Pension and Postretirement Benefits (Assumed Health Care Cost Trend Rates) (Details)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Nov. 27, 2011
Expense [Member]
Defined Benefit Plan Disclosure [Line Items]
Ultimate health care cost trend rate	5.00%	5.00%	5.00%
Expense [Member] | DP&L [Member]
Defined Benefit Plan Disclosure [Line Items]
Ultimate health care cost trend rate	5.00%	5.00%	5.00%
Expense [Member] | Pre-Age 65 [Member]
Defined Benefit Plan Disclosure [Line Items]
Current health care cost trend rate	8.50%	8.50%	9.50%
Year trend reaches ultimate	2019	2018	2015	2019
Expense [Member] | Pre-Age 65 [Member] | DP&L [Member]
Defined Benefit Plan Disclosure [Line Items]
Current health care cost trend rate	8.50%	8.50%	9.50%
Year trend reaches ultimate	2019	2018	2015
Expense [Member] | Post-Age 65 [Member]
Defined Benefit Plan Disclosure [Line Items]
Current health care cost trend rate	8.00%	8.00%	9.00%
Year trend reaches ultimate	2018	2017	2014	2018
Expense [Member] | Post-Age 65 [Member] | DP&L [Member]
Defined Benefit Plan Disclosure [Line Items]
Current health care cost trend rate	8.00%	8.00%	9.00%
Year trend reaches ultimate	2018	2017	2014
Benefit Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Ultimate health care cost trend rate	5.00%	5.00%	5.00%
Benefit Obligations [Member] | DP&L [Member]
Defined Benefit Plan Disclosure [Line Items]
Ultimate health care cost trend rate	5.00%	5.00%	5.00%
Benefit Obligations [Member] | Pre-Age 65 [Member]
Defined Benefit Plan Disclosure [Line Items]
Current health care cost trend rate	8.00%	8.50%	8.50%
Year trend reaches ultimate	2019	2019	2018	2019
Benefit Obligations [Member] | Pre-Age 65 [Member] | DP&L [Member]
Defined Benefit Plan Disclosure [Line Items]
Current health care cost trend rate	8.00%	8.50%	8.50%
Year trend reaches ultimate	2019	2019	2018
Benefit Obligations [Member] | Post-Age 65 [Member]
Defined Benefit Plan Disclosure [Line Items]
Current health care cost trend rate	7.50%	8.00%	8.00%
Year trend reaches ultimate	2018	2018	2017	2018
Benefit Obligations [Member] | Post-Age 65 [Member] | DP&L [Member]
Defined Benefit Plan Disclosure [Line Items]
Current health care cost trend rate	7.50%	8.00%	8.00%
Year trend reaches ultimate	2018	2018	2017