Business Segments (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2012
Service area, counties	24
Service area, square miles	6,000
Number of coal fired power plants	8
Approximate number of retail customers	500,000
Number of MC Squared Retail Customers	$ 4,000
Competitive Retail [Member]
Approximate number of retail customers	45,000