Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Jun. 30, 2012 THE DAYTON POWER AND LIGHT COMPANY [Member]	Dec. 31, 2011 THE DAYTON POWER AND LIGHT COMPANY [Member]	Jun. 30, 2012 Successor [Member]	Dec. 31, 2011 Successor [Member]
Current assets:
Cash and cash equivalents	$ 25.7	$ 32.2	$ 152.3	$ 173.5
Accounts receivable, net (Note 3)	157.0	178.5	208.1	219.1
Inventories (Note 3)	125.6	123.1	127.0	125.8
Taxes applicable to subsequent years	33.4	71.9	35.8	76.5
Regulatory assets, current (Note 4)	19.3	17.7	22.3	20.8
Other prepayments and current assets	23.1	25.0	35.2	36.2
Total current assets	384.1	448.4	580.7	651.9
Property, plant and equipment:
Property, plant and equipment	5,376.2	5,277.9	2,481.6	2,316.9
Less: Accumulated depreciation and amortization	(2,627.0)	(2,568.9)	(120.3)	(7.5)
Property, plant and equipment, net of depreciation	2,749.2	2,709.0	2,361.3	2,309.4
Construction work in process	144.2	150.7	145.2	152.3
Total net property, plant and equipment	2,893.4	2,859.7	2,506.5	2,461.7
Other noncurrent assets:
Regulatory assets, non-current (Note 4)	170.9	177.8	170.9	177.8
Goodwill			2,559.1	2,559.1
Intangible asset, net of amortization	10.0	6.5	111.9	165.4
Other deferred assets	30.1	33.3	42.3	51.8
Total other noncurrent assets	211.0	217.6	2,884.2	2,954.1
Total Assets	3,488.5	3,525.7	5,971.4	6,067.7
Current liabilities:
Current portion - long-term debt (Note 6)	0.4	0.4	0.4	0.4
Accounts payable	104.5	106.0	111.0	111.1
Accrued taxes	63.9	72.8	64.9	76.3
Accrued interest	13.2	7.9	32.0	30.2
Customer security deposits	16.4	15.8	16.5	15.9
Regulatory liabilities, current (Note 4)			0	0.5
Dividends payable			25.0	0
Insurance and claims costs			14.2	14.2
Other current liabilities	54.4	41.4	55.0	56.1
Total current liabilities	252.8	244.3	319.0	304.7
Noncurrent liabilities:
Long-term debt (Note 6)	902.8	903.0	2,619.2	2,628.9
Deferred taxes (Note 7)	639.2	637.7	499.0	510.5
Taxes Payable	55.5	93.9	56.4	96.9
Regulatory liabilities, non-current (Note 4)	118.2	118.6	118.2	118.6
Pension, retiree and other benefits	47.2	47.5	47.2	47.5
Derivative liability	2.7	3.9	42.2	36.9
Unamortized investment tax credit	28.6	29.9	3.5	3.6
Other deferred credits	63.3	66.1	68.0	71.0
Total noncurrent liabilities	1,857.5	1,900.6	3,453.7	3,513.9
Redeemable preferred stock	22.9	22.9	18.4	18.4
Commitments and contingencies (Note 12)
Common shareholders' equity:
Common stock, at par value of $0.01 per share:	0.4	0.4
Other paid-in capital	803.1	803.1	2,236.6	2,237.3
Accumulated other comprehensive loss	(36.3)	(34.7)	(6.8)	(0.4)
Retained earnings	588.1	589.1	(49.5)	(6.2)
Total common shareholders' equity	1,355.3	1,357.9	2,180.3	2,230.7
Total Liabilities and Shareholders' Equity	$ 3,488.5	$ 3,525.7	$ 5,971.4	$ 6,067.7