Condensed Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Electric plant:
In service	$ 8,307,346	$ 8,050,103
Less: Accumulated provision for depreciation	(3,729,922)	(3,615,375)
Total in service	4,577,424	4,434,728
Nuclear fuel, at amortized cost	339,697	341,012
Construction work in progress	2,277,147	2,212,224
Total electric plant	7,194,268	6,987,964
Investments and funds:
Nuclear decommissioning trust fund	355,832	343,698
Investment in associated companies	65,496	66,437
Long-term investments	83,689	81,720
Restricted cash and investments	96,432	34,975
Other	16,884	16,098
Total investments and funds	618,333	542,928
Current assets:
Cash and cash equivalents	312,206	408,193
Restricted cash and short-term investments	247,699	272,686
Receivables	134,573	128,992
Inventories, at average cost	263,795	286,168
Prepayments and other current assets	31,439	16,894
Total current assets	989,712	1,112,933
Deferred charges:
Deferred debt expense, being amortized	98,695	57,175
Regulatory assets	412,456	331,108
Other	51,786	63,104
Total deferred charges	562,937	451,387
Total assets	9,365,250	9,095,212
Capitalization:
Patronage capital and membership fees	765,361	714,489
Accumulated other comprehensive margin (deficit)	160	(549)
Total patronage capital and membership fees and accumulated other comprehensive margin	765,521	713,940
Long-term debt	6,881,522	6,817,518
Obligation under capital leases	102,280	121,731
Other	16,166	15,379
Total capitalization	7,765,489	7,668,568
Current liabilities:
Long-term debt and capital leases due within one year	299,960	152,153
Short-term borrowings	264,624	279,407
Accounts payable	67,809	101,529
Accrued interest	52,837	58,193
Member power bill prepayments, current	100,430	82,405
Other current liabilities	45,354	42,253
Total current liabilities	831,014	715,940
Deferred credits and other liabilities:
Gain on sale of plant, being amortized	21,047	22,157
Asset retirement obligations	426,212	408,050
Member power bill prepayments, non-current	71,819	32,313
Power sale agreement, being amortized	16,028	26,107
Regulatory liabilities	167,250	158,789
Other	66,391	63,288
Total deferred credits and other liabilities	768,747	710,704
Total equity and liabilities	$ 9,365,250	$ 9,095,212