Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net income	$ (51.2)	$ (105.0)
Adjustments to reconcile net income / (loss) to net cash from operating activities:
Depreciation and amortization	54.5	69.4
Charge for early retirement of debt	0.3	2.6
Deferred income taxes	(1.8)	(95.9)
Impairment of Long-Lived Assets Held-for-use	66.4	235.5
Loss on asset disposal	0.0	(49.2)
Gain (Loss) on Sale of Assets and Asset Impairment Charges	16.2	0.1
Changes in certain assets and liabilities:
Accounts receivable	22.4	52.7
Inventories	7.7	21.6
Prepaid taxes	0.0	0.2
Taxes applicable to subsequent years	40.0	41.7
Deferred regulatory costs, net	(9.1)	8.0
Accounts payable	(38.4)	(11.7)
Accrued taxes payable	(65.3)	(25.7)
Accrued interest payable	(0.1)	(0.8)
Security deposits	1.7	0.0
Increase (Decrease) Deferred Investment Tax Credit	(0.2)	(0.2)
Increase (Decrease) in Self Insurance Reserve	(0.1)	(0.4)
Increase (Decrease) in Pension and Postretirement Obligations	2.0	(4.2)
Other	(4.8)	(6.3)
Net cash provided by operating activities	40.2	132.4
Cash flows from investing activities:
Capital expenditures	(66.4)	(79.1)
Proceeds from sale of business	0.0	75.5
Insurance proceeds	0.9	3.2
Purchase of intangible assets	(0.1)	(0.2)
Increase / (decrease) in restricted cash	27.5	(16.0)
Other investing activities, net	0.2	0.7
Net cash provided by / (used in) investing activities	(37.9)	(15.9)
Cash flows from financing activities:
Retirement of long-term debt	(22.8)	(75.4)
Proceeds from (Payments for) Other Financing Activities	0.0	(0.1)
Net cash provided by / (used in) financing activities	(22.8)	(75.5)
Cash and cash equivalents:
Net change	(20.5)	41.0
Balance at beginning of period	54.6	32.4
Cash and cash equivalents at end of period	34.1	73.4
Supplemental cash flow information:
Interest paid, net of amounts capitalized	51.8	51.1
Proceeds from Income Tax Refunds	0.0	0.1
Non-cash financing and investing activities:
Accruals for capital expenditures	9.9	8.3
THE DAYTON POWER AND LIGHT COMPANY [Member]
Adjustments to Additional Paid in Capital, Dividends in Excess of Retained Earnings	(9.0)	0.0
Cash flows from operating activities:
Net income	(25.7)	(497.9)
Adjustments to reconcile net income / (loss) to net cash from operating activities:
Depreciation and amortization	45.5	71.1
Charge for early retirement of debt	0.1	0.0
Deferred income taxes	3.2	(308.7)
Impairment of Long-Lived Assets Held-for-use	66.3	857.1
Gain (Loss) on Sale of Assets and Asset Impairment Charges	16.2	0.2
Changes in certain assets and liabilities:
Accounts receivable	26.3	20.5
Inventories	8.0	21.6
Prepaid taxes	0.0	2.7
Taxes applicable to subsequent years	39.1	40.7
Deferred regulatory costs, net	(9.1)	8.0
Accounts payable	(38.0)	(13.8)
Accrued taxes payable	(75.7)	(43.3)
Accrued interest payable	(0.1)	0.2
Security deposits	1.7	0.0
Increase (Decrease) in Pension and Postretirement Obligations	2.0	(4.2)
Other	(2.3)	5.3
Net cash provided by operating activities	57.5	159.5
Cash flows from investing activities:
Capital expenditures	(57.6)	(71.8)
Insurance proceeds	1.3	3.4
Purchase of intangible assets	(0.1)	(0.3)
Increase / (decrease) in restricted cash	27.5	(16.1)
Other investing activities, net	0.2	0.8
Net cash provided by / (used in) investing activities	(28.7)	(84.0)
Cash flows from financing activities:
Retirement of long-term debt	(10.3)	0.0
Issuance of short-term debt - related party	30.0	5.0
Repayment of short-term debt - related party	(35.0)	(40.0)
Proceeds from (Payments for) Other Financing Activities	0.0	(0.1)
Dividends paid on preferred stock	0.0	(0.4)
Net cash provided by / (used in) financing activities	(24.3)	(35.5)
Cash and cash equivalents:
Net change	4.5	40.0
Balance at beginning of period	1.6	5.4
Cash and cash equivalents at end of period	6.1	45.4
Supplemental cash flow information:
Interest paid, net of amounts capitalized	13.6	8.0
Non-cash financing and investing activities:
Accruals for capital expenditures	$ 9.1	$ 8.3