Business Segments (Narrative) (Details)	9 Months Ended
	Sep. 30, 2014 sqmi
Service area, square miles	6,000
Number of coal fired power plants	7
Approximate number of retail customers	515,000
Approximate Number Of Competitive Retail Customers	274,000
Electric generation through competitive bid	10.00%
Number of MC Squared Retail Customers	117,000
DP&L [Member]
Service area, square miles	6,000
Approximate number of retail customers	515,000