Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended			1 Months Ended	12 Months Ended	11 Months Ended	12 Months Ended
	Dec. 31, 2012 THE DAYTON POWER AND LIGHT COMPANY [Member]	Dec. 31, 2011 THE DAYTON POWER AND LIGHT COMPANY [Member]	Dec. 31, 2010 THE DAYTON POWER AND LIGHT COMPANY [Member]	Dec. 31, 2011 Successor [Member]	Dec. 31, 2012 Successor [Member]	Nov. 27, 2011 Predecessor [Member]	Dec. 31, 2010 Predecessor [Member]	Dec. 31, 2012 Emission Allowances [Member] THE DAYTON POWER AND LIGHT COMPANY [Member]	Dec. 31, 2011 Emission Allowances [Member] THE DAYTON POWER AND LIGHT COMPANY [Member]	Dec. 31, 2010 Emission Allowances [Member] THE DAYTON POWER AND LIGHT COMPANY [Member]	Dec. 31, 2012 Emission Allowances [Member] Successor [Member]	Dec. 31, 2010 Emission Allowances [Member] Predecessor [Member]	Dec. 31, 2012 Renewable Energy Certificates [Member] THE DAYTON POWER AND LIGHT COMPANY [Member]	Dec. 31, 2011 Renewable Energy Certificates [Member] THE DAYTON POWER AND LIGHT COMPANY [Member]	Dec. 31, 2010 Renewable Energy Certificates [Member] THE DAYTON POWER AND LIGHT COMPANY [Member]	Dec. 31, 2012 Renewable Energy Certificates [Member] Successor [Member]	Dec. 31, 2010 Renewable Energy Certificates [Member] Predecessor [Member]
Cash flows from operating activities:
Net income	$ 91.2	$ 193.2	$ 277.7	$ (6.2)	$ (1,729.8)	$ 150.5	$ 290.3
Adjustments to reconcile Net income to Net cash provided by operating activities:
Depreciation and amortization	141.3	134.9	130.7	11.6	125.4	129.4	139.4
Amortization of intangibles				11.6	95.1
Amortization of debt market value adjustments					(19.0)
Deferred income taxes	3.6	50.7	54.3	0.1	(4.2)	65.5	59.9
Gain on liquidation of DPL stock, held in trust		(14.6)		(26.9)
Fixed asset impairment	80.8
Charge for early redemption of debt						15.3
Goodwill Impairment					1,817.2
Recognition of deferred SECA revenue	(17.8)				(17.8)
Changes in certain assets and liabilities:
Accounts receivable	20.9	5.3	15.2	(12.3)	13.4	14.6	(1.5)
Inventories	14.2	(11.8)	12.2	(2.3)	15.6	(8.0)	12.4
Prepaid taxes	0.1	8.1	(8.9)	0.6		7.1	(9.0)
Taxes applicable to subsequent years	5.2	(9.0)	(3.6)	(71.2)	7.2	58.4	(4.1)
Deferred regulatory costs, net	(1.5)	(12.6)	21.8	0.1	(1.1)	(14.4)	21.8
Accounts payable	(15.3)	7.1	16.9	6.6	(16.2)	(0.6)	17.8
Accrued taxes payable	(8.5)	15.2	1.7	78.5	5.1	(58.6)	1.2
Accrued interest payable	5.2	0.2	(5.4)	6.4	1.5	(8.1)	(5.1)
Pension, retiree and other benefits	28.5	(24.0)	(58.2)	10.2	28.5	(34.2)	(58.2)
Unamortized investment tax credit	(2.5)	(2.5)	(2.8)	(0.2)	(0.3)	(2.3)	(2.8)
Insurance and claims costs				(0.1)	(2.8)	4.3	(6.1)
Other	(5.6)	24.0	3.7	(7.9)	(26.3)	15.5	17.1
Net cash provided by operating activities	339.8	364.2	455.3	(1.4)	291.5	334.4	473.1
Cash flows from investing activities:
Capital expenditures	(195.5)	(204.5)	(150.0)	(30.5)	(198.1)	(174.2)	(152.7)
Proceeds from sale of property - other	0.2				1.1
Purchase of MC Squared						(8.3)
Payments to Acquire Intangible Assets								(0.1)	(0.2)	(0.9)	(0.1)	(0.9)	(5.4)	(4.4)	(2.0)	(5.4)	(2.0)
Increase (Decrease) in Restricted Cash	2.9	(3.8)	(6.0)	1.0	2.9	(4.8)	(6.0)
Purchases of short-term investments and securities						(1.7)	(86.4)
Sales of short-term investments and securities						70.9	17.1
Proceeds from liquidation of DPL stock, held in trust		26.9
Other	0.4	1.0	1.4	(0.3)	0.4	1.4	1.4
Net cash used for investing activities	(197.5)	(185.0)	(157.5)	(30.4)	(199.2)	(120.7)	(229.5)
Cash flows from financing activities:
Dividends paid on common stock	(145.0)	(220.0)	(300.0)	(63.0)	(64.1)	(113.0)	(139.7)
Dividends paid on preferred stock	(0.9)	(0.9)	(0.9)
Deferred Finance Costs					(0.8)
Proceeds from liquidation of DPL stock, held in trust				26.9
Early redemption of Capital Trust II debt						(122.0)
Premium paid for early redemption of debt						(12.2)
Payment of MC Squared debt						(13.5)
Payment of long-term debt	(0.1)	(0.1)			(0.1)	(297.5)
Issuance of long-term debt				125.0		300.0
Withdrawals from revolving credit facilities		50.0				50.0
Repayments of borrowings from revolving credit facilities		(50.0)				(50.0)
Contributions to additional paid-in capital from parent		20.0			0.3
Repurchase of DPL common stock							(56.4)
Repurchase of warrants					(9.0)
Exercise of stock options						1.6	1.4
Exercise of warrants						14.7
Tax impact related to exercise of stock options						1.4	0.2
Net cash used for financing activities	(146.0)	(201.0)	(300.9)	88.9	(73.7)	(240.5)	(194.5)
Cash and cash equivalents:
Net change	(3.7)	(21.8)	(3.1)	57.1	18.6	(26.8)	49.1
Assumption of cash aquisition				19.2
Balance at beginning of period	32.2	54.0	57.1	97.2	173.5	124.0	74.9
Cash and cash equivalents at end of period	28.5	32.2	54.0	173.5	192.1	97.2	124.0
Supplemental cash flow information:
Interest paid, net of amounts capitalized	35.1	39.2	45.1	6.0	136.9	62.0	77.1
Income taxes paid, net	61.9	13.9	87.0		47.6	25.6	87.1
Assumption of debit with acquisition				1,250.0
Non-cash financing and investing activities:
Accruals for capital expenditures	16.7	26.5	23.2	26.5	16.7	18.9	23.2
Long-term liability incurred for purchase of assets		$ 18.7				$ 18.7