v3.19.2
Segment Information (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]        
Total operating revenues(1) $ 2,599 [1] $ 2,259 [1] $ 5,198 [2] $ 4,268 [2]
Commodity Margin 752 694 1,531 1,306
Add: Mark-to-market commodity activity, net and other(2) 200 [3] 196 [3] 252 [4] (177) [4]
Operating and maintenance expense 245 242 484 517
Depreciation and amortization expense 175 186 349 387
General and other administrative expense 34 31 66 91
Other operating expenses 19 19 38 56
Impairment losses 40 0 55 0
(Income) loss from unconsolidated investments in power plants (5) (5) (11) (11)
Income from operations 444 417 802 89
Interest expense 157 157 306 308
Debt Extinguishment Costs and Other (Income) Expense, Net 8 62 27 69
Income (loss) before income taxes 279 198 469 (288)
Lease levelization (19) (19) (35) (35)
West [Member]        
Revenues from External Customers and Long-Lived Assets [Line Items]        
Total operating revenues(1) 649 [1] 355 [1] 1,331 [2] 835 [2]
Commodity Margin 251 241 515 426
Add: Mark-to-market commodity activity, net and other(2) 58 [3] (23) [3] 114 [4] (10) [4]
Operating and maintenance expense 84 80 165 170
Depreciation and amortization expense 60 67 133 134
General and other administrative expense 5 5 12 21
Other operating expenses 7 8 16 22
Impairment losses 0   0  
(Income) loss from unconsolidated investments in power plants 0 0 0 0
Income from operations 153 58 303 69
Texas [Member]        
Revenues from External Customers and Long-Lived Assets [Line Items]        
Total operating revenues(1) 899 [1] 993 [1] 1,642 [2] 1,133 [2]
Commodity Margin 173 151 335 317
Add: Mark-to-market commodity activity, net and other(2) 240 [3] 301 [3] 284 [4] (246) [4]
Operating and maintenance expense 66 65 131 145
Depreciation and amortization expense 54 57 99 133
General and other administrative expense 15 13 27 38
Other operating expenses 1 3 3 19
Impairment losses 0   0  
(Income) loss from unconsolidated investments in power plants 0 0 0 0
Income from operations 277 314 359 (264)
East [Member]        
Revenues from External Customers and Long-Lived Assets [Line Items]        
Total operating revenues(1) 646 [1] 341 [1] 1,335 [2] 955 [2]
Commodity Margin 235 225 500 409
Add: Mark-to-market commodity activity, net and other(2) 94 [3] (7) [3] 107 [4] 33 [4]
Operating and maintenance expense 72 65 139 136
Depreciation and amortization expense 48 49 91 94
General and other administrative expense 10 8 19 23
Other operating expenses 11 8 19 15
Impairment losses 40   55  
(Income) loss from unconsolidated investments in power plants (6) (6) (12) (12)
Income from operations 154 94 296 186
Retail [Member]        
Revenues from External Customers and Long-Lived Assets [Line Items]        
Total operating revenues(1) 1,082 [1] 935 [1] 2,080 [2] 1,873 [2]
Commodity Margin 93 77 181 154
Add: Mark-to-market commodity activity, net and other(2) (182) [3] (67) [3] (235) [4] 61 [4]
Operating and maintenance expense 33 41 67 81
Depreciation and amortization expense 13 13 26 26
General and other administrative expense 4 5 8 9
Other operating expenses 0 0 0 0
Impairment losses 0   0  
(Income) loss from unconsolidated investments in power plants 1 1 1 1
Income from operations (140) (50) (156) 98
Consolidation, Eliminations [Member]        
Revenues from External Customers and Long-Lived Assets [Line Items]        
Total operating revenues(1) (677) [1] (365) [1] (1,190) [2] (528) [2]
Commodity Margin 0 0 0 0
Add: Mark-to-market commodity activity, net and other(2) (10) [3] (8) [3] (18) [4] (15) [4]
Operating and maintenance expense (10) (9) (18) (15)
Depreciation and amortization expense 0 0 0 0
General and other administrative expense 0 0 0 0
Other operating expenses 0 0 0 0
Impairment losses 0   0  
(Income) loss from unconsolidated investments in power plants 0 0 0 0
Income from operations 0 1 0 0
Intersegment Eliminations [Member] | West [Member]        
Revenues from External Customers and Long-Lived Assets [Line Items]        
Total operating revenues(1) 100 70 262 184
Intersegment Eliminations [Member] | Texas [Member]        
Revenues from External Customers and Long-Lived Assets [Line Items]        
Total operating revenues(1) 348 276 559 209
Intersegment Eliminations [Member] | East [Member]        
Revenues from External Customers and Long-Lived Assets [Line Items]        
Total operating revenues(1) 228 18 365 133
Intersegment Eliminations [Member] | Retail [Member]        
Revenues from External Customers and Long-Lived Assets [Line Items]        
Total operating revenues(1) 1 1 4 2
Other Assets [Member]        
Revenues from External Customers and Long-Lived Assets [Line Items]        
Amortization of Intangible Assets $ 18 $ 25 $ 39 $ 53
[1] Includes intersegment revenues of $100 million and $70 million in the West, $348 million and $276 million in Texas, $228 million and $18 million in the East and $1 million and $1 million in Retail for the three months ended June 30, 2019 and 2018, respectively.
[2] Includes intersegment revenues of $262 million and $184 million in the West, $559 million and $209 million in Texas, $365 million and $133 million in the East and $4 million and $2 million in Retail for the six months ended June 30, 2019 and 2018, respectively.
[3] Includes $(19) million and $(19) million of lease levelization and $18 million and $25 million of amortization expense for the three months ended June 30, 2019 and 2018, respectively.
[4] Includes $(35) million and $(35) million of lease levelization and $39 million and $53 million of amortization expense for the six months ended June 30, 2019 and 2018, respectively.