Segment Information

9 Months Ended

Sep. 30, 2011

Segment Information [Abstract]

Segment Information

13.Segment Information

We assess our business on a regional basis due to the impact on our financial performance of the differing characteristics of these regions, particularly with respect to competition, regulation and other factors impacting supply and demand. At September30, 2011, our reportable segments were West (including geothermal), Texas, North (including Canada and the assets purchased in the Conectiv Acquisition) and Southeast. We continue to evaluate the optimal manner in which we assess our performance including our segments and future changes may result.

Commodity Margin includes our power and steam revenues, sales of purchased power and physical natural gas, capacity revenue, REC revenue, sales of surplus emission allowances, transmission revenue and expenses, fuel and purchased energy expense, fuel transportation expense, RGGI compliance and other environmental costs, and cash settlements from our marketing, hedging and optimization activities including natural gas transactions hedging future power sales that are included in mark-to-market activity, but excludes the unrealized portion of our mark-to-market activity and other revenues. 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 period indicated (in millions).

	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	$	329	$	162		$	259		$	75	$	—		$	825
Add: Mark-to-market commodity activity, net and other(1) (2)		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(3)		11		(1	)		7			—		2			19
Incomefrom unconsolidated investments in power plants		—		—			(5	)		—		—			(5	)
Incomefrom operations		182		48			159			13		1			403
Interest expense, net of interest income															190
(Gain) loss on interest rate derivatives, net															3
Debt extinguishment costs and other (income) expense, net															—
Incomebefore income taxes and discontinued operations														$	210

	Three Months Ended September 30, 2010
	West		Texas		North			Southeast		Consolidation and Elimination			Total
Revenues from external customers	$	716	$	670	$	468		$	276	$	—		$	2,130
Intersegment revenues		2		6		2			53		(63	)		—
Total operating revenues	$	718	$	676	$	470		$	329	$	(63	)	$	2,130
Commodity Margin	$	338	$	165	$	259		$	90	$	—		$	852
Add: Mark-to-market commodity activity, net and other(1)		42		62		18			18		(6	)		134
Less:
Plant operating expense		86		55		38			28		(8	)		199
Depreciation and amortization expense		52		37		37			28		(2	)		152
Sales, general and other administrative expense		10		13		12			5		1			41
Other operating expenses(3)		14		—		6			—		2			22
Impairment losses		—		—		—			19		—			19
Income from unconsolidated investments in power plants		—		—		(1	)		—		—			(1	)
Income from operations		218		122		185			28		1			554
Interest expense, net of interest income														228
(Gain) loss on interest rate derivatives, net														84
Debt extinguishment costs and other (income) expense, net														23
Incomebefore income taxes and discontinued operations													$	219

	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	$	798	$	357		$	578		$	188		$	—		$	1,921
Add: Mark-to-market commodity activity, net and other(1) (2)		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(3)		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
(Gain) loss on interest rate derivatives, net																149
Debt extinguishment costs and other (income) expense, net																108
Lossbefore income taxes and discontinued operations															$	(221	)

	Nine Months Ended September 30, 2010
	West		Texas		North			Southeast		Consolidation and Elimination			Total
Revenues from external customers	$	1,906	$	1,749	$	725		$	694	$	—		$	5,074
Intersegment revenues		7		16		4			97		(124	)		—
Total operating revenues	$	1,913	$	1,765	$	729		$	791	$	(124	)	$	5,074
Commodity Margin	$	809	$	400	$	390		$	216	$	—		$	1,815
Add: Mark-to-market commodity activity, net and other(1)		60		148		18			31		(20	)		237
Less:
Plant operating expense		264		217		83			87		(21	)		630
Depreciation and amortization expense		155		113		76			84		(5	)		423
Sales, general and other administrative expense		36		29		37			11		—			113
Other operating expenses(3)		43		2		21			2		1			69
Impairment losses		—		—		—			19		—			19
Income from unconsolidated investments in power plants		—		—		(14	)		—		—			(14	)
Incomefrom operations		371		187		205			44		5			812
Interest expense, net of interest income														627
(Gain) loss on interest rate derivatives, net														87
Debt extinguishment costs and other (income) expense, net														36
Incomebefore income taxes and discontinued operations													$	62

_________

(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 Condensed Statements of Operations.

(2) Includes $11 million and $15 million of lease levelization and $4 million and $5 million of contract amortization for the three and nine months ended September 30, 2011, respectively, related to contracts that became effective in 2011.

(3) Excludes $3 million and $1 million of RGGI compliance and other environmental costs for the three months ended September 30, 2011 and 2010, respectively, and $7 million and $6 million for the nine months ended September 30, 2011 and 2010, respectively, which are components of Commodity Margin.