XML 36 R25.htm IDEA: XBRL DOCUMENT v3.8.0.1
Basis of Presentation (Details)
$ in Millions
 3 Months Ended
Mar. 31, 2018
USD ($)
mi²
retail_customers
Mar. 31, 2017
USD ($)
Basis of Presentation [Abstract]    
Service Area Sq Miles | mi² 4,000  
Incorporated Cities 51  
Number of Retail Customers | retail_customers 877,000  
Percent of State's Population 46.00%  
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax $ 0 $ 1
Alternative revenue programs, net of amortization 2 0
Revenues 493 530
Defined Benefit Plan, Non-service Cost 1 $ 1
Defined Benefit Plan, Expected Amortization of Prior Service Cost (Credit), Next Fiscal Year $ 3