Condensed Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flows from operating activities:
Net margin	$ 46,526	$ 24,398
Adjustments to reconcile net margin to net cash provided by operating activities:
Depreciation and amortization, including nuclear fuel	141,876	156,664
Accretion cost	11,307	9,716
Amortization of deferred gains	(893)	(2,830)
Allowance for equity funds used during construction	(1,411)	(1,432)
Deferred outage costs	(31,820)	(13,379)
Deferral of Hawk Road and Smith Energy Facilities effect on net margin	(18,667)	(14,559)
Gain on sale of investments	(17,304)	(5,625)
Regulatory deferral of costs associated with nuclear decommissioning	10,085	165
Other	(3,551)	(3,908)
Change in operating assets and liabilities:
Receivables	(28,158)	(34,699)
Inventories	(3,902)	7,591
Prepayments and other current assets	(1,872)	(2,826)
Accounts payable	(43,540)	(43,758)
Accrued interest	31,022	(7,599)
Accrued taxes	12,808	(4,389)
Other current liabilities	(5,067)	(3,644)
Member power bill prepayments	50,860	(8,331)
Total adjustments	101,773	27,157
Net cash provided by operating activities	148,299	51,555
Cash flows from investing activities:
Property additions	(321,246)	(346,654)
Activity in decommissioning fund - Purchases	(346,211)	(418,240)
Activity in decommissioning fund - Proceeds	343,340	415,247
(Increase) decrease in restricted cash	(27,121)	22,378
(Increase) decrease in restricted short-term investments	(141,540)	43,601
Activity in other long-term investments - Purchases	(19,670)	(2,993)
Activity in other long-term investments - Proceeds	20,103	10,846
Activity on interest rate options - Collateral returned	(46,420)	(43,070)
Activity on interest rate options - Collateral received	73,540	20,690
Other	1,269	11,707
Net cash used in investing activities	(463,956)	(286,488)
Cash flows from financing activities:
Long-term debt proceeds	283,168	79,194
Long-term debt payments	(244,042)	(68,678)
Increase in short-term borrowings, net	201,391	187,029
Other	(2,775)	3,038
Net cash provided by financing activities	237,742	200,583
Net decrease in cash and cash equivalents	(77,915)	(34,350)
Cash and cash equivalents at beginning of period	298,565	443,671
Cash and cash equivalents at end of period	220,650	409,321
Cash paid for -
Interest (net of amounts capitalized)	69,269	115,719
Supplemental disclosure of non-cash investing and financing activities:
Change in plant expenditures included in accounts payable	$ (19,846)	$ (14,733)