DPL (DPL) 10-Q 5 Aug 16 2016 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2016	Aug. 04, 2016
Entity Registrant Name	DPL INC
Entity Central Index Key	787,250
Document Type	10-Q
Document Period End Date	Jun. 30, 2016
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
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2
Entity Voluntary Filers	Yes
Entity Well-known Seasoned Issuer	No
THE DAYTON POWER AND LIGHT COMPANY [Member]
Entity Registrant Name	DAYTON POWER & LIGHT CO
Entity Central Index Key	27,430
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 Voluntary Filers	Yes
Entity Well-known Seasoned Issuer	No

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenues	$ 328.3	$ 365.9	$ 692.3	$ 848.8
Cost of revenues:
Fuel	60.2	54.4	127.1	130.8
Purchased power	96.9	120.3	218.8	313.6
Total cost of revenues	157.1	174.7	345.9	444.4
Gross margin	171.2	191.2	346.4	404.4
Operating expenses:
Operation and maintenance	77.2	84.6	165.7	171.6
Depreciation and amortization	36	33.3	69.4	67.1
General taxes	21.6	22	42.6	45
Impairment of Long-Lived Assets Held-for-use	235.5	0	235.5	0
Other	0	(0.2)	0.1	0.2
Total operating expenses	370.3	139.7	513.3	283.9
Operating income / (loss)	(199.1)	51.5	(166.9)	120.5
Other income / (expense), net
Investment income	0.3	0.2	0.2	0
Interest expense	(26)	(30.9)	(52.3)	(61.4)
Charge for early retirement of debt	0	0	(2.6)	0
Other expense	(0.3)	(0.2)	(0.7)	(0.7)
Total other expense, net	(26)	(30.9)	(55.4)	(62.1)
Earnings / (loss) from continuing operations before income taxes	(225.1)	20.6	(222.3)	58.4
Income tax expense / (benefit) from continuing operations	(88.3)	5.8	(87.7)	16.8
Net income / (loss) from continuing operations	(136.8)	14.8	(134.6)	41.6
Income / (loss) from discontinued operations	0	1.6	(0.7)	5.2
Gain from disposal of discontinued operations	0	0	49.2	0
Income tax expense / (benefit) for discontinued operations	0	(5.3)	18.9	(3.6)
Discontinued operations	0	6.9	29.6	8.8
Net income / (loss)	(136.8)	21.7	(105)	50.4
THE DAYTON POWER AND LIGHT COMPANY [Member]
Revenues	313.7	352.1	662.9	813.4
Cost of revenues:
Fuel	55.6	50.6	118.5	119.9
Purchased power	96.7	120.1	218	309.8
Total cost of revenues	152.3	170.7	336.5	429.7
Gross margin	161.4	181.4	326.4	383.7
Operating expenses:
Operation and maintenance	76.4	83.7	162.5	168.1
Depreciation and amortization	36.8	34.2	71.1	68.9
General taxes	21.1	21.4	41.6	43.9
Impairment of Long-Lived Assets Held-for-use	857.1	0	857.1	0
Gain on termination of contract	0	0	(27.7)	0
Other	0.1	0	0.2	0.4
Total operating expenses	991.5	139.3	1,104.8	281.3
Operating income / (loss)	(830.1)	42.1	(778.4)	102.4
Other income / (expense), net
Investment income	0.3	0.3	0.2	0.2
Interest expense	(5.4)	(9)	(10.7)	(17.7)
Other expense	(0.1)	(0.1)	(0.3)	(0.3)
Total other expense, net	(5.2)	(8.8)	(10.8)	(17.8)
Earnings / (loss) from continuing operations before income taxes	(835.3)	33.3	(789.2)	84.6
Income tax expense / (benefit) from continuing operations	(303.7)	9.4	(291.3)	24.2
Net income / (loss)	(531.6)	23.9	(497.9)	60.4
Dividends on preferred stock	0.2	0.2	0.4	0.4
Income / (loss) attributable to common stock	$ (531.8)	$ 23.7	$ (498.3)	$ 60

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net income	$ (136.8)	$ 21.7	$ (105)	$ 50.4
Available-for-sale securities activity:
Change in fair value of available-for-sale securities, net of income tax	(0.1)	(0.4)	0.1	0.1
Reclassification to earnings, net of income tax	0.1	0.4	0	0
Total change in fair value of available-for-sale securities	0	0	0.1	0.1
Derivative activity:
Change in derivative fair value, net of income tax	(8.5)	1.7	13	1.8
Reclassification of earnings, net of income tax	(10.8)	(1.9)	(19)	(1.4)
Total change in fair value of derivatives	(19.3)	(0.2)	(6)	0.4
Pension and postretirement activity:
Reclassification to earnings, net of income tax	0.1	(0.4)	0	(0.2)
Total change in unfunded pension obligation	0.1	(0.4)	0	(0.2)
Other comprehensive income / (loss)	(19.2)	(0.6)	(5.9)	0.3
Net comprehensive income / (loss)	(156)	21.1	(110.9)	50.7
THE DAYTON POWER AND LIGHT COMPANY [Member]
Net income	(531.6)	23.9	(497.9)	60.4
Available-for-sale securities activity:
Change in fair value of available-for-sale securities, net of income tax	(0.1)	(0.5)	0.1	0
Reclassification to earnings, net of income tax	0.1	0.4	0	0
Total change in fair value of available-for-sale securities	0	(0.1)	0.1	0
Derivative activity:
Change in derivative fair value, net of income tax	(8.5)	1.7	13	1.8
Reclassification of earnings, net of income tax	(10.8)	(1.8)	(19.2)	(1.3)
Total change in fair value of derivatives	(19.3)	(0.1)	(6.2)	0.5
Pension and postretirement activity:
Reclassification to earnings, net of income tax	0.7	0.9	1	1.8
Total change in unfunded pension obligation	0.7	0.9	1	1.8
Other comprehensive income / (loss)	(18.6)	0.7	(5.1)	2.3
Net comprehensive income / (loss)	$ (550.2)	$ 24.6	$ (503)	$ 62.7

Condensed Consolidated Stateme4

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income tax (expense)/benefit on unrealized gains (losses) related to available-for-sale securities	$ 0	$ (0.3)	$ (0.1)	$ 0
Income tax (expense) benefit on reclassification to earnings	0	(0.2)	0	0
Income tax (expense)/benefit on unrealized gains (losses) related to derivative activity	4.7	(1)	(7.1)	(1)
Income tax (expense)/benefit on reclassification of earnings related to derivative activity	5.9	0.9	10.7	0.5
Income tax (expense)/benefit on reclassification of earnings related to pension and postretirement activity	0	(0.5)	(0.2)	(0.4)
THE DAYTON POWER AND LIGHT COMPANY [Member]
Income tax (expense)/benefit on unrealized gains (losses) related to available-for-sale securities	0	0.2	(0.1)	0
Income tax (expense) benefit on reclassification to earnings	0	(0.2)	0	0
Income tax (expense)/benefit on unrealized gains (losses) related to derivative activity	4.7	(1)	(7)	(1)
Income tax (expense)/benefit on reclassification of earnings related to derivative activity	5.9	1	10.5	0.7
Income tax (expense)/benefit on reclassification of earnings related to pension and postretirement activity	$ (0.4)	$ (0.5)	$ (1.2)	$ (1)

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 73.4	$ 32.4
Restricted cash	33.2	92.7
Accounts receivable, net	107.8	120.9
Inventories	87.5	109.1
Taxes applicable to subsequent years	39.4	81.2
Regulatory assets, current	0.3	14.4
Other prepayments and current assets	50.8	44.5
Disposal Group, Including Discontinued Operation, Other Assets, Current	0	62.2
Total current assets	392.4	557.4
Property, plant & equipment:
Property, plant & equipment	2,678.8	2,909
Less: Accumulated depreciation and amortization	(449)	(432.3)
Property, plant and equipment, net of depreciation	2,229.8	2,476.7
Construction work in process	97.6	85
Total net property, plant & equipment	2,327.4	2,561.7
Other non-current assets:
Regulatory assets, non-current	186.1	179.9
Intangible assets, net of amortization	0.9	5
Other deferred assets	24.6	20.7
Total other non-current assets	211.6	205.6
Total assets	2,931.4	3,324.7
Current liabilities:
Current portion of long-term debt	514	572.8
Accounts payable	80.6	97.5
Accrued taxes	157.8	142.4
Accrued interest	20.8	21.4
Security deposits	15.2	15.2
Regulatory liabilities, current	29.9	24.4
Insurance and claims costs	5.6	5.9
Other current liabilities	65	54.5
Deposit, Sale of Business	0	75.5
Disposal Group, Including Discontinued Operation, Liabilities, Current	0	1.6
Total current liabilities	888.9	1,011.2
Non-current liabilities:
Long-term debt	1,409.3	1,420.5
Deferred taxes	467.4	568.7
Taxes payable	39.1	84.1
Regulatory liabilities, non-current	128.7	127
Pension, retiree and other benefits	79.9	87.1
Other deferred credits	91.1	88.3
Total non-current liabilities	2,215.5	2,375.7
Redeemable preferred stock of subsidiary	18.4	18.4
Commitments and contingencies
Common shareholder's equity:
Common stock	0	0
Other paid-in capital	2,237.8	2,237.7
Accumulated other comprehensive income	11.5	17.4
Retained earnings/ (deficit)	(2,440.7)	(2,335.7)
Total common shareholder's equity	(191.4)	(80.6)
Total liabilities and shareholder's equity	2,931.4	3,324.7
THE DAYTON POWER AND LIGHT COMPANY [Member]
Current assets:
Cash and cash equivalents	45.4	5.4
Restricted cash	33.2	44.8
Accounts receivable, net	105.6	119.5
Inventories	86.4	108
Taxes applicable to subsequent years	38.5	79.2
Regulatory assets, current	0.3	14.4
Other prepayments and current assets	50.1	46.3
Total current assets	359.5	417.6
Property, plant & equipment:
Property, plant & equipment	3,051.5	5,244.7
Less: Accumulated depreciation and amortization	(1,262.6)	(2,584)
Property, plant and equipment, net of depreciation	1,788.9	2,660.7
Construction work in process	84	78
Total net property, plant & equipment	1,872.9	2,738.7
Other non-current assets:
Regulatory assets, non-current	186.1	179.9
Intangible assets, net of amortization	0.9	5
Other deferred assets	22.6	18.4
Total other non-current assets	209.6	203.3
Total assets	2,442	3,359.6
Current liabilities:
Current portion of long-term debt	444.6	443.1
Short-term debt	0	35
Accounts payable	75.7	94.1
Accrued taxes	85.5	86.2
Accrued interest	4.4	4.1
Security deposits	15.2	15.1
Regulatory liabilities, current	29.9	24.4
Other current liabilities	64	51
Advance on contract termination	0	27.7
Total current liabilities	719.3	780.7
Non-current liabilities:
Long-term debt	313.8	313.6
Deferred taxes	318.4	631.2
Taxes payable	38	82.1
Regulatory liabilities, non-current	128.7	127
Pension, retiree and other benefits	79.9	87.1
Unamortized investment tax credit	18.8	20
Other deferred credits	85.4	82.3
Total non-current liabilities	983	1,343.3
Redeemable preferred stock of subsidiary	22.9	22.9
Commitments and contingencies
Common shareholder's equity:
Common stock	0.4	0.4
Other paid-in capital	811.2	803.7
Accumulated other comprehensive income	(33.8)	(28.7)
Retained earnings/ (deficit)	(61)	437.3
Total common shareholder's equity	716.8	1,212.7
Total liabilities and shareholder's equity	$ 2,442	$ 3,359.6

Condensed Consolidated Balance6

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2016	Dec. 31, 2015
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	250,000,000
Common stock, shares outstanding	41,172,173
Common stock, par value (in USD per share)	$ 0.01	$ 0.01

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income	$ (105)	$ 50.4
Adjustments to reconcile net income / (loss) to net cash from operating activities:
Depreciation and amortization	69.4	69.3
Amortization of debt market value adjustments	0.1	0
Charge for early retirement of debt	2.6	0
Deferred income taxes	(95.9)	(17.5)
Impairment of Long-Lived Assets Held-for-use	235.5	0
Gain on sale of business	(49.2)	0
Changes in certain assets and liabilities:
Accounts receivable	52.7	25
Inventories	21.6	(4.5)
Prepaid taxes	0.2	(0.5)
Taxes applicable to subsequent years	41.7	38.6
Deferred regulatory costs, net	8	21.3
Accounts payable	(11.7)	3.3
Accrued taxes payable	(25.7)	(15.5)
Accrued interest payable	(0.8)	0
Unamortized Investment tax credit	(0.2)	0
Insurance and claims costs	(0.4)	0
Pension, retiree and other benefits	(4.2)	3.8
Other	(6.3)	(2.2)
Net cash provided by operating activities	132.4	171.5
Cash flows from investing activities:
Capital expenditures	(79.1)	(64.8)
Proceeds from sale of business	75.5	1.3
Insurance proceeds	3.2	0
Purchase of intangible assets	(0.2)	(0.2)
Increase in restricted cash	(16)	(8.4)
Other investing activities, net	0.7	0.4
Net cash used in investing activities	(15.9)	(71.7)
Cash flows from financing activities:
Payments of Deferred Finance Costs	0	(0.1)
Retirement of long-term debt	(75.4)	(0.1)
Borrowings from revolving credit facilities	0	15
Repayment of borrowings from revolving credit facilities	0	(15)
Proceeds from (Payments for) Other Financing Activities	(0.1)	0
Net cash used in financing activities	(75.5)	(0.2)
Cash and cash equivalents:
Net change	41	99.6
Balance at beginning of period	32.4	17
Cash and cash equivalents at end of period	73.4	116.6
Supplemental cash flow information:
Interest paid, net of amounts capitalized	51.1	55.6
Income taxes paid / (refunded), net	0.1	0.5
Non-cash financing and investing activities:
Accruals for capital expenditures	8.3	10
THE DAYTON POWER AND LIGHT COMPANY [Member]
Cash flows from operating activities:
Net income	(497.9)	60.4
Adjustments to reconcile net income / (loss) to net cash from operating activities:
Depreciation and amortization	71.1	68.9
Deferred income taxes	(308.7)	(11.6)
Impairment of Long-Lived Assets Held-for-use	857.1	0
Changes in certain assets and liabilities:
Accounts receivable	20.5	16.2
Inventories	21.6	(4.7)
Prepaid taxes	2.7	(0.2)
Taxes applicable to subsequent years	40.7	37.4
Deferred regulatory costs, net	8	21.3
Accounts payable	(13.8)	3.3
Accrued taxes payable	(43.3)	(8)
Accrued interest payable	0.2	0
Pension, retiree and other benefits	(4.2)	3.8
Other	5.5	(18.9)
Net cash provided by operating activities	159.5	167.9
Cash flows from investing activities:
Capital expenditures	(71.8)	(63.3)
Insurance proceeds	3.4	3.8
Purchase of intangible assets	(0.3)	(0.2)
Increase in restricted cash	(16.1)	(8.4)
Other investing activities, net	0.8	0.4
Net cash used in investing activities	(84)	(67.7)
Cash flows from financing activities:
Borrowings from revolving credit facilities	0	15
Repayment of borrowings from revolving credit facilities	0	(15)
Dividends paid on common stock to parent	0	(20)
Issuance of short-term debt - related party	5	0
Repayment of short-term debt - related party	(40)	(0.1)
Dividends paid on preferred stock	(0.4)	(0.4)
Proceeds from (Payments for) Other Financing Activities	(0.1)	0
Net cash used in financing activities	(35.5)	(20.5)
Cash and cash equivalents:
Net change	40	79.7
Balance at beginning of period	5.4	5.4
Cash and cash equivalents at end of period	45.4	85.1
Supplemental cash flow information:
Interest paid, net of amounts capitalized	8	13.5
Income Taxes Paid, Net	0.1	0.5
Non-cash financing and investing activities:
Accruals for capital expenditures	$ 8.3	$ 10

Overview and Summary of Signifi

Overview and Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2016
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 diversified regional energy company organized in 1985 under the laws of Ohio. DPL’s one reportable segment is the Utility segment, comprised of its DP&L subsidiary. DPLER, which was DPL's competitive retail segment, was sold January 1, 2016. See Note 10 – Business Segments for more information relating to these reportable segments. 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 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, distribution and transmission retail services are still regulated. DP&L has the exclusive right to provide such distribution and transmission services to approximately 517,000 customers located in West Central Ohio. Additionally, DP&L offers retail SSO electric service to residential, commercial, industrial and governmental customers in a 6,000 square mile area of West Central Ohio. DP&L owns multiple coal-fired and peaking electric generating facilities as well as numerous transmission facilities, all of which are included in the financial statements at amortized cost. Under the ESP 2 order, DP&L was required to source 100% of the generation for its SSO customers through a competitive bid process. Principal industries located in DP&L’s service territory include automotive, food processing, paper, plastic, manufacturing and defense. DP&L's distribution sales reflect the general economic conditions, seasonal weather patterns, retail competition in our service territory and the market price of electricity. DP&L sells all of its energy and capacity into the wholesale market. Based on the ESP 2 order, on June 4, 2014, the PUCO issued an entry on rehearing which required DP&L to separate its generation assets from its transmission and distribution assets no later than January 1, 2017. DPL’s other significant subsidiaries include AES Ohio Generation, which owns and operates peaking generating facilities from which it makes wholesale sales of electricity, and MVIC, our captive insurance company that provides insurance services to DPL and our subsidiaries. DPL owns all of the common stock of its subsidiaries. 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 while its generation business is deemed competitive under Ohio law. 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 1,169 people as of June 30, 2016 , of which 1,161 were employed by DP&L . Approximately 62% of all DPL employees are under a collective bargaining agreement that expires on October 31, 2017 . 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. DP&L has undivided ownership interests in five coal-fired generating facilities, various peaking generating facilities and numerous transmission facilities, all of which are included in the financial statements at amortized cost, which was adjusted to fair value at the date of the Merger for DPL . Operating revenues and expenses of these facilities 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. 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, 2015 . 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 June 30, 2016 ; our results of operations for the three and six months ended June 30, 2016 and 2015 and our cash flows for the six months ended June 30, 2016 and 2015 . Unless otherwise noted, all adjustments are normal and recurring in nature. Due to various factors, including, but not limited to, seasonal weather variations, the timing of outages of EGUs, changes in economic conditions involving commodity prices and competition, and other factors, interim results for the three and six months ended June 30, 2016 may not be indicative of our results that will be realized for the full year ending December 31, 2016 . 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: the carrying value of property, plant and equipment; unbilled revenues; the valuation of derivative instruments; the valuation of insurance and claims liabilities; the valuation of allowances for receivables 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. As a result of push down accounting, DPL’s Condensed Consolidated Statements of Operations subsequent to the Merger include depreciation of fixed assets based upon their fair value at the Merger date. 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 June 30, 2016 and 2015 were $11.6 million and $11.5 million, respectively. The amounts of such taxes collected for the six months ended June 30, 2016 and 2015 were $24.5 million and $25.5 million, respectively. Related Party Transactions DPL has issued debt to a wholly-owned business trust, DPL Capital Trust II. See Note 5 – Debt for further information. See Note 9 – Related Party Transactions for more information on related party transactions. New Accounting Pronouncements The following table provides a brief description of recent accounting pronouncements that could have a material impact on our consolidated financial statements: Accounting Standard Description Date of Adoption Effect on the financial statements upon adoption New Accounting Standards Adopted ASU No. 2015-15, Interest - Imputation of Interest (Subtopic 835-30): Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements Given the absence of authoritative guidance within ASU 2015-03, this standard clarifies that the SEC Staff would not object to an entity presenting debt issuance costs related to line-of-credit arrangements as an asset that is subsequently amortized ratably over the term of the line-of-credit arrangement, regardless of whether there are any outstanding borrowings on the line-of-credit arrangement. Transition method: retrospective. January 1, 2016 Deferred financing costs related to lines-of-credit of approximately $3.1 million recorded within Other deferred assets were not reclassified. Accounting Standard Description Date of Adoption Effect on the financial statements upon adoption ASU No. 2015-03, Interest - Imputation of Interest (Subtopic 835-30) The standard simplifies the presentation of debt issuance costs by requiring that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by the standard. Transition method: retrospective. January 1, 2016 Deferred financing costs of approximately $2.1 million previously classified within Other prepayments and current assets and $14.0 million previously classified within Other deferred assets were reclassified to reduce the related debt liabilities. ASU No. 2015-02, Consolidation - Amendments to the Consolidation Analysis (Topic 810) The standard makes targeted amendments to the current consolidation guidance and ends the deferral granted to investment companies from applying the VIE guidance. The standard amends the evaluation of whether (1) fees paid to a decision-maker or service providers represent a variable interest, (2) a limited partnership or similar entity has the characteristics of a VIE and (3) a reporting entity is the primary beneficiary of a VIE. Transition method: retrospective. January 1, 2016 There were no changes to the consolidation conclusions. New Accounting Standards Issued But Not Yet Effective 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments This standard updates the impairment model for financial assets measured at amortized cost to an expected loss model rather than an incurred loss model. It also allows for the presentation of credit losses on available-for-sale debt securities as an allowance rather than a write down. Transition method: various. January 1, 2020 Early adoption is permitted only as of January 1, 2019. We are currently evaluating the impact of adopting the standard on our consolidated financial statements. 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting The standard simplifies the following aspects of accounting for share-based payment awards: accounting for income taxes, classification of excess tax benefits on the statement of cash flows, forfeitures, statutory tax withholding requirements, classification of awards as either equity or liabilities and classification of employee taxes paid on statement of cash flows when an employer withholds shares for tax-withholding purposes. Transition method: Various. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our consolidated financial statements. ASU No. 2016-06, Derivatives and Hedging (Topic 815) - Contingent Put and Call Options in Debt Instruments This standard clarifies the requirements for assessing whether contingent call (put) options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts. When a call (put) option is contingently exercisable, an entity no longer has to assess whether the event that triggers the ability to exercise a call (put) option is related to interest rates or credit risks. Transition method: a modified retrospective basis to existing debt instruments as of the effective date. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard, but do not anticipate a material impact on our consolidated financial statements. ASU No. 2016-05, Derivatives and Hedging (Topic 815) - Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships The standard clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815 does not require de-designation of that hedging relationship provided that all other hedge accounting criteria (including those in paragraphs 815-20-35-14 through 35-18) continue to be met. Transition method: prospective or a modified retrospective basis. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard, but do not anticipate a material impact on our consolidated financial statements. ASU No. 2016-02, Leases (Topic 842) The standard creates Topic 842, Leases which supersedes Topic 840, Leases, and introduces a lessee model that brings substantially all leases onto the balance sheet while retaining most of the principles of the existing lessor model in U.S. GAAP and aligning many of those principles with ASC 606, Revenue from Contracts with Customers. Transition method: modified retrospective approach with certain practical expedients. January 1, 2019. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our consolidated financial statements. Accounting Standard Description Date of Adoption Effect on the financial statements upon adoption ASU No. 2016-01, Financial Instruments - Overall (Topic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities The standard significantly revises an entity’s accounting related to (1) the classification and measurement of investments in equity securities and (2) the presentation of certain fair value changes for financial liabilities measured at fair value. Also, it amends certain disclosure requirements associated with the fair value of financial instruments. Transition: cumulative effect in Retained Earnings as of adoption or prospectively for equity investments without readily determinable fair value. January 1, 2018. Limited early adoption permitted. We are currently evaluating the impact of adopting the standard, but do not anticipate a material impact on our consolidated financial statements. ASU No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory The standard replaces the current lower of cost or market test with a lower of cost or net realizable value test. Transition method: prospectively. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our consolidated financial statements. ASU Nos. 2014-09, 2016-08, 2016-10, 2016-12 Revenue from Contracts with Customers (Topic 606) The Revenue from Contracts with Customers standard provides a single and comprehensive revenue recognition model for all contracts with customers to improve comparability. The revenue standard contains principles that an entity will apply to determine the measurement of revenue and timing revenue recognition. The standard requires an entity to recognize revenue to depict the transfer of goods or services to customers at an amount that the entity expects to be entitled to in exchange for those goods or services. The amendments to the standard provide further clarification on contract revenue recognition specifically related to the implementation of the principal versus agent evaluation, the identification of performance obligations, clarification on accounting for licenses of intellectual property, and allows for the election to account for shipping and handling activities performed after control of a good has been transferred to the customer as a fulfillment cost. Transition method: a full retrospective or modified retrospective approach. January 1, 2018 (deferred by ASU No. 2015-14). Earlier application is permitted only as of January 1, 2017. We are currently evaluating the impact of adopting the standard on our 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, distribution and transmission retail services are still regulated. DP&L has the exclusive right to provide such distribution and transmission services to approximately 517,000 customers located in West Central Ohio. Additionally, DP&L offers retail SSO electric service to residential, commercial, industrial and governmental customers in a 6,000 square mile area of West Central Ohio. DP&L owns multiple coal-fired and peaking electric generating facilities as well as numerous transmission facilities, all of which are included in the financial statements at amortized cost. Under the ESP 2 order, DP&L was required to source 100% of the generation for its SSO customers through a competitive bid process. Principal industries located in DP&L’s service territory include automotive, food processing, paper, plastic, manufacturing and defense. DP&L's distribution sales reflect the general economic conditions, seasonal weather patterns, retail competition in our service territory and the market price of electricity. DP&L sells all of its energy and capacity into the wholesale market. Based on the ESP 2 order, on June 4, 2014, the PUCO issued an entry on rehearing which required DP&L to separate its generation assets from its transmission and distribution assets no later than January 1, 2017. DP&L is a subsidiary of DPL . DP&L’s electric transmission and distribution businesses are subject to rate regulation by federal and state regulators while its generation business is deemed competitive under Ohio law. 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 1,161 people as of June 30, 2016 . Approximately 61% of all employees are under a collective bargaining agreement which expires on October 31, 2017 . Financial Statement Presentation DP&L does not have any subsidiaries. DP&L has undivided ownership interests in five coal-fired generating facilities, peaking electric generating facilities and numerous transmission facilities, all of which are included in the financial statements at amortized cost. Operating revenues and expenses of these facilities are included on a pro rata basis in the corresponding lines in the Condensed Statements of Operations. 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, 2015 . 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 June 30, 2016 ; our results of operations for the three and six months ended June 30, 2016 and 2015 and our cash flows for the six months ended June 30, 2016 and 2015 . Unless otherwise noted, all adjustments are normal and recurring in nature. Due to various factors, including, but not limited to, seasonal weather variations, the timing of outages of EGUs, changes in economic conditions involving commodity prices and competition, and other factors, interim results for the six months ended June 30, 2016 may not be indicative of our results that will be realized for the full year ending December 31, 2016 . 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: the carrying value of property, plant and equipment; unbilled revenues; the valuation of derivative instruments; the valuation of insurance and claims liabilities; the valuation of allowances for receivables 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 June 30, 2016 and 2015 were $11.6 million and $11.5 million, respectively. The amounts of such taxes collected for the six months ended June 30, 2016 and 2015 were $24.5 million and $25.5 million, respectively. New Accounting Pronouncements The following table provides a brief description of recent accounting pronouncements that could have a material impact on our financial statements: Accounting Standard Description Date of Adoption Effect on the financial statements upon adoption New Accounting Standards Adopted ASU No. 2015-15, Interest - Imputation of Interest (Subtopic 835-30): Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements Given the absence of authoritative guidance within ASU 2015-03, this standard clarifies that the SEC Staff would not object to an entity presenting debt issuance costs related to line-of-credit arrangements as an asset that is subsequently amortized ratably over the term of the line-of-credit arrangement, regardless of whether there are any outstanding borrowings on the line-of-credit arrangement. Transition method: retrospective. January 1, 2016 Deferred financing costs related to lines-of-credit of approximately $0.7 million recorded within Other deferred assets were not reclassified. ASU No. 2015-03, Interest - Imputation of Interest (Subtopic 835-30) The standard simplifies the presentation of debt issuance costs by requiring that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by the standard. Transition method: retrospective. January 1, 2016 Deferred financing costs of approximately $1.8 million previously classified within Other prepayments and current assets and $4.5 million previously classified within Other deferred assets were reclassified to reduce the related debt liabilities. ASU No. 2015-02, Consolidation - Amendments to the Consolidation Analysis (Topic 810) The standard makes targeted amendments to the current consolidation guidance and ends the deferral granted to investment companies from applying the VIE guidance. The standard amends the evaluation of whether (1) fees paid to a decision-maker or service providers represent a variable interest, (2) a limited partnership or similar entity has the characteristics of a VIE and (3) a reporting entity is the primary beneficiary of a VIE. Transition method: retrospective. January 1, 2016 There were no changes to the consolidation conclusions. New Accounting Standards Issued But Not Yet Effective 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments This standard updates the impairment model for financial assets measured at amortized cost to an expected loss model rather than an incurred loss model. It also allows for the presentation of credit losses on available-for-sale debt securities as an allowance rather than a write down. Transition method: various. January 1, 2020 Early adoption is permitted only as of January 1, 2019. We are currently evaluating the impact of adopting the standard on our financial statements. 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting The standard simplifies the following aspects of accounting for share-based payment awards: accounting for income taxes, classification of excess tax benefits on the statement of cash flows, forfeitures, statutory tax withholding requirements, classification of awards as either equity or liabilities and classification of employee taxes paid on statement of cash flows when an employer withholds shares for tax-withholding purposes. Transition method: Various. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our financial statements. Accounting Standard Description Date of Adoption Effect on the financial statements upon adoption ASU No. 2016-06, Derivatives and Hedging (Topic 815) - Contingent Put and Call Options in Debt Instruments This standard clarifies the requirements for assessing whether contingent call (put) options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts. When a call (put) option is contingently exercisable, an entity no longer has to assess whether the event that triggers the ability to exercise a call (put) option is related to interest rates or credit risks. Transition method: a modified retrospective basis to existing debt instruments as of the effective date. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard, but do not anticipate a material impact on our financial statements. ASU No. 2016-05, Derivatives and Hedging (Topic 815) - Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships The standard clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815 does not require de-designation of that hedging relationship provided that all other hedge accounting criteria (including those in paragraphs 815-20-35-14 through 35-18) continue to be met. Transition method: prospective or a modified retrospective basis. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard, but do not anticipate a material impact on our financial statements. ASU No. 2016-02, Leases (Topic 842) The standard creates Topic 842, Leases which supersedes Topic 840, Leases, and introduces a lessee model that brings substantially all leases onto the balance sheet while retaining most of the principles of the existing lessor model in U.S. GAAP and aligning many of those principles with ASC 606, Revenue from Contracts with Customers. Transition method: modified retrospective approach with certain practical expedients. January 1, 2019. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our financial statements. ASU No. 2016-01, Financial Instruments - Overall (Topic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities The standard significantly revises an entity’s accounting related to (1) the classification and measurement of investments in equity securities and (2) the presentation of certain fair value changes for financial liabilities measured at fair value. Also, it amends certain disclosure requirements associated with the fair value of financial instruments. Transition: cumulative effect in Retained Earnings as of adoption or prospectively for equity investments without readily determinable fair value. January 1, 2018. Limited early adoption permitted. We are currently evaluating the impact of adopting the standard, but do not anticipate a material impact on our financial statements. ASU No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory The standard replaces the current lower of cost or market test with a lower of cost or net realizable value test. Transition method: prospectively. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our financial statements. ASU Nos. 2014-09, 2016-08, 2016-10, 2016-12 Revenue from Contracts with Customers (Topic 606) The Revenue from Contracts with Customers standard provides a single and comprehensive revenue recognition model for all contracts with customers to improve comparability. The revenue standard contains principles that an entity will apply to determine the measurement of revenue and timing revenue recognition. The standard requires an entity to recognize revenue to depict the transfer of goods or services to customers at an amount that the entity expects to be entitled to in exchange for those goods or services. The amendments to the standard provide further clarification on contract revenue recognition specifically related to the implementation of the principal versus agent evaluation, the identification of performance obligations, clarification on accounting for licenses of intellectual property, and allows for the election to account for shipping and handling activities performed after control of a good has been transferred to the customer as a fulfillment cost. Transition method: a full retrospective or modified retrospective approach. January 1, 2018 (deferred by ASU No. 2015-14). Earlier application is permitted only as of January 1, 2017. We are currently evaluating the impact of adopting the standard on our financial statements.

Supplemental Financial Informat

Supplemental Financial Information	6 Months Ended
	Jun. 30, 2016
Supplemental Financial Information [Line Items]
Supplemental Financial Information	Supplemental Financial Information Accounts receivable and Inventories are as follows at June 30, 2016 and December 31, 2015 : June 30, December 31, $ in millions 2016 2015 Accounts receivable, net: Unbilled revenue $ 38.9 $ 43.3 Customer receivables 54.1 56.4 Amounts due from partners in jointly owned plants 10.9 16.0 Other 4.9 6.0 Provision for uncollectible accounts (1.0 ) (0.8 ) Total accounts receivable, net $ 107.8 $ 120.9 Inventories, at average cost: Fuel and limestone $ 49.9 $ 72.2 Plant materials and supplies 35.7 34.9 Other 1.9 2.0 Total inventories, at average cost $ 87.5 $ 109.1 Accounts receivable of $31.0 million as of December 31, 2015 have been excluded from the above table as they have been reclassified as "Assets held for sale". See Note 11 – Discontinued Operations . Accumulated Other Comprehensive Income / (Loss) The amounts reclassified out of Accumulated Other Comprehensive Income / (Loss) by component during the three and six months ended June 30, 2016 and 2015 are as follows: Details about Accumulated Other Comprehensive Income / (Loss) components Affected line item in the Condensed Consolidated Statements of Operations Three months ended Six months ended June 30, June 30, $ in millions 2016 2015 2016 2015 Gains and losses on Available-for-sale securities activity (Note 3): Other income $ 0.1 $ 0.6 $ — $ — Tax benefit — (0.2 ) — — Net of income taxes 0.1 0.4 — — Gains and losses on cash flow hedges (Note 4): Interest expense (0.3 ) (0.3 ) (0.5 ) (0.5 ) Revenue (20.1 ) (2.9 ) (37.3 ) (3.2 ) Purchased power 3.7 0.4 8.1 1.8 Total before income taxes (16.7 ) (2.8 ) (29.7 ) (1.9 ) Tax expense 5.9 0.9 10.7 0.5 Net of income taxes (10.8 ) (1.9 ) (19.0 ) (1.4 ) Amortization of defined benefit pension items (Note 7): Operation and maintenance 0.1 0.1 0.2 0.2 Tax benefit — (0.5 ) (0.2 ) (0.4 ) Net of income taxes 0.1 (0.4 ) — (0.2 ) Total reclassifications for the period, net of income taxes $ (10.6 ) $ (1.9 ) $ (19.0 ) $ (1.6 ) The changes in the components of Accumulated Other Comprehensive Income / (Loss) during the six months ended June 30, 2016 are as follows: $ in millions Gains / (losses) on available-for-sale securities Gains / (losses) on cash flow hedges Change in unfunded pension obligation Total Balance January 1, 2016 $ 0.4 $ 26.7 $ (9.7 ) $ 17.4 Other comprehensive income before reclassifications 0.1 13.0 — 13.1 Amounts reclassified from accumulated other comprehensive income / (loss) — (19.0 ) — (19.0 ) Net current period other comprehensive income / (loss) 0.1 (6.0 ) — (5.9 ) Balance June 30, 2016 $ 0.5 $ 20.7 $ (9.7 ) $ 11.5
THE DAYTON POWER AND LIGHT COMPANY [Member]
Supplemental Financial Information [Line Items]
Supplemental Financial Information	Supplemental Financial Information Accounts receivable and Inventories are as follows at June 30, 2016 and December 31, 2015 : June 30, December 31, $ in millions 2016 2015 Accounts receivable, net: Unbilled revenue $ 38.9 $ 43.3 Customer receivables 50.8 54.1 Amounts due from partners in jointly owned plants 10.9 16.0 Other 6.0 6.9 Provision for uncollectible accounts (1.0 ) (0.8 ) Total accounts receivable, net $ 105.6 $ 119.5 Inventories, at average cost: Fuel and limestone $ 50.0 $ 72.2 Plant materials and supplies 34.4 33.7 Other 2.0 2.1 Total inventories, at average cost $ 86.4 $ 108.0 Accumulated Other Comprehensive Income / (Loss) The amounts reclassified out of Accumulated Other Comprehensive Income / (Loss) by component during the three and six months ended June 30, 2016 and 2015 are as follows: Details about Accumulated Other Comprehensive Income / (Loss) components Affected line item in the Condensed Statements of Operations Three months ended Six months ended June 30, June 30, $ in millions 2016 2015 2016 2015 Gains and losses on Available-for-sale securities activity (Note 3): Other income $ 0.1 $ 0.6 $ — $ — Tax benefit — (0.2 ) — — Net of income taxes 0.1 0.4 — — Gains and losses on cash flow hedges (Note 4): Interest expense (0.3 ) (0.3 ) (0.6 ) (0.6 ) Revenue (20.1 ) (2.9 ) (37.2 ) (3.2 ) Purchased power 3.7 0.4 8.1 1.8 Total before income taxes (16.7 ) (2.8 ) (29.7 ) (2.0 ) Tax expense 5.9 1.0 10.5 0.7 Net of income taxes (10.8 ) (1.8 ) (19.2 ) (1.3 ) Amortization of defined benefit pension items (Note 7): Operation and maintenance 1.1 1.4 2.2 2.8 Tax benefit (0.4 ) (0.5 ) (1.2 ) (1.0 ) Net of income taxes 0.7 0.9 1.0 1.8 Total reclassifications for the period, net of income taxes $ (10.0 ) $ (0.5 ) $ (18.2 ) $ 0.5 The changes in the components of Accumulated Other Comprehensive Income / (Loss) during the six months ended June 30, 2016 are as follows: $ in millions Gains / (losses) on available-for-sale securities Gains / (losses) on cash flow hedges Change in unfunded pension obligation Total Balance January 1, 2016 $ 0.5 $ 11.2 $ (40.4 ) $ (28.7 ) Other comprehensive income before reclassifications 0.1 13.0 — 13.1 Amounts reclassified from accumulated other comprehensive income / (loss) — (19.2 ) 1.0 (18.2 ) Net current period other comprehensive income / (loss) 0.1 (6.2 ) 1.0 (5.1 ) Balance June 30, 2016 $ 0.6 $ 5.0 $ (39.4 ) $ (33.8 )

Fair Value

Fair Value	6 Months Ended
	Jun. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	Fair Value The fair values of our financial instruments are based on published sources for pricing when possible. We rely on valuation models only when no other methods exist. The value of our financial instruments represents our best estimates of the fair value, which may not be the value realized in the future. The following table presents the fair value, carrying value and cost of our non-derivative instruments at June 30, 2016 and December 31, 2015 . Information about the fair value of our derivative instruments can be found in Note 4 – Derivative Instruments and Hedging Activities . June 30, 2016 December 31, 2015 $ in millions Cost Fair Value Cost Fair Value Assets Money market funds $ 0.3 $ 0.3 $ 0.2 $ 0.2 Equity securities 2.7 3.5 3.0 3.8 Debt securities 4.2 4.2 4.4 4.3 Hedge funds 0.2 0.2 0.4 0.4 Real estate 0.3 0.4 0.3 0.3 Total Assets $ 7.7 $ 8.6 $ 8.3 $ 9.0 Carrying Value Fair Value Carrying Value Fair Value Liabilities Debt $ 1,923.3 $ 1,912.4 $ 1,993.3 $ 1,975.3 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 Debt, which is presented at amortized carrying value. Debt Unrealized gains or losses are not recognized in the financial statements as debt is presented at cost, net of unamortized premium or discount and deferred financing costs in the financial statements. The debt amounts include the current portion payable in the next twelve months and have maturities that range from 2016 to 2061 . Master Trust Assets DP&L established Master Trusts 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 balance sheets and classified as available-for-sale. Any unrealized gains or losses are recorded in AOCI until the securities are sold. DPL had $0.8 million ( $0.6 million after tax) of unrealized gains and immaterial unrealized losses on the Master Trust assets in AOCI at June 30, 2016 and $0.7 million ( $0.5 million after tax) of unrealized gains and $0.1 million ( $0.1 million after tax) in unrealized losses on the Master Trust assets in AOCI at December 31, 2015 . During the six months ended June 30, 2016 , $2.0 million ( $1.3 million after tax) of various investments were sold to facilitate the distribution of benefits and the unrealized gains were reversed into earnings. An immaterial amount of unrealized gains are expected to be reversed to earnings as investments are sold over the next twelve months to facilitate the distribution of benefits. Fair Value Hierarchy Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The fair value hierarchy requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. These inputs are then categorized as: • Level 1 (quoted prices in active markets for identical assets or liabilities); • Level 2 (observable inputs such as quoted prices for similar assets or liabilities or quoted prices in markets that are not active); • Level 3 (unobservable inputs). Valuations of assets and liabilities reflect the value of the instrument including the values associated with counterparty risk. We include our own credit risk and our counterparty’s credit risk in our calculation of fair value using global average default rates based on an annual study conducted by a large rating agency. We did not have any transfers of the fair values of our financial instruments between Level 1 and Level 2 of the fair value hierarchy during the six months ended June 30, 2016 and 2015 . The fair value of assets and liabilities at June 30, 2016 and December 31, 2015 and the respective category within the fair value hierarchy for DPL was determined as follows: Assets and Liabilities at Fair Value Level 1 Level 2 Level 3 $ in millions Fair value at June 30, 2016 Based on Quoted Prices in Active Markets Other Observable Inputs Unobservable Inputs Assets Master Trust assets Money market funds $ 0.3 $ 0.3 $ — $ — Equity securities 3.5 — 3.5 — Debt securities 4.2 — 4.2 — Hedge funds 0.2 — 0.2 — Real estate 0.4 — 0.4 — Total Master Trust assets 8.6 0.3 8.3 — Derivative Assets FTRs 0.1 — — 0.1 Natural gas futures 0.3 0.3 — — Forward power contracts 39.3 — 38.6 0.7 Total Derivative assets 39.7 0.3 38.6 0.8 Total Assets $ 48.3 $ 0.6 $ 46.9 $ 0.8 Liabilities Derivative Liabilities Forward power contracts 45.2 — 38.9 6.3 Total Derivative liabilities 45.2 — 38.9 6.3 Debt 1,912.4 — 1,894.4 18.0 Total Liabilities $ 1,957.6 $ — $ 1,933.3 $ 24.3 Assets and Liabilities at Fair Value Level 1 Level 2 Level 3 $ in millions Fair value at December 31, 2015 Based on Quoted Prices in Active Markets Other Observable Inputs Unobservable Inputs Assets Master Trust assets Money market funds $ 0.2 $ 0.2 $ — $ — Equity securities 3.8 — 3.8 — Debt securities 4.3 — 4.3 — Hedge funds 0.4 — 0.4 — Real estate 0.3 — 0.3 — Total Master Trust assets 9.0 0.2 8.8 — Derivative assets Forward power contracts 30.5 — 30.5 — FTRs 0.2 — — 0.2 Total Derivative assets 30.7 — 30.5 0.2 Total Assets $ 39.7 $ 0.2 $ 39.3 $ 0.2 Liabilities Derivative liabilities FTRs $ 0.5 $ — $ — 0.5 Forward power contracts 27.0 — 23.9 3.1 Total Derivative liabilities 27.5 — 23.9 3.6 Debt 1,975.3 — 1,957.2 18.1 Total Liabilities $ 2,002.8 $ — $ 1,981.1 $ 21.7 Our financial instruments are valued using the market approach in the following categories: • Level 1 inputs are used for derivative contracts such as heating oil futures, natural gas futures and 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 forward power contracts (which are traded on the OTC market but which are valued using prices on the NYMEX for similar contracts on the OTC market). Other Level 2 assets include open-ended mutual funds that are in the Master Trust, which are valued using observable prices based on the end of day net asset value per unit. • Level 3 inputs such as FTRs are considered a Level 3 input because the monthly auctions are considered inactive. Other Level 3 inputs include the credit valuation adjustment on some of the forward power contracts and forward power contracts in less active markets. Our Level 3 inputs are immaterial to our derivative balances as a whole and as such no further disclosures are presented. Approximately 93% of the inputs to the fair value of our derivative instruments are from quoted market prices. Our 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 loan is not publicly traded, fair value is assumed to equal carrying value. These 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 debt is not recorded at fair value. Non-recurring Fair Value Measurements We use the cost approach to determine the fair value of our AROs, which is estimated by discounting expected cash outflows to their present value at the initial recording of the liability. Cash outflows are based on the approximate future disposal cost as determined by market information, historical information or other management estimates. These inputs to the fair value of the AROs would be considered Level 3 inputs under the fair value hierarchy. AROs for ash ponds, asbestos, river structures and underground storage tanks increased by a net amount of $2.3 million and increased by a net amount of $39.8 million during the six months ended June 30, 2016 and 2015 , respectively. When evaluating impairment of long-lived assets, we measure fair value using the applicable fair value measurement guidance. Impairment expense is measured by comparing the fair value at the evaluation date to the carrying amount. The following table summarizes Long-lived assets measured at fair value on a non-recurring basis during the period and their level within the fair value hierarchy (there were no impairments during the six months ended June 30, 2015 ): $ in millions Six months ended June 30, 2016 Carrying Fair Value Gross Amount (b) Level 1 Level 2 Level 3 Loss Assets Long-lived assets (a) DP&L (Killen) $ 315.1 $ — $ — $ 84.3 $ 230.8 DP&L (peaking facilities) $ 9.9 $ — $ — $ 5.2 $ 4.7 (a) See Note 12 – Fixed-asset Impairment for further information (b) Carrying amount at date of valuation The following summarizes the significant unobservable inputs used in the Level 3 measurement on a non-recurring basis during the six months ended June 30, 2016 : $ in millions Fair value Valuation technique Unobservable input Range (weighted average) Long-lived assets held and used: DP&L (Killen) $ 84.3 Discounted cash flow Annual revenue growth -11% to 13% (2%) Annual pre-tax operating margin -50% to 67% (6%) Weighted-average cost of capital 11% DP&L (peaking facilities) $ 5.2 Discounted cash flow Annual revenue growth -22% to 17% (-3%) Annual pre-tax operating margin -29% to 24% (-4%) Weighted-average cost of capital 7%
THE DAYTON POWER AND LIGHT COMPANY [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	Fair Value The fair values of our financial instruments are based on published sources for pricing when possible. We rely on valuation models only when no other methods exist. The value of our financial instruments represents our best estimates of the fair value, which may not be the value realized in the future. The following table presents the fair value, carrying value and cost of our non-derivative instruments at June 30, 2016 and December 31, 2015 . Information about the fair value of our derivative instruments can be found in Note 4 – Derivative Instruments and Hedging Activities . June 30, 2016 December 31, 2015 $ in millions Cost Fair Value Cost Fair Value Assets Money market funds $ 0.3 $ 0.3 $ 0.2 $ 0.2 Equity securities 2.7 3.5 3.0 3.8 Debt securities 4.2 4.2 4.4 4.3 Hedge funds 0.2 0.2 0.4 0.4 Real estate 0.3 0.4 0.3 0.3 Total assets $ 7.7 $ 8.6 $ 8.3 $ 9.0 Carrying Value Fair Value Carrying Value Fair Value Liabilities Debt $ 758.4 $ 764.3 $ 756.7 $ 764.2 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 Debt, which is presented at amortized carrying value. Debt Unrealized gains or losses are not recognized in the financial statements as debt is presented at cost, net of unamortized premium or discount and deferred financing costs in the financial statements. The debt amounts include the current portion payable in the next twelve months and have maturities that range from 2016 to 2061 . Master Trust Assets DP&L established Master Trusts 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 balance sheets and classified as available-for-sale. Any unrealized gains or losses are recorded in AOCI until the securities are sold. DP&L had $0.9 million ( $0.6 million after tax) of unrealized gains and immaterial unrealized losses on the Master Trust assets in AOCI at June 30, 2016 and $0.8 million ( $0.5 million after tax) in unrealized gains and $0.1 million ( $0.1 million after tax) in unrealized losses on the Master Trust assets in AOCI at December 31, 2015 . During the six months ended June 30, 2016 , $2.0 million ( $1.3 million after tax) of various investments were sold to facilitate the distribution of benefits and the unrealized gains were reversed into earnings. An immaterial amount of unrealized gains are expected to be reversed to earnings as investments are sold over the next twelve months to facilitate the distribution of benefits. Fair Value Hierarchy Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The fair value hierarchy requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. These inputs are then categorized as: • Level 1 (quoted prices in active markets for identical assets or liabilities); • Level 2 (observable inputs such as quoted prices for similar assets or liabilities or quoted prices in markets that are not active); • Level 3 (unobservable inputs). Valuations of assets and liabilities reflect the value of the instrument including the values associated with counterparty risk. We include our own credit risk and our counterparty’s credit risk in our calculation of fair value using global average default rates based on an annual study conducted by a large rating agency. We did not have any transfers of the fair values of our financial instruments between Level 1 and Level 2 of the fair value hierarchy during the six months ended June 30, 2016 and 2015 . The fair value of assets and liabilities at June 30, 2016 and December 31, 2015 and the respective category within the fair value hierarchy for DP&L was determined as follows: Assets and Liabilities at Fair Value Level 1 Level 2 Level 3 $ in millions Fair value at June 30, 2016 Based on Quoted Prices in Active Markets Other Observable Inputs Unobservable Inputs Assets Master Trust assets Money market funds $ 0.3 $ 0.3 $ — $ — Equity securities 3.5 — 3.5 — Debt securities 4.2 — 4.2 — Hedge funds 0.2 — 0.2 — Real estate 0.4 — 0.4 — Total Master Trust assets 8.6 0.3 8.3 — Derivative assets FTRs 0.1 — — 0.1 Natural gas futures 0.3 0.3 — — Forward power contracts 39.4 — 38.7 0.7 Total derivative assets 39.8 0.3 38.7 0.8 Total assets $ 48.4 $ 0.6 $ 47.0 $ 0.8 Liabilities Derivative liabilities Forward power contracts $ 45.3 $ — $ 39.0 $ 6.3 Total derivative liabilities 45.3 — 39.0 6.3 Debt 764.3 — 746.3 18.0 Total liabilities $ 809.6 $ — $ 785.3 $ 24.3 Assets and Liabilities at Fair Value Level 1 Level 2 Level 3 $ in millions Fair value at December 31, 2015 Based on Quoted Prices in Active Markets Other Observable Inputs Unobservable Inputs Assets Master Trust assets Money market funds $ 0.2 $ 0.2 $ — $ — Equity securities 3.8 — 3.8 — Debt securities 4.3 — 4.3 — Hedge funds 0.4 — 0.4 — Real estate 0.3 — 0.3 — Total Master Trust assets 9.0 0.2 8.8 — Derivative assets FTRs 0.2 — — 0.2 Forward power contracts 30.6 — 30.6 — Total Derivative assets 30.8 — 30.6 0.2 Total assets $ 39.8 $ 0.2 $ 39.4 $ 0.2 Liabilities Derivative liabilities FTRs $ 0.5 $ — $ — $ 0.5 Forward power contracts 27.0 — 23.9 3.1 Total Derivative liabilities 27.5 — 23.9 3.6 Debt 764.2 — 746.1 18.1 Total liabilities $ 791.7 $ — $ 770.0 $ 21.7 Our financial instruments are valued using the market approach in the following categories: • Level 1 inputs are used for derivative contracts such as heating oil futures, natural gas futures and 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 forward power contracts (which are traded on the OTC market but which are valued using prices on the NYMEX for similar contracts on the OTC market). Other Level 2 assets include open-ended mutual funds that are in the Master Trust, which are valued using observable prices based on the end of day net asset value per unit. • Level 3 inputs such as FTRs are considered a Level 3 input because the monthly auctions are considered inactive. Other Level 3 inputs include the credit valuation adjustment on some of the forward power contracts and forward power contracts in less active markets. Our Level 3 inputs are immaterial to our derivative balances as a whole and as such no further disclosures are presented. Our 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 loan is not publicly traded, fair value is assumed to equal carrying value. These 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 debt is not recorded at fair value. Approximately 93% of the inputs to the fair value of our derivative instruments are from quoted market prices. Non-recurring Fair Value Measurements We use the cost approach to determine the fair value of our AROs, which is estimated by discounting expected cash outflows to their present value at the initial recording of the liability. Cash outflows are based on the approximate future disposal cost as determined by market information, historical information or other management estimates. These inputs to the fair value of the AROs would be considered Level 3 inputs under the fair value hierarchy. AROs for ash ponds, asbestos, river structures and underground storage tanks increased by a net amount of $2.3 million and increased by a net amount of $39.8 million during the six months ended June 30, 2016 and 2015 , respectively. When evaluating impairment of long-lived assets, we measure fair value using the applicable fair value measurement guidance. Impairment expense is measured by comparing the fair value at the evaluation date to the carrying amount. The following table summarizes Long-lived assets measured at fair value on a non-recurring basis during the period and their level within the fair value hierarchy (there were no impairments during the six months ended June 30, 2015 ): $ in millions Six months ended June 30, 2016 Carrying Fair Value Gross Amount (b) Level 1 Level 2 Level 3 Loss Assets Long-lived assets (a) DP&L (Stuart) $ 456.4 $ — $ — $ 164.4 $ 292.0 DP&L (Killen) $ 330.5 $ — $ — $ 84.3 $ 246.2 DP&L (Zimmer) $ 429.9 $ — $ — $ 111.0 $ 318.9 (a) See Note 11 – Fixed-asset Impairment for further information (b) Carrying amount at date of valuation The following summarizes the significant unobservable inputs used in the Level 3 measurement on a non-recurring basis during the six months ended June 30, 2016 : $ in millions Fair value Valuation technique Unobservable input Range (weighted average) Long-lived assets held and used: DP&L (Stuart) $ 164.4 Discounted cash flow Annual revenue growth -9% to 10% (2%) Annual pre-tax operating margin -29% to 52% (5%) Weighted-average cost of capital 9% DP&L (Killen) $ 84.3 Discounted cash flow Annual revenue growth -11% to 13% (2%) Annual pre-tax operating margin -50% to 67% (6%) Weighted-average cost of capital 11% DP&L (Zimmer) $ 111.0 Discounted cash flow Annual revenue growth -14% to 13% (1%) Annual pre-tax operating margin -46% to 80% (4%) Weighted-average cost of capital 9%

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	6 Months Ended
	Jun. 30, 2016
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 arrangements, including derivative financial instruments. We use derivatives principally to manage the risk of changes in market prices for commodities. 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. The objective of the hedging program is to mitigate financial risks while ensuring that we have adequate resources to meet our requirements. 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 normal purchase/normal sale, cash flow hedges or marked to market each reporting period. At June 30, 2016 , DPL had the following outstanding derivative instruments: Commodity Accounting Treatment Unit Purchases (in thousands) Sales (in thousands) Net Purchases/ (Sales) (in thousands) FTRs Not designated MWh 2.5 — 2.5 Natural Gas Futures Not designated Dths 1,442.5 — 1,442.5 Forward power contracts Designated MWh 692.6 (13,380.2 ) (12,687.6 ) Forward power contracts Not designated MWh 4,018.0 (3,537.9 ) 480.1 At December 31, 2015 , DPL had the following outstanding derivative instruments: Commodity Accounting Treatment Unit Purchases (in thousands) Sales (in thousands) Net Purchases/ (Sales) (in thousands) FTRs Not designated MWh 10.2 — 10.2 Forward power contracts Designated MWh 1,676.7 (7,795.8 ) (6,119.1 ) Forward power contracts Not designated MWh 5,049.9 (1,663.0 ) 3,386.9 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 value of cash flow hedges is determined by observable market prices available as of the balance sheet dates and will continue to fluctuate with changes in market prices up to contract expiration. The effective portion of the hedging transaction is recognized in AOCI and transferred to earnings using specific identification of each contract when the forecasted hedged transaction takes place or when the forecasted hedged transaction is probable of not occurring. The ineffective portion of the cash flow hedge is recognized in earnings in the current period. All risk components were taken into account to determine the hedge effectiveness of the cash flow hedges. We enter into forward power contracts to manage commodity price risk exposure related to our generation of electricity. We do not hedge all commodity price risk. We reclassify gains and losses on forward power contracts from AOCI into earnings in those periods in which the contracts settle. The following table provides information for DPL concerning gains or losses recognized in AOCI for the cash flow hedges for the three and six months ended June 30, 2016 and 2015 : Three months ended Three months ended June 30, 2016 June 30, 2015 Interest Interest $ in millions (net of tax) Power Rate Hedge Power Rate Hedge Beginning accumulated derivative gains in AOCI $ 22.5 $ 17.5 $ 1.0 $ 18.2 Net gains / (losses) associated with current period hedging transactions (8.5 ) — 1.7 — Net gains / (losses) reclassified to earnings Interest expense — (0.2 ) — (0.4 ) Revenues (13.0 ) — (1.9 ) — Purchased power 2.4 — 0.3 — Ending accumulated derivative gains in AOCI $ 3.4 $ 17.3 $ 1.1 $ 17.8 Six months ended Six months ended June 30, 2016 June 30, 2015 Interest Interest $ in millions (net of tax) Power Rate Hedge Power Rate Hedge Beginning accumulated derivative gains in AOCI $ 9.2 $ 17.5 $ 0.2 $ 18.3 Net gains associated with current period hedging transactions 13.0 — 1.8 — Net gains / (losses) reclassified to earnings Interest expense — (0.2 ) — (0.5 ) Revenues (24.0 ) — (2.1 ) — Purchased power 5.2 — 1.2 — Ending accumulated derivative gains in AOCI $ 3.4 $ 17.3 $ 1.1 $ 17.8 Portion expected to be reclassified to earnings in the next twelve months (a) $ (3.1 ) $ (0.6 ) Maximum length of time that we are hedging our exposure to variability in future cash flows related to forecasted transactions (in months) 18 0 (a) The actual amounts that we reclassify from AOCI to earnings related to power can differ from the estimate above due to market price changes. Derivatives not designated as hedges Certain derivative contracts are entered into on a regular basis as part of our risk management program but do not qualify for hedge accounting or the normal purchase and sales exceptions under FASC 815. Accordingly, such contracts are recorded at fair value with changes in the fair value charged or credited to the Condensed Consolidated Statements of Operations in the period in which the change occurred. This is commonly referred to as “MTM accounting.” Contracts we enter into as part of our risk management program may be settled financially, by physical delivery, or net settled with the counterparty. FTRs, heating oil futures, natural gas, and certain forward power contracts are currently marked to market. Certain qualifying derivative instruments have been designated as normal purchases or normal sales contracts, as provided under GAAP. Derivative contracts that have been designated as normal purchases or normal sales under GAAP are not subject to MTM accounting and are recognized in the Condensed Consolidated Statements of Operations on an accrual basis. Regulatory Assets and Liabilities In accordance with regulatory accounting under GAAP, a cost or loss that is probable of recovery in future rates should be deferred as a regulatory asset and revenue or a gain that is probable of being returned to customers should be deferred as a regulatory liability. Therefore, a portion of the heating oil futures are assigned to the retail jurisdiction and deferred as a regulatory asset or liability until the contracts settle. If these unrealized gains and losses are no longer deemed to be probable of recovery through our rates, they will be reclassified into earnings in the period such determination is made. Beginning January 1, 2016, we no longer assign any portion of the heating oil futures to our retail jurisdiction as all of our SSO retail sales are sourced through the competitive bid process. The following tables present the amount and classification within the Condensed Consolidated Statements of Operations or Condensed Consolidated Balance Sheets of the gains and losses on DPL’s derivatives not designated as hedging instruments for the three and six months ended June 30, 2016 and 2015 : For the three months ended June 30, 2016 $ in millions FTRs Power Natural Gas Total Change in unrealized gain $ 0.2 $ 2.6 $ 0.5 $ 3.3 Realized gain / (loss) 0.2 (2.4 ) 0.7 (1.5 ) Total $ 0.4 $ 0.2 $ 1.2 $ 1.8 Recorded in Income Statement: gain / (loss) Revenues $ — $ (5.3 ) $ — $ (5.3 ) Purchased power 0.4 5.5 1.2 7.1 Total $ 0.4 $ 0.2 $ 1.2 $ 1.8 For the three months ended June 30, 2015 $ in millions Heating Oil FTRs Power Total Change in unrealized gain / (loss) $ 0.1 $ (0.8 ) $ 1.2 $ 0.5 Realized loss (0.1 ) — (1.5 ) (1.6 ) Total $ — $ (0.8 ) $ (0.3 ) $ (1.1 ) Recorded in Income Statement: gain / (loss) Revenues $ — $ (0.8 ) $ (2.8 ) $ (3.6 ) Purchased power — — 2.5 2.5 Total $ — $ (0.8 ) $ (0.3 ) $ (1.1 ) For the six months ended June 30, 2016 $ in millions FTRs Power Natural Gas Total Change in unrealized gain $ 0.4 $ 1.2 $ 0.3 $ 1.9 Realized gain / (loss) 0.4 (2.9 ) 0.5 (2.0 ) Total $ 0.8 $ (1.7 ) $ 0.8 $ (0.1 ) Recorded in Income Statement: gain / (loss) Revenues $ — $ (6.6 ) $ — $ (6.6 ) Purchased power 0.8 4.9 0.8 6.5 Total $ 0.8 $ (1.7 ) $ 0.8 $ (0.1 ) For the six months ended June 30, 2015 $ in millions Heating Oil FTRs Power Natural Gas Total Change in unrealized gain / (loss) $ 0.2 $ 0.1 $ (1.7 ) $ 0.1 $ (1.3 ) Realized loss (0.1 ) (0.1 ) (3.8 ) (0.1 ) (4.1 ) Total $ 0.1 $ — $ (5.5 ) $ — $ (5.4 ) Recorded on Balance Sheet: gain Regulatory asset $ 0.1 $ — $ — $ — $ 0.1 Recorded in Income Statement: gain / (loss) Revenue — — (7.7 ) — (7.7 ) Purchased power — — 2.2 — 2.2 Total $ 0.1 $ — $ (5.5 ) $ — $ (5.4 ) 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 following tables summarize the derivative positions presented in the balance sheet where a right of offset exists under these arrangements and related cash collateral received or pledged. The following table presents the fair value and balance sheet classification of DPL’s derivative instruments at June 30, 2016 : Fair Values of Derivative Instruments at June 30, 2016 Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets $ in millions Hedging Designation Gross Fair Value as presented in the Condensed Consolidated Balance Sheets Financial Instruments with Same Counterparty in Offsetting Position Cash Collateral Net Balance Fair Value Assets Short-term derivative positions (presented in Other prepayments and current assets) Forward power contracts Designated $ 13.9 $ (11.3 ) $ — $ 2.6 Forward power contracts Not designated 13.8 (12.1 ) — 1.7 Natural gas futures Not designated 0.3 — — 0.3 FTRs Not designated 0.1 — — 0.1 Long-term derivative positions (presented in Other deferred assets) Forward power contracts Designated 9.1 (4.8 ) — 4.3 Forward power contracts Not designated 2.5 (1.4 ) — 1.1 Total assets $ 39.7 $ (29.6 ) $ — $ 10.1 Liabilities Short-term derivative positions (presented in Other current liabilities) Forward power contracts Designated $ 19.4 $ (11.3 ) $ (8.0 ) $ 0.1 Forward power contracts Not designated 19.5 (12.1 ) (3.1 ) 4.3 Long-term derivative positions (presented in Other deferred credits) Forward power contracts Designated 4.9 (4.8 ) — 0.1 Forward power contracts Not designated 1.4 (1.4 ) — — Total liabilities $ 45.2 $ (29.6 ) $ (11.1 ) $ 4.5 The following table presents the fair value and balance sheet classification of DPL’s derivative instruments at December 31, 2015 : Fair Values of Derivative Instruments at December 31, 2015 Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets $ in millions Hedging Designation Gross Fair Value as presented in the Condensed Consolidated Balance Sheets Financial Instruments with Same Counterparty in Offsetting Position Cash Collateral Net Balance Fair Value Assets Short-term derivative positions (presented in Other prepayments and current assets) Forward power contracts Designated $ 16.2 $ (7.1 ) $ — $ 9.1 Forward power contracts Not designated 7.3 (5.5 ) — 1.8 FTRs Not designated 0.2 (0.2 ) — — Long-term derivative positions (presented in Other deferred assets) Forward power contracts Designated 3.0 (2.4 ) — 0.6 Forward power contracts Not designated 4.0 (2.7 ) — 1.3 Total assets $ 30.7 $ (17.9 ) $ — $ 12.8 Liabilities Short-term derivative positions (presented in Other current liabilities) Forward power contracts Designated $ 7.1 $ (7.1 ) $ — $ — Forward power contracts Not designated 14.5 (5.5 ) (8.0 ) 1.0 FTRs Not designated 0.5 (0.2 ) — 0.3 Long-term derivative positions (presented in Other deferred credits) Forward power contracts Designated 2.7 (2.4 ) — 0.3 Forward power contracts Not designated 2.7 (2.7 ) — — Total liabilities $ 27.5 $ (17.9 ) $ (8.0 ) $ 1.6 Credit risk-related contingent features Certain of our OTC commodity derivative contracts are under master netting agreements that contain provisions that require us to post collateral if our credit ratings drop below certain thresholds. We have crossed that threshold with one counterparty to the derivative instruments and they could request that we post collateral of $0.9 million at this time. The aggregate fair value of DPL’s commodity derivative instruments that were in a MTM loss position at June 30, 2016 was $45.2 million . $11.1 million of collateral was posted directly with third parties and in a broker margin account which offsets our loss positions on the forward contracts. This liability position is further offset by the asset position of counterparties with master netting agreements of $29.6 million . Since our debt is below investment grade, we could have to post collateral for the remaining $4.5 million .
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 arrangements, including derivative financial instruments. We use derivatives principally to manage the risk of changes in market prices for commodities. 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. The objective of the hedging program is to mitigate financial risks while ensuring that we have adequate resources to meet our requirements. 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 normal purchase/normal sale, cash flow hedges or marked to market each reporting period. At June 30, 2016 , DP&L had the following outstanding derivative instruments: Commodity Accounting Treatment Unit Purchases (in thousands) Sales (in thousands) Net Purchases/ (Sales) (in thousands) FTRs Not designated MWh 2.5 — 2.5 Natural gas futures Not designated Dths 1,442.5 — 1,442.5 Forward power contracts Designated MWh 692.6 (13,380.2 ) (12,687.6 ) Forward power contracts Not designated MWh 4,018.0 (3,574.8 ) 443.2 At December 31, 2015 , DP&L had the following outstanding derivative instruments: Commodity Accounting Treatment Unit Purchases (in thousands) Sales (in thousands) Net Purchases/ (Sales) (in thousands) FTRs Not designated MWh 10.2 — 10.2 Forward power contracts Designated MWh 1,676.7 (7,795.8 ) (6,119.1 ) Forward power contracts Not designated MWh 5,049.9 (1,665.7 ) 3,384.2 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 value of cash flow hedges is determined by observable market prices available as of the balance sheet dates and will continue to fluctuate with changes in market prices up to contract expiration. The effective portion of the hedging transaction is recognized in AOCI and transferred to earnings using specific identification of each contract when the forecasted hedged transaction takes place or when the forecasted hedged transaction is probable of not occurring. The ineffective portion of the cash flow hedge is recognized in earnings in the current period. All risk components were taken into account to determine the hedge effectiveness of the cash flow hedges. We enter into forward power contracts to manage commodity price risk exposure related to our generation of electricity. We do not hedge all commodity price risk. We reclassify gains and losses on forward power contracts from AOCI into earnings in those periods in which the contracts settle. The following table provides information for DP&L concerning gains or losses recognized in AOCI for the cash flow hedges for the three and six months ended June 30, 2016 and 2015 : Three months ended Three months ended June 30, 2016 June 30, 2015 Interest Interest $ in millions (net of tax) Power Rate Hedge Power Rate Hedge Beginning accumulated derivative gains in AOCI $ 22.5 $ 1.8 $ 1.0 $ 2.4 Net gains / (losses) associated with current period hedging transactions (8.5 ) — 1.7 — Net gains / (losses) reclassified to earnings Interest expense — (0.2 ) — (0.2 ) Revenues (13.0 ) — (1.9 ) — Purchased power 2.4 — 0.3 — Ending accumulated derivative gains in AOCI $ 3.4 $ 1.6 $ 1.1 $ 2.2 Six months ended Six months ended June 30, 2016 June 30, 2015 Interest Interest $ in millions (net of tax) Power Rate Hedge Power Rate Hedge Beginning accumulated derivative gains in AOCI $ 9.2 $ 2.0 $ 0.2 $ 2.6 Net gains associated with current period hedging transactions 13.0 — 1.8 — Net gains / (losses) reclassified to earnings Interest expense — (0.4 ) — (0.4 ) Revenues (24.0 ) — (2.1 ) — Purchased power 5.2 — 1.2 — Ending accumulated derivative gains in AOCI $ 3.4 $ 1.6 $ 1.1 $ 2.2 Portion expected to be reclassified to earnings in the next twelve months (a) $ (3.1 ) $ 0.7 Maximum length of time that we are hedging our exposure to variability in future cash flows related to forecasted transactions (in months) 18 0 (a) The actual amounts that we reclassify from AOCI to earnings related to power can differ from the estimate above due to market price changes. Derivatives not designated as hedges Certain derivative contracts are entered into on a regular basis as part of our risk management program but do not qualify for hedge accounting or the normal purchase and sales exceptions under FASC 815. Accordingly, such contracts are recorded at fair value with changes in the fair value charged or credited to the Condensed Statements of Operations in the period in which the change occurred. This is commonly referred to as “MTM accounting.” Contracts we enter into as part of our risk management program may be settled financially, by physical delivery, or net settled with the counterparty. FTRs, heating oil futures, natural gas, and certain forward power contracts are currently marked to market. Certain qualifying derivative instruments have been designated as normal purchases or normal sales contracts, as provided under GAAP. Derivative contracts that have been designated as normal purchases or normal sales under GAAP are not subject to MTM accounting and are recognized in the Condensed Statements of Operations on an accrual basis. Regulatory Assets and Liabilities In accordance with regulatory accounting under GAAP, a cost or loss that is probable of recovery in future rates should be deferred as a regulatory asset and revenue or a gain that is probable of being returned to customers should be deferred as a regulatory liability. Therefore, a portion of the heating oil futures are assigned to the retail jurisdiction and deferred as a regulatory asset or liability until the contracts settle. If these unrealized gains and losses are no longer deemed to be probable of recovery through our rates, they will be reclassified into earnings in the period such determination is made. Beginning January 1, 2016, we no longer assign any portion of the heating oil futures to our retail jurisdiction as all of our SSO retail sales are sourced through the competitive bid process. The following tables present the amount and classification within the Condensed Statements of Operations or Condensed Balance Sheets of the gains and losses on DPL’s derivatives not designated as hedging instruments for the three and six months ended June 30, 2016 and 2015 : For the three months ended June 30, 2016 $ in millions FTRs Power Natural Gas Total Change in unrealized gain $ 0.2 $ 2.8 $ 0.5 $ 3.5 Realized gain / (loss) 0.2 (2.3 ) 0.7 (1.4 ) Total $ 0.4 $ 0.5 $ 1.2 $ 2.1 Recorded in Income Statement: gain / (loss) Revenues $ — $ (5.1 ) $ — $ (5.1 ) Purchased power 0.4 5.6 1.2 7.2 Total $ 0.4 $ 0.5 $ 1.2 $ 2.1 For the three months ended June 30, 2015 $ in millions Heating Oil FTRs Power Total Change in unrealized gain / (loss) $ 0.1 $ (0.8 ) $ 1.1 $ 0.4 Realized loss (0.1 ) — (1.5 ) (1.6 ) Total $ — $ (0.8 ) $ (0.4 ) $ (1.2 ) Recorded in Income Statement: gain / (loss) Revenues $ — $ (0.8 ) $ (2.9 ) $ (3.7 ) Purchased power — — 2.5 2.5 Total $ — $ (0.8 ) $ (0.4 ) $ (1.2 ) For the six months ended June 30, 2016 $ in millions FTRs Power Natural Gas Total Change in unrealized gain $ 0.4 $ 0.9 $ 0.3 $ 1.6 Realized gain / (loss) 0.4 (2.7 ) 0.5 (1.8 ) Total $ 0.8 $ (1.8 ) $ 0.8 $ (0.2 ) Recorded in Income Statement: gain / (loss) Revenues $ — $ (6.6 ) $ — $ (6.6 ) Purchased power 0.8 4.8 0.8 6.4 Total $ 0.8 $ (1.8 ) $ 0.8 $ (0.2 ) For the six months ended June 30, 2015 $ in millions Heating Oil FTRs Power Natural Gas Total Change in unrealized gain / (loss) $ 0.2 $ 0.1 $ (1.8 ) 0.1 $ (1.4 ) Realized loss (0.1 ) (0.1 ) (3.8 ) (0.1 ) (4.1 ) Total $ 0.1 $ — $ (5.6 ) $ — $ (5.5 ) Recorded in Balance Sheet: Regulatory asset $ 0.1 $ — $ — $ — $ 0.1 Recorded in Income Statement: gain / (loss) Revenues — — 2.2 — 2.2 Purchased power — — (7.8 ) — (7.8 ) Total $ 0.1 $ — $ (5.6 ) $ — $ (5.5 ) 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 following tables summarize the derivative positions presented in the balance sheet where a right of offset exists under these arrangements and related cash collateral received or pledged. The following table presents the fair value and balance sheet classification of DP&L’s derivative instruments at June 30, 2016 : Fair Values of Derivative Instruments at June 30, 2016 Gross Amounts Not Offset in the Condensed Balance Sheets $ in millions Hedging Designation Gross Fair Value as presented in the Condensed Balance Sheets Financial Instruments with Same Counterparty in Offsetting Position Cash Collateral Net Balance Fair Value Assets Short-term derivative positions (presented in Other prepayments and current assets) Forward power contracts Designated $ 13.9 $ (11.3 ) $ — $ 2.6 Forward power contracts Not designated 13.9 (12.1 ) — 1.8 Natural gas futures Not designated 0.3 — — 0.3 FTRs Not designated 0.1 — — 0.1 Long-term derivative positions (presented in Other deferred assets) Forward power contracts Designated 9.1 (4.8 ) — 4.3 Forward power contracts Not designated 2.5 (1.4 ) — 1.1 Total assets $ 39.8 $ (29.6 ) $ — $ 10.2 Liabilities Short-term derivative positions (presented in Other current liabilities) Forward power contracts Designated $ 19.4 $ (11.3 ) $ (8.0 ) $ 0.1 Forward power contracts Not designated 19.6 (12.1 ) (3.1 ) 4.4 Long-term derivative positions (presented in Other deferred credits) Forward power contracts Designated 4.9 (4.8 ) — 0.1 Forward power contracts Not designated 1.4 (1.4 ) — — Total liabilities $ 45.3 $ (29.6 ) $ (11.1 ) $ 4.6 The following table presents the fair value and balance sheet classification of DP&L’s derivative instruments at December 31, 2015 : Fair Values of Derivative Instruments at December 31, 2015 Gross Amounts Not Offset in the Condensed Balance Sheets $ in millions Hedging Designation Gross Fair Value as presented in the Condensed Balance Sheets Financial Instruments with Same Counterparty in Offsetting Position Cash Collateral Net Balance Fair Value Assets Short-term derivative positions (presented in Other prepayments and current assets) Forward power contracts Designated $ 16.2 $ (7.1 ) $ — $ 9.1 Forward power contracts Not designated 7.4 (5.5 ) — 1.9 FTRs Not designated 0.2 (0.2 ) — — Long-term derivative positions (presented in Other deferred assets) Forward power contracts Designated 3.0 (2.4 ) — 0.6 Forward power contracts Not designated 4.0 (2.7 ) — 1.3 Total assets $ 30.8 $ (17.9 ) $ — $ 12.9 Liabilities Short-term derivative positions (presented in Other current liabilities) Forward power contracts Designated $ 7.1 $ (7.1 ) $ — $ — Forward power contracts Not designated 14.5 (5.5 ) (8.0 ) 1.0 FTRs Not designated 0.5 (0.2 ) — 0.3 Long-term derivative positions (presented in Other deferred credits) Forward power contracts Designated 2.7 (2.4 ) — 0.3 Forward power contracts Not designated 2.7 (2.7 ) — — Total liabilities $ 27.5 $ (17.9 ) $ (8.0 ) $ 1.6 Credit risk-related contingent features Certain of our OTC commodity derivative contracts are under master netting agreements that contain provisions that require us to post collateral if our credit ratings drop below certain thresholds. We have crossed that threshold with one counterparty to the derivative instruments and they could request that we post collateral of $0.9 million at this time. The aggregate fair value of DP&L’s commodity derivative instruments that were in a MTM loss position at June 30, 2016 was $45.3 million . $11.1 million of collateral was posted directly with third parties and in a broker margin account which offsets our loss positions on the forward contracts. This liability position is further offset by the asset position of counterparties with master netting agreements of $29.6 million . Since our debt is below investment grade, we could have to post collateral for the remaining $4.6 million .

Debt Obligations

Debt Obligations	6 Months Ended
	Jun. 30, 2016
Debt Instrument [Line Items]
Debt Obligations	Debt Interest June 30, December 31, $ in millions Rate Maturity 2016 2015 First mortgage bonds 1.875% 2016 $ 445.0 $ 445.0 Pollution control series 4.8% 2036 100.0 100.0 Pollution control series - rates from 1.29% - 1.31% and 1.13% - 1.17% (a) 2020 200.0 200.0 U.S. Government note 4.2% 2061 18.0 18.1 Unamortized deferred financing costs (3.4 ) (5.0 ) Unamortized debt discount and premiums, net (3.5 ) (3.6 ) Total long-term debt at subsidiary 756.1 754.5 Bank term loan - rates from 2.67% - 2.71% and 2.44% - 2.67% (a) 2020 125.0 125.0 Senior unsecured bonds 6.5% 2016 57.0 130.0 Senior unsecured bonds 6.75% 2019 200.0 200.0 Senior unsecured bonds 7.25% 2021 780.0 780.0 Note to DPL Capital Trust II (b) 8.125% 2031 15.6 15.6 Unamortized deferred financing costs (9.8 ) (11.1 ) Unamortized debt discounts and premiums, net (0.6 ) (0.7 ) Total long-term debt 1,923.3 1,993.3 Less: current portion (514.0 ) (572.8 ) Total long-term debt $ 1,409.3 $ 1,420.5 (a) Range of interest rates for the six months ended June 30, 2016 and the twelve months ended December 31, 2015 , respectively. (b) Note payable to related party. See Note 9 – Related Party Transactions for additional information. Premiums or discounts recognized at the date of the Merger are amortized over the remaining life of the debt using the effective interest method. Significant transactions On February 5, 2016, $73.0 million of DPL's $130.0 million 6.5% Senior Unsecured Notes Due 2016 were redeemed under the indenture's make-whole call provision, which allows for the bonds to be called prior to maturity with a make-whole payment as determined by discounting the bond's future cash flow by a similarly maturing U.S. Treasury bond's yield plus 50 basis points. On the call date, principal plus the make-whole payment due totaled $75.4 million , which was paid with cash on hand. Debt covenants and restrictions DP&L’s unsecured revolving credit agreement and Bond Purchase and Covenants Agreement have two financial covenants. The first financial covenant measures Total Debt to Total Capitalization. The Total Debt to Total Capitalization ratio 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. The second financial covenant ratio compares EBITDA to Interest Expense. The EBITDA to Interest Expense ratio 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 cost of borrowing under DP&L's unsecured revolving credit agreement and Bond Purchase and Covenants Agreement adjust under certain credit rating scenarios. DPL’s revolving credit agreement and term loan have 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 second financial covenant, an EBITDA to Interest Expense ratio, 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 cost of borrowing under DPL's revolving credit agreement and term loan adjust under certain credit rating scenarios. DPL’s revolving credit agreement, term loan, and senior unsecured notes due 2019 restrict dividend payments from DPL to AES. 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	Debt Interest June 30, December 31, $ in millions Rate Maturity 2016 2015 First mortgage bonds 1.875% 2016 $ 445.0 $ 445.0 Pollution control series 4.8% 2036 100.0 100.0 Pollution control series - rates from 1.29% - 1.31% and 1.13% - 1.17% (a) 2020 200.0 200.0 U.S. Government note 4.2% 2061 18.0 18.1 Unamortized deferred financing costs (4.5 ) (6.2 ) Unamortized debt discount (0.1 ) (0.2 ) Total long-term debt 758.4 756.7 Less: current portion (444.6 ) (443.1 ) Total $ 313.8 $ 313.6 (a) Range of interest rates for the six months ended June 30, 2016 and the twelve months ended December 31, 2015 , respectively. Debt covenants and restrictions DP&L’s unsecured revolving credit agreement and Bond Purchase and Covenants Agreement have 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. The second financial covenant measures EBITDA to Interest Expense. The EBITDA to Interest Expense ratio 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 cost of borrowing under DP&L's unsecured revolving credit agreement and Bond Purchase and Covenants Agreement adjust under certain credit rating scenarios. 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	6 Months Ended
	Jun. 30, 2016
Entity Information [Line Items]
Income Taxes	Income Taxes The following table details the effective tax rates for the three and six months ended June 30, 2016 and 2015 . Three months ended Six months ended June 30, June 30, 2016 2015 2016 2015 DPL 39.2% 28.2% 39.5% 28.8% Income tax expense for the six months ended June 30, 2016 and 2015 was calculated using the estimated annual effective income tax rates for 2016 and 2015 of 38.8% and 31.2% , respectively. For the three and six months ended June 30, 2016 and 2015 , management estimated 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 rates estimated could be materially different from the actual effective tax rates. For the three and six months ended June 30, 2016 , DPL’s current period effective tax rate was greater than the estimated annual effective rate primarily due to a change in its uncertain tax positions. The increase in the annual effective rate compared to the same period in 2015 is primarily due to a forecasted pre-tax loss in the 2016 tax year.
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 and six months ended June 30, 2016 and 2015 . Three months ended Six months ended June 30, June 30, 2016 2015 2016 2015 DP&L 36.4% 28.2% 36.9% 28.6% Income tax expense for the three and six months ended June 30, 2016 and 2015 was calculated using the estimated annual effective income tax rates for 2016 and 2015 of 36.7% and 29.4% , respectively. For the three and six months ended June 30, 2016 and 2015 management estimated 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 rates estimated could be materially different from the actual effective tax rates. For the six months ended June 30, 2016 , DP&L’s current period effective tax rate was greater than the estimated annual effective rate primarily due to a change in its uncertain tax positions and the deduction for the preferred stock dividends. The increase in the annual effective rate compared to the same period in 2015 is primarily due to a forecasted pre-tax loss in the 2016 tax year.

Benefit Plans

Benefit Plans	6 Months Ended
	Jun. 30, 2016
Entity Information [Line Items]
Pension and Postretirement Benefits	Benefit Plans DP&L sponsors a defined benefit pension plan for the vast 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 $5.0 million in employer contributions made during the six months ended June 30, 2016 and no contributions during the six months ended June 30, 2015 . 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 amounts presented for postretirement include both health and life insurance. The pension and postretirement 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 but are still participants in the DP&L plan. See Note 9 – Related Party Transactions . The net periodic benefit cost of the pension and postretirement benefit plans for the three and six months ended June 30, 2016 and 2015 was: Net Periodic Benefit Cost Pension Three months ended Six months ended June 30, June 30, $ in millions 2016 2015 2016 2015 Service cost $ 1.4 $ 1.8 $ 2.8 $ 3.6 Interest cost 3.7 4.3 7.4 8.6 Expected return on plan assets (5.7 ) (5.6 ) (11.4 ) (11.3 ) Amortization of unrecognized: Prior service cost 0.5 0.5 1.0 1.0 Actuarial loss 1.1 1.4 2.1 2.9 Net periodic benefit cost $ 1.0 $ 2.4 $ 1.9 $ 4.8 Net Periodic Benefit Cost Postretirement Three months ended Six months ended June 30, June 30, $ in millions 2016 2015 2016 2015 Service cost $ 0.1 $ — $ 0.1 $ — Interest cost 0.1 0.1 0.2 0.3 Expected return on plan assets — — — — Amortization of unrecognized: Prior service cost — — — — Actuarial gain (0.2 ) (0.1 ) (0.3 ) (0.2 ) Net periodic benefit cost $ — $ — $ — $ 0.1 Benefit payments and Medicare Part D reimbursements, which reflect future service, are estimated to be paid as follows: $ in millions Pension Postretirement 2016 $ 12.3 $ 0.8 2017 25.2 1.6 2018 25.8 1.5 2019 26.3 1.4 2020 26.7 1.4 2021 - 2025 134.8 5.7
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 vast 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 $5.0 million in employer contributions made during the six months ended June 30, 2016 and no contributions during the six months ended June 30, 2015 . 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 amounts presented for postretirement include both health and life insurance. The pension and postretirement 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 but are still participants in the DP&L plan. See Note 10 – Related Party Transactions . The net periodic benefit cost of the pension and postretirement benefit plans for the three and six months ended June 30, 2016 and 2015 was: Net Periodic Benefit Cost Pension Three months ended Six months ended June 30, June 30, $ in millions 2016 2015 2016 2015 Service cost $ 1.4 $ 1.7 $ 2.8 $ 3.5 Interest cost 3.7 4.3 7.4 8.6 Expected return on plan assets (5.7 ) (5.5 ) (11.4 ) (11.2 ) Amortization of unrecognized: Prior service cost 0.7 0.8 1.5 1.6 Actuarial loss 1.8 2.4 3.6 4.8 Net periodic benefit cost $ 1.9 $ 3.7 $ 3.9 $ 7.3 Net Periodic Benefit Cost Postretirement Three months ended Six months ended June 30, June 30, $ in millions 2016 2015 2016 2015 Service cost $ 0.1 $ — $ 0.1 $ — Interest cost 0.2 0.2 0.3 0.4 Expected return on plan assets — — — — Amortization of unrecognized: Prior service cost — — — — Actuarial gain (0.3 ) (0.1 ) (0.4 ) (0.3 ) Net periodic benefit cost $ — $ 0.1 $ — $ 0.1 Benefit payments and Medicare Part D reimbursements, which reflect future service, are estimated to be paid as follows: $ in millions Pension Postretirement 2016 $ 12.3 $ 0.8 2017 25.2 1.6 2018 25.8 1.5 2019 26.3 1.4 2020 26.7 1.4 2021 - 2025 134.8 5.7

Shareholder's Equity

Shareholder's Equity	6 Months Ended
	Jun. 30, 2016
THE DAYTON POWER AND LIGHT COMPANY [Member]
Class of Stock [Line Items]
Shareholder's Equity	Shareholder’s Equity DP&L has 250,000,000 authorized $0.01 par value common shares, of which 41,172,173 are outstanding at June 30, 2016 . All common shares are held by DP&L’s parent, DPL . As part of the PUCO’s approval of the Merger, DP&L agreed to maintain a capital structure that includes an equity ratio, calculated as total equity divided by total capitalization, of at least 50 percent and not to have a negative retained earnings balance. After the fixed-asset impairment recorded during the second quarter of 2016 and as of June 30, 2016, DP&L's equity ratio was 49% and retained earnings balance was negative. It is unknown what impact, if any, this will have on DP&L . In the generation separation order dated September 17, 2014, the PUCO permitted DP&L to temporarily maintain long-term debt of $750.0 million or 75% of its rate base, whichever is greater, until January 1, 2018.

Contractual Obligations, Commer

Contractual Obligations, Commercial Commitments and Contingencies	6 Months Ended
	Jun. 30, 2016
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 these subsidiaries on a stand-alone basis, thereby facilitating the extension of sufficient credit to accomplish these subsidiaries’ intended commercial purposes. At June 30, 2016 , DPL had $14.6 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. The carrying amount of obligations for commercial transactions covered by these guarantees recorded in our Condensed Consolidated Balance Sheets was $2.1 million and $0.5 million at June 30, 2016 and December 31, 2015 , respectively. To date, DPL has not incurred any losses related to the guarantees of AES Ohio Generation ’s obligations and we believe it is remote 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 owns a 4.9% equity ownership interest in OVEC, which is recorded using the cost method of accounting under GAAP. As of June 30, 2016 , DP&L could be responsible for the repayment of 4.9% , or $75.3 million , of a $1,537.4 million debt obligation that has maturities from 2018 to 2040 . This would only happen if OVEC defaulted on its debt payments. As of June 30, 2016 , we have no knowledge of such a default. Commercial Commitments and Contractual Obligations There have been no material changes, outside the ordinary course of business, to our commercial commitments and to the information disclosed in the contractual obligations table in our Form 10-K for the fiscal year ended December 31, 2015 . 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 in light of 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 June 30, 2016 , 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 regarding whether modifications to or maintenance of certain coal-fired generating stations require additional permitting or pollution control technology, or whether emissions from coal-fired generating stations cause or contribute to climate change; • Rules and future rules issued by the USEPA and the Ohio EPA that require substantial reductions in SO 2 , particulates, mercury, acid gases, NOx, and other air emissions. DP&L has installed emission control technology and is taking other measures to comply with required and anticipated reductions; • Rules and future rules issued by the USEPA, the Ohio EPA or other authorities that require reporting and reductions of GHGs; • Rules and future rules issued by the USEPA 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.
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 owns a 4.9% equity ownership interest in OVEC, which is recorded using the cost method of accounting under GAAP. As of June 30, 2016 , DP&L could be responsible for the repayment of 4.9% , or $75.3 million , of a $1,537.4 million debt obligation that has maturities from 2018 to 2040 . This would only happen if OVEC defaulted on its debt payments. As of June 30, 2016 , we have no knowledge of such a default. Commercial Commitments and Contractual Obligations There have been no material changes, outside the ordinary course of business, to our commercial commitments and to the information disclosed in the contractual obligations table in our Form 10-K for the fiscal year ended December 31, 2015 . 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 in light of 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 June 30, 2016 , 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 regarding whether modifications to or maintenance of certain coal-fired generating stations require additional permitting or pollution control technology, or whether emissions from coal-fired generating stations cause or contribute to climate change; • Rules and future rules issued by the USEPA and the Ohio EPA that require substantial reductions in SO 2 , particulates, mercury, acid gases, NOx, and other air emissions. DP&L has installed emission control technology and is taking other measures to comply with required and anticipated reductions; • Rules and future rules issued by the USEPA, the Ohio EPA or other authorities that require reporting and reductions of GHGs; • Rules and future rules issued by the USEPA 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.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2016
Related Party Transaction [Line Items]
Related Party Transactions	Related Party Transactions Service Company Effective January 1, 2014, the Service Company began providing services including operations, accounting, legal, human resources, information technology and other corporate services on behalf of companies that are part of the U.S. SBU, including, among other companies, DPL and DP&L . The Service Company allocates the costs for these services based on cost drivers designed to result in fair and equitable allocations. This includes ensuring that the regulated utilities served, including DP&L , are not subsidizing costs incurred for the benefit of other businesses. Benefit plans DPL has an agreement with AES or one of its affiliates to participate in a group benefits program, including but not limited to, health, dental, vision and life benefits. AES or its affiliate administers the financial aspects of the group insurance program, receives all premium payments from the participating affiliates, and makes all vendor payments. The following table provides a summary of these transactions: Three months ended Six months ended June 30, June 30, $ in millions 2016 2015 2016 2015 Transactions with the Service Company Charges for services provided $ 11.5 $ 9.8 $ 23.1 $ 19.6 Charges to the Service Company $ 1.1 $ 2.8 $ 2.3 $ 3.9 Transactions with other AES affiliates: Charges / (credits) for health, welfare and benefit plans $ (2.4 ) $ 4.2 $ 1.7 $ 8.2 Transactions with the Service Company: At June 30, 2016 At December 31, 2015 Net payable to the Service Company $ (1.1 ) $ (0.5 ) DPL Capital Trust II DPL has a wholly-owned business trust, DPL Capital Trust II (the "Trust"), formed for the purpose of issuing trust capital securities to third-party investors. Effective in 2003, DPL deconsolidated the Trust upon adoption of the accounting standards related to variable interest entities and currently treats the Trust as a nonconsolidated subsidiary. The Trust holds mandatorily redeemable trust capital securities. The investment in the Trust, which amounts to $0.3 million and $0.3 million at June 30, 2016 and December 31, 2015 , respectively, is included in Other deferred assets within Other non-current assets. DPL also has a note payable to the Trust amounting to $15.6 million and $15.6 million at June 30, 2016 and December 31, 2015 , respectively, that was established upon the Trust’s deconsolidation in 2003. See Note 5 – Debt for additional information. In addition to the obligations under the note payable mentioned above, DPL also agreed to a security obligation which represents a full and unconditional guarantee of payments to the capital security holders of the Trust. Income taxes 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. DPL had a net payable balance under this agreement of $78.9 million and $50.5 million as of June 30, 2016 and December 31, 2015 , respectively, which is recorded in the Accrued taxes and Accounts receivable, net lines on the accompanying Condensed Consolidated Balance Sheets a gross basis.
THE DAYTON POWER AND LIGHT COMPANY [Member]
Related Party Transaction [Line Items]
Related Party Transactions	Related Party Transactions Service Company Effective January 1, 2014, the Service Company began providing services including operations, accounting, legal, human resources, information technology and other corporate services on behalf of companies that are part of the U.S. SBU, including, among other companies, DPL and DP&L . The Service Company allocates the costs for these services based on cost drivers designed to result in fair and equitable allocations. This includes ensuring that the regulated utilities served, including DP&L , are not subsidizing costs incurred for the benefit of other businesses. Benefit plans DPL has an agreement with AES or one of its affiliates to participate in a group benefits program, including but not limited to, health, dental, vision and life benefits. AES or its affiliate administers the financial aspects of the group insurance program, receives all premium payments from the participating affiliates, and makes all vendor payments. The following table provides a summary of these transactions: Three months ended Six months ended June 30, June 30, $ in millions 2016 2015 2016 2015 DP&L revenues: Sales to DPLER (including MC Squared) (a) $ — $ 68.3 $ — $ 179.0 DP&L Operation & Maintenance Expenses: Premiums paid for insurance services provided by MVIC (b) $ (0.8 ) $ (0.8 ) $ (1.7 ) $ (1.6 ) Expense recoveries for services provided to DPLER (c) $ — $ 0.6 $ — $ 1.3 Transactions with the Service Company: Charges for services provided $ 10.9 $ 8.3 $ 19.8 $ 16.7 Charges to the Service Company $ 1.0 $ 2.8 $ 2.2 $ 3.9 Transactions with other AES affiliates: Charges / (credits) for health, welfare and benefit plans $ (2.4 ) $ 3.9 $ 1.7 $ 7.8 Balances with related parties: At June 30, 2016 At December 31, 2015 Net payable to the Service Company $ (1.1 ) $ (0.5 ) Short-term loan with DPL (d) $ — $ (35.0 ) (a) DP&L sold power to DPLER and MC Squared to satisfy the electric requirements of their retail customers. The revenue dollars associated with sales to DPLER and MC Squared are recorded as wholesale revenues in DP&L’s Financial Statements. These agreements were terminated upon the sale of DPLER on January 1, 2016. (b) MVIC, a wholly-owned captive insurance subsidiary of DPL , provides insurance coverage to DP&L and other DPL subsidiaries for workers’ compensation, general liability, property damages and directors’ and officers’ liability. These amounts represent insurance premiums paid by DP&L to MVIC. DP&L received insurance proceeds from MVIC of $0.0 million and $2.3 million for the three months ended June 30, 2016 and 2015 , respectively, and $0.2 million and $3.8 million for the six months ended June 30, 2016 and 2015 , respectively. (c) Prior to the sale of DPLER, in the normal course of business DP&L incurred and recorded expenses on behalf of DPLER. Such expenses included but were not limited to employee-related expenses, accounting, information technology, payroll, legal and other administration expenses. DP&L subsequently charged these expenses to DPLER at DP&L’s cost and credited the expense in which they were initially recorded. (d) On December 31, 2015, DPL loaned $35.0 million to DP&L through an intercompany short-term loan at 2.67% . Income taxes AES files federal and state income tax returns which consolidate DPL and its subsidiaries, including DP&L . Under a tax sharing agreement with DPL , DP&L is responsible for the income taxes associated with its own taxable income and records the provision for income taxes using a separate return method. DP&L had a net payable balance under this agreement of $10.8 million as of June 30, 2016 and a net receivable balance of $1.5 million as of December 31, 2015 , which are recorded in the Accrued taxes and Accounts receivable, net lines on the accompanying Condensed Balance Sheets on a gross basis. Gain on termination of contract On January 1, 2016, DPL closed on the sale of DPLER. Also on January 1, 2016, DP&L terminated the contract it had with DPLER for the supply of electricity. The agreement terminating the contract was signed on December 28, 2015 and DP&L received $27.7 million of restricted cash on December 31, 2015 for the early termination of the contract. For the six months ended June 30, 2016 , this amount was recorded in Gain on termination of contract in the Condensed Statements of Operations and the cash received was included in Cash flows from operating activities in the Condensed Statements of Cash Flows.

Business Segments

Business Segments	6 Months Ended
	Jun. 30, 2016
Segment Reporting [Abstract]
Business Segments	Business Segments At December 31, 2015, DPL had two segments consisting of the operations of two of its wholly-owned subsidiaries, DP&L (Utility segment) and DPLER (Competitive Retail segment which included DPLER's wholly-owned subsidiary, MC Squared). This is how we viewed our business and made decisions on how to allocate resources and evaluate performance. The Competitive Retail segment, DPLER’s competitive retail electric service business, was sold on January 1, 2016 (see Note 11 – Discontinued Operations ). DPL now operates through one segment, the Utility segment. Segment disclosures for 2015 have not been restated to show the competitive retail segment as a discontinued operation and therefore do not tie to the Condensed Consolidated Statement of Operations. The Utility segment is comprised of DP&L’s electric generation, transmission and distribution businesses which generate and deliver electricity to residential, commercial, industrial and governmental customers. DP&L generates electricity at five coal-fired power plants and DP&L distributes power to approximately 517,000 retail customers who are located in a 6,000 square mile area of West Central Ohio. Prior to the sale of DPLER, DP&L also sold electricity to DPLER and to other Ohio utilities. Any excess energy and capacity is sold into the PJM wholesale market. DP&L’s transmission and distribution businesses are subject to rate regulation by federal and state regulators while rates for its generation business are deemed competitive under Ohio law. The Competitive Retail segment’s electric energy used to meet its sales obligations was purchased from DP&L . Intercompany sales from DP&L to DPLER were based on fixed-price contracts for each customer; the price approximated market prices for wholesale power at the inception of each customer’s contract. These agreements were terminated in connection with the sale of DPLER on January 1, 2016. Included in the “Other” column in the following tables are other businesses that do not meet the GAAP requirements for disclosure as reportable segments, certain corporate costs including interest expense on DPL’s debt, and adjustments related to purchase accounting from the Merger. Management evaluates segment performance based on gross margin. The accounting policies of the reportable segments are the same as those described in Note 1 – Overview and Summary of Significant Accounting Policies . Intersegment sales and profits are eliminated in consolidation. The following tables present financial information for each of DPL’s reportable business segments: $ in millions Utility Segment Other Adjustments and Eliminations DPL Consolidated For the three months ended June 30, 2016 Revenues from external customers $ 313.4 $ 14.9 $ — $ 328.3 Intersegment revenues 0.3 0.9 (1.2 ) — Total revenues 313.7 15.8 (1.2 ) 328.3 Fuel 55.6 4.6 — 60.2 Purchased power 96.7 0.7 (0.5 ) 96.9 Gross margin $ 161.4 $ 10.5 $ (0.7 ) $ 171.2 Depreciation and amortization $ 36.8 $ (0.8 ) $ — $ 36.0 Fixed-asset impairment $ 857.1 $ (621.6 ) $ — $ 235.5 Interest expense $ 5.4 $ 20.3 $ 0.3 $ 26.0 Income tax expense / (benefit) $ (303.7 ) $ 215.4 $ — $ (88.3 ) Net income / (loss) $ (531.6 ) $ 394.8 $ — $ (136.8 ) Cash capital expenditures $ 36.0 $ 5.4 $ — $ 41.4 $ in millions Utility Segment Competitive Retail Other Adjustments and Eliminations DPL Consolidated For the three months ended June 30, 2015 Revenues from external customers $ 283.8 $ 75.2 $ 13.9 $ — $ 372.9 Intersegment revenues 68.3 — 1.3 (69.6 ) — Total revenues 352.1 75.2 15.2 (69.6 ) 372.9 Fuel 50.6 — 3.8 — 54.4 Purchased power 120.1 68.7 0.6 (68.8 ) 120.6 Gross margin $ 181.4 $ 6.5 $ 10.8 $ (0.8 ) $ 197.9 Depreciation and amortization $ 34.2 $ 0.1 $ — $ — $ 34.3 Interest expense $ 9.0 $ 0.1 $ 21.8 $ — $ 30.9 Income tax expense / (benefit) $ 9.4 $ (5.5 ) $ (3.4 ) $ — $ 0.5 Net income / (loss) $ 23.9 $ 6.7 $ (8.9 ) $ — $ 21.7 Cash capital expenditures $ 30.2 $ 0.1 $ 0.8 $ — $ 31.1 $ in millions Utility Segment Other Adjustments and Eliminations DPL Consolidated For the six months ended June 30, 2016 Revenues from external customers $ 662.3 $ 30.0 $ — $ 692.3 Intersegment revenues 0.6 2.2 (2.8 ) — Total revenues 662.9 32.2 (2.8 ) 692.3 Fuel 118.5 8.6 — 127.1 Purchased power 218.0 1.9 (1.1 ) 218.8 Gross margin $ 326.4 $ 21.7 $ (1.7 ) $ 346.4 Depreciation and amortization $ 71.1 $ (1.7 ) $ — $ 69.4 Fixed-asset impairment $ 857.1 $ (621.6 ) $ — $ 235.5 Interest expense $ 10.7 $ 41.3 $ 0.3 $ 52.3 Income tax expense / (benefit) $ (291.3 ) $ 203.6 $ — $ (87.7 ) Net income / (loss) from continuing operations $ (497.9 ) $ 363.3 $ — $ (134.6 ) Discontinued operations, net of tax $ — $ 29.6 $ — $ 29.6 Net income / (loss) $ (497.9 ) $ 392.9 $ — $ (105.0 ) Cash capital expenditures $ 71.8 $ 7.3 $ — $ 79.1 at June 30, 2016 Total assets $ 2,442.0 $ 1,267.7 $ (778.3 ) $ 2,931.4 $ in millions Utility Segment Competitive Retail Other Adjustments and Eliminations DPL Consolidated For the six months ended June 30, 2015 Revenues from external customers $ 634.4 $ 197.5 $ 35.5 $ — $ 867.4 Intersegment revenues 179.0 — 2.9 (181.9 ) — Total revenues 813.4 197.5 38.4 (181.9 ) 867.4 Fuel 119.9 — 10.9 — 130.8 Purchased power 309.8 180.4 4.8 (180.2 ) 314.8 Gross margin $ 383.7 $ 17.1 $ 22.7 $ (1.7 ) $ 421.8 Depreciation and amortization $ 68.9 $ 0.4 $ — $ — $ 69.3 Interest expense $ 17.7 $ 0.1 $ 43.7 $ (0.1 ) $ 61.4 Income tax expense / (benefit) $ 24.2 $ (4.2 ) $ (6.8 ) $ — $ 13.2 Net income / (loss) $ 60.4 $ 8.3 $ (18.3 ) $ — $ 50.4 Cash capital expenditures $ 63.3 $ 0.3 $ 1.2 $ — $ 64.8 at December 31, 2015 Total assets $ 3,359.6 $ — $ 1,304.5 $ (1,339.4 ) $ 3,324.7

Discontinued Operations

Discontinued Operations	6 Months Ended
	Jun. 30, 2016
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	Discontinued Operations On January 1, 2016, DPL closed on the sale of DPLER, its competitive retail business. The sale agreement was signed on December 28, 2015 and DPL received $75.5 million of restricted cash on December 31, 2015 for the sale. This amount was shown as Restricted cash with the associated liability shown as " Deposit received on sale of DPLER " on the Balance Sheet as of December 31, 2015. Assets and liabilities related to DPLER were reclassified to "Assets held for sale" and "Liabilities held for sale" in the December 31, 2015 Condensed Consolidated Balance Sheet. DPL recorded a gain on this transaction of $49.2 million in the first quarter of 2016. The gain includes the impact of DPLER’s liability to DP&L that transferred with the sale on January 1, 2016 but was eliminated in consolidation at December 31, 2015. Deferred taxes and intercompany balances were not reclassified to held for sale. Operating activities related to DPLER have been reclassified to "Discontinued operations" in the Condensed Consolidated Statements of Operations for the three and six months ended June 30, 2015 . The following table summarizes the major categories of assets, liabilities at the dates indicated, and the revenues, cost of revenues, operating expenses and income tax of discontinued operations for the periods indicated: $ in millions December 31, 2015 Accounts receivable, net $ 31.0 Property, plant & equipment, net 4.6 Intangible assets, net 24.6 Other assets 2.0 Total assets of the disposal group classified as held for sale in the balance sheets $ 62.2 Accounts payable $ 0.8 Other liabilities 0.8 Total liabilities of the disposal group classified as held for sale in the balance sheets $ 1.6 Three months ended June 30, Six months ended June 30, 2016 2015 2016 2015 Revenues $ — $ 75.2 $ — $ 197.5 Cost of revenues — (68.8 ) — (180.5 ) Operating expenses — (4.8 ) (0.7 ) (11.8 ) (Loss) / income from discontinued operations before income taxes — 1.6 (0.7 ) 5.2 Gain from disposal of discontinued operations — — 49.2 — Income tax expense / (benefit) — (5.3 ) 18.9 (3.6 ) Income on discontinued operations $ — $ 6.9 $ 29.6 $ 8.8 DPLER purchased its power from DP&L during 2015. Prior to DPLER being presented as a discontinued operation, this purchased power and DP&L's corresponding wholesale revenue would have been eliminated in consolidation. 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 $(0.7) million and $20.5 million for the six months ended June 30, 2016 and 2015 , respectively. Cash flows from investing activities for discontinued operations were $75.5 million and $1.0 million for the six months ended June 30, 2016 and 2015 , respectively. All cash generated from discontinued operations was paid to DPL through dividends for all periods presented.

Fixed-asset Impairment (Notes)

Fixed-asset Impairment (Notes)	6 Months Ended
	Jun. 30, 2016
Finite-Lived Intangible Assets [Line Items]
Asset Impairment Charges [Text Block]	Fixed-asset Impairment During the second quarter of 2016, we tested the recoverability of our long-lived assets at certain of our generation facilities at DP&L . A ruling by the Supreme Court of Ohio on June 20, 2016, lower expectation of future capacity revenue resulting from the most recent PJM capacity auction and a higher anticipated level of environmental compliance costs resulting from third party studies were collectively determined to be an impairment indicator for these assets. We performed a long-lived asset impairment analysis and determined that the carrying amount of Killen and certain DP&L peaking generating facilities were not recoverable. The asset groups of Killen and these DP&L peaking generating facilities were determined to have fair values of $84.3 million and $5.2 million , respectively, using the discounted cash flows under the income approach. As a result, we recognized an asset impairment expense of $230.8 million and $4.7 million for Killen and these DP&L peaking generating facilities, respectively.
THE DAYTON POWER AND LIGHT COMPANY [Member]
Finite-Lived Intangible Assets [Line Items]
Asset Impairment Charges [Text Block]	Fixed-asset Impairment During the second quarter of 2016, we tested the recoverability of our long-lived assets at certain of our generation facilities at DP&L . A ruling by the Supreme Court of Ohio on June 20, 2016, lower expectation of future capacity revenue resulting from the most recent PJM capacity auction and a higher anticipated level of environmental compliance costs resulting from third party studies were collectively determined to be an impairment indicator for these assets. We performed a long-lived asset impairment test and determined that the carrying amounts of the asset groups of Stuart, Killen and Zimmer were not recoverable. The asset groups of Stuart, Killen and Zimmer were determined to have fair values of $164.4 million , $84.3 million and $111.0 million , respectively, using the discounted cash flows under the income approach. As a result, we recognized asset impairment expenses of $292.0 million , $246.2 million and $318.9 million for Stuart, Killen and Zimmer, respectively.

Summary of Significant Accounti

Summary of Significant Accounting Policies (Policy)	6 Months Ended
	Jun. 30, 2016
Significant Accounting Policies [Line Items]
Description of Business	Description of Business DPL is a diversified regional energy company organized in 1985 under the laws of Ohio. DPL’s one reportable segment is the Utility segment, comprised of its DP&L subsidiary. DPLER, which was DPL's competitive retail segment, was sold January 1, 2016. See Note 10 – Business Segments for more information relating to these reportable segments. 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 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, distribution and transmission retail services are still regulated. DP&L has the exclusive right to provide such distribution and transmission services to approximately 517,000 customers located in West Central Ohio. Additionally, DP&L offers retail SSO electric service to residential, commercial, industrial and governmental customers in a 6,000 square mile area of West Central Ohio. DP&L owns multiple coal-fired and peaking electric generating facilities as well as numerous transmission facilities, all of which are included in the financial statements at amortized cost. Under the ESP 2 order, DP&L was required to source 100% of the generation for its SSO customers through a competitive bid process. Principal industries located in DP&L’s service territory include automotive, food processing, paper, plastic, manufacturing and defense. DP&L's distribution sales reflect the general economic conditions, seasonal weather patterns, retail competition in our service territory and the market price of electricity. DP&L sells all of its energy and capacity into the wholesale market. Based on the ESP 2 order, on June 4, 2014, the PUCO issued an entry on rehearing which required DP&L to separate its generation assets from its transmission and distribution assets no later than January 1, 2017. DPL’s other significant subsidiaries include AES Ohio Generation, which owns and operates peaking generating facilities from which it makes wholesale sales of electricity, and MVIC, our captive insurance company that provides insurance services to DPL and our subsidiaries. DPL owns all of the common stock of its subsidiaries. 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 while its generation business is deemed competitive under Ohio law. 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 1,169 people as of June 30, 2016 , of which 1,161 were employed by DP&L . Approximately 62% of all DPL employees are under a collective bargaining agreement that expires on October 31, 2017 .
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. DP&L has undivided ownership interests in five coal-fired generating facilities, various peaking generating facilities and numerous transmission facilities, all of which are included in the financial statements at amortized cost, which was adjusted to fair value at the date of the Merger for DPL . Operating revenues and expenses of these facilities 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. 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, 2015 . 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 June 30, 2016 ; our results of operations for the three and six months ended June 30, 2016 and 2015 and our cash flows for the six months ended June 30, 2016 and 2015 . Unless otherwise noted, all adjustments are normal and recurring in nature. Due to various factors, including, but not limited to, seasonal weather variations, the timing of outages of EGUs, changes in economic conditions involving commodity prices and competition, and other factors, interim results for the three and six months ended June 30, 2016 may not be indicative of our results that will be realized for the full year ending December 31, 2016 . 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: the carrying value of property, plant and equipment; unbilled revenues; the valuation of derivative instruments; the valuation of insurance and claims liabilities; the valuation of allowances for receivables 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. As a result of push down accounting, DPL’s Condensed Consolidated Statements of Operations subsequent to the Merger include depreciation of fixed assets based upon their fair value at the Merger date.
Accounting for Taxes Collected from Customers and Remitted to Governmental Authorities	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.
Recently Issued Accounting Standards	New Accounting Pronouncements The following table provides a brief description of recent accounting pronouncements that could have a material impact on our consolidated financial statements: Accounting Standard Description Date of Adoption Effect on the financial statements upon adoption New Accounting Standards Adopted ASU No. 2015-15, Interest - Imputation of Interest (Subtopic 835-30): Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements Given the absence of authoritative guidance within ASU 2015-03, this standard clarifies that the SEC Staff would not object to an entity presenting debt issuance costs related to line-of-credit arrangements as an asset that is subsequently amortized ratably over the term of the line-of-credit arrangement, regardless of whether there are any outstanding borrowings on the line-of-credit arrangement. Transition method: retrospective. January 1, 2016 Deferred financing costs related to lines-of-credit of approximately $3.1 million recorded within Other deferred assets were not reclassified. Accounting Standard Description Date of Adoption Effect on the financial statements upon adoption ASU No. 2015-03, Interest - Imputation of Interest (Subtopic 835-30) The standard simplifies the presentation of debt issuance costs by requiring that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by the standard. Transition method: retrospective. January 1, 2016 Deferred financing costs of approximately $2.1 million previously classified within Other prepayments and current assets and $14.0 million previously classified within Other deferred assets were reclassified to reduce the related debt liabilities. ASU No. 2015-02, Consolidation - Amendments to the Consolidation Analysis (Topic 810) The standard makes targeted amendments to the current consolidation guidance and ends the deferral granted to investment companies from applying the VIE guidance. The standard amends the evaluation of whether (1) fees paid to a decision-maker or service providers represent a variable interest, (2) a limited partnership or similar entity has the characteristics of a VIE and (3) a reporting entity is the primary beneficiary of a VIE. Transition method: retrospective. January 1, 2016 There were no changes to the consolidation conclusions. New Accounting Standards Issued But Not Yet Effective 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments This standard updates the impairment model for financial assets measured at amortized cost to an expected loss model rather than an incurred loss model. It also allows for the presentation of credit losses on available-for-sale debt securities as an allowance rather than a write down. Transition method: various. January 1, 2020 Early adoption is permitted only as of January 1, 2019. We are currently evaluating the impact of adopting the standard on our consolidated financial statements. 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting The standard simplifies the following aspects of accounting for share-based payment awards: accounting for income taxes, classification of excess tax benefits on the statement of cash flows, forfeitures, statutory tax withholding requirements, classification of awards as either equity or liabilities and classification of employee taxes paid on statement of cash flows when an employer withholds shares for tax-withholding purposes. Transition method: Various. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our consolidated financial statements. ASU No. 2016-06, Derivatives and Hedging (Topic 815) - Contingent Put and Call Options in Debt Instruments This standard clarifies the requirements for assessing whether contingent call (put) options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts. When a call (put) option is contingently exercisable, an entity no longer has to assess whether the event that triggers the ability to exercise a call (put) option is related to interest rates or credit risks. Transition method: a modified retrospective basis to existing debt instruments as of the effective date. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard, but do not anticipate a material impact on our consolidated financial statements. ASU No. 2016-05, Derivatives and Hedging (Topic 815) - Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships The standard clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815 does not require de-designation of that hedging relationship provided that all other hedge accounting criteria (including those in paragraphs 815-20-35-14 through 35-18) continue to be met. Transition method: prospective or a modified retrospective basis. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard, but do not anticipate a material impact on our consolidated financial statements. ASU No. 2016-02, Leases (Topic 842) The standard creates Topic 842, Leases which supersedes Topic 840, Leases, and introduces a lessee model that brings substantially all leases onto the balance sheet while retaining most of the principles of the existing lessor model in U.S. GAAP and aligning many of those principles with ASC 606, Revenue from Contracts with Customers. Transition method: modified retrospective approach with certain practical expedients. January 1, 2019. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our consolidated financial statements. Accounting Standard Description Date of Adoption Effect on the financial statements upon adoption ASU No. 2016-01, Financial Instruments - Overall (Topic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities The standard significantly revises an entity’s accounting related to (1) the classification and measurement of investments in equity securities and (2) the presentation of certain fair value changes for financial liabilities measured at fair value. Also, it amends certain disclosure requirements associated with the fair value of financial instruments. Transition: cumulative effect in Retained Earnings as of adoption or prospectively for equity investments without readily determinable fair value. January 1, 2018. Limited early adoption permitted. We are currently evaluating the impact of adopting the standard, but do not anticipate a material impact on our consolidated financial statements. ASU No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory The standard replaces the current lower of cost or market test with a lower of cost or net realizable value test. Transition method: prospectively. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our consolidated financial statements. ASU Nos. 2014-09, 2016-08, 2016-10, 2016-12 Revenue from Contracts with Customers (Topic 606) The Revenue from Contracts with Customers standard provides a single and comprehensive revenue recognition model for all contracts with customers to improve comparability. The revenue standard contains principles that an entity will apply to determine the measurement of revenue and timing revenue recognition. The standard requires an entity to recognize revenue to depict the transfer of goods or services to customers at an amount that the entity expects to be entitled to in exchange for those goods or services. The amendments to the standard provide further clarification on contract revenue recognition specifically related to the implementation of the principal versus agent evaluation, the identification of performance obligations, clarification on accounting for licenses of intellectual property, and allows for the election to account for shipping and handling activities performed after control of a good has been transferred to the customer as a fulfillment cost. Transition method: a full retrospective or modified retrospective approach. January 1, 2018 (deferred by ASU No. 2015-14). Earlier application is permitted only as of January 1, 2017. We are currently evaluating the impact of adopting the standard on our 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, distribution and transmission retail services are still regulated. DP&L has the exclusive right to provide such distribution and transmission services to approximately 517,000 customers located in West Central Ohio. Additionally, DP&L offers retail SSO electric service to residential, commercial, industrial and governmental customers in a 6,000 square mile area of West Central Ohio. DP&L owns multiple coal-fired and peaking electric generating facilities as well as numerous transmission facilities, all of which are included in the financial statements at amortized cost. Under the ESP 2 order, DP&L was required to source 100% of the generation for its SSO customers through a competitive bid process. Principal industries located in DP&L’s service territory include automotive, food processing, paper, plastic, manufacturing and defense. DP&L's distribution sales reflect the general economic conditions, seasonal weather patterns, retail competition in our service territory and the market price of electricity. DP&L sells all of its energy and capacity into the wholesale market. Based on the ESP 2 order, on June 4, 2014, the PUCO issued an entry on rehearing which required DP&L to separate its generation assets from its transmission and distribution assets no later than January 1, 2017. DP&L is a subsidiary of DPL . DP&L’s electric transmission and distribution businesses are subject to rate regulation by federal and state regulators while its generation business is deemed competitive under Ohio law. 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 1,161 people as of June 30, 2016 . Approximately 61% of all employees are under a collective bargaining agreement which expires on October 31, 2017 .
Financial Statement Presentation	Financial Statement Presentation DP&L does not have any subsidiaries. DP&L has undivided ownership interests in five coal-fired generating facilities, peaking electric generating facilities and numerous transmission facilities, all of which are included in the financial statements at amortized cost. Operating revenues and expenses of these facilities are included on a pro rata basis in the corresponding lines in the Condensed Statements of Operations. 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, 2015 . 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 June 30, 2016 ; our results of operations for the three and six months ended June 30, 2016 and 2015 and our cash flows for the six months ended June 30, 2016 and 2015 . Unless otherwise noted, all adjustments are normal and recurring in nature. Due to various factors, including, but not limited to, seasonal weather variations, the timing of outages of EGUs, changes in economic conditions involving commodity prices and competition, and other factors, interim results for the six months ended June 30, 2016 may not be indicative of our results that will be realized for the full year ending December 31, 2016 . 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: the carrying value of property, plant and equipment; unbilled revenues; the valuation of derivative instruments; the valuation of insurance and claims liabilities; the valuation of allowances for receivables 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	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.
Recently Issued Accounting Standards	New Accounting Pronouncements The following table provides a brief description of recent accounting pronouncements that could have a material impact on our financial statements: Accounting Standard Description Date of Adoption Effect on the financial statements upon adoption New Accounting Standards Adopted ASU No. 2015-15, Interest - Imputation of Interest (Subtopic 835-30): Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements Given the absence of authoritative guidance within ASU 2015-03, this standard clarifies that the SEC Staff would not object to an entity presenting debt issuance costs related to line-of-credit arrangements as an asset that is subsequently amortized ratably over the term of the line-of-credit arrangement, regardless of whether there are any outstanding borrowings on the line-of-credit arrangement. Transition method: retrospective. January 1, 2016 Deferred financing costs related to lines-of-credit of approximately $0.7 million recorded within Other deferred assets were not reclassified. ASU No. 2015-03, Interest - Imputation of Interest (Subtopic 835-30) The standard simplifies the presentation of debt issuance costs by requiring that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by the standard. Transition method: retrospective. January 1, 2016 Deferred financing costs of approximately $1.8 million previously classified within Other prepayments and current assets and $4.5 million previously classified within Other deferred assets were reclassified to reduce the related debt liabilities. ASU No. 2015-02, Consolidation - Amendments to the Consolidation Analysis (Topic 810) The standard makes targeted amendments to the current consolidation guidance and ends the deferral granted to investment companies from applying the VIE guidance. The standard amends the evaluation of whether (1) fees paid to a decision-maker or service providers represent a variable interest, (2) a limited partnership or similar entity has the characteristics of a VIE and (3) a reporting entity is the primary beneficiary of a VIE. Transition method: retrospective. January 1, 2016 There were no changes to the consolidation conclusions. New Accounting Standards Issued But Not Yet Effective 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments This standard updates the impairment model for financial assets measured at amortized cost to an expected loss model rather than an incurred loss model. It also allows for the presentation of credit losses on available-for-sale debt securities as an allowance rather than a write down. Transition method: various. January 1, 2020 Early adoption is permitted only as of January 1, 2019. We are currently evaluating the impact of adopting the standard on our financial statements. 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting The standard simplifies the following aspects of accounting for share-based payment awards: accounting for income taxes, classification of excess tax benefits on the statement of cash flows, forfeitures, statutory tax withholding requirements, classification of awards as either equity or liabilities and classification of employee taxes paid on statement of cash flows when an employer withholds shares for tax-withholding purposes. Transition method: Various. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our financial statements. Accounting Standard Description Date of Adoption Effect on the financial statements upon adoption ASU No. 2016-06, Derivatives and Hedging (Topic 815) - Contingent Put and Call Options in Debt Instruments This standard clarifies the requirements for assessing whether contingent call (put) options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts. When a call (put) option is contingently exercisable, an entity no longer has to assess whether the event that triggers the ability to exercise a call (put) option is related to interest rates or credit risks. Transition method: a modified retrospective basis to existing debt instruments as of the effective date. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard, but do not anticipate a material impact on our financial statements. ASU No. 2016-05, Derivatives and Hedging (Topic 815) - Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships The standard clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815 does not require de-designation of that hedging relationship provided that all other hedge accounting criteria (including those in paragraphs 815-20-35-14 through 35-18) continue to be met. Transition method: prospective or a modified retrospective basis. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard, but do not anticipate a material impact on our financial statements. ASU No. 2016-02, Leases (Topic 842) The standard creates Topic 842, Leases which supersedes Topic 840, Leases, and introduces a lessee model that brings substantially all leases onto the balance sheet while retaining most of the principles of the existing lessor model in U.S. GAAP and aligning many of those principles with ASC 606, Revenue from Contracts with Customers. Transition method: modified retrospective approach with certain practical expedients. January 1, 2019. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our financial statements. ASU No. 2016-01, Financial Instruments - Overall (Topic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities The standard significantly revises an entity’s accounting related to (1) the classification and measurement of investments in equity securities and (2) the presentation of certain fair value changes for financial liabilities measured at fair value. Also, it amends certain disclosure requirements associated with the fair value of financial instruments. Transition: cumulative effect in Retained Earnings as of adoption or prospectively for equity investments without readily determinable fair value. January 1, 2018. Limited early adoption permitted. We are currently evaluating the impact of adopting the standard, but do not anticipate a material impact on our financial statements. ASU No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory The standard replaces the current lower of cost or market test with a lower of cost or net realizable value test. Transition method: prospectively. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our financial statements. ASU Nos. 2014-09, 2016-08, 2016-10, 2016-12 Revenue from Contracts with Customers (Topic 606) The Revenue from Contracts with Customers standard provides a single and comprehensive revenue recognition model for all contracts with customers to improve comparability. The revenue standard contains principles that an entity will apply to determine the measurement of revenue and timing revenue recognition. The standard requires an entity to recognize revenue to depict the transfer of goods or services to customers at an amount that the entity expects to be entitled to in exchange for those goods or services. The amendments to the standard provide further clarification on contract revenue recognition specifically related to the implementation of the principal versus agent evaluation, the identification of performance obligations, clarification on accounting for licenses of intellectual property, and allows for the election to account for shipping and handling activities performed after control of a good has been transferred to the customer as a fulfillment cost. Transition method: a full retrospective or modified retrospective approach. January 1, 2018 (deferred by ASU No. 2015-14). Earlier application is permitted only as of January 1, 2017. We are currently evaluating the impact of adopting the standard on our financial statements.

Summary of Significant Accoun22

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2016
Related Party Transaction [Line Items]
Schedule of New Accounting Pronouncements	The following table provides a brief description of recent accounting pronouncements that could have a material impact on our consolidated financial statements: Accounting Standard Description Date of Adoption Effect on the financial statements upon adoption New Accounting Standards Adopted ASU No. 2015-15, Interest - Imputation of Interest (Subtopic 835-30): Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements Given the absence of authoritative guidance within ASU 2015-03, this standard clarifies that the SEC Staff would not object to an entity presenting debt issuance costs related to line-of-credit arrangements as an asset that is subsequently amortized ratably over the term of the line-of-credit arrangement, regardless of whether there are any outstanding borrowings on the line-of-credit arrangement. Transition method: retrospective. January 1, 2016 Deferred financing costs related to lines-of-credit of approximately $3.1 million recorded within Other deferred assets were not reclassified. Accounting Standard Description Date of Adoption Effect on the financial statements upon adoption ASU No. 2015-03, Interest - Imputation of Interest (Subtopic 835-30) The standard simplifies the presentation of debt issuance costs by requiring that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by the standard. Transition method: retrospective. January 1, 2016 Deferred financing costs of approximately $2.1 million previously classified within Other prepayments and current assets and $14.0 million previously classified within Other deferred assets were reclassified to reduce the related debt liabilities. ASU No. 2015-02, Consolidation - Amendments to the Consolidation Analysis (Topic 810) The standard makes targeted amendments to the current consolidation guidance and ends the deferral granted to investment companies from applying the VIE guidance. The standard amends the evaluation of whether (1) fees paid to a decision-maker or service providers represent a variable interest, (2) a limited partnership or similar entity has the characteristics of a VIE and (3) a reporting entity is the primary beneficiary of a VIE. Transition method: retrospective. January 1, 2016 There were no changes to the consolidation conclusions. New Accounting Standards Issued But Not Yet Effective 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments This standard updates the impairment model for financial assets measured at amortized cost to an expected loss model rather than an incurred loss model. It also allows for the presentation of credit losses on available-for-sale debt securities as an allowance rather than a write down. Transition method: various. January 1, 2020 Early adoption is permitted only as of January 1, 2019. We are currently evaluating the impact of adopting the standard on our consolidated financial statements. 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting The standard simplifies the following aspects of accounting for share-based payment awards: accounting for income taxes, classification of excess tax benefits on the statement of cash flows, forfeitures, statutory tax withholding requirements, classification of awards as either equity or liabilities and classification of employee taxes paid on statement of cash flows when an employer withholds shares for tax-withholding purposes. Transition method: Various. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our consolidated financial statements. ASU No. 2016-06, Derivatives and Hedging (Topic 815) - Contingent Put and Call Options in Debt Instruments This standard clarifies the requirements for assessing whether contingent call (put) options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts. When a call (put) option is contingently exercisable, an entity no longer has to assess whether the event that triggers the ability to exercise a call (put) option is related to interest rates or credit risks. Transition method: a modified retrospective basis to existing debt instruments as of the effective date. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard, but do not anticipate a material impact on our consolidated financial statements. ASU No. 2016-05, Derivatives and Hedging (Topic 815) - Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships The standard clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815 does not require de-designation of that hedging relationship provided that all other hedge accounting criteria (including those in paragraphs 815-20-35-14 through 35-18) continue to be met. Transition method: prospective or a modified retrospective basis. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard, but do not anticipate a material impact on our consolidated financial statements. ASU No. 2016-02, Leases (Topic 842) The standard creates Topic 842, Leases which supersedes Topic 840, Leases, and introduces a lessee model that brings substantially all leases onto the balance sheet while retaining most of the principles of the existing lessor model in U.S. GAAP and aligning many of those principles with ASC 606, Revenue from Contracts with Customers. Transition method: modified retrospective approach with certain practical expedients. January 1, 2019. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our consolidated financial statements. Accounting Standard Description Date of Adoption Effect on the financial statements upon adoption ASU No. 2016-01, Financial Instruments - Overall (Topic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities The standard significantly revises an entity’s accounting related to (1) the classification and measurement of investments in equity securities and (2) the presentation of certain fair value changes for financial liabilities measured at fair value. Also, it amends certain disclosure requirements associated with the fair value of financial instruments. Transition: cumulative effect in Retained Earnings as of adoption or prospectively for equity investments without readily determinable fair value. January 1, 2018. Limited early adoption permitted. We are currently evaluating the impact of adopting the standard, but do not anticipate a material impact on our consolidated financial statements. ASU No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory The standard replaces the current lower of cost or market test with a lower of cost or net realizable value test. Transition method: prospectively. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our consolidated financial statements. ASU Nos. 2014-09, 2016-08, 2016-10, 2016-12 Revenue from Contracts with Customers (Topic 606) The Revenue from Contracts with Customers standard provides a single and comprehensive revenue recognition model for all contracts with customers to improve comparability. The revenue standard contains principles that an entity will apply to determine the measurement of revenue and timing revenue recognition. The standard requires an entity to recognize revenue to depict the transfer of goods or services to customers at an amount that the entity expects to be entitled to in exchange for those goods or services. The amendments to the standard provide further clarification on contract revenue recognition specifically related to the implementation of the principal versus agent evaluation, the identification of performance obligations, clarification on accounting for licenses of intellectual property, and allows for the election to account for shipping and handling activities performed after control of a good has been transferred to the customer as a fulfillment cost. Transition method: a full retrospective or modified retrospective approach. January 1, 2018 (deferred by ASU No. 2015-14). Earlier application is permitted only as of January 1, 2017. We are currently evaluating the impact of adopting the standard on our consolidated financial statements.
THE DAYTON POWER AND LIGHT COMPANY [Member]
Related Party Transaction [Line Items]
Schedule of New Accounting Pronouncements	The following table provides a brief description of recent accounting pronouncements that could have a material impact on our financial statements: Accounting Standard Description Date of Adoption Effect on the financial statements upon adoption New Accounting Standards Adopted ASU No. 2015-15, Interest - Imputation of Interest (Subtopic 835-30): Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements Given the absence of authoritative guidance within ASU 2015-03, this standard clarifies that the SEC Staff would not object to an entity presenting debt issuance costs related to line-of-credit arrangements as an asset that is subsequently amortized ratably over the term of the line-of-credit arrangement, regardless of whether there are any outstanding borrowings on the line-of-credit arrangement. Transition method: retrospective. January 1, 2016 Deferred financing costs related to lines-of-credit of approximately $0.7 million recorded within Other deferred assets were not reclassified. ASU No. 2015-03, Interest - Imputation of Interest (Subtopic 835-30) The standard simplifies the presentation of debt issuance costs by requiring that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by the standard. Transition method: retrospective. January 1, 2016 Deferred financing costs of approximately $1.8 million previously classified within Other prepayments and current assets and $4.5 million previously classified within Other deferred assets were reclassified to reduce the related debt liabilities. ASU No. 2015-02, Consolidation - Amendments to the Consolidation Analysis (Topic 810) The standard makes targeted amendments to the current consolidation guidance and ends the deferral granted to investment companies from applying the VIE guidance. The standard amends the evaluation of whether (1) fees paid to a decision-maker or service providers represent a variable interest, (2) a limited partnership or similar entity has the characteristics of a VIE and (3) a reporting entity is the primary beneficiary of a VIE. Transition method: retrospective. January 1, 2016 There were no changes to the consolidation conclusions. New Accounting Standards Issued But Not Yet Effective 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments This standard updates the impairment model for financial assets measured at amortized cost to an expected loss model rather than an incurred loss model. It also allows for the presentation of credit losses on available-for-sale debt securities as an allowance rather than a write down. Transition method: various. January 1, 2020 Early adoption is permitted only as of January 1, 2019. We are currently evaluating the impact of adopting the standard on our financial statements. 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting The standard simplifies the following aspects of accounting for share-based payment awards: accounting for income taxes, classification of excess tax benefits on the statement of cash flows, forfeitures, statutory tax withholding requirements, classification of awards as either equity or liabilities and classification of employee taxes paid on statement of cash flows when an employer withholds shares for tax-withholding purposes. Transition method: Various. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our financial statements. Accounting Standard Description Date of Adoption Effect on the financial statements upon adoption ASU No. 2016-06, Derivatives and Hedging (Topic 815) - Contingent Put and Call Options in Debt Instruments This standard clarifies the requirements for assessing whether contingent call (put) options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts. When a call (put) option is contingently exercisable, an entity no longer has to assess whether the event that triggers the ability to exercise a call (put) option is related to interest rates or credit risks. Transition method: a modified retrospective basis to existing debt instruments as of the effective date. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard, but do not anticipate a material impact on our financial statements. ASU No. 2016-05, Derivatives and Hedging (Topic 815) - Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships The standard clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815 does not require de-designation of that hedging relationship provided that all other hedge accounting criteria (including those in paragraphs 815-20-35-14 through 35-18) continue to be met. Transition method: prospective or a modified retrospective basis. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard, but do not anticipate a material impact on our financial statements. ASU No. 2016-02, Leases (Topic 842) The standard creates Topic 842, Leases which supersedes Topic 840, Leases, and introduces a lessee model that brings substantially all leases onto the balance sheet while retaining most of the principles of the existing lessor model in U.S. GAAP and aligning many of those principles with ASC 606, Revenue from Contracts with Customers. Transition method: modified retrospective approach with certain practical expedients. January 1, 2019. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our financial statements. ASU No. 2016-01, Financial Instruments - Overall (Topic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities The standard significantly revises an entity’s accounting related to (1) the classification and measurement of investments in equity securities and (2) the presentation of certain fair value changes for financial liabilities measured at fair value. Also, it amends certain disclosure requirements associated with the fair value of financial instruments. Transition: cumulative effect in Retained Earnings as of adoption or prospectively for equity investments without readily determinable fair value. January 1, 2018. Limited early adoption permitted. We are currently evaluating the impact of adopting the standard, but do not anticipate a material impact on our financial statements. ASU No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory The standard replaces the current lower of cost or market test with a lower of cost or net realizable value test. Transition method: prospectively. January 1, 2017. Early adoption is permitted. We are currently evaluating the impact of adopting the standard on our financial statements. ASU Nos. 2014-09, 2016-08, 2016-10, 2016-12 Revenue from Contracts with Customers (Topic 606) The Revenue from Contracts with Customers standard provides a single and comprehensive revenue recognition model for all contracts with customers to improve comparability. The revenue standard contains principles that an entity will apply to determine the measurement of revenue and timing revenue recognition. The standard requires an entity to recognize revenue to depict the transfer of goods or services to customers at an amount that the entity expects to be entitled to in exchange for those goods or services. The amendments to the standard provide further clarification on contract revenue recognition specifically related to the implementation of the principal versus agent evaluation, the identification of performance obligations, clarification on accounting for licenses of intellectual property, and allows for the election to account for shipping and handling activities performed after control of a good has been transferred to the customer as a fulfillment cost. Transition method: a full retrospective or modified retrospective approach. January 1, 2018 (deferred by ASU No. 2015-14). Earlier application is permitted only as of January 1, 2017. We are currently evaluating the impact of adopting the standard on our financial statements.

Supplemental Financial Inform23

Supplemental Financial Information (Tables)	6 Months Ended
	Jun. 30, 2016
Supplemental Financial Information [Line Items]
Schedule of Supplemental Financial Information	Accounts receivable and Inventories are as follows at June 30, 2016 and December 31, 2015 : June 30, December 31, $ in millions 2016 2015 Accounts receivable, net: Unbilled revenue $ 38.9 $ 43.3 Customer receivables 54.1 56.4 Amounts due from partners in jointly owned plants 10.9 16.0 Other 4.9 6.0 Provision for uncollectible accounts (1.0 ) (0.8 ) Total accounts receivable, net $ 107.8 $ 120.9 Inventories, at average cost: Fuel and limestone $ 49.9 $ 72.2 Plant materials and supplies 35.7 34.9 Other 1.9 2.0 Total inventories, at average cost $ 87.5 $ 109.1
Reclassification out of Accumulated Other Comprehensive Income	The amounts reclassified out of Accumulated Other Comprehensive Income / (Loss) by component during the three and six months ended June 30, 2016 and 2015 are as follows: Details about Accumulated Other Comprehensive Income / (Loss) components Affected line item in the Condensed Consolidated Statements of Operations Three months ended Six months ended June 30, June 30, $ in millions 2016 2015 2016 2015 Gains and losses on Available-for-sale securities activity (Note 3): Other income $ 0.1 $ 0.6 $ — $ — Tax benefit — (0.2 ) — — Net of income taxes 0.1 0.4 — — Gains and losses on cash flow hedges (Note 4): Interest expense (0.3 ) (0.3 ) (0.5 ) (0.5 ) Revenue (20.1 ) (2.9 ) (37.3 ) (3.2 ) Purchased power 3.7 0.4 8.1 1.8 Total before income taxes (16.7 ) (2.8 ) (29.7 ) (1.9 ) Tax expense 5.9 0.9 10.7 0.5 Net of income taxes (10.8 ) (1.9 ) (19.0 ) (1.4 ) Amortization of defined benefit pension items (Note 7): Operation and maintenance 0.1 0.1 0.2 0.2 Tax benefit — (0.5 ) (0.2 ) (0.4 ) Net of income taxes 0.1 (0.4 ) — (0.2 ) Total reclassifications for the period, net of income taxes $ (10.6 ) $ (1.9 ) $ (19.0 ) $ (1.6 )
Schedule of Accumulated Other Comprehensive Income (Loss)	The changes in the components of Accumulated Other Comprehensive Income / (Loss) during the six months ended June 30, 2016 are as follows: $ in millions Gains / (losses) on available-for-sale securities Gains / (losses) on cash flow hedges Change in unfunded pension obligation Total Balance January 1, 2016 $ 0.4 $ 26.7 $ (9.7 ) $ 17.4 Other comprehensive income before reclassifications 0.1 13.0 — 13.1 Amounts reclassified from accumulated other comprehensive income / (loss) — (19.0 ) — (19.0 ) Net current period other comprehensive income / (loss) 0.1 (6.0 ) — (5.9 ) Balance June 30, 2016 $ 0.5 $ 20.7 $ (9.7 ) $ 11.5
THE DAYTON POWER AND LIGHT COMPANY [Member]
Supplemental Financial Information [Line Items]
Schedule of Supplemental Financial Information	Accounts receivable and Inventories are as follows at June 30, 2016 and December 31, 2015 : June 30, December 31, $ in millions 2016 2015 Accounts receivable, net: Unbilled revenue $ 38.9 $ 43.3 Customer receivables 50.8 54.1 Amounts due from partners in jointly owned plants 10.9 16.0 Other 6.0 6.9 Provision for uncollectible accounts (1.0 ) (0.8 ) Total accounts receivable, net $ 105.6 $ 119.5 Inventories, at average cost: Fuel and limestone $ 50.0 $ 72.2 Plant materials and supplies 34.4 33.7 Other 2.0 2.1 Total inventories, at average cost $ 86.4 $ 108.0
Reclassification out of Accumulated Other Comprehensive Income	The amounts reclassified out of Accumulated Other Comprehensive Income / (Loss) by component during the three and six months ended June 30, 2016 and 2015 are as follows: Details about Accumulated Other Comprehensive Income / (Loss) components Affected line item in the Condensed Statements of Operations Three months ended Six months ended June 30, June 30, $ in millions 2016 2015 2016 2015 Gains and losses on Available-for-sale securities activity (Note 3): Other income $ 0.1 $ 0.6 $ — $ — Tax benefit — (0.2 ) — — Net of income taxes 0.1 0.4 — — Gains and losses on cash flow hedges (Note 4): Interest expense (0.3 ) (0.3 ) (0.6 ) (0.6 ) Revenue (20.1 ) (2.9 ) (37.2 ) (3.2 ) Purchased power 3.7 0.4 8.1 1.8 Total before income taxes (16.7 ) (2.8 ) (29.7 ) (2.0 ) Tax expense 5.9 1.0 10.5 0.7 Net of income taxes (10.8 ) (1.8 ) (19.2 ) (1.3 ) Amortization of defined benefit pension items (Note 7): Operation and maintenance 1.1 1.4 2.2 2.8 Tax benefit (0.4 ) (0.5 ) (1.2 ) (1.0 ) Net of income taxes 0.7 0.9 1.0 1.8 Total reclassifications for the period, net of income taxes $ (10.0 ) $ (0.5 ) $ (18.2 ) $ 0.5
Schedule of Accumulated Other Comprehensive Income (Loss)	The changes in the components of Accumulated Other Comprehensive Income / (Loss) during the six months ended June 30, 2016 are as follows: $ in millions Gains / (losses) on available-for-sale securities Gains / (losses) on cash flow hedges Change in unfunded pension obligation Total Balance January 1, 2016 $ 0.5 $ 11.2 $ (40.4 ) $ (28.7 ) Other comprehensive income before reclassifications 0.1 13.0 — 13.1 Amounts reclassified from accumulated other comprehensive income / (loss) — (19.2 ) 1.0 (18.2 ) Net current period other comprehensive income / (loss) 0.1 (6.2 ) 1.0 (5.1 ) Balance June 30, 2016 $ 0.6 $ 5.0 $ (39.4 ) $ (33.8 )

Fair Value (Tables)

Fair Value (Tables)	6 Months Ended
	Jun. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value and Cost Of Non-Derivative Instruments	The following table presents the fair value, carrying value and cost of our non-derivative instruments at June 30, 2016 and December 31, 2015 . Information about the fair value of our derivative instruments can be found in Note 4 – Derivative Instruments and Hedging Activities . June 30, 2016 December 31, 2015 $ in millions Cost Fair Value Cost Fair Value Assets Money market funds $ 0.3 $ 0.3 $ 0.2 $ 0.2 Equity securities 2.7 3.5 3.0 3.8 Debt securities 4.2 4.2 4.4 4.3 Hedge funds 0.2 0.2 0.4 0.4 Real estate 0.3 0.4 0.3 0.3 Total Assets $ 7.7 $ 8.6 $ 8.3 $ 9.0 Carrying Value Fair Value Carrying Value Fair Value Liabilities Debt $ 1,923.3 $ 1,912.4 $ 1,993.3 $ 1,975.3
Fair Value of Assets and Liabilities Measured on Recurring Basis	The fair value of assets and liabilities at June 30, 2016 and December 31, 2015 and the respective category within the fair value hierarchy for DPL was determined as follows: Assets and Liabilities at Fair Value Level 1 Level 2 Level 3 $ in millions Fair value at June 30, 2016 Based on Quoted Prices in Active Markets Other Observable Inputs Unobservable Inputs Assets Master Trust assets Money market funds $ 0.3 $ 0.3 $ — $ — Equity securities 3.5 — 3.5 — Debt securities 4.2 — 4.2 — Hedge funds 0.2 — 0.2 — Real estate 0.4 — 0.4 — Total Master Trust assets 8.6 0.3 8.3 — Derivative Assets FTRs 0.1 — — 0.1 Natural gas futures 0.3 0.3 — — Forward power contracts 39.3 — 38.6 0.7 Total Derivative assets 39.7 0.3 38.6 0.8 Total Assets $ 48.3 $ 0.6 $ 46.9 $ 0.8 Liabilities Derivative Liabilities Forward power contracts 45.2 — 38.9 6.3 Total Derivative liabilities 45.2 — 38.9 6.3 Debt 1,912.4 — 1,894.4 18.0 Total Liabilities $ 1,957.6 $ — $ 1,933.3 $ 24.3 Assets and Liabilities at Fair Value Level 1 Level 2 Level 3 $ in millions Fair value at December 31, 2015 Based on Quoted Prices in Active Markets Other Observable Inputs Unobservable Inputs Assets Master Trust assets Money market funds $ 0.2 $ 0.2 $ — $ — Equity securities 3.8 — 3.8 — Debt securities 4.3 — 4.3 — Hedge funds 0.4 — 0.4 — Real estate 0.3 — 0.3 — Total Master Trust assets 9.0 0.2 8.8 — Derivative assets Forward power contracts 30.5 — 30.5 — FTRs 0.2 — — 0.2 Total Derivative assets 30.7 — 30.5 0.2 Total Assets $ 39.7 $ 0.2 $ 39.3 $ 0.2 Liabilities Derivative liabilities FTRs $ 0.5 $ — $ — 0.5 Forward power contracts 27.0 — 23.9 3.1 Total Derivative liabilities 27.5 — 23.9 3.6 Debt 1,975.3 — 1,957.2 18.1 Total Liabilities $ 2,002.8 $ — $ 1,981.1 $ 21.7
Fair Value Measurements, Nonrecurring [Table Text Block]	When evaluating impairment of long-lived assets, we measure fair value using the applicable fair value measurement guidance. Impairment expense is measured by comparing the fair value at the evaluation date to the carrying amount. The following table summarizes Long-lived assets measured at fair value on a non-recurring basis during the period and their level within the fair value hierarchy (there were no impairments during the six months ended June 30, 2015 ): $ in millions Six months ended June 30, 2016 Carrying Fair Value Gross Amount (b) Level 1 Level 2 Level 3 Loss Assets Long-lived assets (a) DP&L (Killen) $ 315.1 $ — $ — $ 84.3 $ 230.8 DP&L (peaking facilities) $ 9.9 $ — $ — $ 5.2 $ 4.7 (a) See Note 12 – Fixed-asset Impairment for further information (b) Carrying amount at date of valuation
Fair Value Inputs, Assets, Quantitative Information [Table Text Block]	The following summarizes the significant unobservable inputs used in the Level 3 measurement on a non-recurring basis during the six months ended June 30, 2016 : $ in millions Fair value Valuation technique Unobservable input Range (weighted average) Long-lived assets held and used: DP&L (Killen) $ 84.3 Discounted cash flow Annual revenue growth -11% to 13% (2%) Annual pre-tax operating margin -50% to 67% (6%) Weighted-average cost of capital 11% DP&L (peaking facilities) $ 5.2 Discounted cash flow Annual revenue growth -22% to 17% (-3%) Annual pre-tax operating margin -29% to 24% (-4%) Weighted-average cost of capital 7%
THE DAYTON POWER AND LIGHT COMPANY [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value and Cost Of Non-Derivative Instruments	The following table presents the fair value, carrying value and cost of our non-derivative instruments at June 30, 2016 and December 31, 2015 . Information about the fair value of our derivative instruments can be found in Note 4 – Derivative Instruments and Hedging Activities . June 30, 2016 December 31, 2015 $ in millions Cost Fair Value Cost Fair Value Assets Money market funds $ 0.3 $ 0.3 $ 0.2 $ 0.2 Equity securities 2.7 3.5 3.0 3.8 Debt securities 4.2 4.2 4.4 4.3 Hedge funds 0.2 0.2 0.4 0.4 Real estate 0.3 0.4 0.3 0.3 Total assets $ 7.7 $ 8.6 $ 8.3 $ 9.0 Carrying Value Fair Value Carrying Value Fair Value Liabilities Debt $ 758.4 $ 764.3 $ 756.7 $ 764.2
Fair Value of Assets and Liabilities Measured on Recurring Basis	The fair value of assets and liabilities at June 30, 2016 and December 31, 2015 and the respective category within the fair value hierarchy for DP&L was determined as follows: Assets and Liabilities at Fair Value Level 1 Level 2 Level 3 $ in millions Fair value at June 30, 2016 Based on Quoted Prices in Active Markets Other Observable Inputs Unobservable Inputs Assets Master Trust assets Money market funds $ 0.3 $ 0.3 $ — $ — Equity securities 3.5 — 3.5 — Debt securities 4.2 — 4.2 — Hedge funds 0.2 — 0.2 — Real estate 0.4 — 0.4 — Total Master Trust assets 8.6 0.3 8.3 — Derivative assets FTRs 0.1 — — 0.1 Natural gas futures 0.3 0.3 — — Forward power contracts 39.4 — 38.7 0.7 Total derivative assets 39.8 0.3 38.7 0.8 Total assets $ 48.4 $ 0.6 $ 47.0 $ 0.8 Liabilities Derivative liabilities Forward power contracts $ 45.3 $ — $ 39.0 $ 6.3 Total derivative liabilities 45.3 — 39.0 6.3 Debt 764.3 — 746.3 18.0 Total liabilities $ 809.6 $ — $ 785.3 $ 24.3 Assets and Liabilities at Fair Value Level 1 Level 2 Level 3 $ in millions Fair value at December 31, 2015 Based on Quoted Prices in Active Markets Other Observable Inputs Unobservable Inputs Assets Master Trust assets Money market funds $ 0.2 $ 0.2 $ — $ — Equity securities 3.8 — 3.8 — Debt securities 4.3 — 4.3 — Hedge funds 0.4 — 0.4 — Real estate 0.3 — 0.3 — Total Master Trust assets 9.0 0.2 8.8 — Derivative assets FTRs 0.2 — — 0.2 Forward power contracts 30.6 — 30.6 — Total Derivative assets 30.8 — 30.6 0.2 Total assets $ 39.8 $ 0.2 $ 39.4 $ 0.2 Liabilities Derivative liabilities FTRs $ 0.5 $ — $ — $ 0.5 Forward power contracts 27.0 — 23.9 3.1 Total Derivative liabilities 27.5 — 23.9 3.6 Debt 764.2 — 746.1 18.1 Total liabilities $ 791.7 $ — $ 770.0 $ 21.7
Fair Value Measurements, Nonrecurring [Table Text Block]	When evaluating impairment of long-lived assets, we measure fair value using the applicable fair value measurement guidance. Impairment expense is measured by comparing the fair value at the evaluation date to the carrying amount. The following table summarizes Long-lived assets measured at fair value on a non-recurring basis during the period and their level within the fair value hierarchy (there were no impairments during the six months ended June 30, 2015 ): $ in millions Six months ended June 30, 2016 Carrying Fair Value Gross Amount (b) Level 1 Level 2 Level 3 Loss Assets Long-lived assets (a) DP&L (Stuart) $ 456.4 $ — $ — $ 164.4 $ 292.0 DP&L (Killen) $ 330.5 $ — $ — $ 84.3 $ 246.2 DP&L (Zimmer) $ 429.9 $ — $ — $ 111.0 $ 318.9 (a) See Note 11 – Fixed-asset Impairment for further information (b) Carrying amount at date of valuation
Fair Value Inputs, Assets, Quantitative Information [Table Text Block]	The following summarizes the significant unobservable inputs used in the Level 3 measurement on a non-recurring basis during the six months ended June 30, 2016 : $ in millions Fair value Valuation technique Unobservable input Range (weighted average) Long-lived assets held and used: DP&L (Stuart) $ 164.4 Discounted cash flow Annual revenue growth -9% to 10% (2%) Annual pre-tax operating margin -29% to 52% (5%) Weighted-average cost of capital 9% DP&L (Killen) $ 84.3 Discounted cash flow Annual revenue growth -11% to 13% (2%) Annual pre-tax operating margin -50% to 67% (6%) Weighted-average cost of capital 11% DP&L (Zimmer) $ 111.0 Discounted cash flow Annual revenue growth -14% to 13% (1%) Annual pre-tax operating margin -46% to 80% (4%) Weighted-average cost of capital 9%

Derivative Instruments and He25

Derivative Instruments and Hedging Activities (Tables)	6 Months Ended
	Jun. 30, 2016
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Schedule of Notional Amounts of Outstanding Derivative Positions	At June 30, 2016 , DPL had the following outstanding derivative instruments: Commodity Accounting Treatment Unit Purchases (in thousands) Sales (in thousands) Net Purchases/ (Sales) (in thousands) FTRs Not designated MWh 2.5 — 2.5 Natural Gas Futures Not designated Dths 1,442.5 — 1,442.5 Forward power contracts Designated MWh 692.6 (13,380.2 ) (12,687.6 ) Forward power contracts Not designated MWh 4,018.0 (3,537.9 ) 480.1 At December 31, 2015 , DPL had the following outstanding derivative instruments: Commodity Accounting Treatment Unit Purchases (in thousands) Sales (in thousands) Net Purchases/ (Sales) (in thousands) FTRs Not designated MWh 10.2 — 10.2 Forward power contracts Designated MWh 1,676.7 (7,795.8 ) (6,119.1 ) Forward power contracts Not designated MWh 5,049.9 (1,663.0 ) 3,386.9
Gains or Losses Recognized in AOCI for the Cash Flow Hedges	The following table provides information for DPL concerning gains or losses recognized in AOCI for the cash flow hedges for the three and six months ended June 30, 2016 and 2015 : Three months ended Three months ended June 30, 2016 June 30, 2015 Interest Interest $ in millions (net of tax) Power Rate Hedge Power Rate Hedge Beginning accumulated derivative gains in AOCI $ 22.5 $ 17.5 $ 1.0 $ 18.2 Net gains / (losses) associated with current period hedging transactions (8.5 ) — 1.7 — Net gains / (losses) reclassified to earnings Interest expense — (0.2 ) — (0.4 ) Revenues (13.0 ) — (1.9 ) — Purchased power 2.4 — 0.3 — Ending accumulated derivative gains in AOCI $ 3.4 $ 17.3 $ 1.1 $ 17.8 Six months ended Six months ended June 30, 2016 June 30, 2015 Interest Interest $ in millions (net of tax) Power Rate Hedge Power Rate Hedge Beginning accumulated derivative gains in AOCI $ 9.2 $ 17.5 $ 0.2 $ 18.3 Net gains associated with current period hedging transactions 13.0 — 1.8 — Net gains / (losses) reclassified to earnings Interest expense — (0.2 ) — (0.5 ) Revenues (24.0 ) — (2.1 ) — Purchased power 5.2 — 1.2 — Ending accumulated derivative gains in AOCI $ 3.4 $ 17.3 $ 1.1 $ 17.8 Portion expected to be reclassified to earnings in the next twelve months (a) $ (3.1 ) $ (0.6 ) Maximum length of time that we are hedging our exposure to variability in future cash flows related to forecasted transactions (in months) 18 0 (a) The actual amounts that we reclassify from AOCI to earnings related to power can differ from the estimate above due to market price changes.
Schedule of Other Derivatives Not Designated as Hedging Instruments, Statements of Financial Performance and Financial Position, Location	The following tables present the amount and classification within the Condensed Consolidated Statements of Operations or Condensed Consolidated Balance Sheets of the gains and losses on DPL’s derivatives not designated as hedging instruments for the three and six months ended June 30, 2016 and 2015 : For the three months ended June 30, 2016 $ in millions FTRs Power Natural Gas Total Change in unrealized gain $ 0.2 $ 2.6 $ 0.5 $ 3.3 Realized gain / (loss) 0.2 (2.4 ) 0.7 (1.5 ) Total $ 0.4 $ 0.2 $ 1.2 $ 1.8 Recorded in Income Statement: gain / (loss) Revenues $ — $ (5.3 ) $ — $ (5.3 ) Purchased power 0.4 5.5 1.2 7.1 Total $ 0.4 $ 0.2 $ 1.2 $ 1.8 For the three months ended June 30, 2015 $ in millions Heating Oil FTRs Power Total Change in unrealized gain / (loss) $ 0.1 $ (0.8 ) $ 1.2 $ 0.5 Realized loss (0.1 ) — (1.5 ) (1.6 ) Total $ — $ (0.8 ) $ (0.3 ) $ (1.1 ) Recorded in Income Statement: gain / (loss) Revenues $ — $ (0.8 ) $ (2.8 ) $ (3.6 ) Purchased power — — 2.5 2.5 Total $ — $ (0.8 ) $ (0.3 ) $ (1.1 ) For the six months ended June 30, 2016 $ in millions FTRs Power Natural Gas Total Change in unrealized gain $ 0.4 $ 1.2 $ 0.3 $ 1.9 Realized gain / (loss) 0.4 (2.9 ) 0.5 (2.0 ) Total $ 0.8 $ (1.7 ) $ 0.8 $ (0.1 ) Recorded in Income Statement: gain / (loss) Revenues $ — $ (6.6 ) $ — $ (6.6 ) Purchased power 0.8 4.9 0.8 6.5 Total $ 0.8 $ (1.7 ) $ 0.8 $ (0.1 ) For the six months ended June 30, 2015 $ in millions Heating Oil FTRs Power Natural Gas Total Change in unrealized gain / (loss) $ 0.2 $ 0.1 $ (1.7 ) $ 0.1 $ (1.3 ) Realized loss (0.1 ) (0.1 ) (3.8 ) (0.1 ) (4.1 ) Total $ 0.1 $ — $ (5.5 ) $ — $ (5.4 ) Recorded on Balance Sheet: gain Regulatory asset $ 0.1 $ — $ — $ — $ 0.1 Recorded in Income Statement: gain / (loss) Revenue — — (7.7 ) — (7.7 ) Purchased power — — 2.2 — 2.2 Total $ 0.1 $ — $ (5.5 ) $ — $ (5.4 )
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	The following tables summarize the derivative positions presented in the balance sheet where a right of offset exists under these arrangements and related cash collateral received or pledged. The following table presents the fair value and balance sheet classification of DPL’s derivative instruments at June 30, 2016 : Fair Values of Derivative Instruments at June 30, 2016 Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets $ in millions Hedging Designation Gross Fair Value as presented in the Condensed Consolidated Balance Sheets Financial Instruments with Same Counterparty in Offsetting Position Cash Collateral Net Balance Fair Value Assets Short-term derivative positions (presented in Other prepayments and current assets) Forward power contracts Designated $ 13.9 $ (11.3 ) $ — $ 2.6 Forward power contracts Not designated 13.8 (12.1 ) — 1.7 Natural gas futures Not designated 0.3 — — 0.3 FTRs Not designated 0.1 — — 0.1 Long-term derivative positions (presented in Other deferred assets) Forward power contracts Designated 9.1 (4.8 ) — 4.3 Forward power contracts Not designated 2.5 (1.4 ) — 1.1 Total assets $ 39.7 $ (29.6 ) $ — $ 10.1 Liabilities Short-term derivative positions (presented in Other current liabilities) Forward power contracts Designated $ 19.4 $ (11.3 ) $ (8.0 ) $ 0.1 Forward power contracts Not designated 19.5 (12.1 ) (3.1 ) 4.3 Long-term derivative positions (presented in Other deferred credits) Forward power contracts Designated 4.9 (4.8 ) — 0.1 Forward power contracts Not designated 1.4 (1.4 ) — — Total liabilities $ 45.2 $ (29.6 ) $ (11.1 ) $ 4.5 The following table presents the fair value and balance sheet classification of DPL’s derivative instruments at December 31, 2015 : Fair Values of Derivative Instruments at December 31, 2015 Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets $ in millions Hedging Designation Gross Fair Value as presented in the Condensed Consolidated Balance Sheets Financial Instruments with Same Counterparty in Offsetting Position Cash Collateral Net Balance Fair Value Assets Short-term derivative positions (presented in Other prepayments and current assets) Forward power contracts Designated $ 16.2 $ (7.1 ) $ — $ 9.1 Forward power contracts Not designated 7.3 (5.5 ) — 1.8 FTRs Not designated 0.2 (0.2 ) — — Long-term derivative positions (presented in Other deferred assets) Forward power contracts Designated 3.0 (2.4 ) — 0.6 Forward power contracts Not designated 4.0 (2.7 ) — 1.3 Total assets $ 30.7 $ (17.9 ) $ — $ 12.8 Liabilities Short-term derivative positions (presented in Other current liabilities) Forward power contracts Designated $ 7.1 $ (7.1 ) $ — $ — Forward power contracts Not designated 14.5 (5.5 ) (8.0 ) 1.0 FTRs Not designated 0.5 (0.2 ) — 0.3 Long-term derivative positions (presented in Other deferred credits) Forward power contracts Designated 2.7 (2.4 ) — 0.3 Forward power contracts Not designated 2.7 (2.7 ) — — Total liabilities $ 27.5 $ (17.9 ) $ (8.0 ) $ 1.6
THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Schedule of Notional Amounts of Outstanding Derivative Positions	At June 30, 2016 , DP&L had the following outstanding derivative instruments: Commodity Accounting Treatment Unit Purchases (in thousands) Sales (in thousands) Net Purchases/ (Sales) (in thousands) FTRs Not designated MWh 2.5 — 2.5 Natural gas futures Not designated Dths 1,442.5 — 1,442.5 Forward power contracts Designated MWh 692.6 (13,380.2 ) (12,687.6 ) Forward power contracts Not designated MWh 4,018.0 (3,574.8 ) 443.2 At December 31, 2015 , DP&L had the following outstanding derivative instruments: Commodity Accounting Treatment Unit Purchases (in thousands) Sales (in thousands) Net Purchases/ (Sales) (in thousands) FTRs Not designated MWh 10.2 — 10.2 Forward power contracts Designated MWh 1,676.7 (7,795.8 ) (6,119.1 ) Forward power contracts Not designated MWh 5,049.9 (1,665.7 ) 3,384.2
Gains or Losses Recognized in AOCI for the Cash Flow Hedges	The following table provides information for DP&L concerning gains or losses recognized in AOCI for the cash flow hedges for the three and six months ended June 30, 2016 and 2015 : Three months ended Three months ended June 30, 2016 June 30, 2015 Interest Interest $ in millions (net of tax) Power Rate Hedge Power Rate Hedge Beginning accumulated derivative gains in AOCI $ 22.5 $ 1.8 $ 1.0 $ 2.4 Net gains / (losses) associated with current period hedging transactions (8.5 ) — 1.7 — Net gains / (losses) reclassified to earnings Interest expense — (0.2 ) — (0.2 ) Revenues (13.0 ) — (1.9 ) — Purchased power 2.4 — 0.3 — Ending accumulated derivative gains in AOCI $ 3.4 $ 1.6 $ 1.1 $ 2.2 Six months ended Six months ended June 30, 2016 June 30, 2015 Interest Interest $ in millions (net of tax) Power Rate Hedge Power Rate Hedge Beginning accumulated derivative gains in AOCI $ 9.2 $ 2.0 $ 0.2 $ 2.6 Net gains associated with current period hedging transactions 13.0 — 1.8 — Net gains / (losses) reclassified to earnings Interest expense — (0.4 ) — (0.4 ) Revenues (24.0 ) — (2.1 ) — Purchased power 5.2 — 1.2 — Ending accumulated derivative gains in AOCI $ 3.4 $ 1.6 $ 1.1 $ 2.2 Portion expected to be reclassified to earnings in the next twelve months (a) $ (3.1 ) $ 0.7 Maximum length of time that we are hedging our exposure to variability in future cash flows related to forecasted transactions (in months) 18 0 (a) The actual amounts that we reclassify from AOCI to earnings related to power can differ from the estimate above due to market price changes.
Schedule of Other Derivatives Not Designated as Hedging Instruments, Statements of Financial Performance and Financial Position, Location	The following tables present the amount and classification within the Condensed Statements of Operations or Condensed Balance Sheets of the gains and losses on DPL’s derivatives not designated as hedging instruments for the three and six months ended June 30, 2016 and 2015 : For the three months ended June 30, 2016 $ in millions FTRs Power Natural Gas Total Change in unrealized gain $ 0.2 $ 2.8 $ 0.5 $ 3.5 Realized gain / (loss) 0.2 (2.3 ) 0.7 (1.4 ) Total $ 0.4 $ 0.5 $ 1.2 $ 2.1 Recorded in Income Statement: gain / (loss) Revenues $ — $ (5.1 ) $ — $ (5.1 ) Purchased power 0.4 5.6 1.2 7.2 Total $ 0.4 $ 0.5 $ 1.2 $ 2.1 For the three months ended June 30, 2015 $ in millions Heating Oil FTRs Power Total Change in unrealized gain / (loss) $ 0.1 $ (0.8 ) $ 1.1 $ 0.4 Realized loss (0.1 ) — (1.5 ) (1.6 ) Total $ — $ (0.8 ) $ (0.4 ) $ (1.2 ) Recorded in Income Statement: gain / (loss) Revenues $ — $ (0.8 ) $ (2.9 ) $ (3.7 ) Purchased power — — 2.5 2.5 Total $ — $ (0.8 ) $ (0.4 ) $ (1.2 ) For the six months ended June 30, 2016 $ in millions FTRs Power Natural Gas Total Change in unrealized gain $ 0.4 $ 0.9 $ 0.3 $ 1.6 Realized gain / (loss) 0.4 (2.7 ) 0.5 (1.8 ) Total $ 0.8 $ (1.8 ) $ 0.8 $ (0.2 ) Recorded in Income Statement: gain / (loss) Revenues $ — $ (6.6 ) $ — $ (6.6 ) Purchased power 0.8 4.8 0.8 6.4 Total $ 0.8 $ (1.8 ) $ 0.8 $ (0.2 ) For the six months ended June 30, 2015 $ in millions Heating Oil FTRs Power Natural Gas Total Change in unrealized gain / (loss) $ 0.2 $ 0.1 $ (1.8 ) 0.1 $ (1.4 ) Realized loss (0.1 ) (0.1 ) (3.8 ) (0.1 ) (4.1 ) Total $ 0.1 $ — $ (5.6 ) $ — $ (5.5 ) Recorded in Balance Sheet: Regulatory asset $ 0.1 $ — $ — $ — $ 0.1 Recorded in Income Statement: gain / (loss) Revenues — — 2.2 — 2.2 Purchased power — — (7.8 ) — (7.8 ) Total $ 0.1 $ — $ (5.6 ) $ — $ (5.5 )
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	DP&L’s derivative instruments at June 30, 2016 : Fair Values of Derivative Instruments at June 30, 2016 Gross Amounts Not Offset in the Condensed Balance Sheets $ in millions Hedging Designation Gross Fair Value as presented in the Condensed Balance Sheets Financial Instruments with Same Counterparty in Offsetting Position Cash Collateral Net Balance Fair Value Assets Short-term derivative positions (presented in Other prepayments and current assets) Forward power contracts Designated $ 13.9 $ (11.3 ) $ — $ 2.6 Forward power contracts Not designated 13.9 (12.1 ) — 1.8 Natural gas futures Not designated 0.3 — — 0.3 FTRs Not designated 0.1 — — 0.1 Long-term derivative positions (presented in Other deferred assets) Forward power contracts Designated 9.1 (4.8 ) — 4.3 Forward power contracts Not designated 2.5 (1.4 ) — 1.1 Total assets $ 39.8 $ (29.6 ) $ — $ 10.2 Liabilities Short-term derivative positions (presented in Other current liabilities) Forward power contracts Designated $ 19.4 $ (11.3 ) $ (8.0 ) $ 0.1 Forward power contracts Not designated 19.6 (12.1 ) (3.1 ) 4.4 Long-term derivative positions (presented in Other deferred credits) Forward power contracts Designated 4.9 (4.8 ) — 0.1 Forward power contracts Not designated 1.4 (1.4 ) — — Total liabilities $ 45.3 $ (29.6 ) $ (11.1 ) $ 4.6 The following table presents the fair value and balance sheet classification of DP&L’s derivative instruments at December 31, 2015 : Fair Values of Derivative Instruments at December 31, 2015 Gross Amounts Not Offset in the Condensed Balance Sheets $ in millions Hedging Designation Gross Fair Value as presented in the Condensed Balance Sheets Financial Instruments with Same Counterparty in Offsetting Position Cash Collateral Net Balance Fair Value Assets Short-term derivative positions (presented in Other prepayments and current assets) Forward power contracts Designated $ 16.2 $ (7.1 ) $ — $ 9.1 Forward power contracts Not designated 7.4 (5.5 ) — 1.9 FTRs Not designated 0.2 (0.2 ) — — Long-term derivative positions (presented in Other deferred assets) Forward power contracts Designated 3.0 (2.4 ) — 0.6 Forward power contracts Not designated 4.0 (2.7 ) — 1.3 Total assets $ 30.8 $ (17.9 ) $ — $ 12.9 Liabilities Short-term derivative positions (presented in Other current liabilities) Forward power contracts Designated $ 7.1 $ (7.1 ) $ — $ — Forward power contracts Not designated 14.5 (5.5 ) (8.0 ) 1.0 FTRs Not designated 0.5 (0.2 ) — 0.3 Long-term derivative positions (presented in Other deferred credits) Forward power contracts Designated 2.7 (2.4 ) — 0.3 Forward power contracts Not designated 2.7 (2.7 ) — — Total liabilities $ 27.5 $ (17.9 ) $ (8.0 ) $ 1.6

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2016
Debt Instrument [Line Items]
Long-term Debt	Interest June 30, December 31, $ in millions Rate Maturity 2016 2015 First mortgage bonds 1.875% 2016 $ 445.0 $ 445.0 Pollution control series 4.8% 2036 100.0 100.0 Pollution control series - rates from 1.29% - 1.31% and 1.13% - 1.17% (a) 2020 200.0 200.0 U.S. Government note 4.2% 2061 18.0 18.1 Unamortized deferred financing costs (3.4 ) (5.0 ) Unamortized debt discount and premiums, net (3.5 ) (3.6 ) Total long-term debt at subsidiary 756.1 754.5 Bank term loan - rates from 2.67% - 2.71% and 2.44% - 2.67% (a) 2020 125.0 125.0 Senior unsecured bonds 6.5% 2016 57.0 130.0 Senior unsecured bonds 6.75% 2019 200.0 200.0 Senior unsecured bonds 7.25% 2021 780.0 780.0 Note to DPL Capital Trust II (b) 8.125% 2031 15.6 15.6 Unamortized deferred financing costs (9.8 ) (11.1 ) Unamortized debt discounts and premiums, net (0.6 ) (0.7 ) Total long-term debt 1,923.3 1,993.3 Less: current portion (514.0 ) (572.8 ) Total long-term debt $ 1,409.3 $ 1,420.5
THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Long-term Debt	Interest June 30, December 31, $ in millions Rate Maturity 2016 2015 First mortgage bonds 1.875% 2016 $ 445.0 $ 445.0 Pollution control series 4.8% 2036 100.0 100.0 Pollution control series - rates from 1.29% - 1.31% and 1.13% - 1.17% (a) 2020 200.0 200.0 U.S. Government note 4.2% 2061 18.0 18.1 Unamortized deferred financing costs (4.5 ) (6.2 ) Unamortized debt discount (0.1 ) (0.2 ) Total long-term debt 758.4 756.7 Less: current portion (444.6 ) (443.1 ) Total $ 313.8 $ 313.6
Current Portion - Long-term Debt	(a) Range of interest rates for the six months ended June 30, 2016 and the twelve months ended December 31, 2015 , respectively.

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2016
Entity Information [Line Items]
Schedule of Effective Income Tax Rates	The following table details the effective tax rates for the three and six months ended June 30, 2016 and 2015 . Three months ended Six months ended June 30, June 30, 2016 2015 2016 2015 DPL 39.2% 28.2% 39.5% 28.8%
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 and six months ended June 30, 2016 and 2015 . Three months ended Six months ended June 30, June 30, 2016 2015 2016 2015 DP&L 36.4% 28.2% 36.9% 28.6%

Benefit Plans (Tables)

Benefit Plans (Tables)	6 Months Ended
	Jun. 30, 2016
Entity Information [Line Items]
Schedule of Net Periodic Benefit Cost / (Income)	The net periodic benefit cost of the pension and postretirement benefit plans for the three and six months ended June 30, 2016 and 2015 was: Net Periodic Benefit Cost Pension Three months ended Six months ended June 30, June 30, $ in millions 2016 2015 2016 2015 Service cost $ 1.4 $ 1.8 $ 2.8 $ 3.6 Interest cost 3.7 4.3 7.4 8.6 Expected return on plan assets (5.7 ) (5.6 ) (11.4 ) (11.3 ) Amortization of unrecognized: Prior service cost 0.5 0.5 1.0 1.0 Actuarial loss 1.1 1.4 2.1 2.9 Net periodic benefit cost $ 1.0 $ 2.4 $ 1.9 $ 4.8 Net Periodic Benefit Cost Postretirement Three months ended Six months ended June 30, June 30, $ in millions 2016 2015 2016 2015 Service cost $ 0.1 $ — $ 0.1 $ — Interest cost 0.1 0.1 0.2 0.3 Expected return on plan assets — — — — Amortization of unrecognized: Prior service cost — — — — Actuarial gain (0.2 ) (0.1 ) (0.3 ) (0.2 ) Net periodic benefit cost $ — $ — $ — $ 0.1
Estimated Future Benefit Payments and Medicare Part D Reimbursements	Benefit payments and Medicare Part D reimbursements, which reflect future service, are estimated to be paid as follows: $ in millions Pension Postretirement 2016 $ 12.3 $ 0.8 2017 25.2 1.6 2018 25.8 1.5 2019 26.3 1.4 2020 26.7 1.4 2021 - 2025 134.8 5.7
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 and postretirement benefit plans for the three and six months ended June 30, 2016 and 2015 was: Net Periodic Benefit Cost Pension Three months ended Six months ended June 30, June 30, $ in millions 2016 2015 2016 2015 Service cost $ 1.4 $ 1.7 $ 2.8 $ 3.5 Interest cost 3.7 4.3 7.4 8.6 Expected return on plan assets (5.7 ) (5.5 ) (11.4 ) (11.2 ) Amortization of unrecognized: Prior service cost 0.7 0.8 1.5 1.6 Actuarial loss 1.8 2.4 3.6 4.8 Net periodic benefit cost $ 1.9 $ 3.7 $ 3.9 $ 7.3 Net Periodic Benefit Cost Postretirement Three months ended Six months ended June 30, June 30, $ in millions 2016 2015 2016 2015 Service cost $ 0.1 $ — $ 0.1 $ — Interest cost 0.2 0.2 0.3 0.4 Expected return on plan assets — — — — Amortization of unrecognized: Prior service cost — — — — Actuarial gain (0.3 ) (0.1 ) (0.4 ) (0.3 ) Net periodic benefit cost $ — $ 0.1 $ — $ 0.1
Estimated Future Benefit Payments and Medicare Part D Reimbursements	Benefit payments and Medicare Part D reimbursements, which reflect future service, are estimated to be paid as follows: $ in millions Pension Postretirement 2016 $ 12.3 $ 0.8 2017 25.2 1.6 2018 25.8 1.5 2019 26.3 1.4 2020 26.7 1.4 2021 - 2025 134.8 5.7

Related Party Transactions (Tab

Related Party Transactions (Tables)	6 Months Ended
	Jun. 30, 2016
Related Party Transaction [Line Items]
Schedule of Related Party Transactions	The following table provides a summary of these transactions: Three months ended Six months ended June 30, June 30, $ in millions 2016 2015 2016 2015 Transactions with the Service Company Charges for services provided $ 11.5 $ 9.8 $ 23.1 $ 19.6 Charges to the Service Company $ 1.1 $ 2.8 $ 2.3 $ 3.9 Transactions with other AES affiliates: Charges / (credits) for health, welfare and benefit plans $ (2.4 ) $ 4.2 $ 1.7 $ 8.2 Transactions with the Service Company: At June 30, 2016 At December 31, 2015 Net payable to the Service Company $ (1.1 ) $ (0.5 )
THE DAYTON POWER AND LIGHT COMPANY [Member]
Related Party Transaction [Line Items]
Schedule of Related Party Transactions	The following table provides a summary of these transactions: Three months ended Six months ended June 30, June 30, $ in millions 2016 2015 2016 2015 DP&L revenues: Sales to DPLER (including MC Squared) (a) $ — $ 68.3 $ — $ 179.0 DP&L Operation & Maintenance Expenses: Premiums paid for insurance services provided by MVIC (b) $ (0.8 ) $ (0.8 ) $ (1.7 ) $ (1.6 ) Expense recoveries for services provided to DPLER (c) $ — $ 0.6 $ — $ 1.3 Transactions with the Service Company: Charges for services provided $ 10.9 $ 8.3 $ 19.8 $ 16.7 Charges to the Service Company $ 1.0 $ 2.8 $ 2.2 $ 3.9 Transactions with other AES affiliates: Charges / (credits) for health, welfare and benefit plans $ (2.4 ) $ 3.9 $ 1.7 $ 7.8 Balances with related parties: At June 30, 2016 At December 31, 2015 Net payable to the Service Company $ (1.1 ) $ (0.5 ) Short-term loan with DPL (d) $ — $ (35.0 ) (a) DP&L sold power to DPLER and MC Squared to satisfy the electric requirements of their retail customers. The revenue dollars associated with sales to DPLER and MC Squared are recorded as wholesale revenues in DP&L’s Financial Statements. These agreements were terminated upon the sale of DPLER on January 1, 2016. (b) MVIC, a wholly-owned captive insurance subsidiary of DPL , provides insurance coverage to DP&L and other DPL subsidiaries for workers’ compensation, general liability, property damages and directors’ and officers’ liability. These amounts represent insurance premiums paid by DP&L to MVIC. DP&L received insurance proceeds from MVIC of $0.0 million and $2.3 million for the three months ended June 30, 2016 and 2015 , respectively, and $0.2 million and $3.8 million for the six months ended June 30, 2016 and 2015 , respectively. (c) Prior to the sale of DPLER, in the normal course of business DP&L incurred and recorded expenses on behalf of DPLER. Such expenses included but were not limited to employee-related expenses, accounting, information technology, payroll, legal and other administration expenses. DP&L subsequently charged these expenses to DPLER at DP&L’s cost and credited the expense in which they were initially recorded.

Business Segments (Tables)

Business Segments (Tables)	6 Months Ended
	Jun. 30, 2016
Segment Reporting [Abstract]
Financial Reporting for Reportable Business Segments	The following tables present financial information for each of DPL’s reportable business segments: $ in millions Utility Segment Other Adjustments and Eliminations DPL Consolidated For the three months ended June 30, 2016 Revenues from external customers $ 313.4 $ 14.9 $ — $ 328.3 Intersegment revenues 0.3 0.9 (1.2 ) — Total revenues 313.7 15.8 (1.2 ) 328.3 Fuel 55.6 4.6 — 60.2 Purchased power 96.7 0.7 (0.5 ) 96.9 Gross margin $ 161.4 $ 10.5 $ (0.7 ) $ 171.2 Depreciation and amortization $ 36.8 $ (0.8 ) $ — $ 36.0 Fixed-asset impairment $ 857.1 $ (621.6 ) $ — $ 235.5 Interest expense $ 5.4 $ 20.3 $ 0.3 $ 26.0 Income tax expense / (benefit) $ (303.7 ) $ 215.4 $ — $ (88.3 ) Net income / (loss) $ (531.6 ) $ 394.8 $ — $ (136.8 ) Cash capital expenditures $ 36.0 $ 5.4 $ — $ 41.4 $ in millions Utility Segment Competitive Retail Other Adjustments and Eliminations DPL Consolidated For the three months ended June 30, 2015 Revenues from external customers $ 283.8 $ 75.2 $ 13.9 $ — $ 372.9 Intersegment revenues 68.3 — 1.3 (69.6 ) — Total revenues 352.1 75.2 15.2 (69.6 ) 372.9 Fuel 50.6 — 3.8 — 54.4 Purchased power 120.1 68.7 0.6 (68.8 ) 120.6 Gross margin $ 181.4 $ 6.5 $ 10.8 $ (0.8 ) $ 197.9 Depreciation and amortization $ 34.2 $ 0.1 $ — $ — $ 34.3 Interest expense $ 9.0 $ 0.1 $ 21.8 $ — $ 30.9 Income tax expense / (benefit) $ 9.4 $ (5.5 ) $ (3.4 ) $ — $ 0.5 Net income / (loss) $ 23.9 $ 6.7 $ (8.9 ) $ — $ 21.7 Cash capital expenditures $ 30.2 $ 0.1 $ 0.8 $ — $ 31.1 $ in millions Utility Segment Other Adjustments and Eliminations DPL Consolidated For the six months ended June 30, 2016 Revenues from external customers $ 662.3 $ 30.0 $ — $ 692.3 Intersegment revenues 0.6 2.2 (2.8 ) — Total revenues 662.9 32.2 (2.8 ) 692.3 Fuel 118.5 8.6 — 127.1 Purchased power 218.0 1.9 (1.1 ) 218.8 Gross margin $ 326.4 $ 21.7 $ (1.7 ) $ 346.4 Depreciation and amortization $ 71.1 $ (1.7 ) $ — $ 69.4 Fixed-asset impairment $ 857.1 $ (621.6 ) $ — $ 235.5 Interest expense $ 10.7 $ 41.3 $ 0.3 $ 52.3 Income tax expense / (benefit) $ (291.3 ) $ 203.6 $ — $ (87.7 ) Net income / (loss) from continuing operations $ (497.9 ) $ 363.3 $ — $ (134.6 ) Discontinued operations, net of tax $ — $ 29.6 $ — $ 29.6 Net income / (loss) $ (497.9 ) $ 392.9 $ — $ (105.0 ) Cash capital expenditures $ 71.8 $ 7.3 $ — $ 79.1 at June 30, 2016 Total assets $ 2,442.0 $ 1,267.7 $ (778.3 ) $ 2,931.4 $ in millions Utility Segment Competitive Retail Other Adjustments and Eliminations DPL Consolidated For the six months ended June 30, 2015 Revenues from external customers $ 634.4 $ 197.5 $ 35.5 $ — $ 867.4 Intersegment revenues 179.0 — 2.9 (181.9 ) — Total revenues 813.4 197.5 38.4 (181.9 ) 867.4 Fuel 119.9 — 10.9 — 130.8 Purchased power 309.8 180.4 4.8 (180.2 ) 314.8 Gross margin $ 383.7 $ 17.1 $ 22.7 $ (1.7 ) $ 421.8 Depreciation and amortization $ 68.9 $ 0.4 $ — $ — $ 69.3 Interest expense $ 17.7 $ 0.1 $ 43.7 $ (0.1 ) $ 61.4 Income tax expense / (benefit) $ 24.2 $ (4.2 ) $ (6.8 ) $ — $ 13.2 Net income / (loss) $ 60.4 $ 8.3 $ (18.3 ) $ — $ 50.4 Cash capital expenditures $ 63.3 $ 0.3 $ 1.2 $ — $ 64.8 at December 31, 2015 Total assets $ 3,359.6 $ — $ 1,304.5 $ (1,339.4 ) $ 3,324.7

Discontinued Operations (Tables

Discontinued Operations (Tables)	6 Months Ended
	Jun. 30, 2016
Discontinued Operations and Disposal Groups [Abstract]
Summary of Balance Sheet and Profit and Loss Information for Discontinued Operations	The following table summarizes the major categories of assets, liabilities at the dates indicated, and the revenues, cost of revenues, operating expenses and income tax of discontinued operations for the periods indicated: $ in millions December 31, 2015 Accounts receivable, net $ 31.0 Property, plant & equipment, net 4.6 Intangible assets, net 24.6 Other assets 2.0 Total assets of the disposal group classified as held for sale in the balance sheets $ 62.2 Accounts payable $ 0.8 Other liabilities 0.8 Total liabilities of the disposal group classified as held for sale in the balance sheets $ 1.6 Three months ended June 30, Six months ended June 30, 2016 2015 2016 2015 Revenues $ — $ 75.2 $ — $ 197.5 Cost of revenues — (68.8 ) — (180.5 ) Operating expenses — (4.8 ) (0.7 ) (11.8 ) (Loss) / income from discontinued operations before income taxes — 1.6 (0.7 ) 5.2 Gain from disposal of discontinued operations — — 49.2 — Income tax expense / (benefit) — (5.3 ) 18.9 (3.6 ) Income on discontinued operations $ — $ 6.9 $ 29.6 $ 8.8

Summary of Significant Accoun32

Summary of Significant Accounting Policies (Narrative) (Details) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2016	Jun. 30, 2016USD ($)employee	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)mi²employeesegmentgenerating_facilitycustomer	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Significant Accounting Policies [Line Items]
Number of reportable segments | segment				1
Entity number of employees | employee		1,169		1,169
Employees under a collective bargaining agreement which expires in October-2011				62.00%
Excise taxes collected		$ 11.6	$ 11.5	$ 24.5	$ 25.5
THE DAYTON POWER AND LIGHT COMPANY [Member]
Significant Accounting Policies [Line Items]
Approximate number of retail customers | customer				517,000
Service area, square miles | mi²				6,000
Entity number of employees | employee		1,161		1,161
Employees under a collective bargaining agreement which expires in October-2011				61.00%
Number of generating facilities | generating_facility				5
Excise taxes collected		$ 11.6	$ 11.5	$ 24.5	$ 25.5
Line of Credit [Member]
Significant Accounting Policies [Line Items]
Noncurrent portion of deferred finance costs						$ 3.1
Line of Credit [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Significant Accounting Policies [Line Items]
Noncurrent portion of deferred finance costs						0.7
Adjustments for New Accounting Pronouncement [Member]
Significant Accounting Policies [Line Items]
Current portion of deferred finance costs						2.1
Noncurrent portion of deferred finance costs						14
Adjustments for New Accounting Pronouncement [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Significant Accounting Policies [Line Items]
Current portion of deferred finance costs						1.8
Noncurrent portion of deferred finance costs						$ 4.5
Year 2016 [Member]
Significant Accounting Policies [Line Items]
Electric generation through competitive bid	100.00%

Supplemental Financial Inform33

Supplemental Financial Information (Supplemental Financial Information) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Supplemental Financial Information [Line Items]
Accounts receivable, net		$ 31
Unbilled revenue	$ 38.9	43.3
Customer receivables	54.1	56.4
Amounts due from partners in jointly owned stations	10.9	16
Other	4.9	6
Provision for uncollectible accounts	(1)	(0.8)
Total accounts receivable, net	107.8	120.9
Fuel and limestone	49.9	72.2
Plant materials and supplies	35.7	34.9
Other	1.9	2
Total inventories, at average cost	87.5	109.1
THE DAYTON POWER AND LIGHT COMPANY [Member]
Supplemental Financial Information [Line Items]
Unbilled revenue	38.9	43.3
Customer receivables	50.8	54.1
Amounts due from partners in jointly owned stations	10.9	16
Other	6	6.9
Provision for uncollectible accounts	(1)	(0.8)
Total accounts receivable, net	105.6	119.5
Fuel and limestone	50	72.2
Plant materials and supplies	34.4	33.7
Other	2	2.1
Total inventories, at average cost	$ 86.4	$ 108

Supplemental Financial Inform34

Supplemental Financial Information (Reclassification out of ACOI) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other income	$ (26)	$ (30.9)	$ (55.4)	$ (62.1)
Tax expense	88.3	(5.8)	87.7	(16.8)
Net income / (loss)	(136.8)	21.7	(105)	50.4
Interest expense	(26)	(30.9)	(52.3)	(61.4)
Revenue	328.3	365.9	692.3	848.8
Purchased power	(96.9)	(120.3)	(218.8)	(313.6)
Operating Expenses	(370.3)	(139.7)	(513.3)	(283.9)
THE DAYTON POWER AND LIGHT COMPANY [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other income	(5.2)	(8.8)	(10.8)	(17.8)
Tax expense	303.7	(9.4)	291.3	(24.2)
Net income / (loss)	(531.6)	23.9	(497.9)	60.4
Interest expense	(5.4)	(9)	(10.7)	(17.7)
Revenue	313.7	352.1	662.9	813.4
Purchased power	(96.7)	(120.1)	(218)	(309.8)
Operating Expenses	(991.5)	(139.3)	(1,104.8)	(281.3)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net income / (loss)	(10.6)	(1.9)	(19)	(1.6)
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 / (loss)	(10)	(0.5)	(18.2)	0.5
Gains / (losses) on available-for-sale securities [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other income	0.1	0.6	0	0
Tax expense	0	(0.2)	0	0
Net income / (loss)	0.1	0.4	0	0
Gains / (losses) on available-for-sale securities [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]
Other income	0.1	0.6	0	0
Tax expense	0	(0.2)	0	0
Net income / (loss)	0.1	0.4	0	0
Gains / (losses) on cash flow hedges [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Tax expense	5.9	0.9	10.7	0.5
Net income / (loss)	(10.8)	(1.9)	(19)	(1.4)
Interest expense	(0.3)	(0.3)	(0.5)	(0.5)
Revenue	(20.1)	(2.9)	(37.3)	(3.2)
Purchased power	3.7	0.4	8.1	1.8
Total before income taxes	(16.7)	(2.8)	(29.7)	(1.9)
Gains / (losses) on cash flow hedges [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	5.9	1	10.5	0.7
Net income / (loss)	(10.8)	(1.8)	(19.2)	(1.3)
Interest expense	(0.3)	(0.3)	(0.6)	(0.6)
Revenue	(20.1)	(2.9)	(37.2)	(3.2)
Purchased power	3.7	0.4	8.1	1.8
Total before income taxes	(16.7)	(2.8)	(29.7)	(2)
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	(0.5)	(0.2)	(0.4)
Net income / (loss)	0.1	(0.4)	0	(0.2)
Operating Expenses	0.1	0.1	0.2	0.2
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	(0.4)	(0.5)	(1.2)	(1)
Net income / (loss)	0.7	0.9	1	1.8
Operating Expenses	$ 1.1	$ 1.4	$ 2.2	$ 2.8

Supplemental Financial Inform35

Supplemental Financial Information (Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period			$ 17.4
Other comprehensive income before reclassifications			13.1
Amounts reclassified from accumulated other comprehensive income / (loss)			(19)
Other comprehensive income / (loss)	$ (19.2)	$ (0.6)	(5.9)	$ 0.3
Balance, end of period	11.5		11.5
THE DAYTON POWER AND LIGHT COMPANY [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period			(28.7)
Other comprehensive income before reclassifications			13.1
Amounts reclassified from accumulated other comprehensive income / (loss)			(18.2)
Other comprehensive income / (loss)	(18.6)	$ 0.7	(5.1)	$ 2.3
Balance, end of period	(33.8)		(33.8)
Gains / (losses) on available-for-sale securities [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period			0.4
Other comprehensive income before reclassifications			0.1
Amounts reclassified from accumulated other comprehensive income / (loss)			0
Other comprehensive income / (loss)			0.1
Balance, end of period	0.5		0.5
Gains / (losses) on available-for-sale securities [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period			0.5
Other comprehensive income before reclassifications			0.1
Amounts reclassified from accumulated other comprehensive income / (loss)			0
Other comprehensive income / (loss)			0.1
Balance, end of period	0.6		0.6
Gains / (losses) on cash flow hedges [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period			26.7
Other comprehensive income before reclassifications			13
Amounts reclassified from accumulated other comprehensive income / (loss)			(19)
Other comprehensive income / (loss)			(6)
Balance, end of period	20.7		20.7
Gains / (losses) on cash flow hedges [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period			11.2
Other comprehensive income before reclassifications			13
Amounts reclassified from accumulated other comprehensive income / (loss)			(19.2)
Other comprehensive income / (loss)			(6.2)
Balance, end of period	5		5
Change in unfunded pension obligation [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period			(9.7)
Other comprehensive income before reclassifications			0
Amounts reclassified from accumulated other comprehensive income / (loss)			0
Other comprehensive income / (loss)			0
Balance, end of period	(9.7)		(9.7)
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			(40.4)
Other comprehensive income before reclassifications			0
Amounts reclassified from accumulated other comprehensive income / (loss)			1
Other comprehensive income / (loss)			1
Balance, end of period	$ (39.4)		$ (39.4)

Fair Value (Narrative) (Details

Fair Value (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Long-term debt, earliest maturities	2,016
Long-term debt, latest maturities	2,061
Unrealized gains in AOCI, before tax	$ 0.8
Unrealized gains in AOCI, net of tax	0.6
Unrealized gains and immaterial unrealized losses in AOCI, before tax			$ 0.7
Unrealized gains and immaterial unrealized losses in AOCI, after tax			0.5
Unrealized losses in AOCI, before tax			0.1
Unrealized losses in AOCI, net of tax			0.1
Realized gains on investments sold to facilitate the distribution of benefits	2
Realized gains on investments sold to facilitate the distribution of benefits, after tax	$ 1.3
Percent of inputs to the fair value of derivative instruments from quoted market prices (percent)	93.00%
Gross additions to our existing landfill and asbestos AROs	$ 2.3	$ 39.8
THE DAYTON POWER AND LIGHT COMPANY [Member]
Long-term debt, earliest maturities	2,016
Long-term debt, latest maturities	2,061
Unrealized gains in AOCI, before tax	$ 0.9
Unrealized gains in AOCI, net of tax	0.6
Unrealized gains and immaterial unrealized losses in AOCI, before tax			0.8
Unrealized gains and immaterial unrealized losses in AOCI, after tax			0.5
Unrealized losses in AOCI, before tax			0.1
Unrealized losses in AOCI, net of tax			$ 0.1
Realized gains on investments sold to facilitate the distribution of benefits	2
Realized gains on investments sold to facilitate the distribution of benefits, after tax	$ 1.3
Percent of inputs to the fair value of derivative instruments from quoted market prices (percent)	93.00%
Gross additions to our existing landfill and asbestos AROs	$ 2.3	$ 39.8

Fair Value (Fair Value and Cost

Fair Value (Fair Value and Cost of Non-Derivative Instruments) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Cost [Member]
Total Assets	$ 7.7	$ 8.3
Cost [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Assets	7.7	8.3
Fair Value [Member]
Total Master Trust Assets, Fair Value	8.6	9
Total Assets	8.6	9
Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	8.6	9
Total Assets	8.6	9
Money Market Funds [Member] | Cost [Member]
Total Master Trust Assets, Cost	0.3	0.2
Money Market Funds [Member] | Cost [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Cost	0.3	0.2
Money Market Funds [Member] | Fair Value [Member]
Total Master Trust Assets, Fair Value	0.3	0.2
Money Market Funds [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0.3	0.2
Equity Securities [Member] | Cost [Member]
Total Master Trust Assets, Cost	2.7	3
Equity Securities [Member] | Cost [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Cost	2.7	3
Equity Securities [Member] | Fair Value [Member]
Total Master Trust Assets, Fair Value	3.5	3.8
Equity Securities [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	3.5	3.8
Debt Securities [Member] | Cost [Member]
Total Master Trust Assets, Cost	4.2	4.4
Debt Securities [Member] | Cost [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Cost	4.2	4.4
Debt Securities [Member] | Fair Value [Member]
Total Master Trust Assets, Fair Value	4.2	4.3
Debt Securities [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	4.2	4.3
Hedge Funds [Member] | Cost [Member]
Total Master Trust Assets, Cost	0.2	0.4
Hedge Funds [Member] | Cost [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Cost	0.2	0.4
Hedge Funds [Member] | Fair Value [Member]
Total Master Trust Assets, Fair Value	0.2	0.4
Hedge Funds [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0.2	0.4
Real Estate Funds [Member] | Cost [Member]
Total Master Trust Assets, Cost	0.3	0.3
Real Estate Funds [Member] | Cost [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Cost	0.3	0.3
Real Estate Funds [Member] | Fair Value [Member]
Total Master Trust Assets, Fair Value	0.4	0.3
Real Estate Funds [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0.4	0.3
Debt [Member] | Cost [Member]
Debt, Cost	1,923.3	1,993.3
Debt [Member] | Cost [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt, Cost	758.4	756.7
Debt [Member] | Fair Value [Member]
Debt, Fair Value	1,912.4	1,975.3
Debt [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt, Fair Value	$ 764.3	$ 764.2

Fair Value (Fair Value of Asset

Fair Value (Fair Value of Assets and Liabilities Measured on Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Level 1 [Member]
Total Master Trust Assets, Fair Value	$ 0.3	$ 0.2
Total Derivative Assets	0.3	0
Total Assets	0.6	0.2
Total Derivative Liabilities	0	0
Total Liabilities	0	0
Level 1 [Member] | Commodity Contract - FTR [Member]
Total Derivative Assets	0	0
Total Derivative Liabilities		0
Level 1 [Member] | Natural Gas Futures [Member]
Total Derivative Assets	0.3
Level 1 [Member] | Forward Contract Power [Member]
Total Derivative Assets	0	0
Total Derivative Liabilities	0	0
Level 1 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0.3	0.2
Total Derivative Assets	0.3	0
Total Assets	0.6	0.2
Total Derivative Liabilities	0	0
Total Liabilities	0	0
Level 1 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Commodity Contract - FTR [Member]
Total Derivative Assets	0	0
Total Derivative Liabilities		0
Level 1 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Natural Gas Futures [Member]
Total Derivative Assets	0.3
Level 1 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Forward Contract Power [Member]
Total Derivative Assets	0	0
Total Derivative Liabilities	0	0
Level 2 [Member]
Total Master Trust Assets, Fair Value	8.3	8.8
Total Derivative Assets	38.6	30.5
Total Assets	46.9	39.3
Total Derivative Liabilities	38.9	23.9
Total Liabilities	1,933.3	1,981.1
Level 2 [Member] | Commodity Contract - FTR [Member]
Total Derivative Assets	0	0
Total Derivative Liabilities		0
Level 2 [Member] | Natural Gas Futures [Member]
Total Derivative Assets	0
Level 2 [Member] | Forward Contract Power [Member]
Total Derivative Assets	38.6	30.5
Total Derivative Liabilities	38.9	23.9
Level 2 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	8.3	8.8
Total Derivative Assets	38.7	30.6
Total Assets	47	39.4
Total Derivative Liabilities	39	23.9
Total Liabilities	785.3	770
Level 2 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Commodity Contract - FTR [Member]
Total Derivative Assets	0	0
Total Derivative Liabilities		0
Level 2 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Natural Gas Futures [Member]
Total Derivative Assets	0
Level 2 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Forward Contract Power [Member]
Total Derivative Assets	38.7	30.6
Total Derivative Liabilities	39	23.9
Level 3 [Member]
Total Master Trust Assets, Fair Value	0	0
Total Derivative Assets	0.8	0.2
Total Assets	0.8	0.2
Total Derivative Liabilities	6.3	3.6
Total Liabilities	24.3	21.7
Level 3 [Member] | Commodity Contract - FTR [Member]
Total Derivative Assets	0.1	0.2
Total Derivative Liabilities		0.5
Level 3 [Member] | Natural Gas Futures [Member]
Total Derivative Assets	0
Level 3 [Member] | Forward Contract Power [Member]
Total Derivative Assets	0.7	0
Total Derivative Liabilities	6.3	3.1
Level 3 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0
Total Derivative Assets	0.8	0.2
Total Assets	0.8	0.2
Total Derivative Liabilities	6.3	3.6
Total Liabilities	24.3	21.7
Level 3 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Commodity Contract - FTR [Member]
Total Derivative Assets	0.1	0.2
Total Derivative Liabilities		0.5
Level 3 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Natural Gas Futures [Member]
Total Derivative Assets	0
Level 3 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Forward Contract Power [Member]
Total Derivative Assets	0.7	0
Total Derivative Liabilities	6.3	3.1
Fair Value [Member]
Total Master Trust Assets, Fair Value	8.6	9
Total Derivative Assets	39.7	30.7
Total Assets	48.3	39.7
Total Derivative Liabilities	45.2	27.5
Total Liabilities	1,957.6	2,002.8
Fair Value [Member] | Commodity Contract - FTR [Member]
Total Derivative Assets	0.1	0.2
Total Derivative Liabilities		0.5
Fair Value [Member] | Natural Gas Futures [Member]
Total Derivative Assets	0.3
Fair Value [Member] | Forward Contract Power [Member]
Total Derivative Assets	39.3	30.5
Total Derivative Liabilities	45.2	27
Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	8.6	9
Total Derivative Assets	39.8	30.8
Total Assets	48.4	39.8
Total Derivative Liabilities	45.3	27.5
Total Liabilities	809.6	791.7
Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Commodity Contract - FTR [Member]
Total Derivative Assets	0.1	0.2
Total Derivative Liabilities		0.5
Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Natural Gas Futures [Member]
Total Derivative Assets	0.3
Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Forward Contract Power [Member]
Total Derivative Assets	39.4	30.6
Total Derivative Liabilities	45.3	27
Money Market Funds [Member] | Level 1 [Member]
Total Master Trust Assets, Fair Value	0.3	0.2
Money Market Funds [Member] | Level 1 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0.3	0.2
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	0.3	0.2
Money Market Funds [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0.3	0.2
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	3.5	3.8
Equity Securities [Member] | Level 2 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	3.5	3.8
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	3.5	3.8
Equity Securities [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	3.5	3.8
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	4.2	4.3
Debt Securities [Member] | Level 2 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	4.2	4.3
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	4.2	4.3
Debt Securities [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	4.2	4.3
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	0.2	0.4
Hedge Funds [Member] | Level 2 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0.2	0.4
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	0.2	0.4
Hedge Funds [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0.2	0.4
Real Estate Funds [Member] | Level 1 [Member]
Total Master Trust Assets, Fair Value	0	0
Real Estate Funds [Member] | Level 1 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0
Real Estate Funds [Member] | Level 2 [Member]
Total Master Trust Assets, Fair Value	0.4	0.3
Real Estate Funds [Member] | Level 2 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0.4	0.3
Real Estate Funds [Member] | Level 3 [Member]
Total Master Trust Assets, Fair Value	0	0
Real Estate Funds [Member] | Level 3 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0	0
Real Estate Funds [Member] | Fair Value [Member]
Total Master Trust Assets, Fair Value	0.4	0.3
Real Estate Funds [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Total Master Trust Assets, Fair Value	0.4	0.3
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	1,894.4	1,957.2
Debt [Member] | Level 2 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt	746.3	746.1
Debt [Member] | Level 3 [Member]
Debt	18	18.1
Debt [Member] | Level 3 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt	18	18.1
Debt [Member] | Fair Value [Member]
Debt	1,912.4	1,975.3
Debt [Member] | Fair Value [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt	$ 764.3	$ 764.2

Fair Value Fair Value Measureme

Fair Value Fair Value Measurements (Fair Value of Assets and Liabilities Measured on a Non-recurring Basis) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant and Equipment, Net	$ 2,327.4		$ 2,327.4		$ 2,561.7
Impairment of Long-Lived Assets Held-for-use	235.5	$ 0	235.5	$ 0
Killen [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant and Equipment, Net	315.1		315.1
Impairment of Long-Lived Assets Held-for-use			230.8
Killen [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	0		0
Killen [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	0		0
Killen [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	84.3		84.3
Peaking Generating Facilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant and Equipment, Net	9.9		9.9
Impairment of Long-Lived Assets Held-for-use			4.7
Peaking Generating Facilities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	0		0
Peaking Generating Facilities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	0		0
Peaking Generating Facilities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	5.2		5.2
THE DAYTON POWER AND LIGHT COMPANY [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant and Equipment, Net	1,872.9		1,872.9		$ 2,738.7
Impairment of Long-Lived Assets Held-for-use	857.1	$ 0	857.1	$ 0
THE DAYTON POWER AND LIGHT COMPANY [Member] | Stuart [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant and Equipment, Net	456.4		456.4
Impairment of Long-Lived Assets Held-for-use			292
THE DAYTON POWER AND LIGHT COMPANY [Member] | Stuart [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	0		0
THE DAYTON POWER AND LIGHT COMPANY [Member] | Stuart [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	0		0
THE DAYTON POWER AND LIGHT COMPANY [Member] | Stuart [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	164.4		164.4
THE DAYTON POWER AND LIGHT COMPANY [Member] | Zimmer [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant and Equipment, Net	429.9		429.9
Impairment of Long-Lived Assets Held-for-use			318.9
THE DAYTON POWER AND LIGHT COMPANY [Member] | Zimmer [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	0		0
THE DAYTON POWER AND LIGHT COMPANY [Member] | Zimmer [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	0		0
THE DAYTON POWER AND LIGHT COMPANY [Member] | Zimmer [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	111		111
THE DAYTON POWER AND LIGHT COMPANY [Member] | Killen [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant and Equipment, Net	330.5		330.5
Impairment of Long-Lived Assets Held-for-use			246.2
THE DAYTON POWER AND LIGHT COMPANY [Member] | Killen [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	0		0
THE DAYTON POWER AND LIGHT COMPANY [Member] | Killen [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	0		0
THE DAYTON POWER AND LIGHT COMPANY [Member] | Killen [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	$ 84.3		$ 84.3

Derivative Instruments and He40

Derivative Instruments and Hedging Activities (Narrative) (Details) $ in Millions	Jun. 30, 2016USD ($)
Additional Collateral, Aggregate Fair Value, OTC Commodity Derivatives	$ 0.9
Fair value of commodity derivative instruments	45.2
Collateral Already Posted, Aggregate Fair Value	11.1
Liability position offset by the asset position of counterparties with master netting agreements	29.6
Collateral if debt were to fall below investment grade	4.5
THE DAYTON POWER AND LIGHT COMPANY [Member]
Additional Collateral, Aggregate Fair Value, OTC Commodity Derivatives	0.9
Fair value of commodity derivative instruments	45.3
Collateral Already Posted, Aggregate Fair Value	11.1
Liability position offset by the asset position of counterparties with master netting agreements	29.6
Collateral if debt were to fall below investment grade	$ 4.6

Derivative Instruments and He41

Derivative Instruments and Hedging Activities (Outstanding Derivative Instruments) (Details)	Jun. 30, 2016MMBTUMWh	Dec. 31, 2015MWh
Not Designated as Hedging Instrument [Member] | Commodity Contract - FTR [Member]
Purchase of Units Derivative Instruments Financial Transmission Rights	2,500	10,200
Sale of Units Derivative Instruments Financial Transmission Rights	0	0
Derivative, Nonmonetary Notional Amount MWh	2,500	10,200
Not Designated as Hedging Instrument [Member] | Natural Gas [Member]
Purchase of Units Derivative Instruments Natural Gas | MMBTU	1,442,500
Sale of Units Derivative Instruments Natural Gas | MMBTU	0
Derivative, Nonmonetary Notional Amount MWh | MMBTU	1,442,500
Not Designated as Hedging Instrument [Member] | Forward Contract Power [Member]
Purchase of Units Derivative Instruments Forward Power Contracts Not Designated as Hedged	4,018,000	5,049,900
Sales of Units Derivative Instruments Forward Power Contracts Not Designated as Hedged	(3,537,900)	(1,663,000)
Derivative, Nonmonetary Notional Amount MWh	480,100	3,386,900
Not Designated as Hedging Instrument [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Commodity Contract - FTR [Member]
Purchase of Units Derivative Instruments Financial Transmission Rights	2,500	10,200
Sale of Units Derivative Instruments Financial Transmission Rights	0	0
Derivative, Nonmonetary Notional Amount MWh	2,500	10,200
Not Designated as Hedging Instrument [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Natural Gas [Member]
Purchase of Units Derivative Instruments Natural Gas | MMBTU	1,442,500
Sale of Units Derivative Instruments Natural Gas | MMBTU	0
Derivative, Nonmonetary Notional Amount MWh | MMBTU	1,442,500
Not Designated as Hedging Instrument [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Forward Contract Power [Member]
Purchase of Units Derivative Instruments Forward Power Contracts Not Designated as Hedged	4,018,000	5,049,900
Sales of Units Derivative Instruments Forward Power Contracts Not Designated as Hedged	(3,574,800)	(1,665,700)
Derivative, Nonmonetary Notional Amount MWh	443,200	3,384,200
Designated as Hedging Instrument [Member] | Forward Contract Power [Member]
Purchase of Units Derivative Instruments Forward Power Contracts Designated as Cash Flow Hedge	692,600	1,676,700
Sales of Units Derivative Instruments Forward Power Contracts Designated as Cash Flow Hedge	(13,380,200)	(7,795,800)
Derivative, Nonmonetary Notional Amount MWh	(12,687,600)	(6,119,100)
Designated as Hedging Instrument [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Forward Contract Power [Member]
Purchase of Units Derivative Instruments Forward Power Contracts Designated as Cash Flow Hedge	692,600	1,676,700
Sales of Units Derivative Instruments Forward Power Contracts Designated as Cash Flow Hedge	(13,380,200)	(7,795,800)
Derivative, Nonmonetary Notional Amount MWh	(12,687,600)	(6,119,100)

Derivative Instruments and He42

Derivative Instruments and Hedging Activities (Gains or Losses Recognized in AOCI for the Cash Flow Hedges) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Forward Contract Power [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Beginning accumulated derivative gain / (loss) in AOCI	$ 22.5	$ 1	$ 9.2	$ 0.2
Net gains / (losses) associated with current period hedging transactions	(8.5)	1.7	13	1.8
Ending accumulated derivative gain / (loss) in AOCI	3.4	1.1	3.4	1.1
Portion expected to be reclassified to earnings in the next twelve months	(3.1)		$ (3.1)
Maximum length of time that we are hedging our exposure to variability in future cash flows related to forecasted transactions (in months)			18 months
Interest Rate Contract [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Beginning accumulated derivative gain / (loss) in AOCI	17.5	18.2	$ 17.5	18.3
Net gains / (losses) associated with current period hedging transactions	0	0	0	0
Ending accumulated derivative gain / (loss) in AOCI	17.3	17.8	17.3	17.8
Portion expected to be reclassified to earnings in the next twelve months	(0.6)		$ (0.6)
Maximum length of time that we are hedging our exposure to variability in future cash flows related to forecasted transactions (in months)			0 months
THE DAYTON POWER AND LIGHT COMPANY [Member] | Forward Contract Power [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Beginning accumulated derivative gain / (loss) in AOCI	22.5	1	$ 9.2	0.2
Net gains / (losses) associated with current period hedging transactions	(8.5)	1.7	13	1.8
Ending accumulated derivative gain / (loss) in AOCI	3.4	1.1	3.4	1.1
Portion expected to be reclassified to earnings in the next twelve months	(3.1)		$ (3.1)
Maximum length of time that we are hedging our exposure to variability in future cash flows related to forecasted transactions (in months)			18 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	1.8	2.4	$ 2	2.6
Net gains / (losses) associated with current period hedging transactions	0	0	0	0
Ending accumulated derivative gain / (loss) in AOCI	1.6	2.2	1.6	2.2
Portion expected to be reclassified to earnings in the next twelve months	0.7		$ 0.7
Maximum length of time that we are hedging our exposure to variability in future cash flows related to forecasted transactions (in months)			0 months
Interest Expense [Member] | Forward Contract Power [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Net gains losses reclassified to earnings	0	0	$ 0	0
Interest Expense [Member] | Interest Rate Contract [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Net gains losses reclassified to earnings	(0.2)	(0.4)	(0.2)	(0.5)
Interest Expense [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Forward Contract Power [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Net gains losses reclassified to earnings	0	0	0	0
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	(0.2)	(0.2)	(0.4)	(0.4)
Revenue [Member] | Forward Contract Power [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Net gains losses reclassified to earnings	(13)	(1.9)	(24)	(2.1)
Revenue [Member] | Interest Rate Contract [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Net gains losses reclassified to earnings	0	0	0	0
Revenue [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Forward Contract Power [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Net gains losses reclassified to earnings	(13)	(1.9)	(24)	(2.1)
Revenue [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	0	0	0
Purchased Power [Member] | Forward Contract Power [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Net gains losses reclassified to earnings	2.4	0.3	5.2	1.2
Purchased Power [Member] | Interest Rate Contract [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Net gains losses reclassified to earnings	0	0	0	0
Purchased Power [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Forward Contract Power [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Net gains losses reclassified to earnings	2.4	0.3	5.2	1.2
Purchased Power [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	$ 0	$ 0	$ 0

Derivative Instruments and He43

Derivative Instruments and Hedging Activities (Classification within the Condensed Consolidated Statements of Results of Operations or Balance Sheets of the Gains and Losses) (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Change in unrealized gain / (loss)	$ 3.3	$ 0.5	$ 1.9	$ (1.3)
Realized loss	(1.5)	(1.6)	(2)	(4.1)
Derivative, Gain (Loss) on Derivative, Net	1.8	(1.1)	(0.1)	(5.4)
Commodity Contract - Heating Oil [Member]
Change in unrealized gain / (loss)		0.1		0.2
Realized loss		(0.1)		(0.1)
Derivative, Gain (Loss) on Derivative, Net		0		0.1
Commodity Contract - FTR [Member]
Change in unrealized gain / (loss)	0.2	(0.8)	0.4	0.1
Realized loss	0.2	0	0.4	(0.1)
Derivative, Gain (Loss) on Derivative, Net	0.4	(0.8)	0.8	0
Forward Contract Power [Member]
Change in unrealized gain / (loss)	2.6	1.2	1.2	(1.7)
Realized loss	(2.4)	(1.5)	(2.9)	(3.8)
Derivative, Gain (Loss) on Derivative, Net	0.2	(0.3)	(1.7)	(5.5)
Natural Gas [Member]
Change in unrealized gain / (loss)	0.5		0.3	0.1
Realized loss	0.7		0.5	(0.1)
Derivative, Gain (Loss) on Derivative, Net	1.2		0.8	0
THE DAYTON POWER AND LIGHT COMPANY [Member]
Change in unrealized gain / (loss)	3.5	0.4	1.6	(1.4)
Realized loss	(1.4)	(1.6)	(1.8)	(4.1)
Derivative, Gain (Loss) on Derivative, Net	2.1	(1.2)	(0.2)	(5.5)
THE DAYTON POWER AND LIGHT COMPANY [Member] | Commodity Contract - Heating Oil [Member]
Change in unrealized gain / (loss)		0.1		0.2
Realized loss		(0.1)		(0.1)
Derivative, Gain (Loss) on Derivative, Net		0		0.1
THE DAYTON POWER AND LIGHT COMPANY [Member] | Commodity Contract - FTR [Member]
Change in unrealized gain / (loss)	0.2	(0.8)	0.4	0.1
Realized loss	0.2	0	0.4	(0.1)
Derivative, Gain (Loss) on Derivative, Net	0.4	(0.8)	0.8	0
THE DAYTON POWER AND LIGHT COMPANY [Member] | Forward Contract Power [Member]
Change in unrealized gain / (loss)	2.8	1.1	0.9	(1.8)
Realized loss	(2.3)	(1.5)	(2.7)	(3.8)
Derivative, Gain (Loss) on Derivative, Net	0.5	(0.4)	(1.8)	(5.6)
THE DAYTON POWER AND LIGHT COMPANY [Member] | Natural Gas [Member]
Change in unrealized gain / (loss)	0.5		0.3	0.1
Realized loss	0.7		0.5	(0.1)
Derivative, Gain (Loss) on Derivative, Net	1.2		0.8	0
Regulatory Asset [Member]
Derivative, Gain (Loss) on Derivative, Net				0.1
Regulatory Asset [Member] | Commodity Contract - Heating Oil [Member]
Derivative, Gain (Loss) on Derivative, Net				0.1
Regulatory Asset [Member] | Commodity Contract - FTR [Member]
Derivative, Gain (Loss) on Derivative, Net				0
Regulatory Asset [Member] | Forward Contract Power [Member]
Derivative, Gain (Loss) on Derivative, Net				0
Regulatory Asset [Member] | Natural Gas [Member]
Derivative, Gain (Loss) on Derivative, Net				0
Regulatory Asset [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative, Gain (Loss) on Derivative, Net				0.1
Regulatory Asset [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Commodity Contract - Heating Oil [Member]
Derivative, Gain (Loss) on Derivative, Net				0.1
Regulatory Asset [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Commodity Contract - FTR [Member]
Derivative, Gain (Loss) on Derivative, Net				0
Regulatory Asset [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Forward Contract Power [Member]
Derivative, Gain (Loss) on Derivative, Net				0
Regulatory Asset [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Natural Gas [Member]
Derivative, Gain (Loss) on Derivative, Net				0
Revenue [Member]
Derivative, Gain (Loss) on Derivative, Net	(5.3)	(3.6)	(6.6)	(7.7)
Revenue [Member] | Commodity Contract - Heating Oil [Member]
Derivative, Gain (Loss) on Derivative, Net		0		0
Revenue [Member] | Commodity Contract - FTR [Member]
Derivative, Gain (Loss) on Derivative, Net	0	(0.8)	0	0
Revenue [Member] | Forward Contract Power [Member]
Derivative, Gain (Loss) on Derivative, Net	(5.3)	(2.8)	(6.6)	(7.7)
Revenue [Member] | Natural Gas [Member]
Derivative, Gain (Loss) on Derivative, Net	0		0	0
Revenue [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative, Gain (Loss) on Derivative, Net	(5.1)	(3.7)	(6.6)	2.2
Revenue [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Commodity Contract - Heating Oil [Member]
Derivative, Gain (Loss) on Derivative, Net		0		0
Revenue [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Commodity Contract - FTR [Member]
Derivative, Gain (Loss) on Derivative, Net	0	(0.8)	0	0
Revenue [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Forward Contract Power [Member]
Derivative, Gain (Loss) on Derivative, Net	(5.1)	(2.9)	(6.6)	2.2
Revenue [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Natural Gas [Member]
Derivative, Gain (Loss) on Derivative, Net	0		0	0
Purchased Power [Member]
Derivative, Gain (Loss) on Derivative, Net	7.1	2.5	6.5	2.2
Purchased Power [Member] | Commodity Contract - Heating Oil [Member]
Derivative, Gain (Loss) on Derivative, Net		0		0
Purchased Power [Member] | Commodity Contract - FTR [Member]
Derivative, Gain (Loss) on Derivative, Net	0.4	0	0.8	0
Purchased Power [Member] | Forward Contract Power [Member]
Derivative, Gain (Loss) on Derivative, Net	5.5	2.5	4.9	2.2
Purchased Power [Member] | Natural Gas [Member]
Derivative, Gain (Loss) on Derivative, Net	1.2		0.8	0
Purchased Power [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative, Gain (Loss) on Derivative, Net	7.2	2.5	6.4	(7.8)
Purchased Power [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Commodity Contract - Heating Oil [Member]
Derivative, Gain (Loss) on Derivative, Net		0		0
Purchased Power [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Commodity Contract - FTR [Member]
Derivative, Gain (Loss) on Derivative, Net	0.4	0	0.8	0
Purchased Power [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Forward Contract Power [Member]
Derivative, Gain (Loss) on Derivative, Net	5.6	$ 2.5	4.8	(7.8)
Purchased Power [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Natural Gas [Member]
Derivative, Gain (Loss) on Derivative, Net	$ 1.2		$ 0.8	$ 0

Derivative Instruments and He44

Derivative Instruments and Hedging Activities (Fair Value and Balance Sheet Location (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Derivative Liability, Fair Value	$ 45.2
Liability position offset by the asset position of counterparties with master netting agreements	29.6
THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Liability, Fair Value	45.3
Liability position offset by the asset position of counterparties with master netting agreements	29.6
Total Assets [Member]
Derivative Asset, Fair Value	39.7	$ 30.7
Derivative, Collateral, Obligation to Return Securities	(29.6)	(17.9)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	10.1	12.8
Total Assets [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Asset, Fair Value	39.8	30.8
Derivative, Collateral, Obligation to Return Securities	(29.6)	(17.9)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	10.2	12.9
Total Liabilities [Member]
Derivative Liability, Fair Value	45.2	27.5
Derivative, Collateral, Right to Reclaim Securities	(29.6)	(17.9)
Derivative, Collateral, Right to Reclaim Cash	(11.1)	(8)
Liability position offset by the asset position of counterparties with master netting agreements	4.5	1.6
Total Liabilities [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Liability, Fair Value	45.3	27.5
Derivative, Collateral, Right to Reclaim Securities	(29.6)	(17.9)
Derivative, Collateral, Right to Reclaim Cash	(11.1)	(8)
Liability position offset by the asset position of counterparties with master netting agreements	4.6	1.6
Cash Flow Hedging [Member] | Forward Contract Power [Member] | Short-term Derivative Positions [Member] | Other Prepayments and Current Assets [Member]
Derivative Asset, Fair Value	13.9	16.2
Derivative, Collateral, Obligation to Return Securities	(11.3)	(7.1)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	2.6	9.1
Cash Flow Hedging [Member] | Forward Contract Power [Member] | Short-term Derivative Positions [Member] | Other Prepayments and Current Assets [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Asset, Fair Value	13.9	16.2
Derivative, Collateral, Obligation to Return Securities	(11.3)	(7.1)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	2.6	9.1
Cash Flow Hedging [Member] | Forward Contract Power [Member] | Short-term Derivative Positions [Member] | Other Current Liabilities [Member]
Derivative Liability, Fair Value	19.4	7.1
Derivative, Collateral, Right to Reclaim Securities	(11.3)	(7.1)
Derivative, Collateral, Right to Reclaim Cash	(8)	0
Liability position offset by the asset position of counterparties with master netting agreements	0.1	0
Cash Flow Hedging [Member] | Forward Contract Power [Member] | Short-term Derivative Positions [Member] | Other Current Liabilities [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Liability, Fair Value	19.4	7.1
Derivative, Collateral, Right to Reclaim Securities	(11.3)	(7.1)
Derivative, Collateral, Right to Reclaim Cash	(8)	0
Liability position offset by the asset position of counterparties with master netting agreements	0.1	0
Cash Flow Hedging [Member] | Forward Contract Power [Member] | Long-term Derivative Positions [Member] | Other Deferred Asset [Member]
Derivative Asset, Fair Value	9.1	3
Derivative, Collateral, Obligation to Return Securities	(4.8)	(2.4)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	4.3	0.6
Cash Flow Hedging [Member] | Forward Contract Power [Member] | Long-term Derivative Positions [Member] | Other Deferred Asset [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Asset, Fair Value	9.1	3
Derivative, Collateral, Obligation to Return Securities	(4.8)	(2.4)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	4.3	0.6
Cash Flow Hedging [Member] | Forward Contract Power [Member] | Long-term Derivative Positions [Member] | Other Deferred Credit [Member]
Derivative Liability, Fair Value	4.9	2.7
Derivative, Collateral, Right to Reclaim Securities	(4.8)	(2.4)
Derivative, Collateral, Right to Reclaim Cash	0	0
Liability position offset by the asset position of counterparties with master netting agreements	0.1	0.3
Cash Flow Hedging [Member] | Forward Contract Power [Member] | Long-term Derivative Positions [Member] | Other Deferred Credit [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Liability, Fair Value	4.9	2.7
Derivative, Collateral, Right to Reclaim Securities	(4.8)	(2.4)
Derivative, Collateral, Right to Reclaim Cash	0	0
Liability position offset by the asset position of counterparties with master netting agreements	0.1	0.3
Fair Value Hedging [Member] | Commodity Contract - FTR [Member] | Short-term Derivative Positions [Member] | Other Prepayments and Current Assets [Member]
Derivative Asset, Fair Value	0.1	0.2
Derivative, Collateral, Obligation to Return Securities	0	(0.2)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	0.1	0
Fair Value Hedging [Member] | Commodity Contract - FTR [Member] | Short-term Derivative Positions [Member] | Other Prepayments and Current Assets [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Asset, Fair Value	0.1	0.2
Derivative, Collateral, Obligation to Return Securities	0	(0.2)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	0.1	0
Fair Value Hedging [Member] | Commodity Contract - FTR [Member] | Short-term Derivative Positions [Member] | Other Current Liabilities [Member]
Derivative Liability, Fair Value		0.5
Derivative, Collateral, Right to Reclaim Securities		(0.2)
Derivative, Collateral, Right to Reclaim Cash		0
Liability position offset by the asset position of counterparties with master netting agreements		0.3
Fair Value Hedging [Member] | Commodity Contract - FTR [Member] | Short-term Derivative Positions [Member] | Other Current Liabilities [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Liability, Fair Value		0.5
Derivative, Collateral, Right to Reclaim Securities		(0.2)
Derivative, Collateral, Right to Reclaim Cash		0
Liability position offset by the asset position of counterparties with master netting agreements		0.3
Fair Value Hedging [Member] | Forward Contract Power [Member] | Short-term Derivative Positions [Member] | Other Prepayments and Current Assets [Member]
Derivative Asset, Fair Value	13.8	7.3
Derivative, Collateral, Obligation to Return Securities	(12.1)	(5.5)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	1.7	1.8
Fair Value Hedging [Member] | Forward Contract Power [Member] | Short-term Derivative Positions [Member] | Other Prepayments and Current Assets [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Asset, Fair Value	13.9	7.4
Derivative, Collateral, Obligation to Return Securities	(12.1)	(5.5)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	1.8	1.9
Fair Value Hedging [Member] | Forward Contract Power [Member] | Short-term Derivative Positions [Member] | Other Current Liabilities [Member]
Derivative Liability, Fair Value	19.5	14.5
Derivative, Collateral, Right to Reclaim Securities	(12.1)	(5.5)
Derivative, Collateral, Right to Reclaim Cash	(3.1)	(8)
Liability position offset by the asset position of counterparties with master netting agreements	4.3	1
Fair Value Hedging [Member] | Forward Contract Power [Member] | Short-term Derivative Positions [Member] | Other Current Liabilities [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Liability, Fair Value	19.6	14.5
Derivative, Collateral, Right to Reclaim Securities	(12.1)	(5.5)
Derivative, Collateral, Right to Reclaim Cash	(3.1)	(8)
Liability position offset by the asset position of counterparties with master netting agreements	4.4	1
Fair Value Hedging [Member] | Forward Contract Power [Member] | Long-term Derivative Positions [Member] | Other Deferred Asset [Member]
Derivative Asset, Fair Value	2.5	4
Derivative, Collateral, Obligation to Return Securities	(1.4)	(2.7)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	1.1	1.3
Fair Value Hedging [Member] | Forward Contract Power [Member] | Long-term Derivative Positions [Member] | Other Deferred Asset [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Asset, Fair Value	2.5	4
Derivative, Collateral, Obligation to Return Securities	(1.4)	(2.7)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	1.1	1.3
Fair Value Hedging [Member] | Forward Contract Power [Member] | Long-term Derivative Positions [Member] | Other Deferred Credit [Member]
Derivative Liability, Fair Value	1.4	2.7
Derivative, Collateral, Right to Reclaim Securities	(1.4)	(2.7)
Derivative, Collateral, Right to Reclaim Cash	0	0
Liability position offset by the asset position of counterparties with master netting agreements	0	0
Fair Value Hedging [Member] | Forward Contract Power [Member] | Long-term Derivative Positions [Member] | Other Deferred Credit [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Liability, Fair Value	1.4	2.7
Derivative, Collateral, Right to Reclaim Securities	(1.4)	(2.7)
Derivative, Collateral, Right to Reclaim Cash	0	0
Liability position offset by the asset position of counterparties with master netting agreements	0	$ 0
Fair Value Hedging [Member] | Natural Gas Futures [Member] | Short-term Derivative Positions [Member] | Other Prepayments and Current Assets [Member]
Derivative Asset, Fair Value	0.3
Derivative, Collateral, Obligation to Return Securities	0
Derivative, Collateral, Obligation to Return Cash	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	0.3
Fair Value Hedging [Member] | Natural Gas Futures [Member] | Short-term Derivative Positions [Member] | Other Prepayments and Current Assets [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Derivative Asset, Fair Value	0.3
Derivative, Collateral, Obligation to Return Securities	0
Derivative, Collateral, Obligation to Return Cash	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	$ 0.3

Debt (Narrative) (Details)

Debt (Narrative) (Details) $ in Millions	Feb. 05, 2016USD ($)	Jun. 30, 2016USD ($)fiscal_quarterdebt_covenant	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Debt Instrument [Line Items]
Retirement of long-term debt		$ 75.4	$ 0.1
Senior unsecured due in October 2016 - 6.5% [Member]
Debt Instrument [Line Items]
Debt called/redeemed	$ 73
Term loan outstanding		$ 57		$ 130
Debt instrument interest percentage		6.50%		6.50%
Basis points on Treasury bond yield (percent)	0.50%
Retirement of long-term debt	$ 75.4
Revolving Credit Agreement and Standby Letters of Credit [Member] | THE DAYTON POWER AND LIGHT COMPANY [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
Revolving Credit Agreement and Term Loan [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 (Long-term Debt) (Details)

Debt (Long-term Debt) (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Unamortized deferred finance costs	$ (3.4)	$ (5)
Unamortized deferred finance costs	(9.8)	(11.1)
Unamortized debt discount and premiums, net	(0.6)	(0.7)
Total long-term debt at subsidiary	756.1	754.5
Total long-term debt	1,923.3	1,993.3
Less: current portion	(514)	(572.8)
Long-term debt	$ 1,409.3	1,420.5
Long-term debt, earliest maturities	2,016
Long-term debt, latest maturities	2,061
THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Unamortized deferred finance costs	$ (4.5)	(6.2)
Unamortized debt discount and premiums, net	(3.5)	(3.6)
Unamortized debt discount	(0.1)	(0.2)
Total long-term debt	758.4	756.7
Less: current portion	(444.6)	(443.1)
Long-term debt	$ 313.8	313.6
Long-term debt, earliest maturities	2,016
Long-term debt, latest maturities	2,061
First Mortgage Bonds Maturing in September 2016 - 1.875% [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 445	445
Debt instrument maturity year	Sep. 1, 2016
Debt instrument interest percentage	1.875%
First Mortgage Bonds Maturing in September 2016 - 1.875% [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 445	445
Pollution Control Series Maturing in September 2036 - 4.80% [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 100	100
Debt instrument maturity year	Sep. 1, 2036
Debt instrument interest percentage	4.80%
Pollution Control Series Maturing in September 2036 - 4.80% [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 100	$ 100
Pollution Control Series Maturing in August 2020 - 1.13% - 1.14% [Member]
Debt Instrument [Line Items]
Debt instrument maturity year	Aug. 1, 2020
Debt instrument interest percentage minimum		1.13%
Debt instrument interest percentage maximum		1.17%
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	$ 200	$ 200
Zero Point Two Three To Zero Point Two Nine And Zero Point One Six To Zero Point Three Six Percentage Of Pollution Control Series Maturing In November Two Thousand Forty [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage minimum	1.29%	1.13%
Debt instrument interest percentage maximum	1.31%	1.17%
U.S. Government note maturing in February 2061 - 4.20% [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 18	$ 18.1
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	$ 18	18.1
Bank term loan due in July 2020 - rates from: 2.44% - 2.45% [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 125	$ 125
Debt instrument maturity year	Jul. 31, 2020
Debt instrument interest percentage minimum	2.67%	2.44%
Debt instrument interest percentage maximum	2.71%	2.67%
Senior unsecured due in October 2016 - 6.5% [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 57	$ 130
Debt instrument maturity year	Oct. 1, 2016
Debt instrument interest percentage	6.50%	6.50%
Senior unsecured due in October 2019 - 6.75% [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 200	$ 200
Debt instrument maturity year	Oct. 1, 2019
Debt instrument interest percentage	6.75%
Senior unsecured due in October 2021 - 7.25% [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 780	780
Debt instrument maturity year	Oct. 1, 2021
Debt instrument interest percentage	7.25%
Note to DPL Capital Trust II Maturing in September 2031 - 8.125% [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 15.6	$ 15.6
Debt instrument maturity year	Sep. 1, 2031
Debt instrument interest percentage	8.125%

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Entity Information [Line Items]
Effective income tax rates	39.20%	28.20%	39.50%	28.80%
Estimated annual effective income tax rate			38.80%	31.20%
THE DAYTON POWER AND LIGHT COMPANY [Member]
Entity Information [Line Items]
Effective income tax rates	36.40%	28.20%	36.90%	28.60%
Estimated annual effective income tax rate			36.70%	29.40%

Benefit Plans (Net Periodic Ben

Benefit Plans (Net Periodic Benefit Cost (Income)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Pension [Member]
Contributions by employer			$ 5	$ 0
Service cost	$ 1.4	$ 1.8	2.8	3.6
Interest cost	3.7	4.3	7.4	8.6
Expected return on assets	(5.7)	(5.6)	(11.4)	(11.3)
Prior service cost	0.5	0.5	1	1
Actuarial loss / (gain)	1.1	1.4	2.1	2.9
Net periodic benefit cost	1	2.4	1.9	4.8
Postretirement [Member]
Service cost	0.1	0	0.1	0
Interest cost	0.1	0.1	0.2	0.3
Expected return on assets	0	0	0	0
Prior service cost	0	0	0	0
Actuarial loss / (gain)	(0.2)	(0.1)	(0.3)	(0.2)
Net periodic benefit cost	0	0	0	0.1
THE DAYTON POWER AND LIGHT COMPANY [Member] | Pension [Member]
Contributions by employer			5	0
Service cost	1.4	1.7	2.8	3.5
Interest cost	3.7	4.3	7.4	8.6
Expected return on assets	(5.7)	(5.5)	(11.4)	(11.2)
Prior service cost	0.7	0.8	1.5	1.6
Actuarial loss / (gain)	1.8	2.4	3.6	4.8
Net periodic benefit cost	1.9	3.7	3.9	7.3
THE DAYTON POWER AND LIGHT COMPANY [Member] | Postretirement [Member]
Service cost	0.1	0	0.1	0
Interest cost	0.2	0.2	0.3	0.4
Expected return on assets	0	0	0	0
Prior service cost	0	0	0	0
Actuarial loss / (gain)	(0.3)	(0.1)	(0.4)	(0.3)
Net periodic benefit cost	$ 0	$ 0.1	$ 0	$ 0.1

Benefit Plans (Estimated Future

Benefit Plans (Estimated Future Benefit Payments and Medicare Part D Reimbursements) (Details) $ in Millions	Jun. 30, 2016USD ($)
Pension [Member]
2,016	$ 12.3
2,017	25.2
2,018	25.8
2,019	26.3
2,020	26.7
2021 - 2025	134.8
Postretirement [Member]
2,016	0.8
2,017	1.6
2,018	1.5
2,019	1.4
2,020	1.4
2021 - 2025	5.7
THE DAYTON POWER AND LIGHT COMPANY [Member] | Pension [Member]
2,016	12.3
2,017	25.2
2,018	25.8
2,019	26.3
2,020	26.7
2021 - 2025	134.8
THE DAYTON POWER AND LIGHT COMPANY [Member] | Postretirement [Member]
2,016	0.8
2,017	1.6
2,018	1.5
2,019	1.4
2,020	1.4
2021 - 2025	$ 5.7

Shareholder's Equity (Details)

Shareholder's Equity (Details) - USD ($)	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Common stock, shares authorized	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	250,000,000
Par value common shares (in USD per share)	$ 0.01	$ 0.01
Common stock, shares outstanding	41,172,173
PUCO merger equity ratio approval (at least)	50.00%
PUCO Equity Ratio	49.00%
PUCO merger, maximum long-term debt allowed	$ 750,000,000
PUCO merger, maximum long-term debt as percent of rate base (percent)	75.00%

Contractual Obligations, Comm51

Contractual Obligations, Commercial Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Public Utility, Property, Plant and Equipment [Line Items]
Due to third parties, current	$ 2.1	$ 0.5
THE DAYTON POWER AND LIGHT COMPANY [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Debt maturity, earliest	2,018
Debt maturity, latest	2,040
DPLE [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Third party guarantees	$ 14.6
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	$ 75.3
Electric Generation Company [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Debt obligation	$ 1,537.4

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Millions	Dec. 31, 2015	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Related Party Transaction [Line Items]
Charges for services provided		$ 11.5	$ 9.8	$ 23.1	$ 19.6
Sales to related party		1.1	2.8	2.3	3.9
Net advance / (payable) to the Service Company	$ (0.5)	(1.1)		(1.1)		$ (0.5)
Investment in trust	$ 0.3	0.3		0.3		0.3
Debt Instrument, Interest Rate, Stated Percentage	2.67%
Notes Payable, Related Parties	$ 35	0		0		35
Note to DPL Capital Trust II Maturing in September 2031 - 8.125% [Member]
Related Party Transaction [Line Items]
Note payable to trust	15.6	15.6		15.6		15.6
Prepaid Expenses and Other Current Assets [Member]
Related Party Transaction [Line Items]
Accounts Receivable, Related Parties, Current	50.5	78.9		78.9		50.5
Charges for health, welfare and benefit plans [Member] | AES affiliates [Member]
Related Party Transaction [Line Items]
Transactions with other AES affiliates		(2.4)	4.2	1.7	8.2
THE DAYTON POWER AND LIGHT COMPANY [Member]
Related Party Transaction [Line Items]
Charges for services provided		10.9	8.3	19.8	16.7
Sales to related party		1	2.8	2.2	3.9
Premiums paid for insurance services provided by MVIC		(0.8)	(0.8)	(1.7)	(1.6)
Expense recoveries for services provided to DPLER		0	0.6	0	1.3
Net advance / (payable) to the Service Company	(0.5)	(1.1)		(1.1)		(0.5)
Gain on termination of contract		0	0	27.7	0
Notes Payable, Related Parties				(5)	0	(35)
THE DAYTON POWER AND LIGHT COMPANY [Member] | Prepaid Expenses and Other Current Assets [Member]
Related Party Transaction [Line Items]
Accounts Receivable, Related Parties, Current	$ 1.5	10.8		10.8		$ 1.5
THE DAYTON POWER AND LIGHT COMPANY [Member] | Insurance Proceeds Received [Member] | AES affiliates [Member]
Related Party Transaction [Line Items]
Transactions with other AES affiliates		0	2.3	0.2	3.8
THE DAYTON POWER AND LIGHT COMPANY [Member] | Charges for health, welfare and benefit plans [Member] | AES affiliates [Member]
Related Party Transaction [Line Items]
Transactions with other AES affiliates		(2.4)	3.9	1.7	7.8
THE DAYTON POWER AND LIGHT COMPANY [Member] | Dpler [Member]
Related Party Transaction [Line Items]
Sales to related party		$ 0	$ 68.3	$ 0	$ 179

Business Segments (Narrative) (

Business Segments (Narrative) (Details)	6 Months Ended
	Jun. 30, 2016mi²segmentcustomerpower_plant
Segment Reporting Information [Line Items]
Number of operating segments | segment	2
THE DAYTON POWER AND LIGHT COMPANY [Member]
Segment Reporting Information [Line Items]
Number of coal fired power plants | power_plant	5
Approximate number of retail customers | customer	517,000
Service area, square miles | mi²	6,000

Business Segments (Segment Fina

Business Segments (Segment Financial Information) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
External customer revenues	$ 328.3	$ 372.9	$ 692.3	$ 867.4
Total revenues	328.3	372.9	692.3	867.4
Fuel Costs	60.2	54.4	127.1	130.8
Purchased power	96.9	120.6	218.8	314.8
Gross margin	171.2	197.9	346.4	421.8
Depreciation and amortization	36	34.3	69.4	69.3
Impairment of Long-Lived Assets Held-for-use	235.5	0	235.5	0
Interest expense	26	30.9	52.3	61.4
Income tax expense / (benefit)	(88.3)	0.5	(87.7)	13.2
Net income / (loss) from continuing operations	(136.8)	14.8	(134.6)	41.6
Discontinued operations, net of tax	0	6.9	29.6	8.8
Net income/ (loss)	(136.8)	21.7	(105)	50.4
Capital expenditures	41.4	31.1	79.1	64.8
Total assets	2,931.4		2,931.4		$ 3,324.7
Operating Segments [Member] | Utility [Member]
Segment Reporting Information [Line Items]
External customer revenues	313.4	283.8	662.3	634.4
Intersegment revenues	0.3	68.3	0.6	179
Total revenues	313.7	352.1	662.9	813.4
Fuel Costs	55.6	50.6	118.5	119.9
Purchased power	96.7	120.1	218	309.8
Gross margin	161.4	181.4	326.4	383.7
Depreciation and amortization	36.8	34.2	71.1	68.9
Impairment of Long-Lived Assets Held-for-use	857.1		857.1
Interest expense	5.4	9	10.7	17.7
Income tax expense / (benefit)	(303.7)	9.4	(291.3)	24.2
Net income / (loss) from continuing operations			(497.9)
Discontinued operations, net of tax			0
Net income/ (loss)	(531.6)	23.9	(497.9)	60.4
Capital expenditures	36	30.2	71.8	63.3
Total assets	2,442		2,442		3,359.6
Operating Segments [Member] | Competitive Retail [Member]
Segment Reporting Information [Line Items]
External customer revenues		75.2		197.5
Intersegment revenues		0		0
Total revenues		75.2		197.5
Fuel Costs		0		0
Purchased power		68.7		180.4
Gross margin		6.5		17.1
Depreciation and amortization		0.1		0.4
Interest expense		0.1		0.1
Income tax expense / (benefit)		(5.5)		(4.2)
Net income/ (loss)		6.7		8.3
Capital expenditures		0.1		0.3
Total assets					0
Other [Member]
Segment Reporting Information [Line Items]
External customer revenues	14.9	13.9	30	35.5
Intersegment revenues	0.9	1.3	2.2	2.9
Total revenues	15.8	15.2	32.2	38.4
Fuel Costs	4.6	3.8	8.6	10.9
Purchased power	0.7	0.6	1.9	4.8
Gross margin	10.5	10.8	21.7	22.7
Depreciation and amortization	(0.8)	0	(1.7)	0
Impairment of Long-Lived Assets Held-for-use	(621.6)		(621.6)
Interest expense	20.3	21.8	41.3	43.7
Income tax expense / (benefit)	215.4	(3.4)	203.6	(6.8)
Net income / (loss) from continuing operations			363.3
Discontinued operations, net of tax			29.6
Net income/ (loss)	394.8	(8.9)	392.9	(18.3)
Capital expenditures	5.4	0.8	7.3	1.2
Total assets	1,267.7		1,267.7		1,304.5
Adjustments and Eliminations [Member]
Segment Reporting Information [Line Items]
External customer revenues	0	0	0	0
Intersegment revenues	(1.2)	(69.6)	(2.8)	(181.9)
Total revenues	(1.2)	(69.6)	(2.8)	(181.9)
Fuel Costs	0	0	0	0
Purchased power	(0.5)	(68.8)	(1.1)	(180.2)
Gross margin	(0.7)	(0.8)	(1.7)	(1.7)
Depreciation and amortization	0	0	0	0
Impairment of Long-Lived Assets Held-for-use	0		0
Interest expense	0.3	0	0.3	(0.1)
Income tax expense / (benefit)	0	0	0	0
Net income / (loss) from continuing operations			0
Discontinued operations, net of tax			0
Net income/ (loss)	0	0	0	0
Capital expenditures	0	$ 0	0	$ 0
Total assets	$ (778.3)		$ (778.3)		$ (1,339.4)

Discontinued Operations (Detail

Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accounts receivable, net					$ 31
Deposit received on sale of DPLER	$ 0		$ 0		75.5
Property, plant & equipment, net					4.6
Intangible assets, net					24.6
Other assets					2
Total assets of the disposal group classified as held for sale in the balance sheets					62.2
Accounts payable					0.8
Other liabilities					0.8
Total liabilities of the disposal group classified as held for sale in the balance sheets					1.6
Revenues	0	$ 75.2	0	$ 197.5
Cost of revenues	0	(68.8)	0	(180.5)
Operating expenses	0	(4.8)	(0.7)	(11.8)
(Loss) / income from discontinued operations before income taxes	0	1.6	(0.7)	5.2
Gain from disposal of discontinued operations	0	0	49.2	0
Income tax expense / (benefit) for discontinued operations	0	(5.3)	18.9	(3.6)
Discontinued operations	$ 0	$ 6.9	29.6	8.8
Cash flows from operating activities for discontinued operations			(0.7)	20.5
Cash flows from investing activities for discontinued operations			$ 75.5	$ 1
Dpler [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Deposit received on sale of DPLER					$ 75.5

Fixed-asset Impairment Fixed-as

Fixed-asset Impairment Fixed-asset Impairment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Impairment of Long-Lived Assets Held-for-use	$ 235.5	$ 0	$ 235.5	$ 0
Killen [Member]
Impairment of Long-Lived Assets Held-for-use			230.8
Peaking Generating Facilities [Member]
Impairment of Long-Lived Assets Held-for-use			4.7
THE DAYTON POWER AND LIGHT COMPANY [Member]
Impairment of Long-Lived Assets Held-for-use	857.1	$ 0	857.1	$ 0
THE DAYTON POWER AND LIGHT COMPANY [Member] | Stuart [Member]
Impairment of Long-Lived Assets Held-for-use			292
THE DAYTON POWER AND LIGHT COMPANY [Member] | Killen [Member]
Impairment of Long-Lived Assets Held-for-use			246.2
THE DAYTON POWER AND LIGHT COMPANY [Member] | Zimmer [Member]
Impairment of Long-Lived Assets Held-for-use			318.9
Level 3 [Member] | Killen [Member]
Property, Plant, and Equipment, Fair Value Disclosure	84.3		84.3
Level 3 [Member] | Peaking Generating Facilities [Member]
Property, Plant, and Equipment, Fair Value Disclosure	5.2		5.2
Level 3 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Stuart [Member]
Property, Plant, and Equipment, Fair Value Disclosure	164.4		164.4
Level 3 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Killen [Member]
Property, Plant, and Equipment, Fair Value Disclosure	84.3		84.3
Level 3 [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Zimmer [Member]
Property, Plant, and Equipment, Fair Value Disclosure	$ 111		$ 111