Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net income	$ 1.9	$ 42.1
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	17.8	(3.1)
Deferred income taxes	3.4	5.2
Changes in certain assets and liabilities:
Accounts receivable, net	14.2	4.1
Inventories	3.4	(1.2)
Taxes applicable to subsequent years	17.0	18.7
Deferred regulatory costs, net	(5.0)	7.7
Accounts payable	(7.6)	(14.0)
Accrued taxes payable / receivable	(39.2)	(35.2)
Accrued interest	15.1	15.6
Increase (Decrease) in Obligation, Pension and Other Postretirement Benefits	(8.2)	(6.9)
Other	(0.4)	3.6
Net Cash Provided by (Used in) Operating Activities	12.4	36.6
Cash flows from investing activities:
Capital expenditures	(44.6)	(34.3)
Proceeds from Sale of Productive Assets	5.1	0.0
Other investing activities, net	(0.7)	0.0
Net cash used in investing activities	(40.2)	(34.3)
Cash flows from financing activities:
Repayments of Lines of Credit	(10.0)	0.0
Proceeds from Lines of Credit	45.0	0.0
Retirement of long-term debt, including early payment premium	0.0	(1.1)
Proceeds from (Payments for) Other Financing Activities	0.0	(0.1)
Net cash provided by / (used in) financing activities	35.0	(1.2)
Cash, cash equivalents, and restricted cash:
Restricted Cash and Cash Equivalents	54.2	112.8
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect	7.2	1.1
Supplemental cash flow information:
Interest paid, net of amounts capitalized	2.3	6.7
Non-cash financing and investing activities:
Accruals for capital expenditures	5.0	4.4
Non-cash capital contribution	0.0	1.5
THE DAYTON POWER AND LIGHT COMPANY [Member]
Cash flows from operating activities:
Net income	11.7	29.0
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	17.3	18.0
Deferred income taxes	3.0	(0.9)
Changes in certain assets and liabilities:
Accounts receivable, net	2.8	2.6
Inventories	1.3	(0.5)
Taxes applicable to subsequent years	17.0	18.1
Deferred regulatory costs, net	(5.0)	7.7
Accounts payable	(8.6)	(12.7)
Accrued taxes payable / receivable	(36.7)	(27.4)
Accrued interest	4.1	0.1
Increase (Decrease) in Obligation, Pension and Other Postretirement Benefits	(8.2)	(6.8)
Other	1.3	2.3
Net Cash Provided by (Used in) Operating Activities	0.0	29.5
Cash flows from investing activities:
Capital expenditures	(43.7)	(33.7)
Other investing activities, net	(0.7)	0.0
Net cash used in investing activities	(44.4)	(33.7)
Cash flows from financing activities:
Proceeds from Lines of Credit	45.0	0.0
Retirement of long-term debt, including early payment premium	0.0	(1.1)
Proceeds from (Payments for) Other Financing Activities	0.0	(0.1)
Net cash provided by / (used in) financing activities	45.0	(1.2)
Cash, cash equivalents, and restricted cash:
Restricted Cash and Cash Equivalents	21.9	60.8
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect	0.6	(5.4)
Supplemental cash flow information:
Interest paid, net of amounts capitalized	0.7	5.9
Non-cash financing and investing activities:
Accruals for capital expenditures	$ 4.8	$ 4.8