Pension and Postretirement Benefits (Pension and Postretirement Benefit Plans' Obligations and Assets) (Details) (USD $) In Millions, unless otherwise specified					1 Months Ended	11 Months Ended	12 Months Ended					1 Months Ended	11 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 DP&L [Member]	Dec. 31, 2012 DP&L [Member]	Dec. 31, 2011 Pension [Member]	Nov. 27, 2011 Pension [Member]	Dec. 31, 2013 Pension [Member]	Dec. 31, 2012 Pension [Member]	Dec. 31, 2013 Pension [Member] DP&L [Member]	Dec. 31, 2012 Pension [Member] DP&L [Member]	Dec. 31, 2011 Pension [Member] DP&L [Member]	Dec. 31, 2011 Postretirement [Member]	Nov. 27, 2011 Postretirement [Member]	Dec. 31, 2013 Postretirement [Member]	Dec. 31, 2012 Postretirement [Member]	Dec. 31, 2013 Postretirement [Member] DP&L [Member]	Dec. 31, 2012 Postretirement [Member] DP&L [Member]	Dec. 31, 2011 Postretirement [Member] DP&L [Member]	Dec. 31, 2013 Regulatory Asset [Member] Pension [Member]	Dec. 31, 2012 Regulatory Asset [Member] Pension [Member]	Dec. 31, 2013 Regulatory Asset [Member] Pension [Member] DP&L [Member]	Dec. 31, 2012 Regulatory Asset [Member] Pension [Member] DP&L [Member]	Dec. 31, 2012 Regulatory Asset [Member] Postretirement [Member]	Dec. 31, 2012 Regulatory Asset [Member] Postretirement [Member] DP&L [Member]	Dec. 31, 2013 Regulatory Liability [Member] Postretirement [Member]	Dec. 31, 2012 Regulatory Liability [Member] Postretirement [Member]	Dec. 31, 2013 Regulatory Liability [Member] Postretirement [Member] DP&L [Member]	Dec. 31, 2012 Regulatory Liability [Member] Postretirement [Member] DP&L [Member]	Dec. 31, 2013 Accumulated Other Comprehensive Income/(Loss) [Member] Pension [Member]	Dec. 31, 2012 Accumulated Other Comprehensive Income/(Loss) [Member] Pension [Member]	Dec. 31, 2013 Accumulated Other Comprehensive Income/(Loss) [Member] Pension [Member] DP&L [Member]	Dec. 31, 2012 Accumulated Other Comprehensive Income/(Loss) [Member] Pension [Member] DP&L [Member]	Dec. 31, 2013 Accumulated Other Comprehensive Income/(Loss) [Member] Postretirement [Member]	Dec. 31, 2012 Accumulated Other Comprehensive Income/(Loss) [Member] Postretirement [Member]	Dec. 31, 2013 Accumulated Other Comprehensive Income/(Loss) [Member] Postretirement [Member] DP&L [Member]	Dec. 31, 2012 Accumulated Other Comprehensive Income/(Loss) [Member] Postretirement [Member] DP&L [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at January 1							$ 395.6	$ 365.2	$ 395.6	$ 365.2				$ 22.4	$ 21.7	$ 22.4	$ 21.7
Service cost					0.5	4.5	7.2	6.2	7.2	6.2	5.0		0.1	0.2	0.1	0.2	0.1	0.1
Interest cost					1.5	15.5	15.6	17.3	15.6	17.3	17.0	0.1	0.9	0.8	0.9	0.8	0.9	1.0
Actuarial (gain) / loss							(26.5)	29.1	(26.5)	29.1				(2.2)	1.2	(2.2)	1.2
Benefits paid							(21.4)	(22.2)	(21.4)	(22.2)				(1.5)	(1.7)	(1.5)	(1.7)
Medicare Part D Reimbursement															0.2		0.2
Benefit obligation at December 31					365.2		370.5	395.6	370.5	395.6	365.2	21.7		19.7	22.4	19.7	22.4	21.7
Fair value of plan assets at January 1	349.1		349.1	361.4			361.4	335.9	361.4	335.9				4.2	4.5	4.2	4.5
Actual return / (loss) on plan assets							8.7	46.2	8.7	46.2					0.2		0.2
Contributions to plan assets							0.4	1.5	0.4	1.5				1.0	1.2	1.0	1.2
Fair value of plan assets at December 31	349.1		349.1	361.4	335.9		349.1	361.4	349.1	361.4	335.9	4.5		3.7	4.2	3.7	4.2	4.5
Funded Status of Plan							(21.4)	(34.2)	(21.4)	(34.2)				(16.0)	(18.2)	(16.0)	(18.2)
Current liabilities							(0.4)	(0.4)	(0.4)	(0.4)				(0.5)	(0.6)	(0.5)	(0.6)
Noncurrent liabilities	(51.6)	(61.6)					(21.0)	(33.8)	(21.0)	(33.8)				(15.5)	(17.6)	(15.5)	(17.6)
Net asset / (liability) at December 31							(21.4)	(34.2)	(21.4)	(34.2)				(16.0)	(18.2)	(16.0)	(18.2)
Prior service cost / (credit)							63.0	79.9	16.3	19.0				(6.0)	(4.5)	0.7	0.8
Net actuarial loss / (gain)							8.8	10.3	115.1	136.1				0.5	0.5	(6.9)	(5.7)
Accumulated other comprehensive income, regulatory assets and regulatory liabilities, pre-tax							$ 71.8	$ 90.2	$ 131.4	$ 155.1				$ (5.5)	$ (4.0)	$ (6.2)	$ (4.9)		$ 76.3	$ 88.0	$ 76.3	$ 88.0	$ 0.5	$ 0.5	$ (5.2)	$ (5.0)	$ (5.2)	$ (5.0)	$ (4.5)	$ 2.2	$ 55.1	$ 67.1	$ (0.3)	$ 0.5	$ (1.0)	$ (0.4)