XML 85 R82.htm IDEA: XBRL DOCUMENT v3.20.1
Revenue (Details)
$ in Millions
 3 Months Ended 6 Months Ended
Mar. 31, 2020
USD ($)
percent
Mar. 31, 2019
USD ($)
Mar. 31, 2020
USD ($)
percent
Mar. 31, 2019
USD ($)
State [Line Items]        
Electric revenue $ (2,488) $ (2,712) $ (5,019) $ (5,392)
Sales of Electricity 2,489 2,712 5,021 5,393
Off System Sales of Electricity 1 0 2 1
Other revenue $ 32 38 $ 78 82
Total long duration contract revenue recognition 2,301   4,658  
Total number of customers that represent a percent of sales | percent 1   1  
Revenues $ 2,521 $ 2,750 $ 5,099 $ 5,475
20-year Termination Notice [Member]        
State [Line Items]        
Number of customers that represent the percent of sales | percent 1   1  
Revenues $ 1,737   $ 3,506  
10-year Termination Notice [Member]        
State [Line Items]        
Number of customers that represent the percent of sales | percent 0   0  
Revenues $ 15   $ 30  
5-year termination notice [Member]        
State [Line Items]        
Number of customers that represent the percent of sales | percent 0   0  
Revenues $ 549   $ 1,122