The tables below show our financial data for our segments for the periods indicated (in millions).



	Three Months Ended September 30, 2012
	West			Texas			North			Southeast			Consolidation and Elimination			Total
Revenues from external customers	$	509		$	886		$	407		$	194		$	—		$	1,996
Intersegment revenues	2			(34		)	4			68			(40		)	—
Total operating revenues	$	511		$	852		$	411		$	262		$	(40	)	$	1,996
Commodity Margin⁽¹⁾	$	330		$	218		$	266		$	83		$	—		$	897
Add: Mark-to-market commodity activity, net and other⁽²⁾⁽³⁾	(40		)	249			(26		)	27			(8		)	202
Less:
Plant operating expense	88			49			51			29			(10		)	207
Depreciation and amortization expense	52			35			33			21			(1		)	140
Sales, general and other administrative expense	9			12			8			8			(1		)	36
Other operating expenses⁽⁴⁾	10			1			6			(1		)	2			18
(Income) from unconsolidated investments in power plants	—			—			(7		)	—			—			(7		)
Income from operations	131			370			149			53			2			705
Interest expense, net of interest income																181
Other (income) expense, net																6
Income before income taxes																$	518



	Three Months Ended September 30, 2011
	West		Texas			North			Southeast		Consolidation and Elimination			Total
Revenues from external customers	$	688	$	843		$	430		$	248	$	—		$	2,209
Intersegment revenues	3		3			(8		)	31		(29		)	—
Total operating revenues	$	691	$	846		$	422		$	279	$	(29	)	$	2,209
Commodity Margin⁽¹⁾	$	329	$	162		$	259		$	75	$	—		$	825
Add: Mark-to-market commodity activity, net and other⁽²⁾⁽³⁾	20		(21		)	(11		)	—		(8		)	(20		)
Less:
Plant operating expense	94		50			44			33		(9		)	212
Depreciation and amortization expense	52		34			36			22		(1		)	143
Sales, general and other administrative expense	10		10			7			7		(1		)	33
Other operating expenses⁽⁴⁾	11		(1		)	7			—		2			19
(Income) from unconsolidated investments in power plants	—		—			(5		)	—		—			(5		)
Income from operations	182		48			159			13		1			403
Interest expense, net of interest income														190
Loss on interest rate derivatives														3
Debt extinguishment costs and other (income) expense, net														—
Income before income taxes														$	210



	Nine Months Ended September 30, 2012
	West			Texas		North			Southeast			Consolidation and Elimination			Total
Revenues from external customers	$	1,183		$	1,430	$	974		$	524		$	—		$	4,111
Intersegment revenues	7			27		9			84			(127		)	—
Total operating revenues	$	1,190		$	1,457	$	983		$	608		$	(127	)	$	4,111
Commodity Margin⁽¹⁾	$	748		$	472	$	591		$	212		$	—		$	2,023
Add: Mark-to-market commodity activity, net and other⁽²⁾⁽⁵⁾	(80		)	66		(17		)	(5		)	(22		)	(58		)
Less:
Plant operating expense	281			189		154			98			(23		)	699
Depreciation and amortization expense	151			104		100			66			(3		)	418
Sales, general and other administrative expense	23			36		22			23			—			104
Other operating expenses⁽⁴⁾	30			4		21			2			1			58
(Income) from unconsolidated investments in power plants	—			—		(21		)	—			—			(21		)
Income from operations	183			205		298			18			3			707
Interest expense, net of interest income															545
Loss on interest rate derivatives															14
Debt extinguishment costs and other (income) expense, net															26
Income before income taxes															$	122



	Nine Months Ended September 30, 2011
	West		Texas			North			Southeast			Consolidation and Elimination			Total
Revenues from external customers	$	1,753	$	1,939		$	1,025		$	624		$	—		$	5,341
Intersegment revenues	7		13			5			116			(141		)	—
Total operating revenues	$	1,760	$	1,952		$	1,030		$	740		$	(141	)	$	5,341
Commodity Margin⁽¹⁾	$	798	$	357		$	578		$	188		$	—		$	1,921
Add: Mark-to-market commodity activity, net and other⁽²⁾⁽⁵⁾	36		(54		)	(12		)	(4		)	(23		)	(57		)
Less:
Plant operating expense	297		193			136			107			(22		)	711
Depreciation and amortization expense	140		99			102			67			(3		)	405
Sales, general and other administrative expense	29		33			19			18			—			99
Other operating expenses⁽⁴⁾	30		2			23			3			(1		)	57
(Income) from unconsolidated investments in power plants	—		—			(12		)	—			—			(12		)
Income (loss) from operations	338		(24		)	298			(11		)	3			604
Interest expense, net of interest income															568
Loss on interest rate derivatives															149
Debt extinguishment costs and other (income) expense, net															108
Loss before income taxes															$	(221	)

_________


(1)	Our North segment includes Commodity Margin related to Riverside Energy Center, LLC of $32 million and $31 million for the three months ended September 30, 2012 and 2011, respectively, and $64 million and $62 million for the nine months ended September 30, 2012 and 2011, respectively.


(2)	Mark-to-market commodity activity represents the change in the unrealized portion of our mark-to-market activity, net, included in operating revenues and fuel and purchased energy expense on our Consolidated Condensed Statements of Operations.


(3)	Includes $16 million and $11 million of lease levelization for the three months ended September 30, 2012 and 2011, respectively, and $4 million of amortization expense for each of the three months ended September 30, 2012 and 2011.


(4)	Excludes $4 million and $3 million of RGGI compliance and other environmental costs for the three months ended September 30, 2012 and 2011, respectively, and $9 million and $7 million for the nine months ended September 30, 2012 and 2011, respectively, which are components of Commodity Margin.


(5)	Includes $7 million and $15 million of lease levelization and $11 million and $5 million of amortization expense for the nine months ended September 30, 2012 and 2011, respectively.