Segment Information (Details Textuals)	3 Months Ended
	Mar. 31, 2014 Segments
Segment Reporting Information [Line Items]
Number of reportable operating segments	3
Regulated Distribution
Segment Reporting Information [Line Items]
Number of existing utility operating companies	10
Number of customers served by utility operating companies	6,000,000
Number of square miles in service area	65,000
Megawatts of net demonstrated capacity of competitive segment	3,780
Competitive Energy Services
Segment Reporting Information [Line Items]
Megawatts of net demonstrated capacity of competitive segment	14,000
Competitive Energy Services | Unregulated Plants Expected to be Closed by 9/1/2012
Segment Reporting Information [Line Items]
Megawatt capacity of plants expected to be closed	885