Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Cash flows from operating activities:
Net income (loss)	$ 199		$ (189)		$ 31
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization expense(1)	605	[1]	587	[1]	615	[1]
Debt extinguishment costs	0		82		91
Deferred income taxes	1		(21)		(26)
Impairment losses	0		0		116
(Gain) loss on sale of power plants and other, net	(212)		13		(314)
Unrealized mark-to-market (gain) loss	(72)	[2]	(30)	[2]	56	[2]
(Income) from unconsolidated investments in power plants	(28)		(21)		(16)
Return on unconsolidated investments in power plants	24		6		11
Stock-based compensation expense	25		24		24
Change in operating assets and liabilities, net of effects of acquisitions:	1		6		1
Change in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	159		74		91
Derivative instruments, net	(52)		15		(52)
Other assets	(57)		1		277
Accounts payable and accrued expenses	(86)		28		(43)
Settlement of non-hedging interest rate swaps	156		189		69
Other liabilities	(10)		11		(2)
Net cash provided by operating activities	653		775		929
Cash flows from investing activities:
Purchases of property, plant and equipment	(637)		(683)		(369)
Proceeds from sale of power plants, interests and other	825		13		954
Purchase of Bosque Energy Center, Conectiv assets and BRSP, net of cash acquired	(432)		0		(1,680)
Cash acquired due to consolidation of OMEC	0		0		8
Return of investment from unconsolidated investments	5		0		0
Settlement of non-hedging interest rate swaps	(156)		(189)		(69)
(Increase) decrease in restricted cash	(59)		54		322
Purchases of deferred transmission credits	(12)		(31)		0
Other	(4)		0		3
Net cash used in investing activities	(470)		(836)		(831)
Cash flows from financing activities:
Borrowings under First Lien Term Loans	835		1,657		0
Repayments of First Lien Term Loans	(19)		0		0
Repayments on NDH Project Debt	0		(1,283)		0
Issuance of First Lien Notes	0		1,200		3,491
Repayments of First Lien Notes	(590)		0		0
Repayments on First Lien Credit Facility	0		(1,195)		(3,477)
Borrowings from project financing, notes payable and other	389		327		1,272
Repayments of project financing, notes payable and other	(289)		(550)		(937)
Capital contributions from noncontrolling interest holder	0		33		17
Financing costs	(20)		(81)		(136)
Stock repurchases	(463)		(119)		0
Refund of financing costs	0		0		10
Other	6		(3)		0
Net cash provided by (used in) financing activities	(151)		(14)		240
Net increase (decrease) in cash and cash equivalents	32		(75)		338
Cash and cash equivalents, beginning of period	1,252		1,327		989
Cash and cash equivalents, end of period	1,284		1,252		1,327
Cash paid during the period for:
Interest, net of amounts capitalized	719		656		635
Income taxes	16		18		21
Supplemental disclosure of non-cash investing and financing activities:
Change in capital expenditures included in accounts payable	19		(24)		1
Other non-cash additions to property, plant and equipment	13		0		0
Liabilities assumed in BRSP acquisition	0		0		85
Conversion of project debt to noncontrolling interest	$ 0		$ 0		$ 11

[1] Includes depreciation and amortization included in fuel and purchased energy expense, interest expense and discontinued operations on our Consolidated Statements of Operations.

[2] In addition to changes in market value on derivatives not designated as hedges, changes in unrealized gain (loss) also includes de-designation of interest rate swap cash flow hedges and related reclassification from AOCI into earnings, hedge ineffectiveness and adjustments to reflect changes in credit default risk exposure.