Pension and Postretirement Benefits (Weighted Average Assumptions Used to Determine Net Periodic Benefit Cost (Income)) (Details)	1 Months Ended	11 Months Ended	12 Months Ended
	Dec. 31, 2011	Nov. 27, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.31%	4.88%	4.88%		5.75%
Expected rate of return on plan assets	8.00%	7.00%	7.00%		8.50%
Rate of compensation increases			3.94%	3.94%	4.44%
Pension [Member] | DP&L [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate			4.88%	5.31%	5.75%
Expected rate of return on plan assets			7.00%	8.00%	8.50%
Rate of compensation increases			3.94%	3.94%	4.44%
Postretirement [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.96%	4.62%	4.62%		5.35%
Expected rate of return on plan assets	6.00%	6.00%	6.00%		6.00%
Postretirement [Member] | DP&L [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate			4.62%	4.96%	5.35%
Expected rate of return on plan assets			6.00%	6.00%	6.00%