Condensed Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities:
Net margin	$ 48,141	$ 39,236
Adjustments to reconcile net margin to net cash provided by operating activities:
Depreciation and amortization, including nuclear fuel	229,787	231,716
Accretion cost	14,599	13,687
Amortization of deferred gains	(35,579)	(4,245)
Allowance for equity funds used during construction	(2,123)	(2,034)
Deferred outage costs	(22,583)	(43,827)
Deferral of Hawk Road and Smith Energy Facilities effect on net margin	(15,214)	2,168
Gain on sale of investments	(8,001)	(13,306)
Regulatory deferral of costs associated with nuclear decommissioning	(528)	5,825
Other	(6,321)	(5,971)
Change in operating assets and liabilities:
Receivables	(8,742)	(29,995)
Inventories	11,609	2,250
Prepayments and other current assets	206	(462)
Accounts payable	(54,392)	10,407
Accrued interest	(20,080)	(30,500)
Accrued taxes	3,930	(5,197)
Other current liabilities	(3,888)	(5,046)
Member power bill prepayments	12,227	(20,899)
Total adjustments	94,907	104,571
Net cash provided by operating activities	143,048	143,807
Cash flows from investing activities:
Property additions	(495,925)	(634,955)
Plant acquisition		(530,293)
Activity in decommissioning fund-Purchases	(536,224)	(828,008)
Activity in decommissioning fund-Proceeds	532,041	823,598
Decrease in restricted cash and cash equivalents	35,714	5,687
Decrease (Increase) in restricted short-term investments	42,808	(8,537)
Activity in investment in associated organizations	(112)	(78)
Activity in other long-term investments-Purchases	(4,404)	(1,246)
Activity in other long-term investments-Proceeds	13,689	1,100
Activity on interest rate options-Purchases/Collateral returned	(43,070)
Activity on interest rate options-Collateral received	7,810
Other	(17,086)	(7,822)
Net cash used in investing activities	(464,759)	(1,180,554)
Cash flows from financing activities:
Long-term debt proceeds	108,792	1,093,399
Long-term debt payments	(94,706)	(285,067)
Increase (Decrease) in short-term borrowings, net	296,222	(30,202)
Other	5,542	(3,134)
Net cash provided by financing activities	315,850	774,996
Net decrease in cash and cash equivalents	(5,861)	(261,751)
Cash and cash equivalents at beginning of period	443,671	672,212
Cash and cash equivalents at end of period	437,810	410,461
Cash paid for-
Interest (net of amounts capitalized)	181,675	189,258
Supplemental disclosure of non-cash investing and financing activities:
Change in plant expenditures included in accounts payable	$ (13,069)	$ (27,810)