Summary of Significant Accounting Policies (Narrative) (Details)	9 Months Ended
	Sep. 30, 2014 sqmi employee
Service Area Square Miles	6,000
Approximate number of retail customers	515,000
Electric generation through competitive bid	10.00%
Approximate number of DPLER customers	274,000
Entity number of employees	1,197
Number of coal fired power plants	7
Employees under a collective bargaining agreement which expires in October-2011	61.00%
DP&L [Member]
Service Area Square Miles	6,000
Approximate number of retail customers	515,000
Entity number of employees	1,142
Employees under a collective bargaining agreement which expires in October-2011	63.00%
Year 2014 [Member] | DP&L [Member]
Electric generation through competitive bid	10.00%
Year 2015 [Member]
Electric generation through competitive bid	60.00%
Year 2015 [Member] | DP&L [Member]
Electric generation through competitive bid	60.00%
Year 2016 [Member]
Electric generation through competitive bid	100.00%
Year 2016 [Member] | DP&L [Member]
Electric generation through competitive bid	100.00%