Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net income	$ (51.7)	$ 31.8
Adjustments to reconcile net income / (loss) to net cash from operating activities:
Depreciation and amortization	28.0	33.4
Charge for early retirement of debt	0.0	2.6
Deferred income taxes	(4.7)	(9.2)
Impairment of Long-Lived Assets Held-for-use	66.4	0.0
Gain on sale of business	0.0	(49.2)
Gain (Loss) on Sale of Assets and Asset Impairment Charges	19.4	0.1
Changes in certain assets and liabilities:
Accounts receivable	38.1	35.8
Inventories	0.1	19.0
Prepaid taxes	0.0	0.2
Taxes applicable to subsequent years	20.2	21.6
Deferred regulatory costs, net	(23.8)	4.8
Accounts payable	(30.9)	(7.6)
Accrued taxes payable	(66.0)	(13.5)
Accrued interest payable	15.9	7.3
Security deposits	17.6	4.4
Increase (Decrease) Deferred Investment Tax Credit	(0.1)	(0.1)
Increase (Decrease) in Self Insurance Reserve	1.2	(0.4)
Increase (Decrease) in Pension and Postretirement Obligations	1.3	(4.5)
Other	(4.5)	9.1
Net cash provided by operating activities	26.5	83.0
Cash flows from investing activities:
Capital expenditures	(41.4)	(37.7)
Proceeds from sale of business	0.0	75.5
Insurance proceeds	1.2	0.0
Purchase of intangible assets	(0.1)	(0.1)
Decrease in restricted cash	20.6	1.3
Other investing activities, net	0.3	0.6
Net cash used in investing activities	(19.4)	39.6
Cash flows from financing activities:
Retirement of long-term debt	(7.4)	(75.4)
Net cash used in financing activities	(7.4)	(75.4)
Cash and cash equivalents:
Net change	(0.3)	47.2
Balance at beginning of period	54.6	32.4
Cash and cash equivalents at end of period	54.3	79.6
Supplemental cash flow information:
Interest paid, net of amounts capitalized	10.4	19.2
Non-cash financing and investing activities:
Accruals for capital expenditures	10.7	12.5
THE DAYTON POWER AND LIGHT COMPANY [Member]
Cash flows from operating activities:
Net income	(41.8)	33.7
Adjustments to reconcile net income / (loss) to net cash from operating activities:
Depreciation and amortization	23.5	34.3
Deferred income taxes	0.4	(1.8)
Impairment of Long-Lived Assets Held-for-use	66.3	0.0
Gain (Loss) on Sale of Assets and Asset Impairment Charges	19.4	0.1
Changes in certain assets and liabilities:
Accounts receivable	28.4	2.1
Inventories	0.1	19.1
Prepaid taxes	0.0	2.7
Taxes applicable to subsequent years	19.8	21.1
Deferred regulatory costs, net	(23.8)	4.8
Accounts payable	(24.6)	(9.8)
Accrued taxes payable	(52.7)	(28.2)
Accrued interest payable	(1.3)	(3.1)
Security deposits	17.6	4.4
Increase (Decrease) Deferred Investment Tax Credit	(0.5)	0.0
Increase (Decrease) in Pension and Postretirement Obligations	1.3	(4.5)
Other	(9.3)	8.5
Net cash provided by operating activities	22.8	83.4
Cash flows from investing activities:
Capital expenditures	(34.1)	(35.8)
Insurance proceeds	0.0	0.2
Purchase of intangible assets	(0.1)	(0.1)
Decrease in restricted cash	20.6	1.4
Other investing activities, net	0.2	0.5
Net cash used in investing activities	(13.4)	(33.8)
Cash flows from financing activities:
Retirement of long-term debt	(1.1)	0.0
Issuance of short-term debt - related party	30.0	5.0
Repayment of short-term debt - related party	(35.0)	(35.0)
Dividends paid on preferred stock	0.0	(0.2)
Net cash used in financing activities	(6.1)	(30.2)
Cash and cash equivalents:
Net change	3.3	19.4
Balance at beginning of period	1.6	5.4
Cash and cash equivalents at end of period	4.9	24.8
Supplemental cash flow information:
Interest paid, net of amounts capitalized	7.9	7.1
Non-cash financing and investing activities:
Accruals for capital expenditures	$ 8.7	$ 12.5