Consolidated Statements of Shareholders' Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Other Paid-In Capital [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]	Retained Earnings [Member]	THE DAYTON POWER AND LIGHT COMPANY [Member]	THE DAYTON POWER AND LIGHT COMPANY [Member] Common Stock [Member]	THE DAYTON POWER AND LIGHT COMPANY [Member] Other Paid-In Capital [Member]	THE DAYTON POWER AND LIGHT COMPANY [Member] Accumulated Other Comprehensive Income/(Loss) [Member]	THE DAYTON POWER AND LIGHT COMPANY [Member] Retained Earnings [Member]
Balance at Dec. 31, 2012	$ 426.8	$ 0.0	$ 2,236.7	$ (3.9)	$ (1,806.0)	$ 1,299.1	$ 0.4	$ 803.3	$ (38.7)	$ 534.1
Balance (in shares) at Dec. 31, 2012		1					41,172,173
Net comprehensive income/ (loss)	(193.5)			28.5	(222.0)	95.6			12.0	83.6
Common stock dividends	0.0				0.0	(190.0)				(190.0)
Preferred stock dividends						(0.9)				(0.9)
Other	6.2		0.3		5.9	0.2		0.2		0.0
Balance at Dec. 31, 2013	239.5	$ 0.0	2,237.0	24.6	(2,022.1)	1,204.0	$ 0.4	$ 803.5	(26.7)	426.8
Balance (in shares) at Dec. 31, 2013		1					41,172,173
Net comprehensive income/ (loss)	(91.7)			(17.1)	(74.6)	99.4			(15.6)	115.0
Common stock dividends						(159.0)				(159.0)
Preferred stock dividends						(0.9)				(0.9)
Other	0.4		0.4		0.0	(0.1)				(0.1)
Balance at Dec. 31, 2014	148.2	$ 0.0	2,237.4	7.5	(2,096.7)	1,143.4	$ 0.4	$ 803.5	(42.3)	381.8
Balance (in shares) at Dec. 31, 2014		1					41,172,173
Net comprehensive income/ (loss)	(229.1)			9.9	$ (239.0)	120.0			13.6	106.4
Common stock dividends						(50.0)				(50.0)
Preferred stock dividends						(0.9)				$ (0.9)
Other	0.3		0.3			0.2		0.2
Balance at Dec. 31, 2015	$ (80.6)	$ 0.0	$ 2,237.7	$ 17.4	$ (2,335.7)	$ 1,212.7	$ 0.4	$ 803.7	$ (28.7)	$ 437.3
Balance (in shares) at Dec. 31, 2015		1					41,172,173