Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net income	$ 61.4	$ 41.4
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	34.2	62.4
Amortization of Debt Issuance Costs	4.3	4.4
Gain (Loss) on Extinguishment of Debt	(44.9)	(6.4)
Deferred income taxes	(8.7)	(17.8)
Impairment of Long-Lived Assets Held-for-use	0.0	2.8
Gain (Loss) on Disposition of Business, Including Discontinued Operation	(0.1)	13.2
Gain (Loss) on Sale of Assets and Asset Impairment Charges	0.9	(0.6)
Changes in certain assets and liabilities:
Accounts receivable, net	18.0	34.4
Inventories	(3.2)	14.7
Taxes applicable to subsequent years	56.2	57.7
Deferred regulatory costs, net	2.9	(4.1)
Accounts payable	(5.1)	(17.4)
Accrued taxes	(71.0)	(47.1)
Accrued interest	12.9	13.4
Increase (Decrease) in Obligation, Pension and Other Postretirement Benefits	(9.3)	(4.0)
Other	(2.0)	(6.9)
Net Cash Provided by (Used in) Operating Activities	136.3	152.9
Cash flows from investing activities:
Capital expenditures	(122.4)	(75.8)
Proceeds from disposal and sale of business	0.0	234.9
Payments for Removal Costs	0.0	(14.5)
Proceeds from Sale of Property, Plant, and Equipment	0.0	10.6
Proceeds from Insurance Settlement, Investing Activities	0.0	2.8
Payments to Acquire Intangible Assets	3.6	0.0
Other investing activities, net	0.1	(0.5)
Net cash provided by / (used in) investing activities	(125.9)	157.5
Cash flows from financing activities:
Payments of Deferred Finance Costs	(9.2)	0.0
Repayments of Lines of Credit	(35.0)	(40.0)
Proceeds from Issuance of Long-term Debt	821.7	0.0
Proceeds from Lines of Credit	133.0	30.0
Retirement of long-term debt, including early payment premium	(978.0)	(239.4)
Proceeds from (Payments for) Other Financing Activities	(0.2)	0.0
Net cash used in financing activities	(67.7)	(249.4)
Cash, cash equivalents, and restricted cash:
Net Cash Provided by (Used in) Discontinued Operations	0.0	1.5
Restricted Cash and Cash Equivalents	54.4	87.4
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect	(57.3)	62.5
Supplemental cash flow information:
Interest paid, net of amounts capitalized	47.1	55.2
Proceeds from Income Tax Refunds	1.3	(2.0)
Non-cash financing and investing activities:
Accruals for capital expenditures	2.3	7.6
Non-cash Proceeds from Sale of Business	0.0	4.1
Non-cash capital contribution	2.7	30.2
THE DAYTON POWER AND LIGHT COMPANY [Member]
Cash flows from operating activities:
Net income	103.7	61.9
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	52.9	56.5
Gain (Loss) on Extinguishment of Debt	0.0	(0.6)
Deferred income taxes	(17.2)	(7.5)
Gain (Loss) on Disposition of Business	0.0	12.4
Changes in certain assets and liabilities:
Accounts receivable, net	18.9	(3.3)
Inventories	(2.1)	(0.2)
Taxes applicable to subsequent years	54.3	54.0
Deferred regulatory costs, net	2.9	(4.1)
Accounts payable	(4.8)	(1.1)
Accrued taxes	(65.6)	(58.7)
Accrued interest	6.0	(0.3)
Increase (Decrease) in Obligation, Pension and Other Postretirement Benefits	(9.3)	(3.1)
Other	(0.8)	6.1
Net Cash Provided by (Used in) Operating Activities	138.9	113.2
Cash flows from investing activities:
Capital expenditures	(121.1)	(65.0)
Payments for Removal Costs	0.0	(14.5)
Proceeds from Sale of Property, Plant, and Equipment	0.0	10.6
Proceeds from Insurance Settlement, Investing Activities	0.0	0.1
Other investing activities, net	(3.5)	(0.2)
Net cash provided by / (used in) investing activities	(124.6)	(69.0)
Cash flows from financing activities:
Payments of Deferred Finance Costs	(4.6)	0.0
Repayments of Lines of Credit	0.0	(40.0)
Proceeds from Issuance of Long-term Debt	422.3	0.0
Proceeds from Lines of Credit	60.0	30.0
Retirement of long-term debt, including early payment premium	(436.1)	(63.3)
Payments of Ordinary Dividends, Common Stock	(90.0)	(43.8)
Proceeds from Contributions from Parent	0.0	80.0
Proceeds from (Payments for) Other Financing Activities	(0.1)	0.0
Net cash used in financing activities	(48.5)	(37.1)
Cash, cash equivalents, and restricted cash:
Restricted Cash and Cash Equivalents	32.0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect	(34.2)	7.1
Supplemental cash flow information:
Interest paid, net of amounts capitalized	10.8	17.0
Income Taxes Paid, Net	19.0	8.3
Non-cash financing and investing activities:
Accruals for capital expenditures	2.0	7.2
Other Operating Income (Expense) [Member]
Adjustments to reconcile net income to net cash from operating activities:
Impairment of Long-Lived Assets Held-for-use	0.0	2.8
Gain (Loss) on Disposition of Business	$ 0.0	$ 11.7