v3.7.0.1
Segment Information
 3 Months Ended
Mar. 31, 2017
Segment Reporting [Abstract]  
Segment Information
Segment Information
We assess our business on a regional basis due to the effect on our financial performance of the differing characteristics of these regions, particularly with respect to competition, regulation and other factors affecting supply and demand. At March 31, 2017, our reportable segments were West (including geothermal), Texas and East (including Canada). The results of our retail subsidiaries are reflected in the segment which corresponds with the geographic area in which the retail sales occur. We continue to evaluate the optimal manner in which we assess our performance including our segments and future changes may result in changes to the composition of our geographic segments. Commodity Margin is a key operational measure reviewed by our chief operating decision maker to assess the performance of our segments. The tables below show our financial data for our segments for the periods indicated (in millions):
 
Three Months Ended March 31, 2017
 
West
 
Texas
 
East
 
Consolidation
and
Elimination
 
Total
Revenues from external customers
$
712

 
$
799

 
$
770

 
$
—

 
$
2,281

Intersegment revenues
2

 
3

 
2

 
(7
)
 
—

Total operating revenues
$
714

 
$
802

 
$
772

 
$
(7
)
 
$
2,281

Commodity Margin
$
221

 
$
148

 
$
189

 
$
—

 
$
558

Add: Mark-to-market commodity activity, net and other(1)
77

 
(30
)
 
(8
)
 
(8
)
 
31

Less:
 
 
 
 
 
 
 
 
 
Plant operating expense
97

 
96

 
96

 
(7
)
 
282

Depreciation and amortization expense
91

 
62

 
53

 
—

 
206

Sales, general and other administrative expense
13

 
17

 
10

 
—

 
40

Other operating expenses
9

 
3

 
9

 
(1
)
 
20

(Gain) on sale of assets, net
—

 
—

 
(27
)
 
—

 
(27
)
(Income) from unconsolidated subsidiaries
—

 
—

 
(4
)
 
—

 
(4
)
Income (loss) from operations
88

 
(60
)
 
44

 
—

 
72

Interest expense
 
 
 
 
 
 
 
 
159

Debt extinguishment costs and other (income) expense, net
 
 
 
 
 
 
 
 
26

Loss before income taxes
 
 
 
 
 
 
 
 
$
(113
)

 
Three Months Ended March 31, 2016
 
West
 
Texas
 
East
 
Consolidation
and
Elimination
 
Total
Revenues from external customers
$
424

 
$
532

 
$
659

 
$
—

 
$
1,615

Intersegment revenues
2

 
3

 
3

 
(8
)
 
—

Total operating revenues
$
426

 
$
535

 
$
662

 
$
(8
)
 
$
1,615

Commodity Margin
$
197

 
$
153

 
$
230

 
$
—

 
$
580

Add: Mark-to-market commodity activity, net and other(1)
46

 
(110
)
 
(21
)
 
(6
)
 
(91
)
Less:
 
 
 
 
 
 
 
 
 
Plant operating expense
91

 
86

 
84

 
(6
)
 
255

Depreciation and amortization expense
69

 
53

 
58

 
—

 
180

Sales, general and other administrative expense
10

 
16

 
12

 
—

 
38

Other operating expenses
8

 
2

 
10

 
—

 
20

(Income) from unconsolidated subsidiaries
—

 
—

 
(7
)
 
—

 
(7
)
Income (loss) from operations
65

 
(114
)
 
52

 
—

 
3

Interest expense
 
 
 
 
 
 
 
 
157

Other (income) expense, net
 
 
 
 
 
 
 
 
5

Loss before income taxes
 
 
 
 
 
 
 
 
$
(159
)
_________
(1)
Includes $(22) million and $(22) million of lease levelization and $60 million and $27 million of amortization expense for the three months ended March 31, 2017 and 2016, respectively.