v3.20.1
Segment Information (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues [1] $ 2,292 $ 2,599
Commodity Margin 588 779
Add: Mark-to-market commodity activity, net and other(2) [2] 213 52
Operating and maintenance expense 240 239
Depreciation and amortization expense 164 174
General and other administrative expense 31 32
Other operating expenses 17 34
(Income) loss from unconsolidated investments in power plants 0 (6)
Income from operations 349 358
Interest expense 169 149
Debt Extinguishment Costs and Other (Income) Expense, Net 4 19
Income before income taxes 176 190
Lease levelization (18) (16)
West    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues [1] 705 682
Commodity Margin 234 264
Add: Mark-to-market commodity activity, net and other(2) [2] 54 56
Operating and maintenance expense 86 81
Depreciation and amortization expense 56 73
General and other administrative expense 8 7
Other operating expenses 8 9
(Income) loss from unconsolidated investments in power plants   0
Income from operations 130 150
Texas    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues [1] 650 743
Commodity Margin 113 162
Add: Mark-to-market commodity activity, net and other(2) [2] 101 44
Operating and maintenance expense 66 65
Depreciation and amortization expense 50 45
General and other administrative expense 11 12
Other operating expenses 2 2
(Income) loss from unconsolidated investments in power plants   0
Income from operations 85 82
East    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues [1] 542 689
Commodity Margin 150 265
Add: Mark-to-market commodity activity, net and other(2) [2] 82 13
Operating and maintenance expense 63 67
Depreciation and amortization expense 46 43
General and other administrative expense 8 9
Other operating expenses 7 23
(Income) loss from unconsolidated investments in power plants   (6)
Income from operations 108 142
Retail    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues [1] 908 998
Commodity Margin 91 88
Add: Mark-to-market commodity activity, net and other(2) [2] (16) (53)
Operating and maintenance expense 33 34
Depreciation and amortization expense 12 13
General and other administrative expense 4 4
Other operating expenses 0 0
(Income) loss from unconsolidated investments in power plants   0
Income from operations 26 (16)
Consolidation, Eliminations    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues [1] (513) (513)
Commodity Margin 0 0
Add: Mark-to-market commodity activity, net and other(2) [2] (8) (8)
Operating and maintenance expense (8) (8)
Depreciation and amortization expense 0 0
General and other administrative expense 0 0
Other operating expenses 0 0
(Income) loss from unconsolidated investments in power plants   0
Income from operations 0 0
Elimination | West    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues 119 162
Elimination | Texas    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues 218 211
Elimination | East    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues 175 137
Elimination | Retail    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues 1 3
Other Assets    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Amortization of Intangible Assets $ 16 $ 21
[1] Includes intersegment revenues of $119 million and $162 million in the West, $218 million and $211 million in Texas, $175 million and $137 million in the East and $1 million and $3 million in Retail for the three months ended March 31, 2020 and 2019, respectively.
[2] Includes $(18) million and $(16) million of lease levelization and $16 million and $21 million of amortization expense for the three months ended March 31, 2020 and 2019, respectively.