Condensed Consolidated Statements of Results of Operations (USD $) In Millions, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Revenues	$ 511.8	$ 516.9	$ 1,451.4	$ 1,413.6
Cost of revenues:
Fuel	129.0	104.3	320.9	297.1
Purchased power	108.3	119.0	342.7	282.7
Total cost of revenues	237.3	223.3	663.6	579.8
Gross margin	274.5	293.6	787.8	833.8
Operating expenses:
Operation and maintenance	92.0	84.2	298.2	252.3
Depreciation and amortization	35.8	32.2	106.0	105.3
General taxes	33.8	32.6	104.1	96.3
Total operating expenses	161.6	149.0	508.3	453.9
Operating income	112.9	144.6	279.5	379.9
Other income / (expense), net:
Investment income	0.1	0.3	0.3	0.6
Interest expense	(16.8)	(17.6)	(51.3)	(53.0)
Charge for early redemption of debt			(15.3)
Other expense	(0.5)	(0.5)	(1.2)	(1.8)
Total other income / (expense), net	(17.2)	(17.8)	(67.5)	(54.2)
Earnings before income tax	95.7	126.8	212.0	325.7
Income tax expense	28.6	40.4	69.7	106.9
Net income	67.1	86.4	142.3	218.8
Earnings on common stock	67.1	86.4	142.3	218.8
Average number of common shares outstanding (millions):
Basic	115.0	115.8	114.4	115.7
Diluted	115.5	116.3	115.0	116.2
Earnings per share of common stock:
Basic	$ 0.58	$ 0.75	$ 1.24	$ 1.89
Diluted	$ 0.58	$ 0.74	$ 1.24	$ 1.88
Dividends paid per share of common stock	$ 0.3325	$ 0.3025	$ 0.9975	$ 0.9075
THE DAYTON POWER AND LIGHT COMPANY [Member]
Revenues	466.8	487.0	1,339.2	1,348.9
Cost of revenues:
Fuel	124.0	97.4	311.7	286.5
Purchased power	95.6	116.4	317.8	279.3
Total cost of revenues	219.6	213.8	629.5	565.8
Gross margin	247.2	273.2	709.7	783.1
Operating expenses:
Operation and maintenance	80.2	78.7	266.7	243.4
Depreciation and amortization	33.8	30.4	100.3	98.4
General taxes	33.2	32.2	97.6	94.0
Total operating expenses	147.2	141.3	464.6	435.8
Operating income	100.0	131.9	245.1	347.3
Other income / (expense), net:
Investment income	0.4	0.4	1.5	1.3
Interest expense	(9.3)	(9.4)	(28.7)	(27.9)
Other expense	(0.4)	(0.3)	(1.2)	(1.4)
Total other income / (expense), net	(9.3)	(9.3)	(28.4)	(28.0)
Earnings before income tax	90.7	122.6	216.7	319.3
Income tax expense	26.8	39.4	69.3	104.6
Net income	63.9	83.2	147.4	214.7
Dividends on preferred stock	0.2	0.2	0.6	0.6
Earnings on common stock	$ 63.7	$ 83.0	$ 146.8	$ 214.1