Condensed Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net margin	$ 66,630	$ 48,141
Adjustments to reconcile net margin to net cash provided by operating activities:
Depreciation and amortization, including nuclear fuel	218,425	229,787
Accretion cost	17,062	14,599
Amortization of deferred gains	(1,341)	(35,579)
Allowance for equity funds used during construction	(1,938)	(2,123)
Deferred outage costs	(33,347)	(22,583)
Deferral of Hawk Road and Smith Energy Facilities effect on net margin	(25,672)	(15,214)
Gain on sale of investments	(21,694)	(8,001)
Regulatory deferral of costs associated with nuclear decommissioning	10,652	(528)
Other	(5,416)	(6,321)
Change in operating assets and liabilities:
Receivables	(2,995)	(8,742)
Inventories	(13,684)	11,609
Prepayments and other current assets	(234)	206
Accounts payable	(76,892)	(54,392)
Accrued interest	(9,292)	(20,080)
Accrued taxes	19,601	3,930
Other current liabilities	(4,264)	(3,888)
Member power bill prepayments	2,091	12,227
Total adjustments	71,062	94,907
Net cash provided by operating activities	137,692	143,048
Cash flows from investing activities:
Property additions	(414,493)	(495,925)
Activity in decommissioning fund - Purchases	(479,622)	(536,224)
Activity in decommissioning fund - Proceeds	475,446	532,041
(Increase) decrease in restricted cash	(22,111)	35,714
(Increase) decrease in restricted short-term investments	(190,184)	42,808
Activity in other long-term investments - Purchases	(34,510)	(4,404)
Activity in other long-term investments - Proceeds	36,753	13,689
Activity on interest rate options - Collateral returned	(146,730)	(43,070)
Activity on interest rate options - Collateral received	168,840	7,810
Other	11,563	(17,198)
Net cash used in investing activities	(595,048)	(464,759)
Cash flows from financing activities:
Long-term debt proceeds	875,640	108,792
Long-term debt payments	(313,983)	(94,706)
Increase in short-term borrowings, net	34,332	296,222
Other	(559)	5,542
Net cash provided by financing activities	595,430	315,850
Net increase (decrease) in cash and cash equivalents	138,074	(5,861)
Cash and cash equivalents at beginning of period	298,565	443,671
Cash and cash equivalents at end of period	436,639	437,810
Cash paid for -
Interest (net of amounts capitalized)	165,388	181,675
Supplemental disclosure of non-cash investing and financing activities:
Change in plant expenditures included in accounts payable	$ 19,488	$ (13,069)