v3.6.0.2
Segment and Significant Customer Information
 12 Months Ended
Dec. 31, 2016
Segment and Significant Customer Information [Abstract]  
Segment and Significant Customer Information
Segment and Significant Customer 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 December 31, 2016, 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).
 
Year Ended December 31, 2016
 
West
 
Texas
 
East
 
Consolidation
and
Elimination
 
Total
Revenues from external customers
$
1,562

 
$
2,801

 
$
2,353

 
$
—

 
$
6,716

Intersegment revenues
7

 
14

 
11

 
(32
)
 
—

Total operating revenues
$
1,569

 
$
2,815

 
$
2,364

 
$
(32
)
 
$
6,716

Commodity Margin
$
991

 
$
655

 
$
958

 
$
—

 
$
2,604

Add: Mark-to-market commodity activity, net and other(1)
(3
)
 
(23
)
 
(20
)
 
(29
)
 
(75
)
Less:
 
 
 
 
 
 
 
 
 
Plant operating expense
357

 
317

 
332

 
(29
)
 
977

Depreciation and amortization expense
225

 
213

 
224

 
—

 
662

Sales, general and other administrative expense
39

 
56

 
45

 
—

 
140

Other operating expenses
32

 
9

 
38

 
—

 
79

Impairment losses
13

 
—

 
—

 
—

 
13

(Gain) on sale of assets, net
—

 
—

 
(157
)
 
—

 
(157
)
(Income) from unconsolidated subsidiaries
—

 
—

 
(24
)
 
—

 
(24
)
Income from operations
322

 
37

 
480

 
—

 
839

Interest expense
 
 
 
 
 
 
 
 
631

Debt modification and extinguishment costs and other (income) expense, net
 
 
 
 
 
 
 
 
49

Income before income taxes
 
 
 
 
 
 
 
 
$
159


 
Year Ended December 31, 2015
 
West
 
Texas
 
East
 
Consolidation
and
Elimination
 
Total
Revenues from external customers
$
2,089

 
$
2,344

 
$
2,039

 
$
—

 
$
6,472

Intersegment revenues
5

 
15

 
8

 
(28
)
 
—

Total operating revenues
$
2,094

 
$
2,359

 
$
2,047

 
$
(28
)
 
$
6,472

Commodity Margin
$
1,106

 
$
736

 
$
944

 
$
—

 
$
2,786

Add: Mark-to-market commodity activity, net and other(1)
160

 
(120
)
 
(92
)
 
(29
)
 
(81
)
Less:
 
 
 
 
 
 
 
 
 
Plant operating expense
416

 
338

 
292

 
(28
)
 
1,018

Depreciation and amortization expense
250

 
204

 
184

 
—

 
638

Sales, general and other administrative expense
35

 
63

 
40

 
—

 
138

Other operating expenses
37

 
9

 
36

 
(2
)
 
80

(Income) from unconsolidated subsidiaries
—

 
—

 
(24
)
 
—

 
(24
)
Income from operations
528

 
2

 
324

 
1

 
855

Interest expense
 
 
 
 
 
 
 
 
628

Debt modification and extinguishment costs and other (income) expense, net
 
 
 
 
 
 
 
 
54

Income before income taxes
 
 
 
 
 
 
 
 
$
173


 
Year Ended December 31, 2014
 
West
 
Texas
 
East
 
Consolidation
and
Elimination
 
Total
Revenues from external customers
$
2,352

 
$
3,229

 
$
2,449

 
$
—

 
$
8,030

Intersegment revenues
6

 
23

 
47

 
(76
)
 
—

Total operating revenues
$
2,358

 
$
3,252

 
$
2,496

 
$
(76
)
 
$
8,030

Commodity Margin(2)
$
1,050

 
$
760

 
$
949

 
$
—

 
$
2,759

Add: Mark-to-market commodity activity, net and other(1)
220

 
142

 
48

 
(31
)
 
379

Less:
 
 
 
 
 
 
 
 
 
Plant operating expense
385

 
313

 
302

 
(31
)
 
969

Depreciation and amortization expense
245

 
191

 
168

 
(1
)
 
603

Sales, general and other administrative expense
41

 
64

 
39

 
—

 
144

Other operating expenses
50

 
5

 
32

 
1

 
88

Impairment losses
—

 
—

 
123

 
—

 
123

(Gain) on sale of assets, net
—

 
—

 
(753
)
 
—

 
(753
)
(Income) from unconsolidated subsidiaries
—

 
—

 
(25
)
 
—

 
(25
)
Income from operations
549

 
329

 
1,111

 
—

 
1,989

Interest expense
 
 
 
 
 
 
 
 
645

Debt extinguishment costs and other (income) expense, net
 
 
 
 
 
 
 
 
361

Income before income taxes
 
 
 
 
 
 
 
 
$
983

__________
(1)
Includes $(2) million, $(2) million and $(5) million of lease levelization and $122 million, $20 million and $14 million of amortization expense for the years ended December 31, 2016, 2015 and 2014, respectively.
(2)
Our East segment includes Commodity Margin of $81 million for the year ended December 31, 2014 related to the six power plants in our East segment that were sold in July 2014.
Significant Customers
For the year ended December 31, 2016, we had no significant customer that individually accounted for more than 10% of our annual consolidated revenues. For the year ended December 31, 2015, we had two significant customers, PJM Settlement, Inc. and PG&E, that individually accounted for more than 10% of our annual consolidated revenues. For the year ended December 31, 2014, we had one significant customer, PJM Settlement, Inc. that individually accounted for more than 10% of our annual consolidated revenues. Our revenues from PJM Settlement, Inc. for the years ended December 31, 2015 and 2014 were approximately $724 million and $1.0 billion, respectively, and were attributed to our East segment. Our revenues from PG&E for the year ended December 31, 2015 was approximately $642 million, which was attributed to our West segment.