Basis of Presentation (Details) (USD $) Share data in Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014 sqmi retail_customers	Mar. 31, 2013
Basis of Presentation [Abstract]
Service Area Sq Miles	4,000
Incorporated Cities	52
Number of Retail Customers	838,283
Service Area Population	1.7
Percent of State's Population	44.00%
Cash received to be returned to customers pursuant to the Residential Exchange Program	$ 15,000,000	$ 2,000,000
Power Cost Deferrals, Net		2,000,000
Other Comprehensive Income	$ 0	$ 0