CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
CURRENT ASSETS
Cash and cash equivalents	$ 9,526	$ 26,202
Customer and other receivables	299,904	277,225
Accrued unbilled revenues	96,796	94,845
Allowance for doubtful accounts	(3,203)	(3,340)
Materials and supplies (at average cost)	221,682	218,096
Fossil fuel (at average cost)	38,028	31,334
Deferred income taxes (Note 4)	91,152	152,191
Income tax receivable (Note 4)	135,517	2,423
Assets from risk management activities (Note 17)	17,169	25,699
Deferred fuel and purchased power regulatory asset (Note 3)	20,755	72,692
Other regulatory assets (Note 3)	76,388	71,257
Other current assets	39,895	37,102
Total current assets	1,043,609	1,005,726
INVESTMENTS AND OTHER ASSETS
Assets from risk management activities (Note 17)	23,815	35,891
Nuclear decommissioning trust (Notes 14 and 20)	642,007	570,625
Other assets	60,875	62,694
Total investments and other assets	726,697	669,210
PROPERTY, PLANT AND EQUIPMENT (Notes 1, 6 and 10)
Plant in service and held for future use	15,200,464	14,346,367
Accumulated depreciation and amortization	(5,300,219)	(4,929,613)
Net	9,900,245	9,416,754
Construction work in progress	581,369	565,716
Palo Verde sale leaseback, net of accumulated depreciation of $225,925 and $222,055 (Note 19)	125,125	128,995
Intangible assets, net of accumulated amortization of $439,703 and $411,543	157,689	162,150
Nuclear fuel, net of accumulated amortization of $146,057 and $133,950	124,557	122,778
Total property, plant and equipment	10,888,985	10,396,393
DEFERRED DEBITS
Regulatory assets (Notes 1, 3 and 4)	711,712	1,099,900
Income tax receivable (Note 4)		70,389
Other	137,683	137,997
Total deferred debits	849,395	1,308,286
TOTAL ASSETS	13,508,686	13,379,615
CURRENT LIABILITIES
Accounts payable	284,516	221,312
Accrued taxes (Note 4)	130,998	124,939
Accrued interest	48,351	49,380
Common dividends payable	62,528	59,789
Short-term borrowings (Note 5)	153,125	92,175
Current maturities of long-term debt (Note 6)	540,424	122,828
Customer deposits	76,101	79,689
Liabilities from risk management activities (Note 17)	31,892	73,741
Liability for asset retirements (Note 12)	32,896
Regulatory liabilities (Note 3)	99,273	88,116
Other current liabilities	158,540	171,573
Total current liabilities	1,618,644	1,083,542
LONG-TERM DEBT LESS CURRENT MATURITIES (Note 6)	2,796,465	3,199,088
DEFERRED CREDITS AND OTHER
Deferred income taxes (Note 4)	2,351,882	2,151,371
Regulatory liabilities (Notes 1, 3 and 4)	801,297	759,201
Liability for asset retirements (Note 12)	313,833	357,097
Liabilities for pension and other postretirement benefits (Note 8)	513,628	1,058,755
Liabilities from risk management activities (Note 17)	70,315	85,264
Customer advances	114,480	109,359
Coal mine reclamation	207,453	118,860
Deferred investment tax credit	152,361	99,819
Unrecognized tax benefits (Note 4)	42,209	71,135
Other	185,659	183,835
Total deferred credits and other	4,753,117	4,994,696
COMMITMENTS AND CONTINGENCIES (SEE NOTES)
EQUITY (Note 7)
Common stock, no par value; authorized 150,000,000 shares, issued 110,280,703 at end of 2013 and 109,837,957 at end of 2012	2,491,558	2,466,923
Treasury stock at cost; 98,944 shares at end of 2013 and 95,192 shares at end of 2012	(4,308)	(4,211)
Total common stock	2,487,250	2,462,712
Retained earnings	1,785,273	1,624,102
Accumulated other comprehensive loss:
Pension and other postretirement benefits (Note 8)	(54,995)	(64,416)
Derivative instruments (Note 17)	(23,058)	(49,592)
Total accumulated other comprehensive loss	(78,053)	(114,008)
Total shareholders' equity	4,194,470	3,972,806
Noncontrolling interests (Note 19)	145,990	129,483
Total equity	4,340,460	4,102,289
TOTAL LIABILITIES AND EQUITY	$ 13,508,686	$ 13,379,615