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 June 30, 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 June 30, 2017
	West			Texas			East			Consolidation and Elimination			Total
Revenues from external customers	$	401		$	797		$	886		$	—		$	2,084
Intersegment revenues	—			5			2			(7		)	—
Total operating revenues	$	401		$	802		$	888		$	(7	)	$	2,084
Commodity Margin	$	244		$	167		$	236		$	—		$	647
Add: Mark-to-market commodity activity, net and other⁽¹⁾	(38		)	(30		)	(18		)	(6		)	(92		)
Less:
Plant operating expense	111			109			89			(7		)	302
Depreciation and amortization expense	63			65			58			—			186
Sales, general and other administrative expense	8			21			11			—			40
Other operating expenses	8			3			8			1			20
(Income) from unconsolidated subsidiaries	—			—			(6		)	—			(6		)
Income (loss) from operations	16			(61		)	58			—			13
Interest expense													154
Debt extinguishment costs and other (income) expense, net													8
Loss before income taxes													$	(149	)



	Three Months Ended June 30, 2016
	West			Texas		East			Consolidation and Elimination			Total
Revenues from external customers	$	211		$	530	$	423		$	—		$	1,164
Intersegment revenues	1			4		4			(9		)	—
Total operating revenues	$	212		$	534	$	427		$	(9	)	$	1,164
Commodity Margin	$	254		$	160	$	243		$	—		$	657
Add: Mark-to-market commodity activity, net and other⁽¹⁾	(62		)	7		28			(8		)	(35		)
Less:
Plant operating expense	98			85		96			(8		)	271
Depreciation and amortization expense	56			53		53			—			162
Sales, general and other administrative expense	8			14		12			1			35
Other operating expenses	7			2		10			(2		)	17
(Income) from unconsolidated subsidiaries	—			—		(3		)	—			(3		)
Income from operations	23			13		103			1			140
Interest expense												157
Debt extinguishment costs and other (income) expense, net												21
Loss before income taxes												$	(38	)



	Six Months Ended June 30, 2017
	West		Texas			East			Consolidation and Elimination			Total
Revenues from external customers	$	1,113	$	1,596		$	1,656		$	—		$	4,365
Intersegment revenues	2		8			4			(14		)	—
Total operating revenues	$	1,115	$	1,604		$	1,660		$	(14	)	$	4,365
Commodity Margin	$	465	$	315		$	425		$	—		$	1,205
Add: Mark-to-market commodity activity, net and other⁽²⁾	39		(60		)	(26		)	(14		)	(61		)
Less:
Plant operating expense	208		205			185			(14		)	584
Depreciation and amortization expense	154		127			111			—			392
Sales, general and other administrative expense	21		38			21			—			80
Other operating expenses	17		6			17			—			40
(Gain) on sale of assets, net	—		—			(27		)	—			(27		)
(Income) from unconsolidated subsidiaries	—		—			(10		)	—			(10		)
Income (loss) from operations	104		(121		)	102			—			85
Interest expense												313
Debt extinguishment costs and other (income) expense, net												34
Loss before income taxes												$	(262	)



	Six Months Ended June 30, 2016
	West			Texas			East			Consolidation and Elimination			Total
Revenues from external customers	$	635		$	1,062		$	1,082		$	—		$	2,779
Intersegment revenues	3			7			7			(17		)	—
Total operating revenues	$	638		$	1,069		$	1,089		$	(17	)	$	2,779
Commodity Margin	$	451		$	313		$	473		$	—		$	1,237
Add: Mark-to-market commodity activity, net and other⁽²⁾	(16		)	(103		)	7			(14		)	(126		)
Less:
Plant operating expense	189			171			180			(14		)	526
Depreciation and amortization expense	125			106			111			—			342
Sales, general and other administrative expense	18			30			24			1			73
Other operating expenses	15			4			20			(2		)	37
(Income) from unconsolidated subsidiaries	—			—			(10		)	—			(10		)
Income (loss) from operations	88			(101		)	155			1			143
Interest expense													314
Debt extinguishment costs and other (income) expense, net													26
Loss before income taxes													$	(197	)

_________


(1)	Includes $(24) million and $(20) million of lease levelization and $44 million and $27 million of amortization expense for the three months ended June 30, 2017 and 2016, respectively.


(2)	Includes $(46) million and $(42) million of lease levelization and $104 million and $54 million of amortization expense for the six months ended June 30, 2017 and 2016, respectively.