Consolidated Statements of Comprehensive Income/(Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net loss	$ (485.2)	$ (239.0)	$ (74.6)
Available-for-sale securities activity:
Change in fair value of available-for-sale securities, net of income tax benefit/(expense)	0.2	(0.1)	(0.3)
Reclassification to earnings of available-for-sale securities, net of income tax expense/(benefit)	0.0	0.0	0.2
Total change in fair value of available-for-sale securities	0.2	(0.1)	(0.1)
Derivative activity:
Change in derivative fair value, net of income tax benefit/(expense)	16.1	18.2	(19.0)
Reclassification of earnings, net of income tax benefit/(expense)	(29.7)	(10.0)	16.9
Total change in fair value of derivatives	(13.6)	8.2	(2.1)
Pension and postretirement activity:
Prior service cost for the period, net of income tax benefit/(expense)	0.0	0.0	(2.2)
Net loss for the period, net of income tax benefit/(expense)	(4.7)	1.6	(12.7)
Reclassification to earnings, net of income tax benefit/(expense)	1.0	0.2	0.0
Total change in unfunded pension obligation	(3.7)	1.8	(14.9)
Other comprehensive income / (loss)	(17.1)	9.9	(17.1)
Net comprehensive income / (loss)	(502.3)	(229.1)	(91.7)
THE DAYTON POWER AND LIGHT COMPANY [Member]
Net loss	(772.7)	106.4	115.0
Available-for-sale securities activity:
Change in fair value of available-for-sale securities, net of income tax benefit/(expense)	0.2	(0.2)	(0.3)
Reclassification to earnings of available-for-sale securities, net of income tax expense/(benefit)	0.0	0.0	0.2
Total change in fair value of available-for-sale securities	0.2	(0.2)	(0.1)
Derivative activity:
Change in derivative fair value, net of income tax benefit/(expense)	16.1	18.2	(18.8)
Reclassification of earnings, net of income tax benefit/(expense)	(30.0)	(9.8)	15.4
Total change in fair value of derivatives	(13.9)	8.4	(3.4)
Pension and postretirement activity:
Prior service cost for the period, net of income tax benefit/(expense)	(0.1)	0.0	(2.3)
Net loss for the period, net of income tax benefit/(expense)	(5.9)	1.7	(12.5)
Reclassification to earnings, net of income tax benefit/(expense)	5.9	3.7	2.7
Total change in unfunded pension obligation	(0.1)	5.4	(12.1)
Other comprehensive income / (loss)	(13.8)	13.6	(15.6)
Net comprehensive income / (loss)	$ (786.5)	$ 120.0	$ 99.4