Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Current assets:
Accounts receivable, net (Note 3)	$ 224.4	$ 219.1
Inventories (Note 3)	126.4	125.8
Regulatory assets, current (Note 4)	15.2	20.2
Other noncurrent assets:
Regulatory assets, non-current (Note 4)	172.9	177.8
Goodwill	2,489.3
Current liabilities:
Regulatory liabilities, current (Note 4)		0.6
Noncurrent liabilities:
Regulatory liabilities, non-current (Note 4)	118.5	118.6
Common shareholders' equity:
Accumulated other comprehensive loss	6.7	(0.4)
THE DAYTON POWER AND LIGHT COMPANY [Member]
Current assets:
Cash and cash equivalents	23.4	32.2
Accounts receivable, net (Note 3)	181.1	178.5
Inventories (Note 3)	125.1	123.1
Taxes applicable to subsequent years	50.4	71.9
Regulatory assets, current (Note 4)	12.7	17.7
Other prepayments and current assets	24.6	25.0
Total current assets	417.3	448.4
Property, plant and equipment:
Property, plant and equipment	5,318.6	5,277.9
Less: Accumulated depreciation and amortization	(2,596.5)	(2,568.9)
Property, plant and equipment, net of depreciation	2,722.1	2,709.0
Construction work in process	149.4	150.7
Total net property, plant and equipment	2,871.5	2,859.7
Other noncurrent assets:
Regulatory assets, non-current (Note 4)	172.9	177.8
Intangible asset, net of amortization	7.3	6.5
Other deferred assets	32.6	33.3
Total other noncurrent assets	212.8	217.6
Total Assets	3,501.6	3,525.7
Current liabilities:
Current portion - long-term debt (Note 6)	0.4	0.4
Accounts payable	97.8	106.0
Accrued taxes	95.6	72.8
Accrued interest	15.4	7.9
Customer security deposits	16.4	15.8
Other current liabilities	47.3	41.4
Total current liabilities	272.9	244.3
Noncurrent liabilities:
Long-term debt (Note 6)	902.9	903.0
Deferred taxes (Note 7)	634.0	637.7
Regulatory liabilities, non-current (Note 4)	118.5	118.6
Pension, retiree and other benefits	47.7	47.5
Unamortized investment tax credit	29.3	29.9
Other deferred credits	124.3	163.9
Total noncurrent liabilities	1,856.7	1,900.6
Redeemable preferred stock	22.9	22.9
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
Accumulated other comprehensive loss	(36.4)	(34.7)
Retained earnings	582.0	589.1
Total common shareholders' equity	1,349.1	1,357.9
Total Liabilities and Shareholders' Equity	3,501.6	3,525.7
Successor [Member]
Current assets:
Cash and cash equivalents	162.1	173.5
Accounts receivable, net (Note 3)	224.4	219.1
Inventories (Note 3)	126.4	125.8
Taxes applicable to subsequent years	53.6	76.5
Regulatory assets, current (Note 4)	15.2	20.2
Other prepayments and current assets	37.5	36.2
Total current assets	619.2	651.3
Property, plant and equipment:
Property, plant and equipment	2,482.3	2,431.0
Less: Accumulated depreciation and amortization	(41.1)	(7.5)
Property, plant and equipment, net of depreciation	2,441.2	2,423.5
Construction work in process	151.1	152.3
Total net property, plant and equipment	2,592.3	2,575.8
Other noncurrent assets:
Regulatory assets, non-current (Note 4)	172.9	177.8
Goodwill	2,489.3	2,489.3
Intangible asset, net of amortization	133.8	161.5
Other deferred assets	49.3	51.8
Total other noncurrent assets	2,845.3	2,880.4
Total Assets	6,056.8	6,107.5
Current liabilities:
Current portion - long-term debt (Note 6)	0.4	0.4
Accounts payable	103.3	111.1
Accrued taxes	94.7	76.3
Accrued interest	59.5	30.2
Customer security deposits	16.4	15.9
Regulatory liabilities, current (Note 4)	0	0.6
Insurance and claims costs	15.0	14.2
Other current liabilities	48.7	56.1
Total current liabilities	338.0	304.8
Noncurrent liabilities:
Long-term debt (Note 6)	2,624.1	2,628.9
Deferred taxes (Note 7)	543.1	549.4
Regulatory liabilities, non-current (Note 4)	118.5	118.6
Pension, retiree and other benefits	47.7	47.5
Unamortized investment tax credit	3.7	3.6
Other deferred credits	146.8	205.6
Total noncurrent liabilities	3,483.9	3,553.6
Redeemable preferred stock	18.4	18.4
Commitments and contingencies (Note 12)
Common shareholders' equity:
Other paid-in capital	2,239.3	2,237.3
Accumulated other comprehensive loss	6.7	(0.4)
Retained earnings	(29.5)	(6.2)
Total common shareholders' equity	2,216.5	2,230.7
Total Liabilities and Shareholders' Equity	$ 6,056.8	$ 6,107.5