Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Utility Plant
Plant in Service	$ 4,634,661	$ 4,452,928
Utility Plant under Capital Leases	582,669	583,374
Construction Work in Progress	222,235	210,971
Total Utility Plant	5,439,565	5,247,273
Less Accumulated Depreciation and Amortization	(1,859,610)	(1,824,843)
Less Accumulated Amortization of Capital Lease Assets	(472,683)	(460,932)
Total Utility Plant - Net	3,107,272	2,961,498
Investments and Other Property
Investments in Lease Debt and Equity	66,103	103,844
Other	34,413	61,676
Total Investments and Other Property	100,516	165,520
Current Assets
Cash and Cash Equivalents	60,437	67,599
Accounts Receivable - Customer	122,916	98,333
Unbilled Accounts Receivable	49,087	53,084
Allowance for Doubtful Accounts	(5,521)	(6,125)
Fuel Inventory	25,170	29,216
Materials and Supplies	70,073	65,832
Derivative Instruments	9,811	5,214
Regulatory Assets - Current	76,146	56,962
Deferred Income Taxes - Current	17,884	30,822
Other	39,431	30,091
Total Current Assets	465,434	431,028
Regulatory and Other Assets
Regulatory Assets - Noncurrent	158,439	192,966
Derivative Instruments	3,946	9,806
Other Assets	27,762	30,425
Total Regulatory and Other Assets	190,147	233,197
Total Assets	3,863,369	3,791,243
Capitalization
Common Stock Equity	893,669	830,756
Capital Lease Obligations	350,912	429,074
Long-Term Debt	1,454,615	1,352,977
Total Capitalization	2,699,196	2,612,807
Current Liabilities
Current Obligations Under Capital Leases	77,060	60,347
Borrowing Under Revolving Credit Facility	5,000	0
Current Maturities of Long-Term Debt	0	57,000
Accounts Payable - Trade	104,695	108,950
Interest Accrued	23,126	39,120
Accrued Taxes Other Than Income Taxes	56,188	39,140
Accrued Employee Expenses	26,520	26,969
Customer Deposits	31,450	29,795
Regulatory Liabilities - Current	44,725	69,483
Derivative Instruments	27,695	30,574
Other	5,248	1,678
Total Current Liabilities	401,707	463,056
Deferred Credits and Other Liabilities
Deferred Income Taxes - Noncurrent	297,767	246,466
Regulatory Liabilities - Noncurrent	228,825	201,329
Derivative Instruments	19,668	22,969
Pension and Other Postretirement Benefits	113,330	127,343
Other	102,876	117,273
Total Deferred Credits and Other Liabilities	762,466	715,380
Commitments, Contingencies and Proposed Environmental Matters (Note 6)
Total Capitalization and Other Liabilities	3,863,369	3,791,243
TEP [Member]
Utility Plant
Plant in Service	4,014,702	3,863,431
Utility Plant under Capital Leases	582,669	582,669
Construction Work in Progress	140,036	153,981
Total Utility Plant	4,737,407	4,600,081
Less Accumulated Depreciation and Amortization	(1,748,845)	(1,729,747)
Less Accumulated Amortization of Capital Lease Assets	(472,683)	(460,257)
Total Utility Plant - Net	2,515,879	2,410,077
Investments and Other Property
Investments in Lease Debt and Equity	66,103	103,844
Other	32,598	43,588
Total Investments and Other Property	98,701	147,432
Current Assets
Cash and Cash Equivalents	14,025	19,983
Accounts Receivable - Customer	104,812	78,200
Unbilled Accounts Receivable	39,817	32,217
Allowance for Doubtful Accounts	(3,779)	(4,106)
Accounts Receivable - Due from Affiliates	3,289	5,444
Fuel Inventory	24,887	29,209
Materials and Supplies	58,910	54,732
Derivative Instruments	2,104	1,318
Regulatory Assets - Current	56,642	34,023
Deferred Income Taxes - Current	21,324	32,077
Other	22,352	26,467
Total Current Assets	344,383	309,564
Regulatory and Other Assets
Regulatory Assets - Noncurrent	147,169	182,304
Derivative Instruments	1,360	1,834
Other Assets	22,354	24,767
Total Regulatory and Other Assets	170,883	208,905
Total Assets	3,129,846	3,075,978
Capitalization
Common Stock Equity	792,451	709,884
Capital Lease Obligations	350,912	429,074
Long-Term Debt	1,003,615	1,003,615
Total Capitalization	2,146,978	2,142,573
Current Liabilities
Current Obligations Under Capital Leases	77,060	60,309
Borrowing Under Revolving Credit Facility	5,000	0
Accounts Payable - Trade	79,693	77,021
Accounts Payable - Due to Affiliates	7,669	3,990
Interest Accrued	20,525	31,771
Accrued Taxes Other Than Income Taxes	46,414	29,873
Accrued Employee Expenses	23,713	23,710
Customer Deposits	22,716	21,191
Regulatory Liabilities - Current	30,534	58,936
Derivative Instruments	5,432	7,288
Other	3,735	3,379
Total Current Liabilities	322,491	317,468
Deferred Credits and Other Liabilities
Deferred Income Taxes - Noncurrent	269,968	227,615
Regulatory Liabilities - Noncurrent	195,052	170,223
Derivative Instruments	13,049	11,650
Pension and Other Postretirement Benefits	107,957	120,590
Other	74,351	85,859
Total Deferred Credits and Other Liabilities	660,377	615,937
Commitments, Contingencies and Proposed Environmental Matters (Note 6)
Total Capitalization and Other Liabilities	$ 3,129,846	$ 3,075,978