Condensed Statements Of Consolidated Cash Flows (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows - operating activities:
Net income (loss)	$ (686)	$ (1,298)
Adjustments to reconcile net loss to cash provided by (used in) operating activities:
Depreciation and amortization	1,142	1,137
Deferred income tax benefit, net	(401)	(716)
Income tax benefit due to audit resolutions (Note 12)	(80)	0
Unrealized net loss from mark-to-market valuations of commodity positions	693	1,290
Unrealized net (gain) loss from mark-to-market valuations of interest rate swaps (Note 5)	(899)	16
Interest expense on toggle notes payable in additional principal (Notes 5 and 12)	0	136
Amortization of debt related costs, discounts, fair value discounts and losses on dedesignated cash flow hedges (Note 12)	209	152
Interest expense related to pushed-down debt of parent (Notes 5 and 12)	5	57
Other asset impairments	3	24
Bad debt expense (Note 4)	23	20
Accretion expense related primarily to mining reclamation obligations (Note 12)	24	27
Stock-based incentive compensation expense	1	5
Other, net	2	10
Changes in operating assets and liabilities:
Margin deposits, net	(197)	(321)
Other operating assets and liabilities	40	(210)
Cash provided by (used in) operating activities	(121)	329
Cash flows — financing activities:
Repayments/repurchases of long-term debt (Note 5)	(94)	(30)
Net short-term borrowings under accounts receivable securitization program (Note 4)	90	80
Decrease in other short-term borrowings (Note 5)	0	(385)
Notes/advances due to affiliates	4	0
Decrease in income tax-related note payable to Oncor (Note 11)	0	(20)
Settlement of reimbursement agreements with Oncor (Note 11)	0	(159)
Contributions from noncontrolling interests (Note 7)	3	6
Sale/leaseback of equipment	0	15
Other, net	(10)	0
Cash used in financing activities	(7)	(493)
Cash flows — investing activities:
Capital expenditures	(353)	(498)
Nuclear fuel purchases	(59)	(155)
Settlements of notes due from affiliates	698	922
Purchase of right to use certain computer-related assets from parent (Note 11)	(6)	0
Proceeds from sales of assets	3	1
Acquisition of combustion turbine trust interest (Note 5)	(40)	0
Changes in restricted cash	0	112
Purchases of environmental allowances and credits	(13)	(19)
Proceeds from sales of nuclear decommissioning trust fund securities	128	56
Investments in nuclear decommissioning trust fund securities	(140)	(68)
Other, net	(3)	2
Cash provided by (used in) investing activities	215	353
Net change in cash and cash equivalents	87	189
Cash and cash equivalents – beginning balance	1,175	120
Cash and cash equivalents – ending balance	$ 1,262	$ 309