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



	Year Ended December 31, 2011
	West		Texas			North			Southeast			Consolidation and Elimination			Total
Revenues from external customers	$	2,372	$	2,306		$	1,336		$	786		$	—		$	6,800
Intersegment revenues	12		23			7			135			(177		)	—
Total operating revenues	$	2,384	$	2,329		$	1,343		$	921		$	(177	)	$	6,800
Commodity Margin	$	1,061	$	469		$	704		$	240		$	—		$	2,474
Add: Mark-to-market commodity activity, net and other⁽¹⁾⁽²⁾	113		(102		)	(13		)	1			(32		)	(33		)
Less:
Plant operating expense	380		235			177			141			(29		)	904
Depreciation and amortization expense	192		135			138			90			(5		)	550
Sales, general and other administrative expense	43		43			24			22			(1		)	131
Other operating expenses⁽³⁾	41		3			30			5			(2		)	77
(Income) from unconsolidated investments in power plants	—		—			(21		)	—			—			(21		)
Income (loss) from operations	518		(49		)	343			(17		)	5			800
Interest expense, net of interest income															751
Loss on interest rate derivatives															145
Debt extinguishment costs and other (income) expense, net															115
Loss before income taxes and discontinued operations															$	(211	)



	Year Ended December 31, 2010
	West		Texas			North			Southeast		Consolidation and Elimination			Total
Revenues from external customers	$	2,525	$	2,162		$	978		$	880	$	—		$	6,545
Intersegment revenues	12		22			6			138		(178		)	—
Total operating revenues	$	2,537	$	2,184		$	984		$	1,018	$	(178	)	$	6,545
Commodity Margin	$	1,080	$	504		$	535		$	272	$	—		$	2,391
Add: Mark-to-market commodity activity, net and other⁽¹⁾	69		89			21			22		(30		)	171
Less:
Plant operating expense	351		285			138			123		(29		)	868
Depreciation and amortization expense	207		150			111			109		(7		)	570
Sales, general and other administrative expense	55		38			45			12		1			151
Other operating expenses⁽³⁾	59		2			28			4		(2		)	91
Impairment losses	97		—			—			19		—			116
(Gain) on sale of assets, net	—		(119		)	—			—		—			(119		)
(Income) from unconsolidated investments in power plants	—		—			(16		)	—		—			(16		)
Income from operations	380		237			250			27		7			901
Interest expense, net of interest income														802
Loss on interest rate derivatives														223
Debt extinguishment costs and other (income) expense, net														106
Loss before income taxes and discontinued operations														$	(230	)



	Year Ended December 31, 2009
	West			Texas			North			Southeast			Consolidation and Elimination			Total
Revenues from external customers	$	3,311		$	1,816		$	558		$	778		$	—		$	6,463
Intersegment revenues	28			63			16			97			(204		)	—
Total operating revenues	$	3,339		$	1,879		$	574		$	875		$	(204	)	$	6,463
Commodity Margin	$	1,245		$	644		$	268		$	304		$	—		$	2,461
Add: Mark-to-market commodity activity, net and other⁽¹⁾	143			(40		)	46			(5		)	(44		)	100
Less:
Plant operating expense	408			232			91			134			3			868
Depreciation and amortization expense	188			129			67			80			(8		)	456
Sales, general and other administrative expense	66			63			18			27			—			174
Other operating expenses⁽³⁾	73			14			30			11			(32		)	96
Impairment losses	4			—			—			—			—			4
(Income) from unconsolidated investments in power plants	(32		)	—			(18		)	—			—			(50		)
Income from operations	681			166			126			47			(7		)	1,013
Interest expense, net of interest income																799
Debt extinguishment costs and other (income) expense, net																89
Income before income taxes and discontinued operations																$	125

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(1)	Mark-to-market commodity activity represents the unrealized portion of our mark-to-market activity, net, included in operating revenues and fuel and purchased energy expense on our Consolidated Statements of Operations for the years ended December 31, 2011, 2010 and 2009, as well as a non-cash gain from amortization of prepaid power sales agreements for the year ended December 31, 2009.


(2)	Includes $12 million of lease levelization and $8 million of contract amortization for the year ended December 31, 2011 related to contracts that became effective in 2011.


(3)	Excludes $10 million, $9 million and $5 million of RGGI compliance and other environmental costs for the years ended December 31, 2011, 2010 and 2009, respectively, which are components of Commodity Margin.