v3.19.1
Segment Information (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues(1) [1] $ 2,599 $ 2,009
Commodity Margin 779 612
Add: Mark-to-market commodity activity, net and other(2) [2] 52 (373)
Operating and maintenance expense 239 275
Depreciation and amortization expense 174 201
General and other administrative expense 32 60
Other operating expenses 34 37
(Income) loss from unconsolidated investments in power plants (6) (6)
Income (loss) from operations 358 (328)
Interest expense 149 151
Debt Extinguishment Costs and Other (Income) Expense, Net 19 7
Income (loss) before income taxes 190 (486)
Lease levelization (16) (16)
West [Member]    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues(1) [1] 682 480
Commodity Margin 264 185
Add: Mark-to-market commodity activity, net and other(2) [2] 56 13
Operating and maintenance expense 81 90
Depreciation and amortization expense 73 67
General and other administrative expense 7 16
Other operating expenses 9 14
(Income) loss from unconsolidated investments in power plants 0 0
Income (loss) from operations 150 11
Texas [Member]    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues(1) [1] 743 140
Commodity Margin 162 166
Add: Mark-to-market commodity activity, net and other(2) [2] 44 (547)
Operating and maintenance expense 65 80
Depreciation and amortization expense 45 76
General and other administrative expense 12 25
Other operating expenses 2 16
(Income) loss from unconsolidated investments in power plants 0 0
Income (loss) from operations 82 (578)
East [Member]    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues(1) [1] 689 614
Commodity Margin 265 184
Add: Mark-to-market commodity activity, net and other(2) [2] 13 40
Operating and maintenance expense 67 71
Depreciation and amortization expense 43 45
General and other administrative expense 9 15
Other operating expenses 23 7
(Income) loss from unconsolidated investments in power plants (6) (6)
Income (loss) from operations 142 92
Retail [Member]    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues(1) [1] 998 938
Commodity Margin 88 77
Add: Mark-to-market commodity activity, net and other(2) [2] (53) 128
Operating and maintenance expense 34 40
Depreciation and amortization expense 13 13
General and other administrative expense 4 4
Other operating expenses 0 0
(Income) loss from unconsolidated investments in power plants 0 0
Income (loss) from operations (16) 148
Consolidation, Eliminations [Member]    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues(1) [1] (513) (163)
Commodity Margin 0 0
Add: Mark-to-market commodity activity, net and other(2) [2] (8) (7)
Operating and maintenance expense (8) (6)
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 0
Income (loss) from operations 0 (1)
Intersegment Eliminations [Member] | West [Member]    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues(1) 162 114
Intersegment Eliminations [Member] | Texas [Member]    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues(1) 211 (67)
Intersegment Eliminations [Member] | East [Member]    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues(1) 137 115
Intersegment Eliminations [Member] | Retail [Member]    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Total operating revenues(1) 3 1
Other Assets [Member]    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Amortization of Intangible Assets $ 21 $ 28
[1] Includes intersegment revenues of $162 million and $114 million in the West, $211 million and $(67) million in Texas, $137 million and $115 million in the East and $3 million and $1 million in Retail for the three months ended March 31, 2019 and 2018, respectively.
[2] Includes $(16) million and $(16) million of lease levelization and $21 million and $28 million of amortization expense for the three months ended March 31, 2019 and 2018, respectively.