31, 2019 Revenues from external customers $ 201.1 $ 7.9 $ — $ 209.0 Intersegment revenues 0.3 0.8 (1.1 ) — Total revenues $ 201.4 $ 8.7 $ (1.1 ) $ 209.0 Depreciation and amortization $ 18.0 $ 0.4 $ — $ 18.4 Interest expense $ 7.1 $ 16.6 $ — $ 23.7 Income / (loss) from continuing operations before income tax $ 35.1 $ (15.9 ) $ — $ 19.2 Cash capital expenditures $ 33.7 $ 0.6 $ — $ 34.3 Total Assets March 31, 2020 December 31, 2019 Utility $ 1,874.6 $ 1,883.2 All Other (a) 43.8 52.6 DPL Consolidated $ 1,918.4 $ 1,935.8 (a) "All Other" includes Total assets related to the assets of discontinued operations and held-for-sale businesses and Eliminations for all periods presented.

Revenue (Notes)

Revenue (Notes)	3 Months Ended
	Mar. 31, 2020
Revenue from Contract with Customer [Text Block]	Revenue Revenue is primarily earned from retail and wholesale electricity sales and electricity transmission and distribution delivery services. Revenue is recognized upon transfer of control to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those goods or services. Revenue is recorded net of any taxes assessed on and collected from customers, which are remitted to the governmental authorities. For further discussion of our Retail, Wholesale, RTO ancillary, and Capacity revenues, see Note 14 — Revenue in Item 8.— Financial Statements and Supplementary Data of our Form 10-K. DPL's revenue from contracts with customers was $170.5 million and $208.3 million for the three months ended March 31, 2020 and 2019, respectively. The following table presents our revenue from contracts with customers and other revenue by segment for the three months ended March 31, 2020 and 2019 : $ in millions Utility Other Adjustments and Eliminations Total Three months ended March 31, 2020 Retail revenue Retail revenue from contracts with customers $ 150.2 $ — $ — $ 150.2 Other retail revenue (a) 3.3 — — 3.3 Wholesale revenue Wholesale revenue from contracts with customers 2.7 2.5 (0.3 ) 4.9 RTO ancillary revenue 10.7 0.1 — 10.8 Capacity revenue 1.2 1.0 — 2.2 Miscellaneous revenue Miscellaneous revenue from contracts with customers (b) — 2.4 — 2.4 Other miscellaneous revenue 0.9 0.8 (0.8 ) 0.9 Total revenues $ 169.0 $ 6.8 $ (1.1 ) $ 174.7 Three months ended March 31, 2019 Retail revenue Retail revenue from contracts with customers $ 182.7 $ — $ (0.3 ) $ 182.4 Other retail revenue (a) 0.7 — — 0.7 Wholesale revenue Wholesale revenue from contracts with customers 5.0 3.4 — 8.4 RTO ancillary revenue 10.9 — — 10.9 Capacity revenue 2.1 1.6 — 3.7 Miscellaneous revenue Miscellaneous revenue from contracts with customers (b) — 2.9 — 2.9 Other miscellaneous revenue — 0.8 (0.8 ) — Total revenues $ 201.4 $ 8.7 $ (1.1 ) $ 209.0 (a) Other retail revenue primarily includes alternative revenue programs not accounted for under FASC 606. (b) Miscellaneous revenue from contracts with customers primarily includes revenues for various services provided by Miami Valley Lighting. The balances of receivables from contracts with customers were $60.3 million and $65.7 million as of March 31, 2020 and December 31, 2019 , respectively. Payment terms for all receivables from contracts with customers are typically within 30 days.
Subsidiaries [Member]
Revenue from Contract with Customer [Text Block]	Revenue Revenue is primarily earned from retail and wholesale electricity sales and electricity transmission and distribution delivery services. Revenue is recognized upon transfer of control to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those goods or services. Revenue is recorded net of any taxes assessed on and collected from customers, which are remitted to the governmental authorities. For further discussion of our Retail, Wholesale, RTO ancillary, and Capacity revenues, see Note 13 — Revenue in Item 8.— Financial Statements and Supplementary Data of our Form 10-K. DP&L's revenue from contracts with customers was $164.8 million and $200.7 million for the three months ended March 31, 2020 and 2019, respectively. The following table presents our revenue from contracts with customers and other revenue for the three months ended March 31, 2020 and 2019 : Three months ended March 31, $ in millions 2020 2019 Retail revenue Retail revenue from contracts with customers $ 150.2 $ 182.7 Other retail revenue (a) 3.3 0.7 Wholesale revenue Wholesale revenue from contracts with customers 2.7 5.0 RTO ancillary revenue 10.7 10.9 Capacity revenue 1.2 2.1 Miscellaneous revenue 0.9 — Total revenues $ 169.0 $ 201.4 (a) Other retail revenue primarily includes alternative revenue programs not accounted for under FASC 606. The balances of receivables from contracts with customers were $59.1 million and $64.4 million as of March 31, 2020 and December 31, 2019 , respectively. Payment terms for all receivables from contracts with customers are typically within 30 days.

Dispositions (Notes)

Dispositions (Notes)	3 Months Ended
	Mar. 31, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operations	Discontinued Operations On May 31, 2018, DPL and AES Ohio Generation retired the Stuart Station coal-fired and diesel-fired generating units and the Killen Station coal-fired generating unit and combustion turbine, as planned. On December 20, 2019, DPL and AES Ohio Generation, together with AES Ohio Generation's joint owners in the retired Stuart and Killen generating facilities, completed the transfer of the retired generating facilities, including the associated environmental liabilities, to an unaffiliated third-party purchaser. Together with the sales of the Peaker Assets in 2018 and Miami Fort and Zimmer in 2017, DPL determined that the disposal of this group of components as a whole represents a strategic shift to exit generation, and, as such, qualifies to be presented as discontinued operations. Therefore, the results of operations, assets and liabilities of this group of components were reported as such in the Condensed Consolidated Statements of Operations and Condensed Consolidated Balance Sheets for all periods presented. The following table summarizes the major categories of assets and liabilities at the dates indicated: $ in millions March 31, 2020 December 31, 2019 Accounts receivable, net $ 1.8 $ 17.4 Prepayments and other current assets 0.1 0.3 Total assets of the disposal group classified as assets of discontinued operations and held-for-sale businesses in the balance sheets $ 1.9 $ 17.7 Accounts payable $ 3.4 $ 3.8 Accrued and other current liabilities 2.5 3.1 Other non-current liabilities 6.2 6.2 Total liabilities of the disposal group classified as liabilities of discontinued operations and held-for-sale businesses in the balance sheets $ 12.1 $ 13.1 The following table summarizes the revenues, operating costs, other expenses and income tax of discontinued operations for the periods indicated: Three months ended March 31, $ in millions 2020 2019 Revenues $ 10.0 $ 16.3 Operating costs and other expenses (8.7 ) 13.5 Income from discontinued operations 1.3 29.8 Gain from disposal of discontinued operations — 0.1 Income tax expense from discontinued operations 0.3 4.3 Net income from discontinued operations $ 1.0 $ 25.6 Cash flows related to discontinued operations are included in our Condensed Consolidated Statements of Cash Flows. Cash flows from operating activities for discontinued operations were $15.8 million and $8.1 million for the three months ended March 31, 2020 and 2019 , respectively. There were no cash flows from investing activities for the three months ended March 31, 2020 and 2019, respectively. AROs of Discontinued Operations Prior to the transfer of the retired Stuart and Killen generating facilities, the facilities carried ARO liabilities consisting primarily of river intake and discharge structures, coal unloading facilities, landfills and ash disposal facilities. In the first quarter of 2019, DPL reduced the ARO liability related to the Stuart and Killen ash ponds and landfills by $22.5 million based on updated internal analyses that reduced estimated closure costs associated with these ash ponds and landfills. As these plants were no longer in service, the reduction to the ARO liability was recorded as a credit to depreciation and amortization expense in the same amount. The credit to depreciation and amortization expense is included in operating and other expenses of discontinued operations for the three months ended March 31, 2019 in the table above.

Discontinued Operations

Discontinued Operations	3 Months Ended
	Mar. 31, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operations	Discontinued Operations On May 31, 2018, DPL and AES Ohio Generation retired the Stuart Station coal-fired and diesel-fired generating units and the Killen Station coal-fired generating unit and combustion turbine, as planned. On December 20, 2019, DPL and AES Ohio Generation, together with AES Ohio Generation's joint owners in the retired Stuart and Killen generating facilities, completed the transfer of the retired generating facilities, including the associated environmental liabilities, to an unaffiliated third-party purchaser. Together with the sales of the Peaker Assets in 2018 and Miami Fort and Zimmer in 2017, DPL determined that the disposal of this group of components as a whole represents a strategic shift to exit generation, and, as such, qualifies to be presented as discontinued operations. Therefore, the results of operations, assets and liabilities of this group of components were reported as such in the Condensed Consolidated Statements of Operations and Condensed Consolidated Balance Sheets for all periods presented. The following table summarizes the major categories of assets and liabilities at the dates indicated: $ in millions March 31, 2020 December 31, 2019 Accounts receivable, net $ 1.8 $ 17.4 Prepayments and other current assets 0.1 0.3 Total assets of the disposal group classified as assets of discontinued operations and held-for-sale businesses in the balance sheets $ 1.9 $ 17.7 Accounts payable $ 3.4 $ 3.8 Accrued and other current liabilities 2.5 3.1 Other non-current liabilities 6.2 6.2 Total liabilities of the disposal group classified as liabilities of discontinued operations and held-for-sale businesses in the balance sheets $ 12.1 $ 13.1 The following table summarizes the revenues, operating costs, other expenses and income tax of discontinued operations for the periods indicated: Three months ended March 31, $ in millions 2020 2019 Revenues $ 10.0 $ 16.3 Operating costs and other expenses (8.7 ) 13.5 Income from discontinued operations 1.3 29.8 Gain from disposal of discontinued operations — 0.1 Income tax expense from discontinued operations 0.3 4.3 Net income from discontinued operations $ 1.0 $ 25.6 Cash flows related to discontinued operations are included in our Condensed Consolidated Statements of Cash Flows. Cash flows from operating activities for discontinued operations were $15.8 million and $8.1 million for the three months ended March 31, 2020 and 2019 , respectively. There were no cash flows from investing activities for the three months ended March 31, 2020 and 2019, respectively. AROs of Discontinued Operations Prior to the transfer of the retired Stuart and Killen generating facilities, the facilities carried ARO liabilities consisting primarily of river intake and discharge structures, coal unloading facilities, landfills and ash disposal facilities. In the first quarter of 2019, DPL reduced the ARO liability related to the Stuart and Killen ash ponds and landfills by $22.5 million based on updated internal analyses that reduced estimated closure costs associated with these ash ponds and landfills. As these plants were no longer in service, the reduction to the ARO liability was recorded as a credit to depreciation and amortization expense in the same amount. The credit to depreciation and amortization expense is included in operating and other expenses of discontinued operations for the three months ended March 31, 2019 in the table above.

Risk & Uncertainties (Notes)

Risk & Uncertainties (Notes)	3 Months Ended
	Mar. 31, 2020
Unusual Risk or Uncertainty [Line Items]
Risks and Uncertainties [Text Block]	Risks and Uncertainties COVID-19 Pandemic The COVID-19 pandemic has severely impacted global economic activity, including electricity and energy consumption, and caused significant volatility and negative pressure in financial markets. The global impact of the outbreak has been rapidly evolving and many countries, including the United States, have reacted by instituting quarantines, mandating business and school closures, and restricting travel. The State of Ohio has implemented, among other things, stay-at-home and other social distancing measures to slow the spread of the virus, which has resulted in decreased energy demand within our service territory. On March 12, 2020, the PUCO also issued an emergency order prohibiting electric utilities, including us, from discontinuing electric utility service to customers. We are taking a variety of measures in response to the spread of COVID-19 to ensure our ability to transmit, distribute and sell electric energy, ensure the health and safety of our employees, contractors, customers and communities and provide essential services to the communities in which we operate. In addition to reduced revenues and lower margins resulting from decreased energy demand within our service territory, we also will incur expenses relating to COVID-19, and such expenses may include those that relate to events outside of our control. For the quarter ending March 31, 2020, COVID-19 had a limited impact on our financial results and operations, as the full extent of the economic impact of the pandemic only started to materialize in Ohio in the second half of March 2020. The magnitude and duration of the COVID-19 pandemic is unknown at this time and may have material and adverse effects on our results of operations, financial condition and cash flows in future periods. We continue to explore regulatory measures which we believe could partially mitigate the impact of COVID-19 on our financial results. See Note 3 – Regulatory Matters for a discussion of regulatory measures we have taken which we believe could partially mitigate the impact of COVID-19 on our financial results.
Subsidiaries [Member]
Unusual Risk or Uncertainty [Line Items]
Risks and Uncertainties [Text Block]	Risks and Uncertainties COVID-19 Pandemic The COVID-19 pandemic has severely impacted global economic activity, including electricity and energy consumption, and caused significant volatility and negative pressure in financial markets. The global impact of the outbreak has been rapidly evolving and many countries, including the United States, have reacted by instituting quarantines, mandating business and school closures, and restricting travel. The State of Ohio has implemented, among other things, stay-at-home and other social distancing measures to slow the spread of the virus, which has resulted in decreased energy demand within our service territory. On March 12, 2020, the PUCO also issued an emergency order prohibiting electric utilities, including us, from discontinuing electric utility service to customers. We are taking a variety of measures in response to the spread of COVID-19 to ensure our ability to transmit, distribute and sell electric energy, ensure the health and safety of our employees, contractors, customers and communities and provide essential services to the communities in which we operate. In addition to reduced revenues and lower margins resulting from decreased energy demand within our service territory, we also will incur expenses relating to COVID-19, and such expenses may include those that relate to events outside of our control. For the quarter ending March 31, 2020, COVID-19 had a limited impact on our financial results and operations, as the full extent of the economic impact of the pandemic only started to materialize in Ohio in the second half of March 2020. The magnitude and duration of the COVID-19 pandemic is unknown at this time and may have material and adverse effects on our results of operations, financial condition and cash flows in future periods. We continue to explore regulatory measures which we believe could partially mitigate the impact of COVID-19 on our financial results. See Note 3 – Regulatory Matters for a discussion of regulatory measures we have taken which we believe could partially mitigate the impact of COVID-19 on our financial results.

Summary of Significant Accounti

Summary of Significant Accounting Policies (Policy)	3 Months Ended
	Mar. 31, 2020
Significant Accounting Policies [Line Items]
Description of Business	Description of Business DPL is a regional energy company organized in 1985 under the laws of Ohio. DPL has one reportable segment: the Utility segment. See Note 11 – Business Segments for more information relating to this reportable segment. The terms “we,” “us,” “our” and “ours” are used to refer to DPL and its subsidiaries. DPL is an indirectly wholly-owned subsidiary of AES. DP&L , a wholly-owned subsidiary of DPL , is a public utility incorporated in 1911 under the laws of Ohio. Beginning in 2001, Ohio law gave Ohio consumers the right to choose the electric generation supplier from whom they purchase retail generation service; however, retail transmission and distribution services are still regulated. DP&L has the exclusive right to provide such transmission and distribution services to approximately 527,000 customers located in West Central Ohio. Additionally, DP&L provides retail SSO electric service to residential, commercial, industrial and governmental customers in a 6,000 - square mile area of West Central Ohio. Principal industries located in DP&L’s service territory include automotive, food processing, paper, plastic, health care, data management, manufacturing and defense. DP&L's sales typically reflect the seasonal weather patterns and the growth of energy efficiency initiatives. However, the impacts of weather, energy efficiency programs and economic changes in customer demand were almost entirely eliminated in 2019 by DP&L’s Decoupling Rider, which was in place from January 1, 2019 until December 18, 2019. See Note 3 – Regulatory Matters for more information. DP&L sells its proportional share of energy and capacity from its investment in OVEC into the wholesale market. DPL’s other primary subsidiaries include MVIC and AES Ohio Generation. MVIC is our captive insurance company that provides insurance services to DPL and our other subsidiaries. AES Ohio Generation's only operating asset is an undivided interest in Conesville. AES Ohio Generation sells all of its energy and capacity into the wholesale market. DPL's subsidiaries are all wholly-owned. DPL also has a wholly-owned business trust, DPL Capital Trust II, formed for the purpose of issuing trust capital securities to investors. DP&L’s electric transmission and distribution businesses are subject to rate regulation by federal and state regulators. Accordingly, DP&L applies the accounting standards for regulated operations to its electric transmission and distribution businesses and records regulatory assets when incurred costs are expected to be recovered in future customer rates, and regulatory liabilities when current cost recoveries in customer rates relate to expected future costs. DPL and its subsidiaries employed 625 people as of March 31, 2020 , of which 622 were employed by DP&L. Approximately 58% of all DPL employees are under a collective bargaining agreement, which expires October 31, 2020 .
Financial Statement Presentation	Financial Statement Presentation DPL’s Condensed Consolidated Financial Statements include the accounts of DPL and its wholly-owned subsidiaries except for DPL Capital Trust II, which is not consolidated, consistent with the provisions of GAAP. As of March 31, 2020 , AES Ohio Generation has an undivided ownership interest in one coal-fired generating facility, which is included in the financial statements at a carrying value of zero as it has been fully impaired. Operating revenues and expenses of this facility are included on a pro rata basis in the corresponding lines in the Condensed Consolidated Statements of Operations. Certain immaterial amounts from prior periods have been reclassified to conform to the current period presentation. All material intercompany accounts and transactions are eliminated in consolidation. We have evaluated subsequent events through the date this report is issued. These financial statements have been prepared in accordance with GAAP for interim financial statements, the instructions of Form 10-Q and Regulation S-X. Accordingly, certain information and footnote disclosures normally included in the annual financial statements prepared in accordance with GAAP have been omitted from this interim report. Therefore, our interim financial statements in this report should be read along with the annual financial statements included in our Form 10-K for the fiscal year ended December 31, 2019 . In the opinion of our management, the Condensed Consolidated Financial Statements presented in this report contain all adjustments necessary to fairly state our financial position as of March 31, 2020 ; our results of operations for the three months ended March 31, 2020 and 2019 , our cash flows for the three months ended March 31, 2020 and 2019 and the changes in our equity for the three months ended March 31, 2020 and 2019 . Unless otherwise noted, all adjustments are normal and recurring in nature. Due to various factors, interim results for the three months ended March 31, 2020 may not be indicative of our results that will be realized for the full year ending December 31, 2020 . The preparation of financial statements in conformity with GAAP requires us to make estimates and judgments that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities, and the revenues and expenses of the periods reported. Actual results could differ from these estimates. Significant items subject to such estimates and judgments include: recognition of revenue including unbilled revenues, the carrying value of property, plant and equipment; the valuation of derivative instruments; the valuation of insurance and claims liabilities; the valuation of allowances for credit losses and deferred income taxes; regulatory assets and liabilities; liabilities recorded for income tax exposures; litigation; contingencies; the valuation of AROs; and assets and liabilities related to employee benefits.
Accounting for Taxes Collected from Customers and Remitted to Governmental Authorities	DP&L collects certain excise taxes levied by state or local governments from its customers. These taxes are accounted for on a net basis and not included in revenue. The amounts of such taxes collected for the three months ended March 31, 2020 and 2019 were $12.4 million and $13.9 million, respectively.
Recently Issued Accounting Standards	New accounting pronouncements adopted in 2020 – The following table provides a brief description of recently adopted accounting pronouncements that had an impact on our consolidated financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or did not have a material impact on our consolidated financial statements. ASU Number and Name Description Date of Adoption Effect on the financial statements upon adoption 2016-13, 2018-19, 2019-04, 2019-05, 2019-10, 2019-11, 2020-02, 2020-03 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments See discussion of the ASU below. January 1, 2020 See impact upon adoption of the standard below. ASU 2016-13 and its subsequent corresponding updates revised the impairment model for financial assets measured at amortized cost, known as the Current Expected Credit Loss (CECL) model. For trade and other receivables, held-to-maturity debt securities, loans and other instruments, entities are required to use a new forward-looking "expected loss" model that generally will result in the earlier recognition of allowance for losses. For available-for-sale debt securities with unrealized losses, entities measure credit losses as it is done today, except that unrealized losses due to credit-related factors are recognized as an allowance on the balance sheet with a corresponding adjustment to earnings in the income statement. The new current expected credit loss model primarily impacts the calculation of expected credit losses on $61.6 million in gross trade accounts receivable. The application of CECL on our trade accounts receivable did not have a material impact on our condensed consolidated financial statements. New Accounting Pronouncements Issued But Not Yet Effective – The following table provides a brief description of recent accounting pronouncements that could have a material impact on our consolidated financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or are expected to have no material impact on our consolidated financial statements. ASU Number and Name Description Date of Adoption Effect on the financial statements upon adoption 2020-04, Reference Rate Form (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting The standard provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions that reference to LIBOR or another reference rate expected to be discontinued by reference rate reform. April 1, 2020 - December 31, 2022 We are currently evaluating the impact of adopting the standard on our condensed consolidated financial statements. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting For Income Taxes The standard removes certain exceptions for recognizing deferred taxes for investments, performing intraperiod allocation and calculating income taxes in interim periods. It also adds guidance to reduce complexity in certain areas, including recognizing deferred taxes for tax goodwill and allocating taxes to members of a consolidated group. January 1, 2021. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our condensed consolidated financial statements.
THE DAYTON POWER AND LIGHT COMPANY [Member]
Significant Accounting Policies [Line Items]
Description of Business	Description of Business DP&L is a public utility incorporated in 1911 under the laws of Ohio. Beginning in 2001, Ohio law gave Ohio consumers the right to choose the electric generation supplier from whom they purchase retail generation service; however, retail transmission and distribution services are still regulated. DP&L has the exclusive right to provide such transmission and distribution services to approximately 527,000 customers located in West Central Ohio. Additionally, DP&L provides retail SSO electric service to residential, commercial, industrial and governmental customers in a 6,000 - square mile area of West Central Ohio. As a result of Generation Separation, DP&L now only has one reportable segment, the Utility segment. In addition to DP&L's electric transmission and distribution businesses, the Utility segment includes revenues and costs associated with DP&L's investment in OVEC and the historical results of DP&L’s Beckjord and Hutchings Coal generating facilities, which have either been sold or closed. Principal industries located in DP&L’s service territory include automotive, food processing, paper, plastic, health care, data management, manufacturing and defense. DP&L's sales typically reflect the seasonal weather patterns and the growth of energy efficiency initiatives. However, the impacts of weather, energy efficiency programs and economic changes in customer demand were almost entirely eliminated in 2019 by DP&L’s Decoupling Rider, which was in place from January 1, 2019 until December 18, 2019. See Note 3 – Regulatory Matters for more information. DP&L sells its proportional share of energy and capacity from its investment in OVEC into the wholesale market. DP&L is a subsidiary of DPL. The terms “we,” “us,” “our” and “ours” are used to refer to DP&L . DP&L’s electric transmission and distribution businesses are subject to rate regulation by federal and state regulators. Accordingly, DP&L applies the accounting standards for regulated operations to its electric transmission and distribution businesses and records regulatory assets when incurred costs are expected to be recovered in future customer rates, and regulatory liabilities when current cost recoveries in customer rates relate to expected future costs. DP&L employed 622 people as of March 31, 2020 . Approximately 58% of DP&L employees are under a collective bargaining agreement, which expires October 31, 2020 .
Financial Statement Presentation	Financial Statement Presentation DP&L does not have any subsidiaries. We have evaluated subsequent events through the date this report is issued. Certain immaterial amounts from prior periods have been reclassified to conform to the current period presentation. These financial statements have been prepared in accordance with GAAP for interim financial statements, the instructions of Form 10-Q and Regulation S-X. Accordingly, certain information and footnote disclosures normally included in the annual financial statements prepared in accordance with GAAP have been omitted from this interim report. Therefore, our interim financial statements in this report should be read along with the annual financial statements included in our Form 10-K for the fiscal year ended December 31, 2019 . In the opinion of our management, the Condensed Financial Statements presented in this report contain all adjustments necessary to fairly state our financial position as of March 31, 2020 ; our results of operations for the three months ended March 31, 2020 and 2019 , our cash flows for the three months ended March 31, 2020 and 2019 and the changes in our equity for the three months ended March 31, 2020 and 2019 . Unless otherwise noted, all adjustments are normal and recurring in nature. Due to various factors, interim results for the three months ended March 31, 2020 may not be indicative of our results that will be realized for the full year ending December 31, 2020 . The preparation of financial statements in conformity with GAAP requires us to make estimates and judgments that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities, and the revenues and expenses of the periods reported. Actual results could differ from these estimates. Significant items subject to such estimates and judgments include: recognition of revenue including unbilled revenues, the carrying value of property, plant and equipment; the valuation of derivative instruments; the valuation of insurance and claims liabilities; the valuation of allowances for credit losses and deferred income taxes; regulatory assets and liabilities; liabilities recorded for income tax exposures; litigation; contingencies; the valuation of AROs; and assets and liabilities related to employee benefits.
Accounting for Taxes Collected from Customers and Remitted to Governmental Authorities	DP&L collects certain excise taxes levied by state or local governments from its customers. These taxes are accounted for on a net basis and not included in revenue. The amounts of such taxes collected for the three months ended March 31, 2020 and 2019 were $12.4 million and $13.9 million, respectively.
Recently Issued Accounting Standards	New accounting pronouncements adopted in 2020 – The following table provides a brief description of recently adopted accounting pronouncements that had an impact on our financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or did not have a material impact on our financial statements. ASU Number and Name Description Date of Adoption Effect on the financial statements upon adoption 2016-13, 2018-19, 2019-04, 2019-05, 2019-10, 2019-11, 2020-02, 2020-03 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments See discussion of the ASU below. January 1, 2020 See impact upon adoption of the standard below. ASU 2016-13 and its subsequent corresponding updates revised the impairment model for financial assets measured at amortized cost, known as the Current Expected Credit Loss (CECL) model. For trade and other receivables, held-to-maturity debt securities, loans and other instruments, entities are required to use a new forward-looking "expected loss" model that generally will result in the earlier recognition of allowance for losses. For available-for-sale debt securities with unrealized losses, entities measure credit losses as it is done today, except that unrealized losses due to credit-related factors are recognized as an allowance on the balance sheet with a corresponding adjustment to earnings in the income statement. The new current expected credit loss model primarily impacts the calculation of expected credit losses on $60.4 million in gross trade accounts receivable. The application of CECL on our trade accounts receivable did not have a material impact on our condensed financial statements. New Accounting Pronouncements Issued But Not Yet Effective – The following table provides a brief description of recent accounting pronouncements that could have a material impact on our financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or are expected to have no material impact on our financial statements. ASU Number and Name Description Date of Adoption Effect on the financial statements upon adoption 2020-04, Reference Rate Form (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting The standard provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions that reference to LIBOR or another reference rate expected to be discontinued by reference rate reform. April 1, 2020 - December 31, 2022 We are currently evaluating the impact of adopting the standard on our condensed financial statements. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting For Income Taxes The standard removes certain exceptions for recognizing deferred taxes for investments, performing intraperiod allocation and calculating income taxes in interim periods. It also adds guidance to reduce complexity in certain areas, including recognizing deferred taxes for tax goodwill and allocating taxes to members of a consolidated group. January 1, 2021. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our condensed financial statements.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2020
Related Party Transaction [Line Items]
New Accounting Pronouncements, Policy [Policy Text Block]	New accounting pronouncements adopted in 2020 – The following table provides a brief description of recently adopted accounting pronouncements that had an impact on our consolidated financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or did not have a material impact on our consolidated financial statements. ASU Number and Name Description Date of Adoption Effect on the financial statements upon adoption 2016-13, 2018-19, 2019-04, 2019-05, 2019-10, 2019-11, 2020-02, 2020-03 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments See discussion of the ASU below. January 1, 2020 See impact upon adoption of the standard below. ASU 2016-13 and its subsequent corresponding updates revised the impairment model for financial assets measured at amortized cost, known as the Current Expected Credit Loss (CECL) model. For trade and other receivables, held-to-maturity debt securities, loans and other instruments, entities are required to use a new forward-looking "expected loss" model that generally will result in the earlier recognition of allowance for losses. For available-for-sale debt securities with unrealized losses, entities measure credit losses as it is done today, except that unrealized losses due to credit-related factors are recognized as an allowance on the balance sheet with a corresponding adjustment to earnings in the income statement. The new current expected credit loss model primarily impacts the calculation of expected credit losses on $61.6 million in gross trade accounts receivable. The application of CECL on our trade accounts receivable did not have a material impact on our condensed consolidated financial statements. New Accounting Pronouncements Issued But Not Yet Effective – The following table provides a brief description of recent accounting pronouncements that could have a material impact on our consolidated financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or are expected to have no material impact on our consolidated financial statements. ASU Number and Name Description Date of Adoption Effect on the financial statements upon adoption 2020-04, Reference Rate Form (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting The standard provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions that reference to LIBOR or another reference rate expected to be discontinued by reference rate reform. April 1, 2020 - December 31, 2022 We are currently evaluating the impact of adopting the standard on our condensed consolidated financial statements. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting For Income Taxes The standard removes certain exceptions for recognizing deferred taxes for investments, performing intraperiod allocation and calculating income taxes in interim periods. It also adds guidance to reduce complexity in certain areas, including recognizing deferred taxes for tax goodwill and allocating taxes to members of a consolidated group. January 1, 2021. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our condensed consolidated financial statements.
Schedule of Cash and Cash Equivalents [Table Text Block]	The following table provides a summary of cash, cash equivalents, and restricted cash amounts reported on the Condensed Consolidated Balance Sheet that reconcile to the total of such amounts as shown on the Condensed Consolidated Statements of Cash Flows: $ in millions March 31, 2020 December 31, 2019 Cash and cash equivalents $ 39.6 $ 36.5 Restricted cash 14.6 10.5 Cash, Cash Equivalents, and Restricted Cash, End of Period $ 54.2 $ 47.0
Schedule of New Accounting Pronouncements	– The following table provides a brief description of recently adopted accounting pronouncements that had an impact on our consolidated financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or did not have a material impact on our consolidated financial statements. ASU Number and Name Description Date of Adoption Effect on the financial statements upon adoption 2016-13, 2018-19, 2019-04, 2019-05, 2019-10, 2019-11, 2020-02, 2020-03 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments See discussion of the ASU below. January 1, 2020 See impact upon adoption of the standard below. ASU 2016-13 and its subsequent corresponding updates revised the impairment model for financial assets measured at amortized cost, known as the Current Expected Credit Loss (CECL) model. For trade and other receivables, held-to-maturity debt securities, loans and other instruments, entities are required to use a new forward-looking "expected loss" model that generally will result in the earlier recognition of allowance for losses. For available-for-sale debt securities with unrealized losses, entities measure credit losses as it is done today, except that unrealized losses due to credit-related factors are recognized as an allowance on the balance sheet with a corresponding adjustment to earnings in the income statement. The new current expected credit loss model primarily impacts the calculation of expected credit losses on $61.6 million in gross trade accounts receivable. The application of CECL on our trade accounts receivable did not have a material impact on our condensed consolidated financial statements. New Accounting Pronouncements Issued But Not Yet Effective – The following table provides a brief description of recent accounting pronouncements that could have a material impact on our consolidated financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or are expected to have no material impact on our consolidated financial statements. ASU Number and Name Description Date of Adoption Effect on the financial statements upon adoption 2020-04, Reference Rate Form (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting The standard provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions that reference to LIBOR or another reference rate expected to be discontinued by reference rate reform. April 1, 2020 - December 31, 2022 We are currently evaluating the impact of adopting the standard on our condensed consolidated financial statements. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting For Income Taxes The standard removes certain exceptions for recognizing deferred taxes for investments, performing intraperiod allocation and calculating income taxes in interim periods. It also adds guidance to reduce complexity in certain areas, including recognizing deferred taxes for tax goodwill and allocating taxes to members of a consolidated group. January 1, 2021. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our condensed consolidated financial statements.
THE DAYTON POWER AND LIGHT COMPANY [Member]
Related Party Transaction [Line Items]
New Accounting Pronouncements, Policy [Policy Text Block]	New accounting pronouncements adopted in 2020 – The following table provides a brief description of recently adopted accounting pronouncements that had an impact on our financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or did not have a material impact on our financial statements. ASU Number and Name Description Date of Adoption Effect on the financial statements upon adoption 2016-13, 2018-19, 2019-04, 2019-05, 2019-10, 2019-11, 2020-02, 2020-03 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments See discussion of the ASU below. January 1, 2020 See impact upon adoption of the standard below. ASU 2016-13 and its subsequent corresponding updates revised the impairment model for financial assets measured at amortized cost, known as the Current Expected Credit Loss (CECL) model. For trade and other receivables, held-to-maturity debt securities, loans and other instruments, entities are required to use a new forward-looking "expected loss" model that generally will result in the earlier recognition of allowance for losses. For available-for-sale debt securities with unrealized losses, entities measure credit losses as it is done today, except that unrealized losses due to credit-related factors are recognized as an allowance on the balance sheet with a corresponding adjustment to earnings in the income statement. The new current expected credit loss model primarily impacts the calculation of expected credit losses on $60.4 million in gross trade accounts receivable. The application of CECL on our trade accounts receivable did not have a material impact on our condensed financial statements. New Accounting Pronouncements Issued But Not Yet Effective – The following table provides a brief description of recent accounting pronouncements that could have a material impact on our financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or are expected to have no material impact on our financial statements. ASU Number and Name Description Date of Adoption Effect on the financial statements upon adoption 2020-04, Reference Rate Form (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting The standard provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions that reference to LIBOR or another reference rate expected to be discontinued by reference rate reform. April 1, 2020 - December 31, 2022 We are currently evaluating the impact of adopting the standard on our condensed financial statements. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting For Income Taxes The standard removes certain exceptions for recognizing deferred taxes for investments, performing intraperiod allocation and calculating income taxes in interim periods. It also adds guidance to reduce complexity in certain areas, including recognizing deferred taxes for tax goodwill and allocating taxes to members of a consolidated group. January 1, 2021. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our condensed financial statements.
Schedule of Cash and Cash Equivalents [Table Text Block]	The following table provides a summary of cash, cash equivalents, and restricted cash amounts reported on the Condensed Balance Sheet that reconcile to the total of such amounts as shown on the Condensed Statements of Cash Flows: $ in millions March 31, 2020 December 31, 2019 Cash and cash equivalents $ 7.3 $ 10.8 Restricted cash 14.6 10.5 Cash, Cash Equivalents, and Restricted Cash, End of Period $ 21.9 $ 21.3

Supplemental Financial Inform_2

Supplemental Financial Information (Tables)	3 Months Ended
	Mar. 31, 2020
Supplemental Financial Information [Line Items]
Schedule of Supplemental Financial Information	Accounts receivable are as follows at March 31, 2020 and December 31, 2019 : March 31, December 31, $ in millions 2020 2019 Accounts receivable, net: Customer receivables $ 45.7 $ 46.3 Unbilled revenue 15.9 19.4 Amounts due from affiliates 0.2 0.3 Due from PJM transmission enhancement settlement 1.8 1.8 Other 2.0 1.2 Allowance for credit losses (0.7 ) (0.4 ) Total accounts receivable, net $ 64.9 $ 68.6
Allowance for Credit Losses on Financing Receivables [Table Text Block]	The following table is a rollforward of our allowance for credit losses related to the accounts receivable balances for the three months ended March 31, 2020 : $ in millions Beginning Allowance Balance at January 1, 2020 Current Period Provision Write-offs Charged Against Allowances Ending Allowance Balance at March 31, 2020 Allowance for credit losses $ 0.4 $ 0.4 $ (0.1 ) $ 0.7
Schedule of Inventory, Current [Table Text Block]	Inventories are as follows at March 31, 2020 and December 31, 2019 : March 31, December 31, $ in millions 2020 2019 Inventories, at average cost: Fuel and limestone $ 1.3 $ 3.5 Materials and supplies 9.4 10.6 Total inventories, at average cost $ 10.7 $ 14.1
Reclassification out of Accumulated Other Comprehensive Income	The amounts reclassified out of Accumulated Other Comprehensive Income / (Loss) by component during the three months ended March 31, 2020 and 2019 are as follows: Details about Accumulated Other Comprehensive Income / (Loss) components Affected line item in the Condensed Consolidated Statements of Operations Three months ended March 31, $ in millions 2020 2019 Gains and losses on cash flow hedges (Note 5): Interest expense $ (0.4 ) $ (0.3 ) Income tax expense 0.1 0.1 Net of income taxes (0.3 ) (0.2 ) Amortization of defined benefit pension items (Note 8): Other expense 0.3 0.1 Income tax benefit — — Net of income taxes 0.3 0.1 Total reclassifications for the period, net of income taxes $ — $ (0.1 )
Schedule of Accumulated Other Comprehensive Income (Loss)	The changes in the components of Accumulated Other Comprehensive Income / (Loss) during the three months ended March 31, 2020 are as follows: $ in millions Gains / (losses) on cash flow hedges Change in unfunded pension and postretirement benefit obligation Total Balance at January 1, 2020 $ 14.5 $ (18.1 ) $ (3.6 ) Other comprehensive loss before reclassifications (0.3 ) — (0.3 ) Amounts reclassified from AOCI to earnings (0.3 ) 0.3 — Net current period other comprehensive income / (loss) (0.6 ) 0.3 (0.3 ) Balance at March 31, 2020 $ 13.9 $ (17.8 ) $ (3.9 )
THE DAYTON POWER AND LIGHT COMPANY [Member]
Supplemental Financial Information [Line Items]
Schedule of Supplemental Financial Information	Accounts receivable are as follows at March 31, 2020 and December 31, 2019 : March 31, December 31, $ in millions 2020 2019 Accounts receivable, net: Customer receivables $ 44.5 $ 45.0 Unbilled revenue 15.9 19.4 Amounts due from affiliates 4.6 3.9 Due from PJM transmission enhancement settlement 1.8 1.8 Other 2.1 1.2 Allowance for credit losses (0.7 ) (0.4 ) Total accounts receivable, net $ 68.2 $ 70.9
Allowance for Credit Losses on Financing Receivables [Table Text Block]	The following table is a rollforward of our allowance for credit losses related to the accounts receivable balances for the three months ended March 31, 2020 : $ in millions Beginning Allowance Balance at January 1, 2020 Current Period Provision Write-offs Charged Against Allowances Ending Allowance Balance at March 31, 2020 Allowance for credit losses $ 0.4 $ 0.4 $ (0.1 ) $ 0.7
Reclassification out of Accumulated Other Comprehensive Income	The amounts reclassified out of Accumulated Other Comprehensive Loss by component during the three months ended March 31, 2020 and 2019 are as follows: Details about Accumulated Other Comprehensive Income / (Loss) components Affected line item in the Condensed Statements of Operations Three months ended March 31, $ in millions 2020 2019 Gains and losses on cash flow hedges (Note 5): Interest expense $ (0.1 ) $ (0.1 ) Income tax expense — — Net of income taxes (0.1 ) (0.1 ) Amortization of defined benefit pension items (Note 8): Other expense 1.0 0.9 Income tax expense / (benefit) (0.2 ) (0.2 ) Net of income taxes 0.8 0.7 Total reclassifications for the period, net of income taxes $ 0.7 $ 0.6
Schedule of Accumulated Other Comprehensive Income (Loss)	The changes in the components of Accumulated Other Comprehensive Loss during the three months ended March 31, 2020 are as follows: $ in millions Gains / (losses) on cash flow hedges Change in unfunded pension and postretirement benefit obligation Total Balance at January 1, 2020 $ (0.4 ) $ (36.5 ) $ (36.9 ) Other comprehensive loss before reclassifications (0.3 ) — (0.3 ) Amounts reclassified from AOCI to earnings (0.1 ) 0.8 0.7 Net current period other comprehensive income / (loss) (0.4 ) 0.8 0.4 Balance at March 31, 2020 $ (0.8 ) $ (35.7 ) $ (36.5 )

Fair Value (Tables)

Fair Value (Tables)	3 Months Ended
	Mar. 31, 2020
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 March 31, 2020 and December 31, 2019 . Further information about the fair value of our derivative instruments can be found in Note 5 – Derivative Instruments and Hedging Activities . March 31, 2020 December 31, 2019 $ in millions Cost Fair Value Cost Fair Value Assets Money market funds $ 0.2 $ 0.2 $ 0.3 $ 0.3 Equity securities 2.1 3.1 2.3 4.2 Debt securities 4.1 4.0 4.0 4.1 Hedge funds — — 0.1 0.1 Tangible assets — — 0.1 0.1 Total Assets $ 6.4 $ 7.3 $ 6.8 $ 8.8 Carrying Value Fair Value Carrying Value Fair Value Liabilities Long-term debt $ 1,363.6 $ 1,376.6 $ 1,363.1 $ 1,404.0
Fair Value of Assets and Liabilities Measured on Recurring Basis	The fair value of assets and liabilities at March 31, 2020 and December 31, 2019 and the respective category within the fair value hierarchy for DPL is as follows: $ in millions Fair value at March 31, 2020 (a) Fair value at December 31, 2019 (a) Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets Master Trust assets Money market funds $ 0.2 $ — $ — $ 0.2 $ 0.3 $ — $ — $ 0.3 Equity securities — 3.1 — 3.1 — 4.2 — 4.2 Debt securities — 4.0 — 4.0 — 4.1 — 4.1 Hedge funds — — — — — 0.1 — 0.1 Tangible assets — — — — — 0.1 — 0.1 Total Master Trust assets 0.2 7.1 — 7.3 0.3 8.5 — 8.8 Derivative assets Interest rate hedges — — — — — 0.1 — 0.1 Total Derivative assets — — — — — 0.1 — 0.1 Total Assets $ 0.2 $ 7.1 $ — $ 7.3 $ 0.3 $ 8.6 $ — $ 8.9 Liabilities Derivative liabilities Interest rate hedges $ — $ 0.3 $ — $ 0.3 $ — $ — $ — $ — Long-term debt — 1,359.1 17.5 1,376.6 — 1,386.5 17.5 1,404.0 Total Liabilities $ — $ 1,359.4 $ 17.5 $ 1,376.9 $ — $ 1,386.5 $ 17.5 $ 1,404.0 (a) Includes credit valuation adjustment
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 March 31, 2020 and December 31, 2019 . Further information about the fair value of our derivative instruments can be found in Note 5 – Derivative Instruments and Hedging Activities . March 31, 2020 December 31, 2019 $ in millions Cost Fair Value Cost Fair Value Assets Money market funds $ 0.2 $ 0.2 $ 0.3 $ 0.3 Equity securities 2.1 3.1 2.3 4.2 Debt securities 4.1 4.0 4.0 4.1 Hedge funds — — 0.1 0.1 Tangible assets — — 0.1 0.1 Total assets $ 6.4 $ 7.3 $ 6.8 $ 8.8 Carrying Value Fair Value Carrying Value Fair Value Liabilities Long-term debt $ 574.5 $ 601.1 $ 574.4 $ 600.5
Fair Value of Assets and Liabilities Measured on Recurring Basis	The fair value of assets and liabilities at March 31, 2020 and December 31, 2019 and the respective category within the fair value hierarchy for DP&L is as follows: $ in millions Fair value at March 31, 2020 (a) Fair value at December 31, 2019 (a) Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets Master Trust assets Money market funds $ 0.2 $ — $ — $ 0.2 $ 0.3 $ — $ — $ 0.3 Equity securities — 3.1 — 3.1 — 4.2 — 4.2 Debt securities — 4.0 — 4.0 — 4.1 — 4.1 Hedge funds — — — — — 0.1 — 0.1 Tangible assets — — — — — 0.1 — 0.1 Total Master Trust assets 0.2 7.1 — 7.3 0.3 8.5 — 8.8 Derivative assets Interest rate hedges — — — — — 0.1 — 0.1 Total derivative assets — — — — — 0.1 — 0.1 Total assets $ 0.2 $ 7.1 $ — $ 7.3 $ 0.3 $ 8.6 $ — $ 8.9 Liabilities Derivative liabilities Interest rate hedges $ — $ 0.3 $ — $ 0.3 $ — $ — $ — $ — Long-term debt — 583.6 17.5 601.1 — 583.0 17.5 600.5 Total liabilities $ — $ 583.9 $ 17.5 $ 601.4 $ — $ 583.0 $ 17.5 $ 600.5 (a) Includes credit valuation adjustment

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Tables)	3 Months Ended
	Mar. 31, 2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gains or Losses Recognized in AOCI for the Cash Flow Hedges	The following tables provide information concerning gains or losses recognized in AOCI for the cash flow hedges for the three months ended March 31, 2020 and 2019 : Three months ended March 31, 2020 March 31, 2019 Interest Interest $ in millions (net of tax) Rate Hedge Rate Hedge Power Beginning accumulated derivative gains in AOCI $ 14.5 $ 16.6 $ 0.4 Net losses associated with current period hedging transactions (0.3 ) (0.3 ) — Net gains reclassified to earnings Interest expense (0.3 ) (0.2 ) — Ending accumulated derivative gains in AOCI $ 13.9 $ 16.1 $ 0.4 Portion expected to be reclassified to earnings in the next twelve months $ (1.1 ) Maximum length of time that we are hedging our exposure to variability in future cash flows related to forecasted transactions (in months) 5 Financial Statement Effect
Schedule of Other Derivatives Not Designated as Hedging Instruments, Statements of Financial Performance and Financial Position, Location	DPL has elected not to offset derivative assets and liabilities and not to offset net derivative positions against the right to reclaim cash collateral pledged (an asset) or the obligation to return cash collateral received (a liability) under derivative agreements. The fair value derivative position of DPL's interest rate swaps are as follows: $ in millions (net of tax) Hedging Designation Balance sheet classification March 31, 2020 December 31, 2019 Interest rate swap Cash Flow Hedge Prepayments and other current assets $ — $ 0.1 Interest rate swap Cash Flow Hedge Accrued and other current liabilities $ (0.3 ) $ — DP&L has elected not to offset derivative assets and liabilities and not to offset net derivative positions against the right to reclaim cash collateral pledged (an asset) or the obligation to return cash collateral received (a liability) under derivative agreements. The fair value derivative position of DP&L's interest rate swaps are as follows: $ in millions (net of tax) Hedging Designation Balance sheet classification March 31, 2020 December 31, 2019 Interest rate swap Cash Flow Hedge Prepayments and other current assets $ — $ 0.1 Interest rate swap Cash Flow Hedge Accrued and other current liabilities $ (0.3 ) $ —
THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gains or Losses Recognized in AOCI for the Cash Flow Hedges	The following tables provide information concerning gains or losses recognized in AOCI for the cash flow hedges for the three months ended March 31, 2020 and 2019 : Three months ended March 31, 2020 March 31, 2019 Interest Interest $ in millions (net of tax) Rate Hedge Rate Hedge Beginning accumulated derivative gains / (losses) in AOCI $ (0.4 ) $ 0.6 Net losses associated with current period hedging transactions (0.3 ) (0.2 ) Net gains reclassified to earnings Interest expense (0.1 ) (0.1 ) Ending accumulated derivative gains / (losses) in AOCI $ (0.8 ) $ 0.3 Portion expected to be reclassified to earnings in the next twelve months $ (0.1 ) Maximum length of time that we are hedging our exposure to variability in future cash flows related to forecasted transactions (in months) 5

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2020
Debt Instrument [Line Items]
Long-term Debt	The following table summarizes DPL's long-term debt. Interest March 31, December 31, $ in millions Rate Maturity 2020 2019 First Mortgage Bonds 3.95% 2049 $ 425.0 $ 425.0 Tax-exempt First Mortgage Bonds - rates from 2.40% - 2.93% (a) and 1.29% - 1.42% (b) 2020 140.0 140.0 U.S. Government note 4.20% 2061 17.5 17.5 Unamortized deferred financing costs (5.3 ) (5.4 ) Unamortized debt discounts and premiums, net (2.7 ) (2.7 ) Total long-term debt at DP&L 574.5 574.4 Senior unsecured bonds 7.25% 2021 380.0 380.0 Senior unsecured bonds 4.35% 2029 400.0 400.0 Note to DPL Capital Trust II (c) 8.125% 2031 15.6 15.6 Unamortized deferred financing costs (5.5 ) (5.9 ) Unamortized debt discounts and premiums, net (1.0 ) (1.0 ) Total long-term debt 1,363.6 1,363.1 Less: current portion (139.9 ) (139.8 ) Long-term debt, net of current portion $ 1,223.7 $ 1,223.3 (a) Range of interest rates for the three months ended March 31, 2020 . (b) Range of interest rates for the year ended December 31, 2019 . (c) Note payable to related party.
THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Long-term Debt	The following table summarizes DP&L's long-term debt. Interest March 31, December 31, $ in millions Rate Maturity 2020 2019 First Mortgage Bonds 3.95% 2049 $ 425.0 $ 425.0 Tax-exempt First Mortgage Bonds - rates from 2.40% - 2.93% (a) and 1.29% - 1.42% (b) 2020 140.0 140.0 U.S. Government note 4.20% 2061 17.5 17.5 Unamortized deferred financing costs (5.3 ) (5.4 ) Unamortized debt discounts and premiums, net (2.7 ) (2.7 ) Total long-term debt 574.5 574.4 Less: current portion (139.9 ) (139.8 ) Long-term debt, net of current portion $ 434.6 $ 434.6 (a) Range of interest rates for the three months ended March 31, 2020 . (b) Range of interest rates for the year ended December 31, 2019 .

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2020
Entity Information [Line Items]
Schedule of Effective Income Tax Rates	The following table details the effective tax rates for the three months ended March 31, 2020 and 2019 . Three months ended March 31, 2020 2019 DPL (11.8)% 14.3%
THE DAYTON POWER AND LIGHT COMPANY [Member]
Entity Information [Line Items]
Schedule of Effective Income Tax Rates	The following table details the effective tax rates for the three months ended March 31, 2020 and 2019 . Three months ended March 31, 2020 2019 DP&L 9.3% 17.4%

Benefit Plans (Tables)

Benefit Plans (Tables)	3 Months Ended
	Mar. 31, 2020
Entity Information [Line Items]
Schedule of Net Periodic Benefit Cost / (Income)	The net periodic benefit cost of the pension benefit plans for the three months ended March 31, 2020 and 2019 was: Three months ended March 31, $ in millions 2020 2019 Service cost $ 0.9 $ 0.9 Interest cost 3.0 3.7 Expected return on plan assets (4.7 ) (5.0 ) Amortization of unrecognized: Prior service cost 0.3 0.3 Actuarial loss 1.5 1.1 Net periodic benefit cost $ 1.0 $ 1.0
THE DAYTON POWER AND LIGHT COMPANY [Member]
Entity Information [Line Items]
Schedule of Net Periodic Benefit Cost / (Income)	The net periodic benefit cost of the pension benefit plans for the three months ended March 31, 2020 and 2019 was: Three months ended March 31, $ in millions 2020 2019 Service cost $ 0.9 $ 0.9 Interest cost 3.0 3.7 Expected return on plan assets (4.7 ) (5.0 ) Amortization of unrecognized: Prior service cost 0.3 0.5 Actuarial loss 2.2 1.7 Net periodic benefit cost $ 1.7 $ 1.8

Business Segments (Tables)

Business Segments (Tables)	3 Months Ended
	Mar. 31, 2020
Segment Reporting Information [Line Items]
Financial Reporting for Reportable Business Segments	The following tables present financial information for DPL’s Utility reportable business segment: $ in millions Utility Other Adjustments and Eliminations DPL Consolidated Three months ended March 31, 2020 Revenues from external customers $ 168.7 $ 6.0 $ — $ 174.7 Intersegment revenues 0.3 0.8 (1.1 ) — Total revenues $ 169.0 $ 6.8 $ (1.1 ) $ 174.7 Depreciation and amortization $ 17.3 $ 0.5 $ — $ 17.8 Interest expense $ 6.2 $ 12.7 $ — $ 18.9 Income / (loss) from continuing operations before income tax $ 12.9 $ (12.5 ) $ — $ 0.4 Cash capital expenditures $ 43.7 $ 0.9 $ — $ 44.6 $ in millions Utility Other Adjustments and Eliminations DPL Consolidated Three months ended March 31, 2019 Revenues from external customers $ 201.1 $ 7.9 $ — $ 209.0 Intersegment revenues 0.3 0.8 (1.1 ) — Total revenues $ 201.4 $ 8.7 $ (1.1 ) $ 209.0 Depreciation and amortization $ 18.0 $ 0.4 $ — $ 18.4 Interest expense $ 7.1 $ 16.6 $ — $ 23.7 Income / (loss) from continuing operations before income tax $ 35.1 $ (15.9 ) $ — $ 19.2 Cash capital expenditures $ 33.7 $ 0.6 $ — $ 34.3 Total Assets March 31, 2020 December 31, 2019 Utility $ 1,874.6 $ 1,883.2 All Other (a) 43.8 52.6 DPL Consolidated $ 1,918.4 $ 1,935.8 (a) "All Other" includes Total assets related to the assets of discontinued operations and held-for-sale businesses and Eliminations for all periods presented.

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 31, 2020
Disaggregation of Revenue [Table Text Block]	DPL's revenue from contracts with customers was $170.5 million and $208.3 million for the three months ended March 31, 2020 and 2019, respectively. The following table presents our revenue from contracts with customers and other revenue by segment for the three months ended March 31, 2020 and 2019 : $ in millions Utility Other Adjustments and Eliminations Total Three months ended March 31, 2020 Retail revenue Retail revenue from contracts with customers $ 150.2 $ — $ — $ 150.2 Other retail revenue (a) 3.3 — — 3.3 Wholesale revenue Wholesale revenue from contracts with customers 2.7 2.5 (0.3 ) 4.9 RTO ancillary revenue 10.7 0.1 — 10.8 Capacity revenue 1.2 1.0 — 2.2 Miscellaneous revenue Miscellaneous revenue from contracts with customers (b) — 2.4 — 2.4 Other miscellaneous revenue 0.9 0.8 (0.8 ) 0.9 Total revenues $ 169.0 $ 6.8 $ (1.1 ) $ 174.7 Three months ended March 31, 2019 Retail revenue Retail revenue from contracts with customers $ 182.7 $ — $ (0.3 ) $ 182.4 Other retail revenue (a) 0.7 — — 0.7 Wholesale revenue Wholesale revenue from contracts with customers 5.0 3.4 — 8.4 RTO ancillary revenue 10.9 — — 10.9 Capacity revenue 2.1 1.6 — 3.7 Miscellaneous revenue Miscellaneous revenue from contracts with customers (b) — 2.9 — 2.9 Other miscellaneous revenue — 0.8 (0.8 ) — Total revenues $ 201.4 $ 8.7 $ (1.1 ) $ 209.0 (a) Other retail revenue primarily includes alternative revenue programs not accounted for under FASC 606. (b) Miscellaneous revenue from contracts with customers primarily includes revenues for various services provided by Miami Valley Lighting.
Subsidiaries [Member]
Disaggregation of Revenue [Table Text Block]	DP&L's revenue from contracts with customers was $164.8 million and $200.7 million for the three months ended March 31, 2020 and 2019, respectively. The following table presents our revenue from contracts with customers and other revenue for the three months ended March 31, 2020 and 2019 : Three months ended March 31, $ in millions 2020 2019 Retail revenue Retail revenue from contracts with customers $ 150.2 $ 182.7 Other retail revenue (a) 3.3 0.7 Wholesale revenue Wholesale revenue from contracts with customers 2.7 5.0 RTO ancillary revenue 10.7 10.9 Capacity revenue 1.2 2.1 Miscellaneous revenue 0.9 — Total revenues $ 169.0 $ 201.4 (a) Other retail revenue primarily includes alternative revenue programs not accounted for under FASC 606.

Discontinued Operations (Tables

Discontinued Operations (Tables)	3 Months Ended
	Mar. 31, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Groups, Including Discontinued Operations [Table Text Block]	The following table summarizes the major categories of assets and liabilities at the dates indicated: $ in millions March 31, 2020 December 31, 2019 Accounts receivable, net $ 1.8 $ 17.4 Prepayments and other current assets 0.1 0.3 Total assets of the disposal group classified as assets of discontinued operations and held-for-sale businesses in the balance sheets $ 1.9 $ 17.7 Accounts payable $ 3.4 $ 3.8 Accrued and other current liabilities 2.5 3.1 Other non-current liabilities 6.2 6.2 Total liabilities of the disposal group classified as liabilities of discontinued operations and held-for-sale businesses in the balance sheets $ 12.1 $ 13.1 The following table summarizes the revenues, operating costs, other expenses and income tax of discontinued operations for the periods indicated: Three months ended March 31, $ in millions 2020 2019 Revenues $ 10.0 $ 16.3 Operating costs and other expenses (8.7 ) 13.5 Income from discontinued operations 1.3 29.8 Gain from disposal of discontinued operations — 0.1 Income tax expense from discontinued operations 0.3 4.3 Net income from discontinued operations $ 1.0 $ 25.6

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020USD ($)mi²employeecustomergenerating_facilitysegment	Mar. 31, 2019USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Significant Accounting Policies [Line Items]
Number of reportable segments | segment	1
Cash and Cash Equivalents, at Carrying Value	$ 39.6		$ 36.5
Entity number of employees | employee	625
Employees under a collective bargaining agreement which expires in October-2011	58.00%
Excise taxes collected	$ 12.4	$ 13.9
Restricted Cash and Cash Equivalents, Current	14.6		10.5
Restricted Cash and Cash Equivalents	54.2	112.8	47	$ 111.7
Public Utilities, Property, Plant and Equipment, Generation or Processing	$ 0
THE DAYTON POWER AND LIGHT COMPANY [Member]
Significant Accounting Policies [Line Items]
Number of reportable segments | segment	1
Cash and Cash Equivalents, at Carrying Value	$ 7.3		10.8
Approximate number of retail customers | customer	527,000
Service area, square miles | mi²	6,000
Number of Operating Segments | segment	1
Entity number of employees | employee	622
Employees under a collective bargaining agreement which expires in October-2011	58.00%
Number Of Generating Facilities | generating_facility	1
Excise taxes collected	$ 12.4	13.9
Restricted Cash and Cash Equivalents, Current	14.6		10.5
Restricted Cash and Cash Equivalents	21.9	$ 60.8	$ 21.3	$ 66.2
Accounting Standards Update 2016-13 [Member]
Significant Accounting Policies [Line Items]
Accounts Receivable, before Allowance for Credit Loss, Current	61.6
Accounting Standards Update 2016-13 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Significant Accounting Policies [Line Items]
Accounts Receivable, before Allowance for Credit Loss, Current	$ 60.4

Supplemental Financial Inform_3

Supplemental Financial Information (Supplemental Financial Information) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Supplemental Financial Information [Line Items]
Other comprehensive loss before reclassifications	$ (0.3)
Allowance for Doubtful Accounts Receivable, Current	0.7		$ 0.4
Customer receivables	45.7		46.3
Unbilled Revenue	15.9		19.4
Amounts due from partners in jointly owned stations	0.2		0.3
Due from PJM transmission settlement	1.8		1.8
Other	2		1.2
Provision for uncollectible accounts	(0.7)		(0.4)
Total accounts receivable, net	64.9		68.6
Fuel and limestone	1.3		3.5
Plant materials and supplies	9.4		10.6
Total inventories, at average cost	10.7		14.1
Other Operating Income (Expense), Net	0.1	$ (0.9)
Provision for Doubtful Accounts	0.4
Allowance for Doubtful Accounts Receivable, Write-offs	(0.1)
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent	0
Other Comprehensive Income (Loss), Net of Tax	(0.3)	(0.4)
THE DAYTON POWER AND LIGHT COMPANY [Member]
Supplemental Financial Information [Line Items]
Other comprehensive loss before reclassifications	(0.3)
Allowance for Doubtful Accounts Receivable, Current	0.7		0.4
Customer receivables	44.5		45
Unbilled Revenue	15.9		19.4
Amounts due from partners in jointly owned stations	4.6		3.9
Due from PJM transmission settlement	1.8		1.8
Other	2.1		1.2
Provision for uncollectible accounts	(0.7)		(0.4)
Total accounts receivable, net	68.2		70.9
Total inventories, at average cost	9.1		$ 10.4
Provision for Doubtful Accounts	0.4
Allowance for Doubtful Accounts Receivable, Write-offs	(0.1)
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent	(0.7)
Other Comprehensive Income (Loss), Net of Tax	0.4	$ 0.4
Amortization of defined benefit pension items [Member]
Supplemental Financial Information [Line Items]
Other comprehensive loss before reclassifications	0
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent	(0.3)
Other Comprehensive Income (Loss), Net of Tax	0.3
Amortization of defined benefit pension items [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Supplemental Financial Information [Line Items]
Other comprehensive loss before reclassifications	0
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent	(0.8)
Other Comprehensive Income (Loss), Net of Tax	0.8
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Supplemental Financial Information [Line Items]
Other comprehensive loss before reclassifications	(0.3)
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent	0.3
Other Comprehensive Income (Loss), Net of Tax	(0.6)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Supplemental Financial Information [Line Items]
Other comprehensive loss before reclassifications	(0.3)
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent	0.1
Other Comprehensive Income (Loss), Net of Tax	$ (0.4)

Supplemental Financial Inform_4

Supplemental Financial Information (Reclassification out of ACOI) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Interest expense	$ (18.9)	$ (23.7)
Tax expense	0.5	(2.7)
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax	1.3	29.8
Discontinued Operation, Tax Effect of Discontinued Operation	(0.3)	(4.3)
Nonoperating Income (Expense)	(19.8)	(22.3)
Net income	1.9	42.1
THE DAYTON POWER AND LIGHT COMPANY [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Interest expense	(6.2)	(7.1)
Tax expense	(1.2)	(6.1)
Nonoperating Income (Expense)	(8)	(6.5)
Net income	11.7	29
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net income	0	(0.1)
Reclassification out of Accumulated Other Comprehensive Income [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net income	0.7	0.6
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Interest expense	(0.4)	(0.3)
Tax expense	0.1	0.1
Net income	(0.3)	(0.2)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Interest expense	(0.1)	(0.1)
Tax expense	0	0
Net income	(0.1)	(0.1)
Amortization of defined benefit pension items [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Tax expense	0	0
Nonoperating Income (Expense)	0.3	0.1
Net income	0.3	0.1
Amortization of defined benefit pension items [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Tax expense	(0.2)	(0.2)
Nonoperating Income (Expense)	1	0.9
Net income	$ 0.8	$ 0.7

Supplemental Financial Inform_5

Supplemental Financial Information (Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	$ (3.6)
Other comprehensive loss before reclassifications	(0.3)
Amounts reclassified from AOCI to earnings	0
Other comprehensive loss	(0.3)	$ (0.4)
Balance, end of period	(3.9)
THE DAYTON POWER AND LIGHT COMPANY [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(36.9)
Other comprehensive loss before reclassifications	(0.3)
Amounts reclassified from AOCI to earnings	0.7
Other comprehensive loss	0.4	$ 0.4
Balance, end of period	(36.5)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	14.5
Other comprehensive loss before reclassifications	(0.3)
Amounts reclassified from AOCI to earnings	(0.3)
Other comprehensive loss	(0.6)
Balance, end of period	13.9
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(0.4)
Other comprehensive loss before reclassifications	(0.3)
Amounts reclassified from AOCI to earnings	(0.1)
Other comprehensive loss	(0.4)
Balance, end of period	(0.8)
Change in unfunded pension obligation [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(18.1)
Other comprehensive loss before reclassifications	0
Amounts reclassified from AOCI to earnings	0.3
Other comprehensive loss	0.3
Balance, end of period	(17.8)
Change in unfunded pension obligation [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(36.5)
Other comprehensive loss before reclassifications	0
Amounts reclassified from AOCI to earnings	0.8
Other comprehensive loss	0.8
Balance, end of period	$ (35.7)

Regulatory Matters (Details)

Regulatory Matters (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Regulatory Assets, Noncurrent		$ 175.8	$ 173.8
Unbilled Revenue		15.9	19.4
Due from PJM transmission settlement		1.8	1.8
Subsidiaries [Member]
Regulatory Assets, Noncurrent		175.8	173.8
Unbilled Revenue		15.9	19.4
Due from PJM transmission settlement		$ 1.8	$ 1.8
Scenario, Forecast [Member]
Increase in revenues from proposed transmission rate change to a formula rate	$ 4.1
Scenario, Forecast [Member] | Subsidiaries [Member]
Increase in revenues from proposed transmission rate change to a formula rate	$ 4.1

Fair Value (Narrative) (Details

Fair Value (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Unrealized Gain (Loss) on Investments	$ (1.1)	$ 0.5
THE DAYTON POWER AND LIGHT COMPANY [Member]
Unrealized Gain (Loss) on Investments	$ (1.1)	$ 0.5

Fair Value (Fair Value and Cost

Fair Value (Fair Value and Cost of Non-Derivative Instruments) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Cost [Member]
Total Assets	$ 6.4	$ 6.8
Cost [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Assets	6.4	6.8
Fair Value [Member]
Total Master Trust Assets, Fair Value	7.3	8.8
Total Assets	7.3	8.8
Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	7.3	8.8
Total Assets	7.3	8.8
Money Market Funds [Member] | Cost [Member]
Total Master Trust Assets, Cost	0.2	0.3
Money Market Funds [Member] | Cost [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Cost	0.2	0.3
Money Market Funds [Member] | Fair Value [Member]
Total Master Trust Assets, Fair Value	0.2	0.3
Money Market Funds [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0.2	0.3
Equity Securities [Member] | Cost [Member]
Total Master Trust Assets, Cost	2.1	2.3
Equity Securities [Member] | Cost [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Cost	2.1	2.3
Equity Securities [Member] | Fair Value [Member]
Total Master Trust Assets, Fair Value	3.1	4.2
Equity Securities [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	3.1	4.2
Debt Securities [Member] | Cost [Member]
Total Master Trust Assets, Cost	4.1	4
Debt Securities [Member] | Cost [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Cost	4.1	4
Debt Securities [Member] | Fair Value [Member]
Total Master Trust Assets, Fair Value	4	4.1
Debt Securities [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	4	4.1
Hedge Funds [Member] | Cost [Member]
Total Master Trust Assets, Cost	0	0.1
Hedge Funds [Member] | Cost [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Cost	0	0.1
Hedge Funds [Member] | Fair Value [Member]
Total Master Trust Assets, Fair Value	0	0.1
Hedge Funds [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0.1
Tangible Assets [Member] | Cost [Member]
Total Master Trust Assets, Cost	0	0.1
Tangible Assets [Member] | Cost [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Cost	0	0.1
Tangible Assets [Member] | Fair Value [Member]
Total Master Trust Assets, Fair Value	0	0.1
Tangible Assets [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0.1
Debt [Member] | Cost [Member]
Debt, Cost	1,363.6	1,363.1
Debt [Member] | Cost [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt, Cost	574.5	574.4
Debt [Member] | Fair Value [Member]
Debt, Fair Value	1,376.6	1,404
Debt [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt, Fair Value	$ 601.1	$ 600.5

Fair Value (Fair Value of Asset

Fair Value (Fair Value of Assets and Liabilities Measured on Recurring Basis) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Level 1 [Member]
Total Master Trust Assets, Fair Value	$ 0.2	$ 0.3
Total Derivative Assets	0	0
Total Assets	0.2	0.3
Total Liabilities	0	0
Level 1 [Member] | Interest Rate Contract [Member]
Total Derivative Assets	0	0
Level 1 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0.2	0.3
Total Derivative Assets	0	0
Total Assets	0.2	0.3
Total Liabilities	0	0
Level 1 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Interest Rate Contract [Member]
Total Derivative Assets	0	0
Derivative Liability	0	0
Level 2 [Member]
Total Master Trust Assets, Fair Value	7.1	8.5
Total Derivative Assets	0	0.1
Total Assets	7.1	8.6
Total Liabilities	1,359.4	1,386.5
Level 2 [Member] | Interest Rate Contract [Member]
Total Derivative Assets	0	0.1
Level 2 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	7.1	8.5
Total Derivative Assets	0	0.1
Total Assets	7.1	8.6
Total Liabilities	583.9	583
Level 2 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Interest Rate Contract [Member]
Total Derivative Assets	0	0.1
Derivative Liability	0.3	0
Level 3 [Member]
Total Master Trust Assets, Fair Value	0	0
Total Derivative Assets	0	0
Total Assets	0	0
Total Liabilities	17.5	17.5
Level 3 [Member] | Interest Rate Contract [Member]
Total Derivative Assets	0	0
Level 3 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0
Total Derivative Assets	0	0
Total Assets	0	0
Total Liabilities	17.5	17.5
Level 3 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Interest Rate Contract [Member]
Total Derivative Assets	0	0
Derivative Liability	0	0
Fair Value [Member]
Total Master Trust Assets, Fair Value	7.3	8.8
Total Derivative Assets	0	0.1
Total Assets	7.3	8.9
Total Liabilities	1,376.9	1,404
Fair Value [Member] | Interest Rate Contract [Member]
Total Derivative Assets	0	0.1
Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	7.3	8.8
Total Derivative Assets	0	0.1
Total Assets	7.3	8.9
Total Liabilities	601.4	600.5
Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Interest Rate Contract [Member]
Total Derivative Assets	0	0.1
Derivative Liability	0.3	0
Money Market Funds [Member] | Level 1 [Member]
Total Master Trust Assets, Fair Value	0.2	0.3
Money Market Funds [Member] | Level 1 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0.2	0.3
Money Market Funds [Member] | Level 2 [Member]
Total Master Trust Assets, Fair Value	0	0
Money Market Funds [Member] | Level 2 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0
Money Market Funds [Member] | Level 3 [Member]
Total Master Trust Assets, Fair Value	0	0
Money Market Funds [Member] | Level 3 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0
Money Market Funds [Member] | Fair Value [Member]
Total Master Trust Assets, Fair Value	0.2	0.3
Money Market Funds [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0.2	0.3
Equity Securities [Member] | Level 1 [Member]
Total Master Trust Assets, Fair Value	0	0
Equity Securities [Member] | Level 1 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0
Equity Securities [Member] | Level 2 [Member]
Total Master Trust Assets, Fair Value	3.1	4.2
Equity Securities [Member] | Level 2 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	3.1	4.2
Equity Securities [Member] | Level 3 [Member]
Total Master Trust Assets, Fair Value	0	0
Equity Securities [Member] | Level 3 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0
Equity Securities [Member] | Fair Value [Member]
Total Master Trust Assets, Fair Value	3.1	4.2
Equity Securities [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	3.1	4.2
Debt Securities [Member] | Level 1 [Member]
Total Master Trust Assets, Fair Value	0	0
Debt Securities [Member] | Level 1 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0
Debt Securities [Member] | Level 2 [Member]
Total Master Trust Assets, Fair Value	4	4.1
Debt Securities [Member] | Level 2 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	4	4.1
Debt Securities [Member] | Level 3 [Member]
Total Master Trust Assets, Fair Value	0	0
Debt Securities [Member] | Level 3 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0
Debt Securities [Member] | Fair Value [Member]
Total Master Trust Assets, Fair Value	4	4.1
Debt Securities [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	4	4.1
Hedge Funds [Member] | Level 1 [Member]
Total Master Trust Assets, Fair Value	0	0
Hedge Funds [Member] | Level 1 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0
Hedge Funds [Member] | Level 2 [Member]
Total Master Trust Assets, Fair Value	0	0.1
Hedge Funds [Member] | Level 2 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0.1
Hedge Funds [Member] | Level 3 [Member]
Total Master Trust Assets, Fair Value	0	0
Hedge Funds [Member] | Level 3 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0
Hedge Funds [Member] | Fair Value [Member]
Total Master Trust Assets, Fair Value	0	0.1
Hedge Funds [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0.1
Tangible Assets [Member] | Level 1 [Member]
Total Master Trust Assets, Fair Value	0	0
Tangible Assets [Member] | Level 1 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0
Tangible Assets [Member] | Level 2 [Member]
Total Master Trust Assets, Fair Value	0	0.1
Tangible Assets [Member] | Level 2 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0.1
Tangible Assets [Member] | Level 3 [Member]
Total Master Trust Assets, Fair Value	0	0
Tangible Assets [Member] | Level 3 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0
Tangible Assets [Member] | Fair Value [Member]
Total Master Trust Assets, Fair Value	0	0.1
Tangible Assets [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0.1
Debt [Member] | Level 1 [Member]
Debt	0	0
Debt [Member] | Level 1 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt	0	0
Debt [Member] | Level 2 [Member]
Debt	1,359.1	1,386.5
Debt [Member] | Level 2 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt	583.6	583
Debt [Member] | Level 3 [Member]
Debt	17.5	17.5
Debt [Member] | Level 3 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt	17.5	17.5
Debt [Member] | Fair Value [Member]
Debt	1,376.6	1,404
Debt [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt	$ 601.1	$ 600.5

Derivative Instruments and He_3

Derivative Instruments and Hedging Activities (Narrative) (Details) $ in Millions	Mar. 31, 2020USD ($)Number_of_interest_rate_swaps	Dec. 31, 2019USD ($)
THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument, Number of Financial Covenants | Number_of_interest_rate_swaps	2
One Point One Three To One Point One Seven Bonds Maturing In August Two Thousand Twenty [Member]
Long-term Debt, Gross	$ 140
One Point One Three To One Point One Seven Bonds Maturing In August Two Thousand Twenty [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Long-term Debt, Gross	140
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]
Derivative, Notional Amount, Purchase (Sales), Net	140
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative, Notional Amount, Purchase (Sales), Net	140
Other Current Liabilities [Member] | Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Liability, Fair Value, Gross Liability	$ (0.3)	$ 0

Derivative Instruments and He_4

Derivative Instruments and Hedging Activities (Outstanding Derivative Instruments) (Details) - Designated as Hedging Instrument [Member] - Interest Rate Swap [Member] $ in Millions	Mar. 31, 2020USD ($)
Derivative, Notional Amount, Purchase (Sales), Net	$ 140
THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative, Notional Amount, Purchase (Sales), Net	$ 140

Derivative Instruments and He_5

Derivative Instruments and Hedging Activities (Gains or Losses Recognized in AOCI for the Cash Flow Hedges) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Forward Contract Power [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Beginning accumulated derivative gain / (loss) in AOCI		$ 0.4
Net gains / (losses) associated with current period hedging transactions		0
Ending accumulated derivative gain / (loss) in AOCI		0.4
Interest Rate Contract [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Beginning accumulated derivative gain / (loss) in AOCI	$ 14.5	16.6
Net gains / (losses) associated with current period hedging transactions	(0.3)	(0.3)
Ending accumulated derivative gain / (loss) in AOCI	13.9	16.1
Portion expected to be reclassified to earnings in the next twelve months	$ (1.1)
Maximum length of time that we are hedging our exposure to variability in future cash flows related to forecasted transactions (in months)	5 months
THE DAYTON POWER AND LIGHT COMPANY [Member] | Interest Rate Contract [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Beginning accumulated derivative gain / (loss) in AOCI	$ (0.4)	0.6
Net gains / (losses) associated with current period hedging transactions	(0.3)	(0.2)
Ending accumulated derivative gain / (loss) in AOCI	(0.8)	0.3
Portion expected to be reclassified to earnings in the next twelve months	$ (0.1)
Maximum length of time that we are hedging our exposure to variability in future cash flows related to forecasted transactions (in months)	5 months
Interest Expense [Member] | Forward Contract Power [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Net gains losses reclassified to earnings		0
Interest Expense [Member] | Interest Rate Contract [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Net gains losses reclassified to earnings	$ (0.3)	(0.2)
Interest Expense [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Interest Rate Contract [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Net gains losses reclassified to earnings		$ (0.1)

Derivative Instruments and He_6

Derivative Instruments and Hedging Activities (Fair Value and Balance Sheet Location (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Other Current Assets [Member]
Derivative Asset, Fair Value	$ 0	$ 0.1

Debt (Narrative) (Details)

Debt (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020USD ($)debt_covenantfiscal_quarter	Mar. 31, 2019USD ($)	Dec. 31, 2019USD ($)
Debt Instrument [Line Items]
Long-term Line of Credit	$ 94		$ 104
Retirement of long-term debt	$ 0	$ 1.1
Debt Covenant, Debt to EBITDA Ratio, Maximum	7
Debt Covenant, Leverage Ratio, Maximum	0.67
Debt Covenant, Interest Coverage Ratio, Minimum	2.25
Interest Coverage Ratio	3.01
THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Long-term Line of Credit	$ 85		40
Retirement of long-term debt	0	$ 1.1
Long Term Indebtedness, Less than or Equal to	$ 750
Debt Covenant, Interest Coverage Ratio, Minimum		2.50
Debt Covenant, Total Debt to Total Capitalization Ratio, Maximum	0.65
Total Debt to Total Capitalization Ratio	0.58
3.95% Senior Notes due 2049 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 425		425
Variable Rate Notes Backed by Term Loan and First Mortgage Bonds [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 140		140
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 EBITDA to interest calculation | fiscal_quarter	4
Debt Covenant, Interest Coverage Ratio, Minimum	2.50
Interest Coverage Ratio	7.83
DPL Revolving Credit Agreement and Term Loan Maturing July 2020 [Member]
Debt Instrument [Line Items]
Number of financial covenants | debt_covenant	2
Number of prior quarters included in EBITDA to interest calculation | fiscal_quarter	4
Number of prior quarters included in debt to EBITDA ratio | fiscal_quarter	4
Debt Covenant, Interest Coverage Ratio, Minimum	2.50
Ten Year Senior Unsecured Notes At725 Maturing At October152021 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 380		$ 380
Debt instrument interest percentage	7.25%
Revolving Credit Facility [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Debt Covenant, Total Debt to Total Capitalization Ratio, Maximum	0.67
Total Debt to Total Capitalization Ratio	0.58

Debt (Long-term Debt) (Details)

Debt (Long-term Debt) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Debt Instrument [Line Items]
Debt to EBITDA Ratio	6.75
Unamortized deferred finance costs	$ (5.5)	$ (5.9)
Unamortized debt discounts and premiums, net	(1)	(1)
Total long-term debt	1,363.6	1,363.1
Less: current portion	(139.9)	(139.8)
Long-term debt	1,223.7	1,223.3
Long-term Line of Credit	$ 94	104
THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Debt Covenant, Total Debt to Total Capitalization Ratio, Maximum	0.65
Long Term Indebtedness, Less than or Equal to	$ 750
Unamortized deferred finance costs	(5.3)	(5.4)
Unamortized deferred finance costs	(5.3)	(5.4)
Unamortized debt discounts and premiums, net	(2.7)	(2.7)
Unamortized debt discounts and premiums, net	(2.7)	(2.7)
Total long-term debt at subsidiary	574.5	574.4
Total long-term debt	574.5	574.4
Less: current portion	(139.9)	(139.8)
Long-term debt	434.6	434.6
Long-term Line of Credit	$ 85	40
Term Loan Maturing 2022 [Domain]
Debt Instrument [Line Items]
Debt instrument maturity year	Jan. 1, 2049
Term Loan Maturing 2022 [Domain] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Debt instrument maturity year	Jan. 1, 2049
3.95% Senior Notes due 2049 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 425	425
Debt instrument maturity year	Aug. 1, 2020
Pollution Control Series Maturing in August 2020 - 1.13% - 1.14% [Member]
Debt Instrument [Line Items]
Debt instrument maturity year	Aug. 1, 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	140
U.S. Government note maturing in February 2061 - 4.20% [Member]
Debt Instrument [Line Items]
Debt instrument maturity year	Feb. 1, 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	$ 17.5	17.5
Senior unsecured due in October 2021 - 7.25% [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 380	380
Debt instrument maturity year	Oct. 1, 2021
Debt instrument interest percentage	7.25%
4.35% Senior Notes due 2029 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 400	400
Debt instrument maturity year	Apr. 15, 2029
Debt instrument interest percentage	4.35%
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. 1, 2031
Debt instrument interest percentage	8.125%
Maximum [Member] | Term Loan Maturing 2022 [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage
Debt Instrument, Interest Rate, Effective Percentage
Maximum [Member] | Pollution Control Series Maturing in August 2020 - 1.13% - 1.14% [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage		1.42%
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	2.93%
Minimum [Member] | Term Loan Maturing 2022 [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage
Debt Instrument, Interest Rate, Effective Percentage	3.95%
Minimum [Member] | Pollution Control Series Maturing in August 2020 - 1.13% - 1.14% [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage	4.20%	1.29%
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 maturity year	Feb. 1, 2061
Debt instrument interest percentage	2.40%

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Entity Information [Line Items]
Effective Income Tax Rate Reconciliation, at Combined Federal and State Statutory Income Tax Rate, Percent	22.30%
Estimated annual effective income tax rate	(14.90%)	14.30%
Effective Income Tax Rate Reconciliation, Including Discontinued Operations, Percent	(11.80%)	14.30%
Non-cash capital contribution	$ 0	$ 1.5
THE DAYTON POWER AND LIGHT COMPANY [Member]
Entity Information [Line Items]
Effective income tax rates		17.40%
Effective Income Tax Rate Reconciliation, at Combined Federal and State Statutory Income Tax Rate, Percent	22.30%
Estimated annual effective income tax rate	9.10%	17.30%
Effective Income Tax Rate Reconciliation, Including Discontinued Operations, Percent	9.30%	9.30%

Benefit Plans (Net Periodic Ben

Benefit Plans (Net Periodic Benefit Cost (Income)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Pension [Member]
Contributions by employer	$ 7.5	$ 7.5
Service cost	0.9	0.9
Interest cost	3	3.7
Expected return on assets	(4.7)	(5)
Prior service cost	0.3	0.3
Actuarial loss / (gain)	1.5	1.1
Net periodic benefit cost	1	1
Postretirement [Member]
Defined Benefit Plan, Funded (Unfunded) Status of Plan	9.7		$ 9.6
THE DAYTON POWER AND LIGHT COMPANY [Member] | Pension [Member]
Contributions by employer	7.5	7.5
Service cost	0.9	0.9
Interest cost	3	3.7
Expected return on assets	(4.7)	(5)
Prior service cost	0.3	0.5
Actuarial loss / (gain)	2.2	1.7
Net periodic benefit cost	1.7	$ 1.8
THE DAYTON POWER AND LIGHT COMPANY [Member] | Postretirement [Member]
Defined Benefit Plan, Funded (Unfunded) Status of Plan	$ 9.7		$ 9.6

Shareholder's Equity (Details)

Shareholder's Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Class of Stock [Line Items]
Non-cash capital contribution	$ 0	$ 1.5
Common Stock, Shares Authorized	1,500	1,500	1,500
Common stock, shares outstanding	1		1
THE DAYTON POWER AND LIGHT COMPANY [Member]
Class of Stock [Line Items]
Common Stock, Shares Authorized	50,000,000	50,000,000	50,000,000
Par value common shares (in USD per share)	$ 0.01	$ 0.01	$ 0.01
Common stock, shares outstanding	41,172,173		41,172,173

Contractual Obligations, Comm_2

Contractual Obligations, Commercial Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Public Utility, Property, Plant and Equipment [Line Items]
Due to third parties, current	$ 0	$ 0
AES Ohio Generation [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Third party guarantees	$ 15.5
Debt Obligation on 4.9% Equity Ownership [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Equity ownership interest	4.90%
Equity ownership interest aggregate cost	$ 65.8
Electric Generation Company [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Debt obligation	$ 1,343.2

Business Segments (Narrative) (

Business Segments (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020USD ($)mi²customersegment	Dec. 31, 2019USD ($)
Segment Reporting Information [Line Items]
Total assets	$ 1,918.4	$ 1,935.8
THE DAYTON POWER AND LIGHT COMPANY [Member]
Segment Reporting Information [Line Items]
Total assets	$ 1,874.6	1,883.2
Number of Operating Segments | segment	1
Approximate number of retail customers | customer	527,000
Service area, square miles | mi²	6,000
Operating Segments [Member] | Utility [Member]
Segment Reporting Information [Line Items]
Total assets	$ 1,874.6	1,883.2
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Total assets	$ 43.8	$ 52.6

Business Segments (Segment Fina

Business Segments (Segment Financial Information) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Segment Reporting Information [Line Items]
External customer revenues	$ 174.7	$ 209
Intersegment revenues	0	0
Total revenues	174.7	209
Depreciation and amortization	17.8	18.4
Fuel Costs	4	3.5
Depreciation and amortization	17.8	(3.1)
Interest expense	18.9	23.7
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	0.4	19.2
Net income / (loss) from continuing operations	0.9	16.5
Discontinued operations, net of tax	1	25.6
Net income/ (loss)	1.9	42.1
Capital expenditures	44.6	34.3
Total assets	1,918.4		$ 1,935.8
Operating Segments [Member] | Utility [Member]
Segment Reporting Information [Line Items]
External customer revenues	168.7	201.1
Intersegment revenues	0.3	0.3
Total revenues	169	201.4
Depreciation and amortization	17.3	18
Interest expense	6.2	7.1
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	12.9	35.1
Capital expenditures	43.7	33.7
Total assets	1,874.6		1,883.2
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
External customer revenues	6	7.9
Intersegment revenues	0.8	0.8
Total revenues	6.8	8.7
Depreciation and amortization	0.5	0.4
Interest expense	12.7	16.6
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	(12.5)	(15.9)
Capital expenditures	0.9	0.6
Total assets	43.8		52.6
Adjustments and Eliminations [Member]
Segment Reporting Information [Line Items]
External customer revenues	0	0
Intersegment revenues	(1.1)	(1.1)
Total revenues	(1.1)	(1.1)
Depreciation and amortization	0	0
Interest expense	0	0
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	0	0
Capital expenditures	0	0
Subsidiaries [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	17.3	18
Fuel Costs	0.6	0.9
Depreciation and amortization	17.3	18
Interest expense	6.2	7.1
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	12.9	35.1
Net income/ (loss)	11.7	$ 29
Total assets	$ 1,874.6		$ 1,883.2

Revenue (Details)

Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Revenue from Contract with Customer, Excluding Assessed Tax	$ 170.5	$ 208.3
Alternative Revenue Programs Accounts Receivable, Gross	0		$ 0
RTO Revenue	10.8	10.9
RTO Capacity Revenue	2.2	3.7
Revenues	174.7	209
Contract with Customer, Asset, Gross	60.3		65.7
Corporate, Non-Segment [Member]
RTO Revenue	0.1	0
RTO Capacity Revenue	1	1.6
Revenues	6.8	8.7
Adjustments and Eliminations [Member]
RTO Revenue	0	0
RTO Capacity Revenue	0	0
Revenues	(1.1)	(1.1)
Utility [Member]
RTO Revenue	10.7	10.9
RTO Capacity Revenue	1.2	2.1
Revenues	169	201.4
Subsidiaries [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	164.8	200.7
Alternative Revenue Programs Accounts Receivable, Gross	0		0
RTO Revenue	10.7	10.9
RTO Capacity Revenue	1.2	2.1
Revenues	169	201.4
Contract with Customer, Asset, Gross	59.1		$ 64.4
Other Revenues [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	2.4	2.9
Other non-606 revenue	0.9	0
Other Revenues [Member] | Corporate, Non-Segment [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	2.4	2.9
Other non-606 revenue	0.8	0.8
Other Revenues [Member] | Adjustments and Eliminations [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Other non-606 revenue	(0.8)	(0.8)
Other Revenues [Member] | Utility [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Other non-606 revenue	0.9	0
Other Revenues [Member] | Subsidiaries [Member]
Other non-606 revenue	0.9	0
Wholesale Revenue [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	4.9	8.4
Wholesale Revenue [Member] | Corporate, Non-Segment [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	2.5	3.4
Wholesale Revenue [Member] | Adjustments and Eliminations [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	(0.3)	0
Wholesale Revenue [Member] | Utility [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	2.7	5
Wholesale Revenue [Member] | Subsidiaries [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	2.7	5
Retail Revenue [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	150.2	182.4
Other non-606 revenue	3.3	0.7
Retail Revenue [Member] | Corporate, Non-Segment [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Other non-606 revenue	0	0
Retail Revenue [Member] | Adjustments and Eliminations [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	0	(0.3)
Other non-606 revenue	0	0
Retail Revenue [Member] | Utility [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	150.2	182.7
Other non-606 revenue	3.3	0.7
Retail Revenue [Member] | Subsidiaries [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	150.2	182.7
Other non-606 revenue	$ 3.3	$ 0.7

Dispositions (Details)

Dispositions (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	$ 0.4	$ 19.2
Property, Plant and Equipment, Additions	44.6	34.3
Subsidiaries [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	$ 12.9	$ 35.1

Discontinued Operations (Detail

Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	$ 0	$ 0.1
Disposal Group, Including Discontinued Operation, Revenue	10	16.3
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net	1.8		$ 17.4
Disposal Group, Including Discontinued Operation, Other Assets, Current	0.1		0.3
Disposal Group, Including Discontinued Operation, Assets	1.9		17.7
Disposal Group, Including Discontinued Operation, Accounts Payable	3.4		3.8
Disposal Group, Including Discontinued Operation, Other Liabilities, Current	2.5		3.1
Disposal Group, Including Discontinued Operation, Other Liabilities, Noncurrent	6.2		6.2
Disposal Group, Including Discontinued Operation, Liabilities	12.1		$ 13.1
Disposal Group, Including Discontinued Operation, Operating and Other Expenses	(8.7)	13.5
Disposal Group, Including Discontinued Operation, Asset Retirement Obligation, Revision of Estimate		22.5
Loss from discontinued operations before income taxes	1.3	29.8
Income tax expense from discontinued operations	0.3	4.3
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	1	25.6
Cash Provided by (Used in) Operating Activities, Discontinued Operations	15.8	$ 8.1
Cash flows from investing activities for discontinued operations	0
Subsidiaries [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Long Term Indebtedness, Less than or Equal to	$ 750