El Paso Electric 10-K 26 Feb 14 2013 FY Annual report Financial data

Document_And_Entity_Informatio

Document And Entity Information (USD $)	12 Months Ended
	Dec. 31, 2013	Jan. 31, 2014	Jun. 30, 2013
Document and Entity Information [Line Items]	'	'	'
Entity Registrant Name	'EL PASO ELECTRIC CO /TX/	'	'
Entity Central Index Key	'0000031978	'	'
Trading Symbol	'EE	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Document Type	'10-K	'	'
Document Period End Date	31-Dec-13	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
Amendment Flag	'false	'	'
Entity Common Stock, Shares Outstanding	'	40,279,810	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Public Float	'	'	$1,401,286,283

BALANCE_SHEETS

BALANCE SHEETS (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Utility plant:	'	'
Electric plant in service	$3,076,549	$2,857,913
Less accumulated depreciation and amortization	-1,214,088	-1,162,483
Net plant in service	1,862,461	1,695,430
Construction work in progress	282,647	287,358
Nuclear fuel; includes fuel in process of $48,492 and $56,129, respectively	188,185	189,921
Less accumulated amortization	-75,820	-70,366
Net nuclear fuel	112,365	119,555
Net utility plant	2,257,473	2,102,343
Current assets:	'	'
Cash and cash equivalents	25,592	111,057
Accounts receivable, principally trade, net of allowance for doubtful accounts of $2,261 and $2,906, respectively	65,350	62,900
Accumulated deferred income taxes	26,965	20,292
Inventories, at cost	45,942	42,358
Undercollection of fuel revenues	7,248	0
Prepayments and other	7,694	9,627
Total current assets	178,791	246,234
Deferred charges and other assets:	'	'
Decommissioning trust funds	214,095	187,053
Regulatory assets	101,050	101,590
Other	34,879	31,830
Total deferred charges and other assets	350,024	320,473
Total assets	2,786,288	2,669,050
Capitalization:	'	'
Common stock, stated value $1 per share, 100,000,000 shares authorized, 65,639,091 and 65,520,551 shares issued, and 120,534 and 84,446 restricted shares, respectively	65,760	65,605
Capital in excess of stated value	314,443	310,994
Retained earnings	985,665	939,131
Accumulated other comprehensive income (loss), net of tax	2,612	-66,084
Total stockholders equity subtotal before treasury stock	1,368,480	1,249,646
Treasury stock, 25,492,919 shares at cost	-424,647	-424,647
Common stock equity	943,833	824,999
Long-term debt	999,620	999,535
Total capitalization	1,943,453	1,824,534
Current liabilities:	'	'
Short-term borrowings under the revolving credit facility	14,352	22,155
Accounts payable, principally trade	61,795	61,581
Taxes accrued	25,206	29,248
Interest accrued	12,189	12,127
Overcollection of fuel revenues	1,048	4,643
Other	22,932	21,995
Total current liabilities	137,522	151,749
Deferred credits and other liabilities:	'	'
Accumulated deferred income taxes	449,925	358,674
Accrued pension liability	84,012	125,690
Accrued postretirement benefit liability	50,655	99,170
Asset retirement obligation	65,214	62,784
Regulatory liabilities	26,416	22,179
Other	29,091	24,270
Total deferred credits and other liabilities	705,313	692,767
Commitments and contingencies	'	'
Total capitalization and liabilities	$2,786,288	$2,669,050

BALANCE_SHEETS_Parentheticals

BALANCE SHEETS (Parentheticals) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified
Nuclear fuel; fuel in process	$48,492	$56,129
Allowance for doubtful accounts receivable, current	$2,261	$2,906
Common stock, par or stated value per share	$1	$1
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	65,639,091	65,520,551
Common stock, restricted shares	120,534	84,446
Treasury stock, shares	25,492,919	25,492,919

STATEMENTS_OF_OPERATIONS

STATEMENTS OF OPERATIONS (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating revenues	$890,362	$852,881	$918,013
Energy expenses:	'	'	'
Fuel	226,768	191,076	223,507
Purchased and interchanged power	62,363	60,251	75,149
Cost of services, energy services	289,131	251,327	298,656
Operating revenues net of energy expenses	601,231	601,554	619,357
Other operating expenses:	'	'	'
Other operations	237,155	236,558	229,570
Maintenance	61,068	60,339	62,092
Depreciation and amortization	79,626	78,556	81,331
Taxes other than income taxes	57,747	57,443	55,561
Utilities operating expense	435,596	432,896	428,554
Operating income	165,635	168,658	190,803
Other income (deductions):	'	'	'
Allowance for equity funds used during construction	10,008	9,427	8,161
Investment and interest income, net	7,033	5,275	5,664
Miscellaneous non-operating income	909	1,415	885
Miscellaneous non-operating deductions	-3,635	-2,013	-3,187
Nonoperating income (expense)	14,315	14,104	11,523
Interest charges (credits):	'	'	'
Interest on long-term debt and revolving credit facility	58,635	54,632	54,115
Other interest	431	1,190	989
Capitalized interest	-5,299	-5,312	-5,177
Allowance for borrowed funds used during construction	-6,055	-5,573	-4,848
Interest expense	47,712	44,937	45,079
Income before income taxes	132,238	137,825	157,247
Income tax expense	43,655	46,979	53,708
Net income	$88,583	$90,846	$103,539
Basic earnings per share	$2.20	$2.27	$2.49
Diluted earnings per share	$2.20	$2.26	$2.48
Dividends declared per share of common stock	$1.04	$0.97	$0.66
Weighted average number of shares outstanding	40,114,594	39,974,022	41,349,883
Weighted average number of shares and dilutive potential shares outstanding	40,126,647	40,055,581	41,587,059

STATEMENTS_OF_COMPREHENSIVE_OP

STATEMENTS OF COMPREHENSIVE OPERATIONS (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net income	$88,583	$90,846	$103,539
Unrecognized pension and postretirement benefit costs:	'	'	'
Net gain (loss) arising during period	82,964	-2,109	-77,678
Prior service benefit	97	0	0
Reclassification adjustments included in net income for amortization of:	'	'	'
Prior service benefit	-5,560	-5,762	-5,812
Net loss	10,472	11,971	6,505
Net unrealized gains/losses on marketable securities:	'	'	'
Net holding gains arising during period	17,699	9,927	1,570
Reclassification adjustments for net (gains) losses included in net income	-553	1,042	1,358
Net losses on cash flow hedges:	'	'	'
Reclassification adjustment for interest expense included in net income	411	385	361
Total other comprehensive income (loss) before income taxes	105,530	15,454	-73,696
Income tax benefit (expense) related to items of other comprehensive income (loss):	'	'	'
Unrecognized pension and postretirement benefit costs	-33,566	-1,464	30,134
Net unrealized gains on marketable securities	-3,100	-2,438	-563
Losses on cash flow hedges	-168	-131	-203
Total income tax benefit (expense)	-36,834	-4,033	29,368
Other comprehensive income (loss), net of tax	68,696	11,421	-44,328
Comprehensive income	$157,279	$102,267	$59,211

STATEMENTS_OF_CHANGES_IN_COMMO

STATEMENTS OF CHANGES IN COMMON STOCK EQUITY (USD $)	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss), Net of Tax	Treasury Stock
In Thousands, except Share data, unless otherwise specified
Balances at beginning of period at Dec. 31, 2010	$810,375	$65,265	$305,068	$810,858	($33,177)	($337,639)
Balances at beginning of period (in shares) at Dec. 31, 2010	'	65,265,060	'	'	'	22,693,995
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'
Restricted common stock grants and deferred compensation (in shares)	'	118,110	'	'	'	'
Restricted common stock grants and deferred compensation	3,205	118	3,087	'	'	'
Performance share awards vested (in shares)	'	40,895	'	'	'	'
Performance share awards vested	628	41	587	'	'	'
Stock awards withheld for taxes (in shares)	'	-23,702	'	'	'	'
Stock awards withheld for taxes	-739	-24	-715	'	'	'
Forfeited restricted common stock (in shares)	'	-2,200	'	'	'	'
Forfeited restricted common stock	-2	-2	'	'	'	'
Deferred taxes on stock incentive plan	1,112	'	1,112	'	'	'
Stock options exercised (in shares)	'	53,910	'	'	'	'
Stock options exercised	692	54	638	'	'	'
Net income	103,539	'	'	103,539	'	'
Other comprehensive income (loss)	-44,328	'	'	'	-44,328	'
Dividends, Common Stock, Cash	27,223	'	'	27,223	'	'
Treasury stock acquired, at cost (in shares)	'	'	'	'	'	2,798,924
Treasury stock acquired, at cost	-87,008	'	'	'	'	-87,008
Balances at end of period at Dec. 31, 2011	760,251	65,452	309,777	887,174	-77,505	-424,647
Balances at end of period (in shares) at Dec. 31, 2011	'	65,452,073	'	'	'	25,492,919
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'
Restricted common stock grants and deferred compensation (in shares)	'	87,428	'	'	'	'
Restricted common stock grants and deferred compensation	1,778	87	1,691	'	'	'
Performance share awards vested (in shares)	'	174,038	'	'	'	'
Performance share awards vested	1,193	174	1,019	'	'	'
Stock awards withheld for taxes (in shares)	'	-52,778	'	'	'	'
Stock awards withheld for taxes	-1,822	-52	-1,770	'	'	'
Forfeited restricted common stock (in shares)	'	-88,100	'	'	'	'
Forfeited restricted common stock	-1,294	-88	-1,206	'	'	'
Deferred taxes on stock incentive plan	1,101	'	1,101	'	'	'
Stock options exercised (in shares)	'	32,336	'	'	'	'
Stock options exercised	414	32	382	'	'	'
Net income	90,846	'	'	90,846	'	'
Other comprehensive income (loss)	11,421	'	'	'	11,421	'
Dividends, Common Stock, Cash	38,889	'	'	38,889	'	'
Balances at end of period at Dec. 31, 2012	824,999	65,605	310,994	939,131	-66,084	-424,647
Balances at end of period (in shares) at Dec. 31, 2012	65,520,551	65,604,997	'	'	'	25,492,919
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'
Restricted common stock grants and deferred compensation (in shares)	'	96,279	'	'	'	'
Restricted common stock grants and deferred compensation	2,798	96	2,702	'	'	'
Performance share awards vested (in shares)	'	64,275	'	'	'	'
Performance share awards vested	849	64	785	'	'	'
Stock awards withheld for taxes (in shares)	'	-23,808	'	'	'	'
Stock awards withheld for taxes	-811	-23	-788	'	'	'
Forfeited restricted common stock (in shares)	'	-1,549	'	'	'	'
Forfeited restricted common stock	-1	-1	'	'	'	'
Deferred taxes on stock incentive plan	427	'	427	'	'	'
Stock options exercised (in shares)	'	15,000	'	'	'	'
Stock options exercised	192	15	177	'	'	'
Grants of share based compensation (in shares)	'	4,431	'	'	'	'
Grants of share based compensation	150	4	146	'	'	'
Net income	88,583	'	'	88,583	'	'
Other comprehensive income (loss)	68,696	'	'	'	68,696	'
Dividends, Common Stock, Cash	42,049	'	'	42,049	'	'
Treasury stock acquired, at cost (in shares)	0	'	'	'	'	'
Balances at end of period at Dec. 31, 2013	$943,833	$65,760	$314,443	$985,665	$2,612	($424,647)
Balances at end of period (in shares) at Dec. 31, 2013	65,639,091	65,759,625	'	'	'	25,492,919

Statements_Of_Cash_Flows

Statements Of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:	'	'	'
Net income	$88,583	$90,846	$103,539
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'
Depreciation and amortization of electric plant in service	79,626	78,556	81,331
Amortization of nuclear fuel	42,537	42,953	37,018
Deferred income taxes, net	44,678	43,561	45,688
Allowance for equity funds used during construction	-10,008	-9,427	-8,161
Other amortization and accretion	16,556	14,724	19,875
Other operating activities	-925	-479	1,036
Change in:	'	'	'
Accounts receivable	-2,450	13,448	-4,663
Inventories	-3,673	-1,926	-3,750
Net overcollection (undercollection) of fuel revenues	-10,843	11,668	-26,001
Prepayments and other	-4,295	-2,784	-2,538
Accounts payable	8,180	1,725	4,401
Taxes accrued	-627	-3,054	11,915
Other current liabilities	958	78	-2,262
Deferred charges and credits	-822	-6,781	-5,911
Net cash provided by operating activities	247,475	273,108	251,517
Cash flows from investing activities:	'	'	'
Cash additions to utility property, plant and equipment	-237,411	-202,387	-178,041
Cash additions to nuclear fuel	-30,535	-46,009	-39,551
Capitalized interest and AFUDC:	'	'	'
Utility property, plant and equipment	-16,063	-15,000	-13,009
Nuclear fuel	-5,299	-5,312	-5,177
Allowance for equity funds used during construction	10,008	9,427	8,161
Decommissioning trust funds:	'	'	'
Purchases, including funding of $4.5 million, $4.5 million and $8.3 million, respectively	-65,491	-107,705	-95,441
Sales and maturities	56,148	98,542	82,926
Proceeds from sale of investments in debt securities	0	0	2,000
Other investing activities	5,879	2,390	727
Net cash used for investing activities	-282,764	-266,054	-237,405
Cash flows from financing activities:	'	'	'
Repurchases of common stock	0	0	-86,508
Dividends paid	-42,049	-38,889	-27,223
Borrowings under the revolving credit facility:	'	'	'
Proceeds	44,883	234,575	120,450
Payments	-52,686	-245,799	-91,775
Pollution control bonds:	'	'	'
Proceeds	0	92,535	0
Payments	0	-92,535	0
Proceeds from issuance of senior notes	0	149,682	0
Other financing activities	-324	-3,774	-32
Net cash provided by (used for) financing activities	-50,176	95,795	-85,088
Net increase (decrease) in cash and cash equivalents	-85,465	102,849	-70,976
Cash and cash equivalents at beginning of period	111,057	8,208	79,184
Cash and cash equivalents at end of period	$25,592	$111,057	$8,208

Statements_of_Cash_Flows_Paren

Statements of Cash Flows Parenthetical (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Payments To Fund Decommissioning Fund	$4.50	$4.50	$8.30

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Significant Accounting Policies	'
	Summary of Significant Accounting Policies
	General. El Paso Electric Company is a public utility engaged in the generation, transmission and distribution of electricity in an area of approximately 10,000 square miles in west Texas and southern New Mexico. El Paso Electric Company also serves a full requirements wholesale customer in Texas.
	Dissolution of Subsidiary. MiraSol Energy Services, Inc. ("MiraSol"), the Company’s wholly owned subsidiary, provided energy efficiency products and discontinued these activities in 2002. MiraSol has had no material effect on the Company’s previously reported consolidated financial statements for the years ended December 31, 2012 and December 31, 2011. The Company dissolved MiraSol in the fourth quarter of 2013. MiraSol’s net assets and stockholders’ equity totaled less than $0.1 million and the dissolution of MiraSol had no material effect on the Company’s financial statements for the twelve months ended December 31, 2013.
	Use of Estimates. The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
	Basis of Presentation. The Company maintains its accounts in accordance with the Uniform System of Accounts prescribed by the Federal Energy Regulatory Commission (the "FERC").
	Application of FASB Guidance for Regulated Operations. Regulated electric utilities typically prepare their financial statements in accordance with the Financial Accounting Standards Board ("FASB") guidance for regulated operations. FASB guidance for regulated operations requires the Company to include an allowance for equity and borrowed funds used during construction ("AEFUDC" and "ABFUDC") as a cost of construction of electric plant in service. AEFUDC is recognized as income and ABFUDC is shown as capitalized interest charges in the Company’s statement of operations. FASB guidance for regulated operations also requires the Company to show certain recoverable costs as either assets or liabilities on a utility’s balance sheet if the regulator provides assurance that these costs will be charged to and collected from the utility’s customers (or has already permitted such cost recovery) or will be credited or refunded to the utility’s customers. The resulting regulatory assets or liabilities are amortized in subsequent periods based upon the respective amortization periods reflected in a utility’s regulated rates. See Note D. The Company applies FASB guidance for regulated operations for all three of the jurisdictions in which it operates.
	Comprehensive Income. Certain gains and losses that are not recognized currently in the statements of operations are reported as other comprehensive income in accordance with FASB guidance for reporting comprehensive income.
	Utility Plant. Utility plant is generally reported at cost. The cost of renewals and betterments are capitalized and the costs of repairs and minor replacements are charged to the appropriate operating expense accounts. Depreciation is provided on a straight-line basis over the estimated remaining lives of the assets (ranging in average from 5 to 48 years). The average composite depreciation rate utilized in 2013, 2012 and 2011 was 2.61%, 2.64%, and 2.80%, respectively. When property subject to composite depreciation is retired or otherwise disposed of in the normal course of business, its cost – together with the cost of removal, less salvage – is charged to accumulated depreciation. For other property dispositions, the applicable cost and accumulated depreciation is removed from the balance sheet accounts and a gain or loss is recognized.
	The cost of nuclear fuel is amortized to fuel expense on a units-of-production basis. A provision for spent fuel disposal costs is charged to expense based on the funding requirements of the Department of Energy (the "DOE") for disposal cost of approximately one-tenth of one cent on each kWh generated. The Company is also amortizing its share of costs associated with on-site spent fuel storage casks at Palo Verde over the burn period of the fuel that will necessitate the use of the storage casks. See Note E.
	Impairment of Long-Lived Assets. Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated undiscounted future cash flows, an impairment charge is recognized for the amount by which the carrying amount of the asset exceeds the fair value of the asset.
	AFUDC and Capitalized Interest. The Company capitalizes interest ("ABFUDC") and common equity ("AEFUDC") costs to construction work in progress and capitalizes interest to nuclear fuel in process in accordance with the FERC Uniform System of Accounts as provided for in FASB guidance. AFUDC is a non-cash component of income and is calculated monthly and charged to all new eligible construction and capital improvement projects. AFUDC is compounded on a semi-annual basis. The AFUDC rates used in 2013, 2012 and 2011 were 8.10%, 8.53% and 8.54%, respectively.
	Asset Retirement Obligation. FASB guidance sets forth accounting requirements for the recognition and measurement of liabilities associated with the retirement of tangible long-lived assets. An asset retirement obligation ("ARO") associated with long-lived assets included within the scope of FASB guidance is that for which a legal obligation exists under enacted laws, statutes, written or oral contracts, including obligations arising under the doctrine of promissory estoppel and legal obligations to perform an asset retirement activity even if the timing and/or settlement are conditioned on a future event that may or may not be within the control of an entity. See Note F. Under FASB guidance, these liabilities are recognized as incurred if a reasonable estimate of fair value can be established and are capitalized as part of the cost of the related tangible long-lived assets. The Company records the increase in the ARO due to the passage of time as an operating expense (accretion expense).
	Cash and Cash Equivalents. All temporary cash investments with an original maturity of three months or less are considered cash equivalents.
	Investments. The Company’s marketable securities, included in decommissioning trust funds in the balance sheets, are reported at fair value and consist of cash, equity securities and municipal, federal and corporate bonds in trust funds established for decommissioning of its interest in Palo Verde. Such marketable securities are classified as "available-for-sale" securities and, as such, unrealized gains and losses are included in accumulated other comprehensive loss as a separate component of common stock equity. However, if declines in fair value of marketable securities below original cost basis are determined to be other than temporary, then the declines are reported as losses in the statement of operations and a new cost basis is established for the affected securities at fair value. Gains and losses are determined using the cost of the security based on the specific identification basis. See Note O.
	Derivative Accounting. Accounting for derivative instruments and hedging activities requires the recognition of derivatives as either assets or liabilities in the balance sheet with measurement of those instruments at fair value. Any changes in the fair value of these instruments are recorded in earnings or other comprehensive income. See Note O.
	Inventories. Inventories, primarily parts, materials, supplies, fuel oil and natural gas are stated at average cost not to exceed recoverable cost.
	Operating Revenues Net of Energy Expenses. The Company accrues revenues for services rendered, including unbilled electric service revenues. Energy expenses are stated at actual cost incurred. The Company’s Texas retail customers are billed under base rates and a fixed fuel factor approved by the Public Utility Commission of Texas ("PUCT"). The Company’s New Mexico retail customers and its sales for resale customer are billed under base rates and a fuel adjustment clause which is adjusted monthly, as approved by the New Mexico Public Regulation Commission ("NMPRC") and the FERC. The Company’s recovery of energy expenses is subject to periodic reconciliations of actual energy expenses incurred to actual fuel revenues collected. The difference between energy expenses incurred and fuel revenues charged to customers is reflected as over/undercollection of fuel revenues in the balance sheets. See Note C.
	Revenues. Revenues related to the sale of electricity are generally recorded when service is rendered or electricity is delivered to customers. The billing of electricity sales to retail customers is based on the reading of their meters, which occurs on a systematic basis throughout the month. Unbilled revenues are estimated based on monthly generation volumes and by applying an average revenue/kWh to the number of estimated kWhs delivered but not billed. Accounts receivable included accrued unbilled revenues of $19.8 million and $17.9 million at December 31, 2013 and 2012, respectively. The Company presents revenues net of sales taxes in its statements of operations.
	Allowance for Doubtful Accounts. The allowance for doubtful accounts represents the Company’s estimate of existing accounts receivable that will ultimately be uncollectible. The allowance is calculated by applying estimated write-off factors to various classes of outstanding receivables. The write-off factors used to estimate uncollectible accounts are based upon consideration of both historical collections experience and management’s best estimate of future collections success given the existing collections environment. Additions, deductions and balances for allowance for doubtful accounts for 2013, 2012 and 2011 are as follows (in thousands):
		2013		2012		2011
	Balance at beginning of year	$	2,906	$	3,015	$	2,885
	Additions:
	Charged to costs and expense	2,098		3,087		6,209
	Recovery of previous write-offs	1,929		2,041		2,034
	Uncollectible receivables written off	4,672		5,237		8,113
	Balance at end of year	$	2,261	$	2,906	$	3,015
	Income Taxes. The Company accounts for federal and state income taxes under the asset and liability method of accounting for income taxes. Deferred income taxes are recognized for the estimated future tax consequences of "temporary differences" by applying enacted statutory tax rates for each taxable jurisdiction applicable to future years to differences between the financial statement carrying amounts and the tax basis of existing assets and liabilities. Certain temporary differences are accorded flow-through treatment by the Company's regulators and impact the Company's effective tax rate. FASB guidance requires that rate-regulated companies record deferred income taxes for temporary differences accorded flow-through treatment at the direction of the regulatory commission. The resulting deferred tax assets and liabilities are recorded at the expected cash flow to be reflected in future rates. Because the Company's regulators have consistently permitted the recovery of tax effects previously flowed-through earnings, the Company has recorded regulatory liabilities and assets offsetting such deferred tax assets and liabilities. The effect on deferred tax assets and liabilities of a change in tax rate is recognized in income in the period that includes the enactment date. The Company recognizes tax assets and liabilities for uncertain tax positions in accordance with the recognition and measurement criteria of FASB guidance for uncertainty in income taxes. See Note J.
	Earnings per Share. The Company’s restricted stock awards are participating securities and earnings per share must be calculated using the two-class method in both the basic and diluted earnings per share calculations. For the basic earnings per share calculation, net income is allocated to the weighted average number of restricted stock awards and to the weighted average number of shares outstanding. The net income allocated to the weighted average number of shares outstanding is then divided by the weighted average number of shares outstanding to derive the basic earnings per share. For the diluted earnings per share, net income is allocated to the weighted average number of restricted stock awards and to the weighted average number of shares and dilutive potential shares outstanding. The Company’s dilutive potential shares outstanding amount is calculated using the treasury stock method for the unvested performance shares and outstanding stock options. Net income allocated to the weighted average number of shares and dilutive potential shares is then divided by the weighted average number of shares and dilutive potential shares outstanding to derive the diluted earnings per share. See Note G.
	Stock-Based Compensation. The Company has a stock-based long-term incentive plan. The Company is required under FASB guidance to measure the cost of employee services received in exchange for an award of equity instruments based on the grant-date fair value of the award. Such costs are recognized over the period during which an employee is required to provide service in exchange for the award (the "requisite service period") which typically is the vesting period. Compensation cost is not recognized for anticipated forfeitures prior to vesting of equity instruments. See Note G.
	Pension and Postretirement Benefit Accounting. See Note M for a discussion of the Company’s accounting policies for its employee benefits.
	Reclassification. Certain amounts in the financial statements for 2012 and 2011 have been reclassified to conform with the 2013 presentation.

New_Accounting_Standards

New Accounting Standards	12 Months Ended
	Dec. 31, 2013
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]	'
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	'
	New Accounting Standards
	In February 2013, the FASB issued new guidance (Accounting Standards Update ("ASU") 2013-02, Comprehensive Income (Topic 220)) to improve the reporting of reclassifications out of accumulated other comprehensive income (loss). ASU 2013-02 requires an entity to report the effect of significant reclassifications out of accumulated other comprehensive income (loss) on the respective line items in net income if the amount being reclassified is required under FASB guidance to be reclassified in its entirety to net income in the same reporting period. For other amounts that are not required under FASB guidance to be reclassified in their entirety to net income in the same reporting period, an entity is required to cross-reference other disclosures required under FASB guidance that provide additional detail about those amounts.
	Substantially all of the information that ASU 2013-02 requires is already required to be disclosed elsewhere in the financial statements under FASB guidance. However, the new requirement to present information about amounts reclassified out of accumulated other comprehensive income (loss) and their corresponding effect on net income now requires the presentation in one place, information about significant amounts reclassified and, in some cases, cross-references to related footnote disclosures. ASU 2013-02 became effective prospectively for reporting periods beginning after December 15, 2012. The Company implemented ASU 2013-02 in the first quarter of 2013 and has presented the corresponding effects of components reclassified out of accumulated other comprehensive income (loss) with cross-references to other disclosures or the respective line items in net income in Note H.
	In July 2013, the FASB issued new guidance (ASU 2013-11, Income Taxes (Topic 740)) to eliminate the diversity in the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. ASU 2013-11 requires an entity to present an unrecognized tax benefit in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward, except in certain circumstances when it would be reflected as a liability. ASU 2013-11 is effective prospectively for all unrecognized tax benefits that exist for reporting periods beginning after December 15, 2013 and early adoption is permitted. Retrospective application is also permitted. The Company anticipates implementing ASU 2013-11 in the first quarter of 2014.The Company is currently assessing the future impact of this ASU, however it is not expected to have a significant impact on the Company's statement of operations or statements of cash flows.

Regulation

Regulation	12 Months Ended
	Dec. 31, 2013
Public Utilities, General Disclosures [Abstract]	'
Regulation	'
	Regulation
	General
	The rates and services of the Company are regulated by incorporated municipalities in Texas, the PUCT, the NMPRC, and the FERC. The PUCT and the NMPRC have jurisdiction to review municipal orders, ordinances and utility agreements regarding rates and services within their respective states and over certain other activities of the Company. The FERC has jurisdiction over the Company's wholesale (sales for resale) transactions, transmission service and compliance with federally-mandated reliability standards. The decisions of the PUCT, the NMPRC and the FERC are subject to judicial review.
	Texas Regulatory Matters
	2012 Texas Retail Rate Case. The Company filed a rate increase request with the PUCT, Docket No. 40094, the City of El Paso, and other Texas cities on February 1, 2012. The rate filing was made in response to a resolution adopted by the El Paso City Council (the "Council") requiring the Company to show cause why its base rates for customers in the El Paso city limits should not be reduced. The filing at the PUCT also included a request to reconcile $356.5 million of fuel expense for the period July 1, 2009 through September 30, 2011.
	On April 17, 2012, the Council approved the settlement of the Company's 2012 Texas retail rate case and fuel reconciliation in PUCT Docket No. 40094. The PUCT issued a final order approving the settlement on May 23, 2012.
	Under the terms of the settlement, among other things, the Company agreed to:
	•	A reduction in its non-fuel base rates of $15 million annually, with the decrease being allocated primarily to Texas retail commercial and industrial customer classes. The rate decrease was effective as of May 1, 2012;
	•	Revised depreciation rates for the Company's gas-fired generating units and for transmission and distribution plant that lower depreciation expense by $4.1 million annually;
	•	Continuation of the 10.125% return on equity for the purpose of calculating the allowance for funds used during construction; and
	•A	two-year amortization of rate case expenses, none of which will be included in future regulatory proceedings.
	As part of the settlement, the Company agreed to withdraw its request to reconcile fuel costs for the period from July 1, 2009 through September 30, 2011 and submit a future fuel reconciliation request covering the period beginning July 1, 2009 and ending no later than June 30, 2013 by December 31, 2013 or as part of its next rate case, if earlier. The settlement also provides for the continuation of the energy efficiency cost recovery factor and the military base discount recovery factor. Both of these surcharges require annual filings to reconcile and revise the recovery factors.
	Fuel and Purchased Power Costs. The Company's actual fuel costs, including purchased power energy costs, are recovered from customers through a fixed fuel factor. The PUCT has adopted a fuel cost recovery rule (the "Texas Fuel Rule") that allows the Company to seek periodic adjustments to its fixed fuel factor. The Company can seek to revise its fixed fuel factor based upon the approved formula at least four months after its last revision except in the month of December. The Texas Fuel Rule requires the Company to request to refund fuel costs in any month when the over-recovery balance exceeds a threshold material amount and it expects fuel costs to continue to be materially over-recovered. The Texas Fuel Rule also permits the Company to seek to surcharge fuel under-recoveries in any month the balance exceeds a threshold material amount and it expects fuel cost recovery to continue to be materially under-recovered. Fuel over and under-recoveries are considered material when they exceed 4% of the previous twelve months' fuel costs. All such fuel revenue and expense activities are subject to periodic final review by the PUCT in fuel reconciliation proceedings.
	The Company filed the following petition with the PUCT to refund fuel cost over-recoveries, due primarily to fluctuations in natural gas markets and consumption levels. The table summarizes the docket number assigned by the PUCT, the date the Company filed the petition and the date a final order was issued by the PUCT approving the refund to customers. The fuel cost over-recovery period represents the months in which the over-recoveries took place, and the refund period represents the billing month in which customers received the refund amounts shown, including interest:
	Docket		Date Filed	Date Approved	Recovery Period	Refund Period	Refund
	No.						Amount Authorized (In Thousands)
	40622		3-Aug-12	28-Sep-12	January 2011- June 2012	Sep-12	$	6,600
	The Company filed the following petitions with the PUCT to revise its fixed fuel factor pursuant to the fuel factor formula authorized in PUCT Docket No. 37690:
	Docket		Date Filed	Date Approved	Increase (Decrease) in	Effective Billing
	No.				Fuel Factor	Month
	40302		April 12, 2012	April 25, 2012	-18.50%	May-12
	41803		September 9, 2013	September 23, 2013	12.20%	Oct-13
	Fuel Reconciliation Proceeding. On September 27, 2013, the Company filed an application with the PUCT, designated as Docket No. 41852, to reconcile $545.3 million of fuel and purchased power expenses incurred during the 45-month period from July 1, 2009 through March 31, 2013. The fuel reconciliation requests to recover $3.4 million of rewards for Palo Verde operations. Intervenor testimony is due February 28, 2014 and PUCT Staff testimony is due March 7, 2014. Hearings in the fuel reconciliation are scheduled to begin March 31, 2014 and a final order must be issued by September 26, 2014.
	Montana Power Station Approvals. The Company has received a Certificate of Convenience and Necessity ("CCN") authorization from the PUCT to construct the first two (of four) units of the Montana Power Station ("the MPS"). The Company must also obtain air permits from state and federal regulatory agencies before it can begin construction. On January 22, 2014, the Texas Commission on Environmental Quality ("TCEQ") issued the required permit. The U.S. Environmental Protection Agency ("EPA") issued a draft permit for greenhouse gas ("GHG") in September 2013 and solicited public comment. EPA is considering comments filed in response to that proposal before issuing a final permit. The Company believes that the type of facility planned at the MPS complies with all EPA regulations for granting a GHG permit and that the issues raised in the comments have previously been resolved in proceedings in other regions in favor of the grant of a permit. If the permit is granted, commenters may challenge the determination before the U.S. EPA’s Environmental Appeals Board. While the Company believes that this application demonstrates compliance with all applicable regulations, it cannot predict the timing or final outcome.
	On September 6, 2013, the Company filed an application with the PUCT for issuance of a CCN to construct, own and operate two additional 88 MW natural gas-fired generating units designated as the MPS Units 3 and 4 in El Paso County, Texas. The case has been designated PUCT Docket No. 41763. Hearings in this case were held in February 2014. In accordance with PUCT rules, the final order must be issued by September 5, 2014.
	The Company filed three transmission line CCN applications with the PUCT as part of the MPS Project:
	•	MPS to Caliente: a 115-kV transmission line from the MPS to the existing Caliente Substation in east El Paso. (PUCT Docket No. 41360)
	•	MPS In & Out: a 115-kV transmission line from the MPS to intersect with the existing Caliente - Coyote 115-kV transmission line. (PUCT Docket No. 41359)
	•	MPS to Montwood: a 115-kV transmission line from the MPS to the existing Montwood Substation in east El Paso. (PUCT Docket No. 41809)
	The transmission CCN filings for both the MPS to Caliente and the MPS In & Out were filed on April 15, 2013, and the transmission CCN filing for the MPS to Montwood was filed on September 24, 2013. The Company is requesting to build these transmission lines to connect the new MPS to the electrical grid in order to meet increased customer growth and electric demand and to improve system reliability. A final order approving a unanimous settlement in the MPS to Caliente transmission CCN filing is expected by the end of the first quarter of 2014. Final orders in the transmission CCN filings for the MPS In & Out and the MPS to Montwood filings are expected no later than October 2014.
	Other Required Approvals. The Company has obtained other required approvals for recovery of fuel costs through fixed fuel factors, other tariffs and approvals as required by the Public Utility Regulatory Act ( the "PURA") and the PUCT.
	New Mexico Regulatory Matters
	2009 New Mexico Stipulation. On December 10, 2009, the NMPRC issued a final order conditionally approving the stipulated rates in NMPRC Case No. 09-00171-UT. The stipulated rates went into effect with January 2010 bills. The stipulated rates provide for an Efficient Use of Energy Factor Rate Rider to recover energy efficiency expenditures which requires an annual filing and approval of the related incentives and adjustment to the recovery factors.
	Fuel and purchased power costs in New Mexico are recovered through a Fuel and Purchased Power Cost Recovery Factor (the "FPPCAC"). On January 8, 2014, the NMPRC approved the continuation of the FPPCAC without modification. The Company recovers its investment in Palo Verde Unit 3 in New Mexico through the FPPCAC as purchased power using a proxy market price approved in the 2009 New Mexico rate stipulation.
	2013 Annual Procurement Plan Pursuant to the Renewable Energy Act. On July 1, 2013, the Company filed its application for approval of its 2013 Annual Procurement Plan pursuant to the New Mexico Renewable Energy Act. On November 20, 2013, the NMPRC issued a final order approving the renewable procurement plan with modifications recommended by the Hearing Examiner. The plan sets out the Company's procurement of renewable resources and estimated costs for 2014 and 2015 to meet Renewable Portfolio Standards ("RPS") and resource diversity requirements. The approved plan provides for the RPS and diversity requirements for 2014 and 2015 to be met with a combination of previously approved resources and grants the Company's request for waiver for meeting the full RPS through 2015 due to reasonable cost threshold limits. The order also grants the Company's requested diversity variances for 2014 and 2015. Costs for purchases of renewable energy delivered to the Company are recovered through the FPPCAC and purchases of unbundled renewable energy credits are recovered through base rates.
	Long-Term Purchased Power Agreement with Macho Springs. On November 21, 2012, the Company filed an application with the NMPRC requesting approval of a Long-Term Purchase Power Agreement (the "LTPPA") with Macho Springs Solar, LLC ("Macho Springs") to purchase energy from a 50 MW solar facility to be constructed by Macho Springs on the Company's New Mexico transmission system. The Company also sought approval of the recovery of costs associated with the LTPPA through the Company's FPPCAC. A final order approving the LTPPA and recovery through the FPPCAC was received May 1, 2013.
	Montana Power Station Approvals. The Company has received a CCN authorization from the NMPRC to construct the first two (of four) units of the MPS. As discussed above, the Company must also obtain air permits from the TCEQ and EPA before it can begin construction. On September 6, 2013, the Company filed an application with the NMPRC for issuance of a CCN to construct, own and operate two additional 88 MW natural gas-fired generating units designated as the MPS Units 3 and 4 in El Paso County, Texas. The case has been designated NMPRC Case No. 13-00297-UT. No protests to the Company's application were filed and the hearing examiner issued a recommended decision to approve the Company's application on February 20, 2014. A final order is expected in the first quarter of 2014.
	Revolving Credit Facility, Issuance of Long-Term Debt and Guarantee of Debt. On October 30, 2013, the Company received approval in NMPRC Case No. 13-00317-UT to amend its current $300 million Revolving Credit Facility ("RCF") to include an option, subject to lender's approval, to expand the amount of the potential borrowings available under the facility to $400 million and extend the maturity date by up to four years; issue up to $300 million in new long-term debt; and to guarantee the issuance of up to $50 million of new debt by Rio Grande Resources Trust ("RGRT") to finance future purchases of nuclear fuel and to refinance existing debt obligations related to the financing of purchases of nuclear fuel.
	On January 14, 2014, the Company and RGRT entered into a second amended and restated credit agreement related to the RCF with JP Morgan Chase Bank, N.A., as administrative agent and issuing bank, and Union Bank, N.A., as syndication agent, and various lending banks party thereto. Under the terms of the agreement, the Company has available $300 million and the ability to increase the RCF by up to $100 million (up to a total of $400 million) upon the satisfaction of certain conditions, more fully set forth in the agreement, including obtaining commitments from lenders or third party financial institutions. The RCF has a term ending January 2019. The Company may extend the maturity date up to two times, in each case for an additional one year period upon the satisfaction of certain conditions.
	Other Required Approvals. The Company has obtained other required approvals for other tariffs, securities transactions, long-term resource plans, recovery of energy efficiency costs through a base rate rider and other approvals as required by the NMPRC.
	Federal Regulatory Matters
	Public Service Company of New Mexico's ("PNM") 2010 Transmission Rate Case. On October 27, 2010, PNM filed a Notice of Transmission Rate Change for transmission delivery services provided by PNM. These rates went into effect on June 1, 2011. The Company takes transmission service from PNM. On January 2, 2013, the FERC issued a letter order approving a unanimous stipulation and agreement. Pursuant to the stipulation, on January 31, 2013, PNM refunded $1.9 million for amounts that PNM collected since June 1, 2011 in excess of settlement rates. This amount was recorded in the fourth quarter of 2012 as a reduction of transmission expense.
	Revolving Credit Facility, Issuance of Long-Term Debt and Guarantee of Debt. On September 30, 2013, the Company filed an application for approval to amend its current $300 million RCF to include an option, subject to lender's approval, to expand the amount of the potential borrowings available under the facility to $400 million and extend the maturity date by up to four years; issue up to $300 million in new long-term debt; and to guarantee the issuance of up to $50 million of new debt by RGRT to finance future purchases of nuclear fuel and to refinance existing debt obligations related to the purchase of nuclear fuel. The FERC issued an order approving the filing on November 15, 2013. The case was assigned to FERC Docket No. ES 13-59-000. As noted above, on January 14, 2014, the Company and RGRT entered into a second amended and restated credit agreement related to the RCF.
	Other Required Approvals. The Company has obtained required approvals for rates and tariffs, securities transactions and other approvals as required by the FERC.
	Department of Energy ("DOE"). The DOE regulates the Company's exports of power to the Comision Federal de Electricidad in Mexico pursuant to a license granted by the DOE and a presidential permit.
	The DOE is authorized to assess operators of nuclear generating facilities a share of the costs of decommissioning the DOE's uranium enrichment facilities and for the ultimate costs of disposal of spent nuclear fuel. See Note E for discussion of spent fuel storage and disposal costs.
	Sales for Resale
	The Company provides firm capacity and associated energy to the RGEC pursuant to an ongoing contract with a two-year notice to terminate provision. The Company also provides network integrated transmission service to the RGEC pursuant to the Company's Open Access Transmission Tariff ("OATT"). The contract includes a formula-based rate that is updated annually to recover non-fuel generation costs and a fuel adjustment clause designed to recover all eligible fuel and purchased power costs allocable to the RGEC.

Regulatory_Assets_and_Liabilit

Regulatory Assets and Liabilities	12 Months Ended
	Dec. 31, 2013
Regulatory Assets and Liabilities Disclosure [Abstract]	'
Schedule of Regulatory Assets and Liabilities	'
	Regulatory Assets and Liabilities
	The Company's operations are regulated by the PUCT, the NMPRC and the FERC. Regulatory assets represent probable future recovery of previously incurred costs, which will be collected from customers through the ratemaking process. Regulatory liabilities represent probable future reductions in revenues associated with amounts that are to be credited to customers through the ratemaking process. Regulatory assets and liabilities reflected in the Company's balance sheets are presented below (in thousands):
		Amortization	December 31, 2013		December 31, 2012
		Period Ends
	Regulatory assets
	Regulatory tax assets (a)	(b)	$	61,772	$	57,551
	Loss on reacquired debt (c)	May-35	18,338		19,191
	Final coal reclamation (f)	Jul-16	4,290		5,473
	Nuclear fuel postload daily financing charge	(d)	4,141		3,833
	Unrecovered issuance costs due to reissuance of PCBs (c)	Aug-42	893		926
	Texas energy efficiency	(e)	—		536
	Texas 2012 rate case costs (f)	Apr-14	581		2,335
	Texas military base discount and recovery factor	(h)	759		2,116
	New Mexico procurement plan costs	(g)	139		139
	New Mexico renewable energy credits	(g)	4,833		4,033
	New Mexico 2010 FPPCAC audit	(g)	433		433
	New Mexico Palo Verde deferred depreciation	(b)	4,871		5,024
	Total regulatory assets		$	101,050	$	101,590
	Regulatory liabilities
	Regulatory tax liabilities (a)	(b)	$	17,752	$	16,666
	Accumulated deferred investment tax credit (i)	(b)	4,656		4,587
	New Mexico energy efficiency	(e)	3,646		926
	Texas energy efficiency	(e)	362		—
	Total regulatory liabilities		$	26,416	$	22,179
	________________
	(a)	No specific return on investment is required since related assets and liabilities offset.
	(b)	The amortization period for this asset is based upon the life of the associated assets or liabilities.
	(c)	This item is recovered as a component of the weighted cost of debt and amortized over the life of the related debt issuance.
	(d)	This item is recovered through fuel recovery mechanisms.
	(e)	This item is recovered or credited through a recovery factor that is set annually.
	(f)	This item is included in rate base which earns a return on investment.
	(g)	Amortization period is anticipated to be established in next general rate case.
	(h)	This item represents the net asset related to the military discount which is recovered from non-military customers through a recovery factor.
	(i)	This item is excluded from rate base.

Utility_Plant_Palo_Verde_and_O

Utility Plant, Palo Verde and Other Jointly-Owned Utility Plant	12 Months Ended
	Dec. 31, 2013
Utility Plant, Palo Verde and Other Jointly-Owned Utility Plant [Abstract]	'
Schedule of Public Utility Property, Plant, and Equipment	'
	Utility Plant, Palo Verde and Other Jointly-Owned Utility Plant
	The table below presents the balance of each major class of depreciable assets at December 31, 2013 (in thousands):
		Gross			Accumulated			Net
		Plant			Depreciation			Plant
	Nuclear production	$	817,665		$	(271,173	)	$	546,492
	Steam and other	668,666			(264,019		)	404,647
	Total production	1,486,331			(535,192		)	951,139
	Transmission	432,674			(246,175		)	186,499
	Distribution	965,674			(337,513		)	628,161
	General	122,209			(58,231		)	63,978
	Intangible	69,661			(36,977		)	32,684
	Total	$	3,076,549		$	(1,214,088	)	$	1,862,461
	Amortization of intangible plant (software) is provided on a straight-line basis over the estimated useful life of the asset (ranging from 5 to 10 years). The table below presents the actual and estimated amortization expense for intangible plant for the previous three years and for the next five years (in thousands):
	2011	$	6,668
	2012	7,183
	2013	7,683
	2014 (estimated)	7,372
	2015 (estimated)	6,540
	2016 (estimated)	5,980
	2017 (estimated)	5,326
	2018 (estimated)	3,713
	The Company owns a 15.8% interest in each of the three nuclear generating units and common facilities at Palo Verde, in Wintersburg, Arizona. The Palo Verde Participants include the Company and six other utilities: Arizona Public Service Company ("APS"), Southern California Edison Company ("SCE"), Public Service Company of New Mexico ("PNM"), Southern California Public Power Authority, Salt River Project Agricultural Improvement and Power District ("SRP") and the Los Angeles Department of Water and Power.
	Other jointly-owned utility plant includes a 7% interest in Units 4 and 5 at Four Corners Generating Station ("Four Corners") and certain other transmission facilities. A summary of the Company’s investment in jointly-owned utility plant, excluding fuel inventories, at December 31, 2013 and 2012 is as follows (in thousands):
		December 31, 2013						December 31, 2012
		Palo Verde			Other			Palo Verde			Other
	Electric plant in service	$	817,665		$	217,137		$	795,259		$	213,155
	Accumulated depreciation	(271,173		)	(173,819		)	(257,540		)	(168,569		)
	Construction work in progress	75,040			2,347			64,623			2,401
	Total	$	621,532		$	45,665		$	602,342		$	46,987
	Palo Verde
	The operation of Palo Verde and the relationship among the Palo Verde Participants is governed by the Arizona Nuclear Power Project Participation Agreement (the "ANPP Participation Agreement"). APS serves as operating agent for Palo Verde, and under the ANPP Participation Agreement, the Company has limited ability to influence operations and costs at Palo Verde. Pursuant to the ANPP Participation Agreement, the Palo Verde Participants share costs and generating entitlements in the same proportion as their percentage interests in the generating units, and each participant is required to fund its share of fuel, other operations, maintenance and capital costs. The Company’s share of direct expenses in Palo Verde and other jointly-owned utility plants is reflected in fuel expense, other operations expense, maintenance expense, miscellaneous other deductions, and taxes other than income taxes in the Company’s statements of operations. The ANPP Participation Agreement provides that if a participant fails to meet its payment obligations, each non-defaulting participant shall pay its proportionate share of the payments owed by the defaulting participant. Because it is impracticable to predict defaulting participants, the Company cannot estimate the maximum potential amount of future payment, if any, which could be required under this provision.
	NRC. The NRC regulates the operation of all commercial nuclear power reactors in the United States, including Palo Verde. The NRC periodically conducts inspections of nuclear facilities and monitors performance indicators to enable the agency to arrive at objective conclusions about a licensee’s safety performance.
	License Extension. On April 21, 2011, the Company, along with the other Palo Verde Participants, was notified that the NRC had renewed the operating licenses for all three units at Palo Verde. The renewed licenses for Units 1, 2 and 3 now expire in 2045, 2046 and 2047, respectively.
	Decommissioning. Pursuant to the ANPP Participation Agreement and federal law, the Company must fund its share of the estimated costs to decommission Palo Verde Units 1, 2 and 3, including the Common Facilities, through the term of their respective operating licenses and is required to maintain a minimum accumulation and funding level in its decommissioning account at the end of each annual reporting period during the life of the plant. The Company has established external trusts with an independent trustee, which enables the Company to record a current deduction for federal income tax purposes for most of the amounts funded. At December 31, 2013, the Company’s decommissioning trust fund had a balance of $214.1 million, which is above its minimum funding level. The Company monitors the status of its decommissioning funds and adjust its deposits, if necessary.
	Decommissioning costs are estimated every three years based upon engineering cost studies performed by outside engineers retained by APS. In December 2013, the Palo Verde Participants approved the 2013 Palo Verde decommissioning study (the "2013 Study"). The 2013 Study estimated that the Company must fund approximately $380.7 million (stated in 2013 dollars) to cover its share of decommissioning costs which was an increase in decommissioning costs of $23.3 million (stated in 2013 dollars) from the 2010 Palo Verde decommissioning study. However, because the cash flows from the 2013 Study were less than the inflated amounts from the 2010 Study, the effect of this change lowered the asset retirement obligation by $1.9 million and will lower annual expenses starting in January 2014. Although the 2013 Study was based on the latest available information, there can be no assurance that decommissioning cost estimates will not increase in the future or that regulatory requirements will not change. In addition, until a new low-level radioactive waste repository opens and operates for a number of years, estimates of the cost to dispose of low-level radioactive waste are subject to significant uncertainty.
	Spent Nuclear Fuel and Waste Disposal. Pursuant to the Nuclear Waste Policy Act of 1982, as amended in 1987 (the "NWPA"), the DOE is legally obligated to accept and dispose of all spent nuclear fuel and other high-level radioactive waste generated by all domestic power reactors by 1998. The DOE's obligations are reflected in a contract for Disposal of Spent Nuclear Fuel and/or High-Level Radioactive Waste (the "Standard Contract") with each nuclear power plant. The DOE failed to begin accepting spent nuclear fuel by 1998. APS (on behalf of itself and the other Palo Verde participants) filed a lawsuit for DOE's breach of the spent nuclear fuel contract in the U.S. Court of Federal Claims. The Court of Federal Claims ruled in favor of APS and in October 2010 awarded $30.0 million in damages to the Palo Verde participants for costs incurred through December 2006. In October 2010, the Company received $4.8 million, representing its share of the award. The majority of the award was refunded to customers through the applicable fuel adjustment clauses. On December 19, 2012, APS, acting on behalf of itself and the participant owners of Palo Verde, filed a second breach of contract lawsuit against the DOE. This lawsuit seeks to recover damages incurred due to DOE's failure to accept Palo Verde's spent nuclear fuel for the period beginning January 1, 2007 through June 30, 2011.The lawsuit is presently pending in the Court of Federal Claims.
	The DOE had planned to meet its disposal obligations by designing, licensing, constructing, and operating a permanent geologic repository at Yucca Mountain, Nevada. In March 2010, the DOE filed a motion to dismiss with prejudice its Yucca Mountain construction authorization application that was pending before the NRC. Several interested parties have intervened in the NRC proceeding, and the proceeding has not been conclusively decided by the NRC or the courts. Additionally, a number of interested parties have filed a variety of lawsuits in different jurisdictions around the country challenging the DOE's authority to withdraw the Yucca Mountain construction authorization application and NRC’s cessation of its review of the Yucca Mountain construction authorization application. The cases have been consolidated into one matter at the D.C. Circuit. In August 2013, the D.C. Circuit ordered the NRC to resume its review of the application with available appropriated funds. The Company cannot predict when spent fuel shipments to the DOE will commence.
	APS and the Company believe that spent fuel storage or disposal methods will be available to allow each Palo Verde unit to continue to operate through the current term of its operating license. The Company expects to incur significant costs for on-site spent fuel storage during the life of Palo Verde which the Company believes are the responsibility of the DOE. These costs are assigned to fuel requiring the additional on-site storage and amortized as that fuel is burned until an agreement is reached with the DOE for recovery of these costs.
	The One-Mill Fee. In 2011, the National Association of Regulatory Utility Commissioners and the Nuclear Energy Institute challenged DOE’s 2010 determination of the adequacy of the one tenth of a cent per kWh fee (the "one-mill fee") paid by the nation’s commercial nuclear power plant owners pursuant to their individual obligations under the Standard Contract. This fee is recovered by the Company through applicable fuel adjustment clauses. In June 2012, the U.S. Court of Appeals for the District of Columbia Circuit (the "D.C. Circuit") held that DOE failed to conduct a sufficient fee analysis in making the 2010 determination. The D.C. Circuit remanded the 2010 determination to the Secretary of the DOE ("Secretary") with instructions to conduct a new fee adequacy determination within six months. In February 2013, upon completion of DOE’s revised one-mill fee adequacy determination, the court reopened the proceedings. On November 19, 2013, the D.C. Circuit ordered the Secretary to notify Congress of his intent to suspend collecting annual fees for nuclear waste disposal from nuclear power plant operators, as he is required to do pursuant to the NWPA and the court’s order. On January 3, 2014, the Secretary notified Congress of his intention to suspend collection of the one-mill fee, subject to Congress’ disapproval.
	NRC Oversight of the Nuclear Energy Industry in the Wake of the Earthquake and Tsunami in Japan. The NRC regulates the operation of all commercial nuclear power reactors in the United States, including Palo Verde. The NRC periodically conducts inspections of nuclear facilities and monitors performance indicators to enable the agency to arrive at objective conclusions about a licensee's safety performance. Following the March 11, 2011 earthquake and tsunami in Japan, the NRC established a task force to conduct a systematic and methodical review of NRC processes and regulations to determine whether the agency should make additional improvements to its regulatory system. On March 12, 2012, the NRC issued the first regulatory requirements based on the recommendations of the NRC's Near Term Task Force. With respect to Palo Verde, the NRC issued two orders requiring safety enhancements regarding: (1) mitigation strategies to respond to extreme natural events resulting in the loss of power at plants; and (2) enhancement of spent fuel pool instrumentation.
	The NRC has issued a series of interim staff guidance documents regarding implementation of these requirements. Due to the developing nature of these requirements, the Company cannot predict the ultimate financial or operational impacts on Palo Verde or the Company; however, the NRC has directed nuclear power plants to implement the first tier recommendations of the NRC’s Near Term Task Force. In response to these recommendations, Palo Verde expects to spend approximately $100 million for capital enhancements to the plant over the next several years (the Company's share is $15.8 million).
	Liability and Insurance Matters. The Palo Verde participants have insurance for public liability resulting from nuclear energy hazards to the full limit of liability under federal law, which is currently at $13.6 billion. This potential liability is covered by primary liability insurance provided by commercial insurance carriers in the amount of $375 million, and the balance is covered by an industry-wide retrospective assessment program. If a loss at a nuclear power plant covered by the programs exceeds the accumulated funds in the primary level of protection, the Company could be assessed retrospective premium adjustments on a per incident basis. Under federal law, the maximum assessment per reactor under the program for each nuclear incident is approximately $127.3 million, subject to an annual limit of $19.0 million. Based upon the Company's 15.8% interest in the three Palo Verde units, the Company's maximum potential assessment per incident for all three units is approximately $60.4 million, with an annual payment limitation of approximately $9.0 million.
	The Palo Verde Participants maintain "all risk" (including nuclear hazards) insurance for property damage to, and decontamination of, property at Palo Verde in the aggregate amount of $2.8 billion, a substantial portion of which must first be applied to stabilization and decontamination. The Company has also secured insurance against portions of any increased cost of generation or purchased power and business interruption resulting from a sudden and unforeseen outage of any of the three units. The insurance coverage discussed in this and the previous paragraph is subject to certain policy conditions and exclusions. A mutual insurance company whose members are utilities with nuclear facilities issues these policies. If losses at any nuclear facility covered by this mutual insurance company were to exceed the accumulated funds for these insurance programs, the Company could be assessed retrospective premium adjustments of up to $9.8 million for the current policy period.
	Four Corners
	The Company owns a 7% interest in Units 4 and 5 at Four Corners. The Company shares power entitlements and certain allocated costs of the two units with APS (the Four Corners operating agent) and the other Four Corners participants. The 50-year participation agreement among the owners of Four Corners expires by its terms in July 2016. The Company has notified the other owners that it has decided to cease its participation in the plant by July 2016. The Company believes that it has better economic and cleaner alternatives for serving the energy needs of its customers than coal-fired generation. The Company has nevertheless agreed to work with the other owners and the Navajo Nation in an attempt to facilitate their efforts to extend the operation of the plant beyond July 2016 in a manner consistent with protecting the Company's ratepayers. In December 2013, the other owners executed a long-term extension of the coal supply agreement for the plant through 2031. The Company did not sign the extension and APS has agreed to assume the resulting 7% shortfall and has also expressed an interest in acquiring the Company’s interest in Four Corners.

Accounting_for_Asset_Retiremen

Accounting for Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2013
Accounting for Asset Retirement Obligations	'
Asset Retirement Obligation Disclosure	'
	Accounting for Asset Retirement Obligations
	The Company complies with FASB guidance for asset retirement obligations ("ARO"). This guidance affects the accounting for the decommissioning of the Company’s Palo Verde and Four Corners Stations and the method used to report the decommissioning obligation. The Company also complies with FASB guidance for conditional asset retirement obligations which primarily affects the accounting for the disposal obligations of the Company’s fuel oil storage tanks, water wells, evaporative ponds and asbestos found at the Company’s gas-fired generating plants. The Company’s AROs are subject to various assumptions and determinations such as: (i) whether a legal obligation exists to remove assets; (ii) estimation of the fair value of the costs of removal; (iii) when final removal will occur; (iv) future changes in decommissioning cost escalation rates; and (v) the credit-adjusted interest rates to be utilized in discounting future liabilities. Changes that may arise over time with regard to these assumptions and determinations will change amounts recorded in the future as an expense for AROs. The Company records the increase in the ARO due to the passage of time as an operating expense (accretion expense). If the Company incurs or assumes any liability in retiring any asset at the end of its useful life without a legal obligation to do so, it will record such retirement costs as incurred.
	The 2013 ARO liability for Palo Verde is based upon the estimated cost of decommissioning the plant from the 2013 Palo Verde decommissioning study. See Note E. The ARO liability is calculated by adjusting the estimated decommissioning costs for spent fuel storage and a profit margin and market-risk premium factor. The resulting costs are escalated over the remaining life of the plant and finally discounted using a credit-risk adjusted discount rate. As Palo Verde approaches the end of its estimated useful life, the difference between the ARO liability and future current cost estimates will narrow over time due to the accretion of the ARO liability. Because the DOE is obligated to assume responsibility for the permanent disposal of spent fuel, spent fuel costs have not been included in the ARO calculation. The Company maintains six external trust funds with an independent trustee that are legally restricted to settling its ARO at Palo Verde. The fair value of the funds at December 31, 2013 is $214.1 million.
	FASB guidance requires the Company to revise its previously recorded ARO for any changes in estimated cash flows including changes in estimated probabilities related to timing of settlements. Any changes that result in an upward revision to estimated cash flows shall be treated as a new liability. Any downward revisions to the estimated cash flows result in a reduction to the previously recorded ARO. In December 2013, the Company implemented the 2013 Palo Verde decommissioning study, and as a result, revised its ARO related to Palo Verde to decrease its estimated cash flows from the 2010 Study to the 2013 Study (see Note E). The assumptions used to calculate the Palo Verde ARO liability are as follows:
		Escalation			Credit-Risk
		Rate			Adjusted
					Discount Rate
	Original ARO liability	3.6	%		9.5	%
	Incremental ARO liability	3.6	%		6.2	%
	A roll forward of the Company’s total ARO liability from January 1, 2011 through December 31, 2013, including the effects of each year’s estimate revisions, is presented below. In 2013, the estimate revision includes a change to the probability of extending Four Corners’ operating term and decreases in the estimated cash flows related to Palo Verde’s decommissioning due to implementing the 2013 Palo Verde decommissioning study. In 2012, the estimate revision includes a change to the probability of extending Four Corners’ operating term. In 2011, the NRC approved the Palo Verde license extension which increased Palo Verde decommissioning estimated cash flows and the related probabilities for life extension in the Company’s ARO calculation.
		2013				2012			2011
	ARO liability at beginning of year	$	62,784			$	56,140		$	92,911
	Liabilities incurred	—				—			—
	Liabilities settled	(36		)		(450		)	(793		)
	Revisions to estimate	(3,401		)		1,929			(41,670		)
	Accretion expense	5,867				5,165			5,692
	ARO liability at end of year	$	65,214			$	62,784		$	56,140
	The Company has transmission and distribution lines which are operated under various property easement agreements. If the easements were to be released, the Company may have a legal obligation to remove the lines; however, the Company has assessed the likelihood of this occurring as remote. The majority of these easements include renewal options which the Company routinely exercises.

Common_Stock_Notes

Common Stock (Notes)	12 Months Ended
	Dec. 31, 2013
Common Stock [Abstract]	'
Shareholders' Equity and Share-based Payments , Including Earnings Per Share Information	'
	Common Stock
	Overview
	The Company’s common stock has a stated value of $1 per share, with no cumulative voting rights or preemptive rights. Holders of the common stock have the right to elect the Company’s directors and to vote on other matters.
	Long-Term Incentive Plan
	On May 2, 2007, the Company’s shareholders approved a stock-based long-term incentive plan (the "2007 LTIP") and authorized the issuance of up to one million shares of common stock for the benefit of directors and employees. Under the 2007 LTIP, common stock may be issued through the award or grant of non-statutory stock options, incentive stock options, stock appreciation rights, restricted stock, bonus stock, performance stock, cash-based awards and other stock-based awards. The Company may issue new shares, purchase shares on the open market, or issue shares from shares the Company has repurchased to meet the share requirements of the 2007 LTIP. As discussed in Note A, the Company accounts for its stock-based long-term incentive plan under FASB guidance for stock-based compensation.
	Stock Options. Stock options have been granted at exercise prices equal to or greater than the market value of the underlying shares at the date of grant. The fair value for these options was estimated at the grant date using the Black-Scholes option pricing model. The options expired ten years from the date of grant unless terminated earlier by the Board of Directors (the “Board”). Stock options have not been granted since 2003.
	The 15,000 options outstanding at December 31, 2012 were exercised during 2013 with a weighted average exercise price of $12.78. The Company received $0.2 million in cash and realized a current tax benefit of $0.1 million. The Company has no stock options outstanding as of December 31, 2013.
	The intrinsic value of stock options exercised in 2013, 2012 and 2011 were $0.3 million, $0.6 million and $1.0 million, respectively. No options were forfeited, vested or expired during 2013, 2012 and 2011. No compensation cost was recognized in 2013, 2012 and 2011 for stock options.
	Restricted Stock. The Company has awarded restricted stock under its long-term incentive plan. Restrictions from resale generally lapse and awards vest over periods of one to three years. The market value of the unvested restricted stock at the date of grant is amortized to expense over the restriction period net of anticipated forfeitures.
	The expense, deferred tax benefit, and current tax expense recognized related to restricted stock awards in 2013, 2012 and 2011 is presented below (in thousands):
			2013				2012				2011
	Expense (a)		$	2,458			$	1,508			$	2,258
	Deferred tax benefit		860				528				790
	Current tax benefit recognized		109				94				518
	_____________________
	(a) Any capitalized costs related to these expenses is less than $0.1 million for all years.
	The aggregate intrinsic value and fair value at grant date of restricted stock which vested in 2013, 2012 and 2011 is presented below (in thousands):
			2013				2012				2011
	Aggregated intrinsic value		$	2,077			$	2,242			$	3,279
	Fair value at grant date		1,765				1,973				1,799
	The unvested restricted stock transactions for 2013 are presented below:
		Total			Weighted				Unrecognized Compensation Expense (a)				Aggregate Intrinsic Value
		Shares			Average
					Grant Date
					Fair Value
									(In thousands)				(In thousands)
	Restricted shares outstanding at December 31, 2012	84,446			$	31.26
	Restricted stock awards	96,279			35.48
	Vested	(58,642	)		30.1
	Forfeitures	(1,549	)		31.28
	Restricted shares outstanding at December 31, 2013	120,534			35.19				$	1,976			$	4,232
	_______________________
	(a) The unrecognized compensation expense is expected to be recognized over the weighted average remaining contractual term of the outstanding restricted stock of approximately one year.
	The weighted average fair value per share at grant date for restricted stock awarded during 2013, 2012 and 2011 were:
		2013				2012				2011
	Weighted average fair value per share	$	35.48			$	32.45			$	28.98
	The holder of a restricted stock award has rights as a shareholder of the Company, including the right to vote and receive cash dividends on restricted stock.
	Performance Shares. The Company has granted performance share awards to certain officers under the Company’s existing long-term incentive plan, which provides for issuance of Company stock based on the achievement of certain performance criteria over a three-year period. The payout varies between 0% to 200% of performance share awards.
	Detail of performance shares vested follows:
	Date Vested		Payout Ratio			Performance Shares Awarded			Compensation Costs Expensed				Period Compensation Costs Expensed		Aggregated Intrinsic Value
									(In thousands)						(In thousands)
	February 18, 2014		0	%		0			$	954			2011-2013		$	—
	January 29, 2013		150	%		64,275			849				2010-2012		2,176
	January 1, 2012		175	%		174,038			1,193				2009-2011		6,029
	September 3, 2011		112.5	%		3,825			40				2008-2011		129
	July 9, 2011		112.5	%		2,250			23				2008-2011		75
	In 2014, 2015 and 2016, subject to meeting certain performance criteria, additional performance shares could be awarded. In accordance with FASB guidance related to stock-based compensation, the Company recognizes the related compensation expense by ratably amortizing the grant date fair value of awards over the requisite service period and the compensation expense is only adjusted for forfeitures. The actual number of shares to be issued can range from zero to 181,894 shares.
	The fair value at the date of each separate grant of performance shares was based upon a Monte Carlo simulation. The Monte Carlo simulation reflected the structure of the performance plan which calculates the share payout on performance of the Company relative to a defined peer group over a three-year performance period based upon total return to shareholders. The fair value was determined as the average payout of one million simulation paths discounted to the grant date using a risk-free interest rate based upon the constant maturity treasury rate yield curve at the grant date. The expected volatility of total return to shareholders is calculated in accordance with the plan’s term structure and includes the volatilities of all members of the defined peer group.
	The outstanding performance share awards at the 100% performance level is summarized below:
		Number			Weighted				Unrecognized Compensation Expense (a)				Aggregate Intrinsic Value
		Outstanding			Average
					Grant Date
					Fair Value
									(In thousands)				(In thousands)
	Performance shares outstanding at December 31, 2012	128,033			$	26.48
	Performance share awards	39,814			34.69
	Performance shares vested	(42,850	)		19.82
	Performance shares outstanding at December 31, 2013	124,997			31.38				$	1,452			$	4,389
	_______________________
	(a) The unrecognized compensation expense is expected to be recognized over the weighted average remaining contractual term of the awards of approximately one year.
	A summary of information related to performance shares for 2013, 2012 and 2011 is presented below:
		2013				2012				2011
	Weighted average per share grant date fair value per share of performance shares awarded	$	34.69			$	32.74			$	23.45
Fair value of performance shares vested (in thousands)	849				1,193				628
Intrinsic value of performance shares vested (in thousands) (a)	1,450				3,464				1,032
Compensation expense (in thousands) (b)	1,188				170				1,573
Deferred tax benefit related to compensation expense (in thousands)	416				59				551
_____________________
(a) Based on a 100% performance level.
(b) Includes adjustments for forfeiture of performance share awards by certain executives.
Repurchase Program
No shares of common stock were repurchased during the twelve months ended December 31, 2013. Detail regarding the Company's stock repurchase program are presented below:
	Since 1999				Authorized
	(a)				Shares
Shares repurchased (b)	25,406,184
Cost, including commission (in thousands)	$	423,647
Total remaining shares available for repurchase at December 31, 2013					393,816
______________________
(a)	Represents repurchased shares and cost since inception of the stock repurchase program in 1999.
(b)	Shares repurchased does not include 86,735 treasury shares related to employee compensation arrangements outside of the Company's repurchase programs.
The Company may in the future make purchases of its common stock pursuant to its authorized program in open market transactions at prevailing prices and may engage in private transactions where appropriate. The repurchased shares will be available for issuance under employee benefit and stock incentive plans, or may be retired.
Dividend Policy
On December 30, 2013, the Company paid $10.7 million in quarterly cash dividends to shareholders. The Company paid a total of $42.0 million, $38.9 million and $27.2 million in cash dividends during the twelve months ended December 31, 2013, 2012 and 2011, respectively. On January 23, 2014, the Board of Directors declared a quarterly cash dividend of $0.265 per share payable on March 31, 2014 to shareholders of record on March 14, 2014.
Basic and Diluted Earnings Per Share
FASB guidance requires the Company to include share-based compensation awards that qualify as participating securities in both basic and diluted earnings per share to the extent they are dilutive. A share-based compensation award is considered a participating security if it receives non-forfeitable dividends or may participate in undistributed earnings with common stock. The Company awards unvested restricted stock which qualifies as a participating security. The basic and diluted earnings per share are presented below:
	Years Ended December 31,
	2013				2012				2011
Weighted average number of common shares outstanding:
Basic number of common shares outstanding	40,114,594				39,974,022				41,349,883
Dilutive effect of unvested performance awards	12,053				66,756				206,658
Dilutive effect of stock options	—				14,803				30,518
Diluted number of common shares outstanding	40,126,647				40,055,581				41,587,059
Basic net income per common share:
Net income	$	88,583			$	90,846			$	103,539
Income allocated to participating restricted stock	(254		)		(256		)		(471		)
Net income available to common shareholders	$	88,329			$	90,590			$	103,068
Diluted net income per common share:
Net income	$	88,583			$	90,846			$	103,539
Income reallocated to participating restricted stock	(254		)		(256		)		(469		)
Net income available to common shareholders	$	88,329			$	90,590			$	103,070
Basic net income per common share:
Distributed earnings	$	1.045			$	0.97			$	0.66
Undistributed earnings	1.155				1.3				1.83
Basic net income per common share	$	2.2			$	2.27			$	2.49
Diluted net income per common share:
Distributed earnings	$	1.045			$	0.97			$	0.66
Undistributed earnings	1.155				1.29				1.82
Diluted net income per common share	$	2.2			$	2.26			$	2.48
The amount of restricted stock awards and performance shares at 100% performance level excluded from the calculation of the diluted number of common shares outstanding because their effect was antidilutive is presented below:
		Year Ended December 31,
		2013			2012			2011
Restricted stock awards		51,189			45,178			81,653
Performance shares (a)		115,044			57,625			—
_____________________
(a)	Certain performance shares were excluded from the computation of diluted earnings per share as no payouts would have been required based upon performance at the end of each corresponding period.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income (Notes)	12 Months Ended
	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]	'
Comprehensive Income (Loss) Note [Text Block]	'
	Accumulated Other Comprehensive Income (Loss)
	Changes in Accumulated Other Comprehensive Income (Loss) (net of tax) by component which are presented below (in thousands):
			Years Ended December 31, 2013
			Unrecognized Pension and Postretirement Benefit Costs				Net Unrealized Gains (Losses) on Marketable Securities			Net Losses on Cash Flow Hedges			Accumulated Other Comprehensive Income (Loss)
	Balance at December 31, 2012		$	(75,737	)		$	22,194		$	(12,541	)	$	(66,084	)
		Other comprehensive income before reclassifications	51,371				14,482			—			65,853
		Amounts reclassified from accumulated other comprehensive income (loss)	3,036				(436		)	243			2,843
	Balance at December 31, 2013		$	(21,330	)		$	36,240		$	(12,298	)	$	2,612
	Amounts reclassified from accumulated other comprehensive income (loss) for the twelve months ended December 31, 2013 are as follows ( in thousands):
	Details about Accumulated Other Comprehensive Income (Loss) Components			2013				Affected Line Item in the Statement of Operations
	Amortization of pension and postretirement benefit costs:
		Prior service benefit		$	5,560			(a)
		Net loss		(10,472		)		(a)
				(4,912		)		(a)
		Income tax effect		1,876
				(3,036		)		(a)
	Marketable securities:
		Net realized gain on sale of securities		553				Investment and interest income, net
				553				Income before income taxes
				(117		)		Income tax expense
				436				Net income
	Loss on cash flow hedge:
		Amortization of loss		(411		)		Interest on long-term debt and revolving credit facility
				(411		)		Income before income taxes
				168				Income tax expense
				(243		)		Net income
		Total reclassifications		$	(2,843	)
	(a) These items are included in the computation of net periodic benefit cost. See Note M, Employee Benefits, for additional information.

LongTerm_Debt_and_Financing_Ob

Long-Term Debt and Financing Obligations (Notes)	12 Months Ended
	Dec. 31, 2013
Long-Term Debt and Financing Obligations [Abstract]	'
Long-term Debt	'
	Long-Term Debt and Financing Obligations
	Outstanding long-term debt and financing obligations are as follows:
		December 31,
		2013			2012
		(In thousands)
	Long-Term Debt:
	Pollution Control Bonds (1):
	7.25% 2009 Series A refunding bonds, due 2040 (7.46% effective interest rate)	$	63,500		$	63,500
	4.50% 2012 Series A refunding bonds, due 2042 (4.63% effective interest rate)	59,235			59,235
	7.25% 2009 Series B refunding bonds, due 2040 (7.49% effective interest rate)	37,100			37,100
	1.875% 2012 Series A refunding bonds, due 2032 (2.35% effective interest rate)	33,300			33,300
	Total Pollution Control Bonds	193,135			193,135
	Senior Notes (2):
	6.00% Senior Notes, net of discount, due 2035 (7.12% effective interest rate)	397,976			397,934
	7.50% Senior Notes, net of discount, due 2038 (7.67% effective interest rate)	148,800			148,783
	3.30% Senior Notes, net of discount, due 2022 (3.43% effective interest rate)	149,709			149,683
	Total Senior Notes	696,485			696,400
	RGRT Senior Notes (3):
	3.67% Senior Notes, Series A, due 2015 (3.87% effective interest rate)	15,000			15,000
	4.47% Senior Notes, Series B, due 2017 (4.62% effective interest rate)	50,000			50,000
	5.04% Senior Notes, Series C, due 2020 (5.16% effective interest rate)	45,000			45,000
	Total RGRT Senior Notes	110,000			110,000
	Total long-term debt	999,620			999,535
	Financing Obligations:
	Revolving Credit Facility ($14,352 due in 2014) (4)	14,352			22,155
	Total long-term debt and financing obligations	1,013,972			1,021,690
	Current Portion (amount due within one year):
	Short-term borrowings under the revolving credit facility	(14,352		)	(22,155		)
		$	999,620		$	999,535
	_____________________
	-1	Pollution Control Bonds ("PCBs")
	The Company has four series of tax exempt unsecured PCBs in aggregate principal amount of $193.1 million. The 1.875% 2012 Series A (El Paso Electric Company Four Corners Project) Pollution Control Refunding Revenue Bonds with an aggregate principal amount of $33.3 million are subject to mandatory tender for purchase in September 2017.
	-2	Senior Notes
	The Senior Notes are unsecured obligations of the Company. They were issued pursuant to bond covenants that provide limitations on the Company’s ability to enter into certain transactions. The 6.00% senior notes have an aggregate principal amount of $400.0 million and were issued in May 2005. The proceeds, net of a $2.3 million discount, were used to fund the retirement of the Company's first mortgage bonds. The Company amortizes the loss associated with a cash flow hedge recorded in accumulated other comprehensive income to earnings as interest expense over the life of the 6.00% senior notes. See Note O, "Financial Instruments and Investments - Treasury Rate Locks". This amortization is included in the effective interest rate of the 6.00% senior notes.
	The 7.50% senior notes have an aggregate principal amount of $150.0 million and were issued in June 2008. The proceeds, net of a $1.3 million discount, were used to repay short-term borrowings of $44.0 million, fund capital expenditures and for other general corporate purposes.
	The 3.30% senior notes have an aggregate principal amount of $150.0 million and were issued in December 2012. The proceeds, net of a $0.3 million discount, were used to fund construction expenditures and for working capital and general corporate purposes.
	-3	RGRT Senior Notes
	In 2010, the Company and RGRT, a Texas grantor trust through which the Company finances its portion of fuel for Palo Verde, entered into a note purchase agreement with various institutional purchasers. Under the terms of the Agreement, RGRT sold to the purchasers $110 million aggregate principal amount of senior notes (the "Notes"). The Company guarantees the payment of principal and interest on the Notes. In the Company’s financial statements, the assets and liabilities of the RGRT are reported as assets and liabilities of the Company.
	RGRT will pay interest on the Notes on February 15, and August 15 of each year until maturity. RGRT may redeem the Notes, in whole or in part, at any time at a redemption price equal to 100% of the principal amount to be redeemed together with the interest on such principal amount accrued to the date of redemption, plus a make-whole amount based on the prevailing market interest rates. The agreement requires compliance with certain
	covenants, including a total debt to capitalization ratio. The Company was in compliance with these requirements throughout 2013.
	The sale of the Notes was made by RGRT in reliance on a private placement exemption from registration under the Securities Act of 1933, as amended.
	The proceeds of $109.4 million, net of issuance costs, from the sale of the Notes was used by RGRT to repay amounts borrowed under the revolving credit facility and will enable future nuclear fuel financing requirements of RGRT to be met with a combination of the Notes and amounts borrowed from the revolving credit facility.
	-4	Revolving Credit Facility
	On January 14, 2014, the Company and RGRT entered into a second amended and restated credit agreement related to the RCF with JP Morgan Chase Bank, N.A., as administrative agent and issuing bank, and Union Bank, N.A., as syndication agent, and various lending banks party thereto. Under the terms of the agreement, the Company has available $300 million and the ability to increase the RCF by up to $100 million (up to a total of $400 million) upon the satisfaction of certain conditions, more fully set forth in the agreement, including obtaining commitments from lenders or third party financial institutions. The RCF has a term ending January 2019. The Company may extend the maturity date up to two times, in each case for an additional one year period upon the satisfaction of certain conditions.
	The RCF provides that amounts borrowed by the Company may be used for, among other things, working capital and general corporate purposes. Any amounts borrowed by RGRT may be used, among other things, to finance the acquisition and processing of nuclear fuel. Amounts borrowed by RGRT are guaranteed by the Company and the balance borrowed under the RCF is recorded as short-term borrowings on the balance sheet. The RCF is unsecured. The RCF requires compliance with certain covenants, including a total debt to capitalization ratio. The Company was in compliance with these requirements throughout 2013. As of December 31, 2013, the total amount borrowed by RGRT was $14.4 million for nuclear fuel under the RCF. As of December 31, 2013, no borrowings were outstanding under this facility for working capital and general corporate purposes. The weighted average interest rate on the RCF was 1.4% as of December 31, 2013.
	As of December 31, 2013, the scheduled maturities for the next five years of long-term debt are as follows (in thousands):
	2014	$	—
	2015	15,000
	2016	—
	2017	83,300
	2018	—
	The $14.4 million outstanding on the RCF for nuclear fuel financing purposes is anticipated to be paid in 2014.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Taxes [Abstract]	'
Income Tax Disclosure	'
	Income Taxes
	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and liabilities at December 31, 2013 and 2012 are presented below (in thousands):
		December 31,
		2013			2012
	Deferred tax assets:
	Benefit of tax loss carryforwards	$	17,709		$	7,798
	Alternative minimum tax credit carryforward	21,638			21,599
	Pensions and benefits	54,652			86,816
	Asset retirement obligation	23,727			21,710
	Deferred fuel	—			1,951
	Other	14,485			14,115
	Total gross deferred tax assets	132,211			153,989
	Deferred tax liabilities:
	Plant, principally due to depreciation and basis differences	(511,847		)	(457,127		)
	Decommissioning	(35,489		)	(29,416		)
	Deferred fuel	(2,171		)	—
	Other	(5,664		)	(5,828		)
	Total gross deferred tax liabilities	(555,171		)	(492,371		)
	Net accumulated deferred income taxes	$	(422,960	)	$	(338,382	)
	Based on the average annual book income before taxes for the prior three years, excluding the effects of extraordinary and unusual or infrequent items, the Company believes that the deferred tax assets will be fully realized at current levels of book and taxable income.
	The Company recognized income tax expense for 2013, 2012 and 2011 as follows (in thousands):
		Years Ended December 31,
		2013			2012			2011
	Income tax expense:
	Federal:
	Current	$	(2,877	)	$	1,487		$	5,084
	Deferred	45,024			43,187			46,864
	Total federal income tax	42,147			44,674			51,948
	State:
	Current	1,854			1,931			2,936
	Deferred	(414		)	697			(924		)
	Total state income tax	1,440			2,628			2,012
	Generation (amortization) of accumulated investment tax credits	68			(323		)	(252		)
	Total income tax expense	$	43,655		$	46,979		$	53,708
	As of December 31, 2013, the Company had $21.6 million of AMT credit carryforwards that have an unlimited life. As of December 31, 2013, the Company had $17.3 million of federal and $0.4 million of state tax loss carryforwards. If unused, the tax loss carryforwards would expire at the end of 2031 through 2033 and 2016 through 2018, for federal and state, respectively.
	Income tax provisions differ from amounts computed by applying the statutory federal income tax rate of 35% to book income before federal income tax as follows (in thousands):
		Years Ended December 31,
		2013			2012			2011
	Federal income tax expense computed on income at statutory rate	$	46,283		$	48,239		$	55,036
	Difference due to:
	State taxes, net of federal benefit	936			1,708			1,308
	AEFUDC	(2,149		)	(1,845		)	(2,295		)
	Permanent tax differences	(1,153		)	(604		)	(303		)
	Other	(262		)	(519		)	(38		)
	Total income tax expense	$	43,655		$	46,979		$	53,708
	Effective income tax rate	33		%	34.1		%	34.2		%
	The Company files income tax returns in the United State ("U.S.") federal jurisdiction and in the states of Texas, New Mexico and Arizona. The Company is no longer subject to tax examination by the taxing authorities in the federal jurisdiction for years prior to 2009 and in New Mexico for years prior to 2009. The Company is currently under audit in Texas for tax years 2007 through 2011. A deficiency notice relating to the Company’s 1998 through 2003 and 2006 and 2007 income tax returns in Arizona challenges a pollution control credit, a research and development credit and the payroll, sales and property apportionment factors. The Company is contesting these adjustments.
	FASB guidance prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. In January 2010, the Company filed for a change of accounting method with the IRS related to the way in which units of property are determined for purposes of determining capitalized tax assets. The change was included in the 2009 federal income tax return, with additional amounts included in the 2010 to 2012 federal income tax returns. The Company recorded an additional unrecognized tax position of $1.6 million and $2.2 million in 2012 and 2011, respectively, related to the change in accounting method in 2009 through 2012. In 2013, a $4.5 million decrease was made to the reserve related to the change in accounting method. The decrease is primarily the result of the completion of IRS audits for tax years 2009 to 2012. Further changes to the unrecognized tax position may be recognized as the IRS releases additional guidance as it pertains to the repair allowance for generation assets. The Company recorded an unrecognized tax position of $0.5 million and $1.4 million in 2013 and 2012, respectively, related to depreciation amounts deducted in current and prior year Texas franchise tax returns. The Company recorded an unrecognized tax position of $1.3 million (net of a decrease of $0.4 million) in 2013 related to tax credits taken in prior year Arizona income tax returns. A reconciliation of the December 31, 2013, 2012 and 2011 amount of unrecognized tax benefits is as follows (in thousands):
		2013			2012			2011
	Balance at January 1	$	9,800		$	9,500		$	7,300
	Additions for tax positions related to the current year	600			1,600			2,200
	Reductions for tax positions related to the current year	—			(900		)	—
	Additions for tax positions of prior years	1,700			1,400			—
	Reductions for tax positions of prior years	(4,900		)	(1,800		)	—
	Balance at December 31	$	7,200		$	9,800		$	9,500
	If recognized, $2.5 million of the unrecognized tax position at December 31, 2013, would affect the effective tax rate. The Company recognized income tax expense for an unrecognized tax position of $1.8 million for the year ended December 31, 2013.
	The Company recognizes in tax expense interest and penalties related to tax benefits that have not been recognized. During the year ended December 31, 2012, the Company recognized a benefit of $0.3 million in interest. For both of the years ended December 31, 2013 and 2011, the Company recognized interest expense of $0.2 million. The Company had approximately $0.4 million and $0.1 million accrued for the payment of interest and penalties at December 31, 2013 and 2012, respectively.

Commitments_Contingencies_and_

Commitments, Contingencies and Uncertainties	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Commitments, Contingencies And Uncertainties	'
	Commitments, Contingencies and Uncertainties
	Power Purchase and Sale Contracts
	To supplement its own generation and operating reserves and to meet required renewable portfolio standards, the Company engages in power purchase arrangements which may vary in duration and amount based on evaluation of the Company’s resource needs, the economics of the transactions, and specific renewable portfolio requirements. The Company had entered into the following significant agreements with various counterparties for forward purchases and sales of electricity:
								Commercial
								Operation
	Type of Contract		Counterparty	Quantity			Term	Date
	Power Purchase and Sale Agreement		Freeport		125	MW	December 2008 through December 2014	N/A
	Power Purchase and Sale Agreement		Freeport		100	MW	January 2015 through December 2021	N/A
	Power Purchase Agreement		Shell	Up to	40	MW	January 2011 through September 2014	N/A
	Power Purchase Agreement		NRG		20	MW	August 2011 through August 2031	Aug-11
	Power Purchase Agreement		Sun Edison 1		10	MW	June 2012 through June 2037	Jun-12
	Power Purchase Agreement		Sun Edison 2		12	MW	May 2012 through May 2037	May 2012
	Power Purchase Agreement		Hatch Solar Energy Center I, LLC		5	MW	July 2011 through June 2036	Jul-11
	Power Purchase Agreement		Macho Springs Solar, LLC		50	MW	20 years after operational start date	Expected May 1, 2014
	Power Purchase Agreement		Newman Solar, LLC		10	MW	30 years after operational start date	Expected December 31, 2014
	The Company has a firm Power Purchase and Sale Agreement with Freeport-McMoran Copper and Gold Energy Services LLC ("Freeport") which provides for Freeport to deliver energy to the Company from its ownership interest in the Luna Energy Facility (a natural gas-fired combined cycle generation facility located in Luna County, New Mexico) and for the Company to deliver a like amount of energy at Greenlee, Arizona. The Company may purchase the quantities noted in the table above at a specified price at times when energy is not exchanged under the Power Purchase and Sale Agreement. Upon mutual agreement, the contract allows the parties to increase the amount of energy that is purchased and sold under the Power Purchase and Sale Agreement. The parties have agreed to increase the amount to 125 MW through December 2014. The contract was approved by the FERC and continues through December 31, 2021.
	The Company entered into an agreement in 2009 to purchase capacity and unit contingent energy during 2010 from Shell Energy North America ("Shell"). Under the agreement, the Company provides natural gas to Pyramid Unit No. 4 where Shell has the right to convert natural gas to electric energy. The Company entered into a contract with Shell on May 17, 2010 to extend the term of the capacity and unit contingent energy purchase from January 1, 2011 through September 30, 2014.
	The Company entered into a 20-year contract with NRG Solar Roadrunner LLC ("NRG") for the purchase of all of the output of a solar photovoltaic plant built in southern New Mexico which began commercial operation in August 2011. The Company has a 25-year purchased power agreement with Hatch Solar Energy Center I, LLC for a solar photovoltaic project located in southern New Mexico which began commercial operation in July 2011. The Company has 25-year purchase power agreements to purchase all of the output of two additional solar photovoltaic projects located in southern New Mexico, SunEdison 1 and SunEdison 2 which achieved commercial operation on June 25, 2012 and May 2, 2012, respectively. The Company entered into these contracts to help meet its renewable portfolio requirements.
	In May 2013, the NMPRC approved the Company's agreement with Macho Springs Solar, LLC to purchase the entire generation output delivered from the 50 MW Macho Springs solar photovoltaic project located in Luna County, New Mexico. The term of the purchased power agreement is 20 years from the commercial operation date of the Macho Springs project which is projected to be May 1, 2014. In addition, on September 5, 2013, the Company entered into a purchased power agreement with Newman Solar LLC to purchase, for a term of 30 years, the total output from a solar photovoltaic generation facility of approximately 10 MW that Newman Solar LLC will construct, own and operate on land subleased from the Company in proximity to its Newman Power Station. This solar project is expected to be on line at the end of 2014.
	Environmental Matters
	General. The Company is subject to extensive laws, regulations and permit requirements with respect to air and greenhouse gas emissions, water discharges, soil and water quality, waste management and disposal, natural resources and other environmental matters by federal, state, regional, tribal and local authorities. Failure to comply with such laws, regulations and requirements can result in actions by authorities or other third parties that might seek to impose on the Company administrative, civil and/or criminal penalties or other sanctions. In addition, releases of pollutants or contaminants into the environment can result in costly cleanup liabilities. These laws, regulations and requirements are subject to change through modification or reinterpretation, or the introduction of new laws and regulations and, as a result, the Company may face additional capital and operating costs to comply. Certain key environmental issues, laws and regulations facing the Company are described further below.
	Air Emissions. The U.S. Clean Air Act ("CAA"), associated regulations and comparable state and local laws and regulations relating to air emissions impose, among other obligations, limitations on pollutants generated during the Company's operations, including sulfur dioxide ("SO2"), particulate matter ("PM"), nitrogen oxides ("NOx") and mercury.
	Clean Air Interstate Rule/Cross State Air Pollution Rule. The EPA Clean Air Interstate Rule ("CAIR"), as applied to the Company since 2009, involves requirements to limit emissions of NOx and SO2 from certain of the Company's power plants in Texas and/or purchase allowances representing other parties' emissions reductions. While the U.S. Court of Appeals for the District of Columbia Circuit voided CAIR in 2008, on appeal the rule was reinstated until such time as the EPA promulgates a replacement rule. Because the appellate court in August 2012 also vacated the EPA’s proposed replacement, which is called the Cross-State Air Pollution Rule ("CSAPR"), CAIR remains in effect. On March 29, 2013, the U.S. Solicitor General petitioned the U.S. Supreme Court to review the D.C. Circuit's decision to vacate CSAPR. On June 24, 2013, the Supreme Court agreed to hear the case, and oral arguments were heard on December 10, 2013. The timing and outcome of the Supreme Court decision is unknown, and in the meantime, the Company remains subject to CAIR.
	National Ambient Air Quality Standards. Under the CAA, the EPA sets National Ambient Air Quality Standards ("NAAQS") for six criteria pollutants considered harmful to public health and the environment, including PM, NOx, carbon monoxide ("CO"), ozone and SO2. NAAQS must be reviewed by the EPA at five-year intervals. In 2010, the EPA tightened the NAAQS for both NOx and SO2. In December 2012, the EPA tightened the NAAQS for fine PM, and it is expected to propose more stringent ozone NAAQS in 2014 (with a final rule in 2015). The Company continues to evaluate what impact these final and proposed NAAQS could have on its operations. If the Company is required to install additional equipment to control emissions at its facilities, the revised NAAQS could have a material impact on its operations and financial results.
	Utility MACT. The operation of coal-fired power plants, such as the Company's Four Corners plant, results in emissions of mercury and other air toxics. In December 2011, the EPA finalized Mercury and Air Toxics Standards (known as the "Utility MACT") for oil-and coal-fired power plants, which requires significant reductions in emissions of mercury and other air toxics. Several judicial and other challenges are being made to this rule. These challenges notwithstanding, companies impacted by the new standards will generally have up to three years to comply. Information from the Four Corners plant operator, APS, indicates that APS currently believes Units 4 and 5 will require no additional modifications to achieve compliance with the Utility MACT standards.
	Other Laws and Regulations and Risks. As stated above, the Company intends to cease its participation in Four Corners at the expiration of the 50-year participation agreement in 2016. The Company believes that it has better economic and cleaner alternatives for serving the energy needs of its customers than coal-fired generation, which is subject to extensive regulation and litigation. For example, as a result of APS’s recent Best Available Retrofit Technology Federal Implementation Plan compliance strategy notification to the EPA, Four Corners is required to install expensive pollution control equipment in order to continue operation in the future. The Company’s share of the cost of these controls is currently estimated by APS to be approximately $39 million if the Company were to extend its participation in the plant. In addition, the EPA has entered into a consent decree which would require it to sign for publication a final action regarding the regulation of coal combustion residuals ("CCR") under the federal Resource, Conservation and Recovery Act by December 19, 2014. Once issued, the Company may be required to incur significant costs to address CCRs either generated in the past and disposed of at or from Four Corners, as well as CCRs generated in connection with the ongoing operations of Four Corners. Further, assured supplies of water are important for the Company's operations and assets, including Four Corners. Four Corners is located in a region that has been experiencing drought conditions which could affect the plant’s water supply. Four Corners has accordingly been involved in negotiations and proceedings with third parties relating to water supply issues. The drought conditions and related negotiations and proceedings could adversely affect the amount of power available, or the price thereof, from Four Corners.
	Climate Change. The U.S. federal government has either considered, proposed and/or finalized legislation or regulations limiting GHG emissions, including carbon dioxide. In particular, the U.S. Congress periodically considers legislation to restrict or regulate GHG emissions. In the past few years, the EPA began using the CAA to regulate carbon dioxide and other GHG emissions, such as the 2009 GHG Reporting Rule and the EPA’s sulfur hexafluoride ("SF6") reporting rule, both of which applied to the Company, as well as the EPA’s 2010 actions to impose permitting requirements on new and modified sources of GHG emissions, which may create significant costs for power plant owners and operators. On June 25, 2013, President Obama set forth his plan to address climate change. He reiterated a goal of reducing GHG "in the range of 17 percent" below 2005 levels by 2020. The plan included a variety of executive actions, including future regulatory measures to reduce carbon emissions from power plants. In a White House memorandum of the same date, the President directed the EPA to issue a new proposal for GHG rulemaking addressing new power plants by September 20, 2013, and a rule for existing power plants by June 1, 2014. The formal proposal for new power plants was published in the Federal Register on January 8, 2014. The Company continues its review of the new proposal and plans to participate in the 60-day post-publication comment period. Given the very significant remaining uncertainties regarding these rules, the Company believes it is impossible to meaningfully quantify the costs of these potential requirements at present.
	In addition, almost half the U.S. states, either individually and/or through multi-state regional initiatives, have begun to consider how to address GHG emissions and have developed, or are actively considering the development of emission inventories or regional GHG cap and trade programs. While a significant portion of the Company's generation assets are nuclear or gas-fired, and as a result, the Company believes that its greenhouse gas emissions are low relative to electric power companies who rely more on coal-fired generation, current and future legislation and regulation of GHGs or any future related litigation could impose significant costs and/or operating restrictions on the Company, reduced demand for the power the Company generates and/or require the Company to purchase rights to emit GHGs, any of which could be material to the Company's business, financial condition, reputation or results of operations.
	Climate change also has potential physical effects that could be relevant to the Company's business. In particular, some studies suggest that climate change could affect the Company's service area by causing higher temperatures, less winter precipitation and less spring runoff, as well as by causing more extreme weather events. Such developments could change the demand for power in the region and could also impact the price or ready availability of water supplies or affect maintenance needs and the reliability of Company equipment. The Company believes that material effects on the Company's business or results of operations may result from the physical consequences of climate change, the regulatory approach to climate change ultimately selected and implemented by governmental authorities, or both. Given the very significant remaining uncertainties regarding whether and how these issues will be regulated, as well as the timing and severity of any physical effects of climate change, the Company believes it is impossible to meaningfully quantify the costs of these potential impacts at present.
	Environmental Litigation and Investigations. Since 2009, the EPA and certain environmental organizations have been scrutinizing, and in some cases, have filed lawsuits, relating to certain air emissions and air permitting matters related to Four Corners. In particular, since July 2011, the U.S. Department of Justice (the "DOJ"), on behalf of the EPA, and APS have been engaged in substantive settlement negotiations in an effort to resolve certain of the pending matters. The allegations being addressed through settlement negotiations are that APS failed to obtain the necessary permits and install the controls necessary under the CAA to reduce SO2, NOx, and PM, and that defendants failed to obtain an operating permit under Title V of the CAA that reflects applicable requirements imposed by law. In March 2012, the DOJ provided APS with a draft consent decree to settle the EPA matter, which decree contains specific provisions for the reduction and control of NOx, SO2, and PM, as well as provisions for a civil penalty, and expenditures on environmental mitigation projects with an emphasis on projects that address alleged harm to the Navajo Nation. Settlement discussions are on-going and the Company is unable to predict the outcome of these settlement negotiations. The Company has accrued a total of $0.5 million as a loss contingency related to this matter.
	The Company received notice that Earthjustice filed a lawsuit in the United States District Court for New Mexico on October 4, 2011 for alleged violations of the Prevention of Significant Deterioration ("PSD") provisions of the CAA related to Four Corners. On January 6, 2012, Earthjustice filed a First Amended Complaint adding claims for violations of the CAA's New Source Performance Standards ("NSPS") program. Among other things, the plaintiffs seek to have the court enjoin operations at Four Corners until APS applies for and obtains any required PSD permits and complies with the referenced NSPS program. The plaintiffs further request the court to order the payment of civil penalties, including a beneficial mitigation project. On April 2, 2012, APS and the other Four Corners' participants filed motions to dismiss with the court. The case is being held in abeyance while the parties seek to negotiate a settlement. On March 30, 2013, upon joint motion of the parties, the court issued an order deeming the motions to dismiss withdrawn without prejudice during pendency of the stay. At such time as the stay is lifted, APS, the Company and the other Four Corners participants may reinstate the motions to dismiss. On February 14, 2014, the parties filed a joint motion to extend the stay in the case by 30 days holding the matter in abeyance until March 17, 2014. The Company is unable to predict the outcome of this litigation.
	New Mexico Tax Matter Related to Coal Supplied to Four Corners
	On May 23, 2013, the New Mexico Taxation and Revenue Department issued a notice of assessment for coal severance surtax, penalty, and interest totaling approximately $30 million related to coal supplied under the coal supply agreement for Four Corners (the "Assessment"). The Company's share of the assessment is approximately $1.5 million. On behalf of the Four Corners participants, the coal supplier made a partial payment of the Assessment and immediately filed a refund claim with respect to that partial payment in August 2013. The New Mexico Taxation and Revenue Department denied the refund claim. On December 19, 2013, the coal supplier and APS, on its own behalf and as operating agent for Four Corners, filed complaints with the New Mexico District Court contesting both the validity of the Assessment and the refund claim denial. APS believes the Assessment and the refund claim denial are without merit. The Company cannot predict the timing, results, or potential impacts of the outcome of this litigation.
	Lease Agreements
	The Company leases land in El Paso adjacent to the Newman Power Station under a lease which expires in June 2033 with a renewal option of 25 years. In addition, the Company leases certain warehouse facilities in El Paso under a lease which expires in December 2015. The Company also has several other leases for office, parking facilities and equipment which expire within the next four years . These lease agreements do not impose any restrictions relating to issuance of additional debt, payment of dividends or entering into other lease arrangements. The Company has no significant capital lease agreements.
	The Company's total annual rental expense related to operating leases was $1.2 million, $1.3 million, and $1.1 million for 2013, 2012 and 2011, respectively. As of December 31, 2013, the Company’s minimum future rental payments for the next five years are as follows (in thousands):
	2014	$	1,081
	2015	1,028
	2016	600
	2017	442
	2018	408
	Union Matters
	The Company has approximately 1,000 employees, about 40% of whom are covered by a collective bargaining agreement. The International Brotherhood of Electrical Workers Local 960 ("Local 960") represents the Company’s employees working primarily in the power plants, substations, line crews, meter reading and collection, facilities services, and customer service. The Company entered into a new collective bargaining agreement effective September 3, 2013, with Local 960 for a three-year term ending September 2, 2016. The agreement provides for pay increases of 3% on September 3, 2013, 3% on September 3, 2014 and 2.25% on September 3, 2015.

Litigation

Litigation	12 Months Ended
	Dec. 31, 2013
Litigation [Abstract]	'
Legal Matters Disclosure	'
	Litigation
	The Company is a party to various legal actions. In many of these matters, the Company has excess casualty liability insurance that covers the various claims, actions and complaints. Based upon a review of these claims and applicable insurance coverage, the Company believes that none of these claims will have a material adverse effect on the financial position, results of operations or cash flows of the Company.
	See Note C and Note K for discussion of the effects of government legislation and regulation on the Company.

Employee_Benefits

Employee Benefits	12 Months Ended
	Dec. 31, 2013
Employee Benefits [Abstract]	'
Pension and Other Postretirement Benefits Disclosure	'
	Employee Benefits
	Retirement Plans
	The Company’s Retirement Income Plan (the "Retirement Plan") covers employees who have completed one year of service with the Company and work at least a minimum number of hours each year. The Retirement Plan is a qualified noncontributory defined benefit plan. Retirement benefits are based on the employee's final average pay and years of service. Upon retirement or death of a vested plan participant, assets of the Retirement Plan are used to pay benefit obligations under the Retirement Plan. Contributions from the Company are at least the minimum funding amounts required by the IRS under provisions of the Retirement Plan, as actuarially calculated. The assets of the Retirement Plan are primarily invested in common collective trusts which hold equity securities, debt securities and cash equivalents and are managed by a professional investment manager appointed by the Company.
	The Company has two non-qualified retirement plans that are non-funded defined benefit plans. The Company's Supplemental Retirement Plan covers certain former employees and directors of the Company. The other plan, the Excess Benefit Plan was adopted in 2004 and covers certain active and former employees of the Company. The benefit cost for the non-qualified retirement plans are based on substantially the same actuarial methods and economic assumptions as those used for the Retirement Plan. The Company complies with FASB guidance on disclosure for pension and other post-retirement plans that requires disclosure of investment policies and strategies, categories of investment and fair value measurements of plan assets, and significant concentrations of risk.
	The obligations and funded status of the plans are presented below (in thousands):
		December 31,
		2013								2012
		Retirement				Non-Qualified				Retirement			Non-Qualified
		Income				Retirement				Income			Retirement
		Plan				Plans				Plan			Plans
	Change in projected benefit obligation:
	Benefit obligation at end of prior year	$	320,846			$	27,241			$	296,293		$	26,547
	Service cost	9,137				190				8,530			299
	Interest cost	12,742				872				12,594			963
	Actuarial (gain) loss	(15,373		)		(533		)		12,417			1,338
	Benefits paid	(9,537		)		(1,872		)		(8,988		)	(1,906		)
	Benefit obligation at end of year	317,815				25,898				320,846			27,241
	Change in plan assets:
	Fair value of plan assets at end of prior year	220,568				—				191,369			—
	Actual return on plan assets	31,800				—				20,187			—
	Employer contribution	15,000				1,872				18,000			1,906
	Benefits paid	(9,537		)		(1,872		)		(8,988		)	(1,906		)
	Fair value of plan assets at end of year	257,831				—				220,568			—
	Funded status at end of year	$	(59,984	)		$	(25,898	)		$	(100,278	)	$	(27,241	)
	Amounts recognized in the Company's balance sheets consist of the following (in thousands):
		December 31,
		2013								2012
		Retirement				Non-Qualified				Retirement			Non-Qualified
		Income				Retirement				Income			Retirement
		Plan				Plans				Plan			Plans
	Current liabilities	$	—			$	(1,870	)		$	—		$	(1,829	)
	Noncurrent liabilities	(59,984		)		(24,028		)		(100,278		)	(25,412		)
	Total	$	(59,984	)		$	(25,898	)		$	(100,278	)	$	(27,241	)
	The accumulated benefit obligation in excess of plan assets is as follows (in thousands):
		December 31,
		2013								2012
		Retirement				Non-Qualified				Retirement			Non-Qualified
		Income				Retirement				Income			Retirement
		Plan				Plans				Plan			Plans
	Projected benefit obligation	$	(317,815	)		$	(25,898	)		$	(320,846	)	$	(27,241	)
	Accumulated benefit obligation	(275,555		)		(25,077		)		(274,890		)	(26,363		)
	Fair value of plan assets	257,831				—				220,568			—
	Amounts recognized in accumulated other comprehensive income consist of the following (in thousands):
		Years Ended December 31,
		2013								2012
		Retirement				Non-Qualified				Retirement			Non-Qualified
		Income				Retirement				Income			Retirement
		Plan				Plans				Plan			Plans
	Net loss	$	85,261			$	8,508			$	125,763		$	9,701
	Prior service cost	—				219				3			314
	Total	$	85,261			$	8,727			$	125,766		$	10,015
	The following are the weighted-average actuarial assumptions used to determine the benefit obligations:
		December 31,
		2013									2012
					Non-Qualified								Non-Qualified
		Retirement			Supplemental			Excess			Retirement		Supplemental			Excess
		Income			Retirement			Benefit			Income		Retirement			Benefit
		Plan			Plan			Plan			Plan		Plan			Plan
	Discount rate	4.9	%		3.9	%		4.9	%		4	%	3.1	%		4	%
	Rate of compensation increase	4.75	%		N/A			4.75	%		4.75	%	N/A			4.75	%
	The Company reassesses various actuarial assumptions at least on an annual basis. The discount rate is reviewed at each measurement date. The discount rate used to measure obligations is based on a spot rate yield curve that matches projected future payments with the appropriate interest rate applicable to the timing of the projected future benefit payments. A 1% increase in the discount rate would decrease the December 31, 2013 retirement plans' projected benefit obligation by 12.5%. A 1% decrease in the discount rate would increase the December 31, 2013 retirement plans' projected benefit obligation by 15.5%.
	The components of net periodic benefit cost are presented below (in thousands):
		Years Ended December 31,
	2013								2012							2011
	Retirement				Non-Qualified				Retirement			Non-Qualified				Retirement				Non-Qualified
	Income				Retirement				Income			Retirement				Income				Retirement
	Plan				Plans				Plan			Plans				Plan				Plans
Service cost	$	9,137			$	190			$	8,530		$	299			$	6,590			$	260
Interest cost	12,742				872				12,594			963				12,871				1,116
Expected return on plan assets	(17,108		)		—				(14,443		)	—				(14,095		)		—
Amortization of:
Net loss	10,437				661				10,729			627				6,190				354
Prior service cost	3				94				21			94				21				94
Net periodic benefit cost	$	15,211			$	1,817			$	17,431		$	1,983			$	11,577			$	1,824
The changes in benefit obligations recognized in other comprehensive income are presented below (in thousands):
	Years Ended December 31,
	2013								2012							2011
	Retirement				Non-Qualified				Retirement			Non-Qualified				Retirement				Non-Qualified
	Income				Retirement				Income			Retirement				Income				Retirement
	Plan				Plans				Plan			Plans				Plan				Plans
Net (gain) loss	$	(30,065	)		$	(533	)		$	6,672		$	1,337			$	40,181			$	2,980
Amortization of:
Net loss	(10,437		)		(661		)		(10,729		)	(627		)		(6,190		)		(354		)
Prior service cost	(3		)		(94		)		(21		)	(94		)		(21		)		(94		)
Total recognized in other comprehensive income	$	(40,505	)		$	(1,288	)		$	(4,078	)	$	616			$	33,970			$	2,532
The total amount recognized in net periodic benefit costs and other comprehensive income are presented below (in thousands):
	Years Ended December 31,
	2013								2012							2011
	Retirement				Non-Qualified				Retirement			Non-Qualified				Retirement				Non-Qualified
	Income				Retirement				Income			Retirement				Income				Retirement
	Plan				Plans				Plan			Plans				Plan				Plans
Total recognized in net periodic benefit cost and other comprehensive income	$	(25,294	)		$	529			$	13,353		$	2,599			$	45,547			$	4,356
The following are amounts in accumulated other comprehensive income that are expected to be recognized as components of net periodic benefit cost during 2014 (in thousands):
	Retirement				Non-Qualified
	Income				Retirement
	Plan				Plans
Net loss	$	6,270			$	570
Prior service cost	—				90
The following are the weighted-average actuarial assumptions used to determine the net periodic benefit cost for the twelve months ended December 31:
	2013									2012								2011
				Non-Qualified								Non-Qualified									Non-Qualified
	Retirement			Supplemental Retirement			Excess			Retirement		Supplemental Retirement			Excess			Retirement			Supplemental Retirement		Excess
	Income			Plan			Benefit			Income		Plan			Benefit			Income			Plan		Benefit
	Plan						Plan			Plan					Plan			Plan					Plan
Discount rate	4	%		3.1	%		4	%		4.3	%	3.6	%		4.1	%		5.4	%		4.6	%	5.3	%
Expected long-term return on plan assets	7.5	%		N/A			N/A			7.5	%	N/A			N/A			7.5	%		N/A		N/A
Rate of compensation increase	4.75	%		N/A			4.75	%		5	%	N/A			5	%		5	%		N/A		5	%
The Company reassesses various actuarial assumptions at least on an annual basis. The discount rate is reviewed at each measurement date. The discount rate used to measure net periodic benefit cost is based on a spot rate yield curve that matches projected future payments with the appropriate interest rate applicable to the timing of the projected future benefit payments.
The Company’s overall expected long-term rate of return on assets is 7.5% effective January 1, 2013, which is both a pre-tax and after-tax rate as pension funds are generally not subject to income tax. The expected long-term rate of return is based on the weighted average of the expected returns on investments based upon the target asset allocation of the pension fund. The Company’s target allocations for the plan’s assets are presented below:
		December 31, 2013
Equity securities		55	%
Fixed income		40	%
Alternative investments		5	%
Total		100	%
The Retirement Plan invests the majority of its plan assets in common collective trusts which includes a diversified portfolio of domestic and international equity securities and fixed income securities. The Retirement Plan fund also invests in a real estate limited partnership. The expected rate of returns for the funds are assessed annually and are based on long-term relationships among major asset classes and the level of incremental returns that can be earned by the successful implementation of different active investment management strategies. Equity returns are based on estimates of long-term inflation rate, real rate of return, 10-year Treasury bond premium over cash and equity risk premium. Fixed income returns are based on maturity, long-term inflation, real rate of return and credit spreads.
FASB guidance on disclosure for pension plans requires disclosure of fair value measurements of plan assets. To increase consistency and comparability in fair value measurements FASB guidance on fair value measurements established a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three levels as follows:
•	Level 1 – Observable inputs that reflect quoted market prices for identical assets and liabilities in active markets. Prices or securities held in the mutual funds and underlying portfolios of the Retirement Plan are primarily obtained from
independent pricing services. These prices are based on observable market data.
•	Level 2 – Inputs other than quoted market prices included in Level 1 that are observable for the asset or liability either directly or indirectly. The fair value of the Guaranteed Investment Contract is based on market interest rates of investments
with similar terms and risk characteristics. The Common Collective Trusts are valued using the net asset value ("NAV") provided by the administrator of the fund. The NAV price is quoted on a restrictive market although the underlying investments are traded on active markets.
•	Level 3 – Unobservable inputs using data that is not corroborated by market data. The fair value of the real estate limited partnership is reported at the NAV of the investment.
During 2013, the Company sold the majority of its assets held in active markets, classified as Level 1, and invested these assets in common collective trusts which are classified as Level 2. The fair value of the Company’s Retirement Plan assets at December 31, 2013 and 2012, and the level within the three levels of the fair value hierarchy defined by FASB guidance on fair value measurements are presented in the table below (in thousands):
Description of Securities	Fair Value as of				Quoted Prices				Significant			Significant
	December 31,				in Active				Other			Unobservable
	2013				Markets for				Observable			Inputs
					Identical Assets				Inputs			(Level 3)
					(Level 1)				(Level 2)
Cash and Cash Equivalents	$	940			$	940			$	—		$	—
Guaranteed Investment Contract	1,126				—				1,126			—
Common Collective Trusts (a)
Equity funds	142,960				—				142,960			—
Fixed income funds	103,948				—				103,948			—
Total Common Collective Trusts	246,908				—				246,908			—
Limited Partnership Interest in Real Estate (b)	8,857				—				—			8,857
Total Plan Investments	$	257,831			$	940			$	248,034		$	8,857
Description of Securities	Fair Value as of				Quoted Prices				Significant			Significant
	December 31,				in Active				Other			Unobservable
	2012				Markets for				Observable			Inputs
					Identical Assets				Inputs			(Level 3)
					(Level 1)				(Level 2)
Cash and Cash Equivalents	$	9,163			$	9,163			$	—		$	—
U.S. Treasury Securities	24,854				24,854				—			—
Guaranteed Investment Contract	1,059				—				1,059			—
Common Stock	52,149				52,149				—			—
Mutual Funds - Fixed Income	59,150				59,150				—			—
Mutual Funds - Equity	65,634				65,634				—			—
Limited Partnership Interest in Real Estate (b)	8,559				—				—			8,559
Total Plan Investments	$	220,568			$	210,950			$	1,059		$	8,559
_____________________
(a)	The Common Collective Trusts are invested in equity or fixed income securities, or a combination thereof. The investment objective of each trust is to produce returns in excess of, or commensurate with, its predefined index.
(b)	This investment is a commercial real estate partnership that purchases land, develops limited infrastructure, and sells it for commercial development. The Company is restricted from selling its partnership interest during the life of the partnership which is generally 5-7 years. Return on investment is realized as land is sold. The fair value of the limited partnership interest in real estate is based on the NAV of the partnership which reflects the appraised value of the land.
The table below reflects the changes in the fair value of investments in real estate during the period (in thousands):
	Fair Value of
	Investments in
	Real Estate
Balances at December 31, 2011	$	8,511
Unrealized gain in fair value	48
Balances at December 31, 2012	8,559
Unrealized gain in fair value	298
Balances at December 31, 2013	$	8,857
There were no transfers in or out of Level 1 and Level 2 fair value measurements categories due to changes in observable inputs during the twelve month periods ending December 31, 2013 and 2012. There were no purchases, sales, issuances, and settlements related to the assets in the Level 3 fair value measurement category during the twelve month periods ending December 31, 2013 and 2012.
The Company adheres to the traditional capital market pricing theory which maintains that over the long term, the risk of owning equities should be rewarded with a greater return than available from fixed income investments. The Company seeks to minimize the risk of owning equity securities by investing in funds that pursue risk minimization strategies and by diversifying its investments to limit its risks during falling markets. The investment manager has full discretionary authority to direct the investment of plan assets held in trust within the guidelines prescribed by the Company through the plan’s investment policy statement including the ability to hold cash equivalents. The investment guidelines of the investment policy statement are in accordance with the Employee Retirement Income Security Act of 1974 ("ERISA") and Department of Labor ("DOL") regulations.
The Company contributes at least the minimum funding amounts required by the IRS for the Retirement Plan, as actuarially calculated. The Company expects to contribute $13.9 million to its retirement plans in 2014.
The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid (in thousands):
	Retirement				Non-Qualified
	Income				Retirement
	Plan				Plans
2014	$	10,902			$	1,870
2015	12,015				1,818
2016	13,180				1,772
2017	14,440				1,829
2018	15,807				1,715
2019-2023	96,510				9,447
In 2014, the Company will implement a redesigned Retirement Income Plan and Excess Benefit Plan. Effective April 1, 2014, the Company will offer a cash balance pension plan as an alternative to its current final average pay pension plan for employees hired prior to January 1, 2014. The cash balance pension plan will also include an enhanced employer matching contribution to the employee’s respective 401(k) Defined Contribution Plan (discussed below). For employees that elect the new cash balance pension plan, the pension benefit earned under the existing final average pay pension plan will be frozen as of March 31, 2014. Employees hired after January 1, 2014 will be automatically enrolled in the cash balance pension plan. The Company anticipates remeasuring the assets and liabilities of the retirement plans during the first quarter of 2014.
401(k) Defined Contribution Plans
The Company sponsors 401(k) defined contribution plans covering substantially all employees. Annual matching contributions made to the savings plans for the years 2013, 2012 and 2011 were $1.9 million, $1.8 million, and $1.7 million, respectively. Historically, the Company has provided a 50 percent matching contribution up to 6 percent of the employee’s compensation subject to certain other limits and exclusions. Effective April 1, 2014, for employees who enroll in the cash balance pension plan (discussed above), the Company will provide a 100 percent matching contribution up to 6 percent of the employee's compensation subject to certain other limits and exclusions.
Other Postretirement Benefits
The Company provides certain health care benefits for retired employees and their eligible dependents and life insurance benefits for retired employees only. Substantially all of the Company’s employees may become eligible for those benefits if they retire while working for the Company. Contributions from the Company are no more than the IRS tax deductible limit, as actuarially calculated. The assets of the plan are primarily invested in common collective trusts which hold equity securities, debt securities, and cash equivalents and are managed by a professional investment manager appointed by the Company.
The Company determined that the prescription drug benefits of its plan were actuarially equivalent to the Medicare Part D benefit provided for in the Medicare Prescription Drug, Improvement, and Modernization Act of 2003. FASB guidance on accounting and disclosure requirements related to the Medicare Prescription Drug, Improvement and Modernization Act of 2003 requires measurement of the postretirement benefit obligation, the plan assets, and the net periodic postretirement benefit cost to reflect the effects of the subsidy. In March 2010, the President signed into law comprehensive health care reform legislation under the Patient Protection and Affordable Care Act and the Health Care Education and Affordability Reconciliation Act (the "Acts"). The Company modified the operations of the plan to conform to the effective provisions of the Acts.
The following table contains a reconciliation of the change in the benefit obligation, the fair value of plan assets, and the funded status of the plan (in thousands):
	December 31,
	2013				2012
Change in benefit obligation:
Benefit obligation at end of prior year	$	135,680			$	133,272
Service cost	3,843				4,378
Interest cost	5,156				5,651
Actuarial gain	(48,778		)		(5,009		)
Amendment (a)	(97		)		—
Benefits paid	(4,013		)		(3,929		)
Retiree contributions	1,056				1,086
Medicare Part D subsidy	—				231
Benefit obligation at end of year	92,847				135,680
Change in plan assets:
Fair value of plan assets at end of prior year	36,510				32,817
Actual return on plan assets	5,539				2,605
Employer contribution	3,100				3,700
Benefits paid	(4,013		)		(3,929		)
Retiree contributions	1,056				1,086
Medicare Part D subsidy	—				231
Fair value of plan assets at end of year	42,192				36,510
Funded status (b)	$	(50,655	)		$	(99,170	)
_____________________
(a)	Amendment relates to modification of the Company's Other Postretirement Benefit Plan which limits the Company's premium contribution. The amendment became effective October 3, 2013 and resulted in a remeasurement of the plan.
(b)	These amounts are recognized in the Company’s balance sheets as a non-current liability.
Amounts recognized in accumulated other comprehensive income that have not been recognized as a component of net periodic cost consist of the following (in thousands):
	December 31,
	2013				2012
Net (gain) loss	$	(38,110	)		$	13,630
Prior service credit	(19,210		)		(24,770		)
	$	(57,320	)		$	(11,140	)
The following are the weighted-average actuarial assumptions used to determine the accrued postretirement benefit obligations:
	December 31,
	2013			2012
Discount rate at end of year	4.9	%		4.1	%
Health care cost trend rates:
Initial	7.5	%		7.75	%
Ultimate	4.5	%		4.5	%
Year ultimate reached	2026			2026
The discount rate is reviewed at each measurement date. The discount rate used to measure obligations is based on a spot rate yield curve that matches projected future payments with the appropriate interest rate applicable to the timing of the projected future benefit payments. A 1% increase in the discount rate would decrease the December 31, 2013 accumulated postretirement benefit obligation by 12.8%. A 1% decrease in the discount rate would increase the December 31, 2013 accumulated postretirement benefit obligation by 16.1%.
Net periodic benefit cost is made up of the components listed below (in thousands):
	Years Ended December 31,
	2013				2012				2011
Service cost	$	3,843			$	4,378			$	2,988
Interest cost	5,156				5,651				5,379
Expected return on plan assets	(1,951		)		(1,714		)		(1,823		)
Amortization of:
Prior service benefit	(5,657		)		(5,877		)		(5,927		)
Net (gain) loss	(626		)		615				(39		)
Net periodic benefit cost	$	765			$	3,053			$	578
The changes in benefit obligations recognized in other comprehensive income are presented below (in thousands):
	Years Ended December 31,
	2013				2012				2011
Net (gain) loss	$	(52,366	)		$	(5,900	)		$	34,517
Prior service benefit	(97		)		—				—
Amortization of:
Prior service benefit	5,657				5,877				5,927
Net gain (loss)	626				(615		)		39
Total recognized in other comprehensive income	$	(46,180	)		$	(638	)		$	40,483
The total recognized in net periodic benefit cost and other comprehensive income are presented below (in thousands):
	Years Ended December 31,
	2013				2012				2011
Total recognized in net periodic benefit cost and other comprehensive income	$	(45,415	)		$	2,415			$	41,061
The amount in accumulated other comprehensive income that is expected to be recognized as a component of net periodic benefit cost during 2014 is a prior service benefit of $4.8 million and a net gain of $2.6 million.
The following are the weighted-average actuarial assumptions used to determine the net periodic benefit cost for the twelve months ended December 31:
	2013 (a)			2012			2011
Discount rate at beginning of year	4.1	%		4.3	%		5.5	%
Expected long-term return on plan assets	5.2	%		5.2	%		5.2	%
Health care cost trend rates:
Initial	7.75	%		8	%		8.5	%
Ultimate	4.5	%		4.5	%		5	%
Year ultimate reached	2026			2026			2018
_____________________
(a) The Other Postretirement Benefits Plan was remeasured at October 3, 2013 due to a plan amendment. The discount rate increased from 4.1% as of January 1, 2013 to 4.9% at the remeasurement date. All other assumptions remained consistent with assumptions used at January 1, 2013.
The Company reassesses various actuarial assumptions at least on an annual basis. The discount rate is reviewed at each measurement date. The discount rate used to measure net periodic benefit cost is based on a spot yield curve that matches projected future payments with the appropriate interest rate applicable to the timing of the projected future benefit payments.
For measurement purposes, an 7.75% annual rate of increase in the per capita cost of covered health care benefits was assumed for 2013. The rate was assumed to decrease gradually to 4.5% for 2026 and remain at that level thereafter. Assumed health care cost trend rates have a significant effect on the amounts reported for the health care plan. The effect of a 1% change in these assumed health care cost trend rates would increase or decrease the December 31, 2013 benefit obligation by $14.3 million or $10.8 million, respectively. In addition, a 1% change in said rate would increase or decrease the aggregate 2013 service and interest cost components of the net periodic benefit cost by $2.1 million or $1.2 million, respectively.
The Company’s overall expected long-term rate of return on assets, on an after-tax basis, is 5.2% effective January 1, 2013. The expected long-term rate of return is based on the after-tax weighted average of the expected returns on investments based upon the target asset allocation. The Company’s target allocations for the plan’s assets are presented below:
		December 31, 2013
Equity securities		65	%
Fixed income		30	%
Alternative investments		5	%
Total		100	%
The Other Postretirement Benefit Plan invests the majority of its plan assets in common collective trusts which includes a diversified portfolio of domestic and international equity securities and fixed income securities. The asset portfolio also includes cash equivalents and a real estate limited partnership.The expected rate of returns for the funds are assessed annually and are based on long-term relationships among major asset classes and the level of incremental returns that can be earned by the successful implementation of different active investment management strategies. Equity returns are based on estimates of long-term inflation rate, real rate of return, 10-year Treasury bond premium over cash and equity risk premium. Fixed income returns are based on maturity, long-term inflation, real rate of return and credit spreads.
FASB guidance on disclosure for other postretirement benefit plans requires disclosure of fair value measurements of plan assets. To increase consistency and comparability in fair value measurements, FASB guidance on fair value measurements established a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three levels as follows:
•	Level 1 – Observable inputs that reflect quoted market prices for identical assets and liabilities in active markets. Prices or securities held in the mutual funds and underlying portfolios of the Other Postretirement Benefits Plan are primarily obtained from independent pricing services. These prices are based on observable market data.
•	Level 2 – Inputs other than quoted market prices included in Level 1 that are observable for the asset or liability either directly or indirectly. The fair value of municipal securities-tax-exempt are reported at fair value based on evaluated prices that reflect observable market information, such as actual trade information of similar securities, adjusted for observable differences. The Common Collective Trusts are valued using the NAV provided by the administrator of the fund. The NAV price is quoted on a restrictive market although the underlying investments are traded on active markets.
•	Level 3 – Unobservable inputs using data that is not corroborated by market data. The fair value of the real estate limited partnership is reported at the NAV of the investment.
During 2013, the Company sold the majority of its assets held in active markets, classified as Level 1, and invested these assets in common collective trusts which are classified as Level 2. The fair value of the Company’s Other Postretirement Benefits Plan assets at December 31, 2013 and 2012, and the level within the three levels of the fair value hierarchy defined by FASB guidance on fair value measurements are presented in the table below (in thousands):
Description of Securities	Fair Value as of				Quoted Prices				Significant			Significant
	December 31,				in Active				Other			Unobservable
	2013				Markets for				Observable			Inputs
					Identical Assets				Inputs			(Level 3)
					(Level 1)				(Level 2)
Cash and Cash Equivalents	$	33			$	33			$	—		$	—
Common Collective Trusts (a)
Equity funds	28,077				—				28,077			—
Fixed income funds	12,421				—				12,421			—
Total Common Collective Trusts	40,498				—				40,498			—
Limited Partnership Interest in Real Estate (b)	1,661				—				—			1,661
Total Plan Investments	$	42,192			$	33			$	40,498		$	1,661
Description of Securities	Fair Value as of				Quoted Prices				Significant			Significant
	December 31,				in Active				Other			Unobservable
	2012				Markets for				Observable			Inputs
					Identical Assets				Inputs			(Level 3)
					(Level 1)				(Level 2)
Cash and Cash Equivalents	$	2,075			$	2,075			$	—		$	—
Municipal Securities – Tax Exempt	12,811				—				12,811			—
Common Stock	14,397				14,397				—			—
Mutual Funds – Equity	5,622				5,622				—			—
Limited Partnership Interest in Real Estate (b)	1,605				—				—			1,605
Total Plan Investments	$	36,510			$	22,094			$	12,811		$	1,605
___________________
(a)	The Common Collective Trusts are invested in equity or fixed income securities, or a combination thereof. The investment objective of each trust is to produce returns in excess of, or commensurate with, its predefined index.
(b)	This investment is a commercial real estate partnership that purchases land, develops limited infrastructure, and sells it for commercial development. The Company is restricted from selling its partnership interest during the life of the partnership which is generally 5-7 years. Return of investment is realized as land is sold. The fair value of the limited partnership interest in real estate is based on the NAV of the partnership which reflects the appraised value of the land.
The table below reflects the changes in the fair value of the investments in real estate during the period (in thousands):
	Fair Value of
	Investments  in
	Real Estate
Balance at December 31, 2011	$	1,596
Unrealized gain in fair value	9
Balance at December 31, 2012	1,605
Unrealized gain in fair value	56
Balance at December 31, 2013	$	1,661
There were no transfers in or out of Level 1 and Level 2 fair value measurements categories due to changes in observable inputs during the twelve month periods ending December 31, 2013 and 2012. There were no purchases, sales, issuances, and settlements related to the assets in the Level 3 fair value measurement category during the twelve month periods ending December 31, 2013 and 2012.
The Company adheres to the traditional capital market pricing theory which maintains that over the long term, the risk of owning equities should be rewarded with a greater return than available from fixed income investments. The Company seeks to minimize the risk of owning equity securities by investing in funds that pursue risk minimization strategies and by diversifying its investments to limit its risks during falling markets. The investment manager has full discretionary authority to direct the investment of plan assets held in trust within the guidelines prescribed by the Company through the plan’s investment policy statement including the ability to hold cash equivalents. The investment guidelines of the investment policy statement are in accordance with the ERISA and DOL regulations.
The Company does not expect to contribute to its other postretirement benefits plan in 2014. The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid (in thousands):
2014	$	3,024
2015	3,414
2016	3,810
2017	4,230
2018	4,639
2019-2023	28,238
Annual Short-Term Incentive Plan
The Annual Short-Term Incentive Plan (the "Incentive Plan") provides for the payment of cash awards to eligible Company employees, including each of its named executive officers. Payment of awards is based on the achievement of performance measures reviewed and approved by the Company’s Board of Directors’ Compensation Committee. Generally, these performance measures are based on meeting certain financial, operational and individual performance criteria. The financial performance goals are based on earnings per share and the operational performance goals are based on safety, regulatory compliance, and customer satisfaction. If a specified level of earnings per share is not attained, no amounts will be paid under the Incentive Plan. In 2013, the Company reached the required levels of earnings per share, safety, regulatory compliance, and customer satisfaction goals for an incentive payment of $4.0 million. The Company reached the required levels of earnings per share, safety, and regulatory compliance goals for an incentive payment of $7.9 million and $7.3 million in 2012 and 2011, respectively. The Company has renewed the Incentive Plan in 2014 with similar goals.

Franchises_and_Significant_Cus

Franchises and Significant Customers	12 Months Ended
	Dec. 31, 2013
Franchises and Significant Customers [Abstract]	'
Franchises And Significant Customers	'
	Franchises and Significant Customers
	El Paso and Las Cruces Franchises
	The Company has a franchise agreement with El Paso, the largest city it serves. The franchise agreement allows the Company to utilize public rights-of-way necessary to serve its retail customers within El Paso. The Company is also providing electric distribution service to Las Cruces under an implied franchise by satisfying all obligations under the franchise agreement that expired on April 30, 2009.
	The franchise arrangements held between the Company and the cities of El Paso and Las Cruces are detailed below:
	City	Period	Franchise Fee	(a)
	El Paso	August 1, 2010 - Present	4.00%	(b)
	Las Cruces	February 1, 2000 - Present	2.00%
	_________________
	(a) Based on a percentage of revenue.
	(b) 0.75% of the El Paso franchise fee is to be placed in a restricted fund to be used solely for economic development and renewable energy purposes.
	Military Installations
	The Company serves Holloman Air Force Base ("Holloman"), White Sands Missile Range ("White Sands") and Fort Bliss. The military installations represent approximately 5% of the Company's annual retail revenues. Fort Bliss takes retail electric service from the Company under the applicable Texas tariffs. The Company is serving White Sands under the applicable New Mexico tariffs. In March 2006, the Company signed a contract with Holloman that provides for the Company to provide retail electric service and limited wheeling services to Holloman for a ten-year term which expires in January 2016.

Financial_Instruments_and_Inve

Financial Instruments and Investments (Notes)	12 Months Ended
	Dec. 31, 2013
Financial Instruments And Investments [Abstract]	'
Financial Instruments and Investments	'
	Financial Instruments and Investments
	FASB guidance requires the Company to disclose estimated fair values for its financial instruments. The Company has determined that cash and temporary investments, investment in debt securities, accounts receivable, decommissioning trust funds, long-term debt, short-term borrowings under the RCF, accounts payable and customer deposits meet the definition of financial instruments. The carrying amounts of cash and temporary investments, accounts receivable, accounts payable and customer deposits approximate fair value because of the short maturity of these items. Investments in debt securities and decommissioning trust funds are carried at fair value.
	Long-Term Debt and Short-Term Borrowings Under the RCF. The fair values of the Company's long-term debt and short-term borrowings under the RCF are based on estimated market prices for similar issues and are presented below (in thousands):
		December 31,
		2013						2012
		Carrying			Estimated			Carrying			Estimated
		Amount			Fair Value			Amount			Fair Value
	Pollution Control Bonds	$	193,135		$	193,990		$	193,135		$	215,228
	Senior Notes	696,485			734,515			696,400			823,497
	RGRT Senior Notes (1)	110,000			115,850			110,000			120,985
	RCF (1)	14,352			14,352			22,155			22,155
	Total	$	1,013,972		$	1,058,707		$	1,021,690		$	1,181,865
	__________________
	-1	Nuclear fuel financing as of December 31, 2013 and December 31, 2012 is funded through the $110 million RGRT Senior Notes and $14.4 million and $22.2 million, respectively under the RCF. As of December 31, 2013 and 2012, no amount was outstanding under the RCF for working capital or general corporate purposes. The interest rate on the Company’s borrowings under the RCF is reset throughout the period reflecting current market rates. Consequently, the carrying value approximates fair value.
	Treasury Rate Locks. The Company entered into treasury rate lock agreements in 2005 to hedge against potential movements in the treasury reference interest rate pending the issuance of the 6% Senior Notes. The treasury rate lock agreements met the criteria for hedge accounting and were designated as a cash flow hedge. In accordance with cash flow hedge accounting, the Company recorded the loss associated with the fair value of the cash flow hedge, net of tax, as a component of accumulated other comprehensive loss and amortizes the accumulated comprehensive loss to earnings as interest expense over the life of the 6% Senior Notes. In 2014, approximately $0.4 million of this accumulated other comprehensive loss item will be reclassified to interest expense.
	Contracts and Derivative Accounting. The Company uses commodity contracts to manage its exposure to price and availability risks for fuel purchases and power sales and purchases and these contracts generally have the characteristics of derivatives. The Company does not trade or use these instruments with the objective of earning financial gains on the commodity price fluctuations. The Company has determined that all such contracts outstanding at December 31, 2013, except for certain natural gas commodity contracts with optionality features, that had the characteristics of derivatives met the "normal purchases and normal sales" exception provided in FASB guidance for accounting for derivative instruments and hedging activities, and, as such, were not required to be accounted for as derivatives.
	The Company determined that certain of its natural gas commodity contracts with optionality features are not eligible for the normal purchases exception and, therefore, are required to be accounted for as derivative instruments pursuant to FASB guidance for accounting for derivative instruments and hedging activities. However, as of December 31, 2013, the variable, market-based pricing provisions of existing gas contracts are such that these derivative instruments have no significant fair value.
	Marketable Securities. The Company’s marketable securities, included in decommissioning trust funds in the balance sheets, are reported at fair value which was $214.1 million and $187.1 million at December 31, 2013 and 2012, respectively. These securities are classified as available for sale under FASB guidance for certain investments in debt and equity securities and are valued using prices and other relevant information generated by market transactions involving identical or comparable securities. The reported fair values include gross unrealized losses on marketable securities whose impairment the Company has deemed to be temporary. The tables below present the gross unrealized losses and the fair value of these securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position (in thousands):
		December 31, 2013
		Less than 12 Months						12 Months or Longer						Total
		Fair			Unrealized			Fair			Unrealized			Fair		Unrealized
		Value			Losses			Value			Losses			Value		Losses
	Description of Securities (1):
	Federal Agency Mortgage Backed Securities	$	6,444		$	(169	)	$	1,421		$	(119	)	$	7,865	$	(288	)
	U.S. Government Bonds	8,114			(245		)	10,866			(840		)	18,980		(1,085		)
	Municipal Obligations	12,286			(335		)	7,782			(479		)	20,068		(814		)
	Corporate Obligations	3,284			(96		)	901			(54		)	4,185		(150		)
	Total Debt Securities	30,128			(845		)	20,970			(1,492		)	51,098		(2,337		)
	Common Stock	2,305			(126		)	—			—			2,305		(126		)
	Total Temporarily Impaired Securities	$	32,433		$	(971	)	$	20,970		$	(1,492	)	$	53,403	$	(2,463	)
	____________________
	-1	Includes approximately 122 securities.
		December 31, 2012
		Less than 12 Months						12 Months or Longer						Total
		Fair			Unrealized			Fair			Unrealized			Fair		Unrealized
		Value			Losses			Value			Losses			Value		Losses
	Description of Securities (2):
	Federal Agency Mortgage Backed Securities	$	1,792		$	(5	)	$	416		$	(9	)	$	2,208	$	(14	)
	U.S. Government Bonds	6,633			(79		)	4,457			(114		)	11,090		(193		)
	Municipal Obligations	5,306			(39		)	5,760			(241		)	11,066		(280		)
	Corporate Obligations	452			(11		)	—			—			452		(11		)
	Total Debt Securities	14,183			(134		)	10,633			(364		)	24,816		(498		)
	Common stock	3,603			(409		)	—			—			3,603		(409		)
	Total Temporarily Impaired Securities	$	17,786		$	(543	)	$	10,633		$	(364	)	$	28,419	$	(907	)
	______________________
	-2	Includes approximately 65 securities.
	The Company monitors the length of time the security trades below its cost basis along with the amount and percentage of the unrealized loss in determining if a decline in fair value of marketable securities below recorded cost is considered to be other than temporary. In addition, the Company will research the future prospects of individual securities as necessary. As a result of these factors, as well as the Company’s intent and ability to hold these securities until their market price recovers, these securities are considered temporarily impaired. The Company does not anticipate expending monies held in trust before 2044 or a later period when the Company begins to decommission Palo Verde.
	The reported fair values also include gross unrealized gains on marketable securities which have not been recognized in the Company’s net income. The table below presents the unrecognized gross unrealized gains and the fair value of these securities, aggregated by investment category (in thousands):
		December 31, 2013						December 31, 2012
		Fair			Unrealized			Fair			Unrealized
		Value			Gains			Value			Gains
	Description of Securities:
	Federal Agency Mortgage Backed Securities	$	9,929		$	433		$	17,289		$	1,036
	U.S. Government Bonds	6,258			126			13,295			678
	Municipal Obligations	8,783			450			22,797			1,531
	Corporate Obligations	9,188			506			12,378			1,134
	Total Debt Securities	34,158			1,515			65,759			4,379
	Common Stock	103,808			43,145			73,210			22,839
	Equity Mutual Funds	16,802			3,081			15,194			1,821
	Cash and Cash Equivalents	5,924			—			4,471			—
	Total	$	160,692		$	47,741		$	158,634		$	29,039
	The Company’s marketable securities include investments in municipal, corporate and federal debt obligations. Substantially all of the Company’s mortgage-backed securities, based on contractual maturity, are due in ten years or more. The mortgage-backed securities have an estimated weighted average maturity which generally range from three years to eight years and reflects anticipated future prepayments. The contractual year for maturity for these available-for-sale securities as of December 31, 2013 is as follows (in thousands):
		Total			2014			2015			2019 through 2023			2024 and Beyond
through
2018
Municipal Debt Obligations	$	28,851		$	1,486		$	13,311		$	10,920		$	3,134
Corporate Debt Obligations	13,373			321			3,711			5,525			3,816
U.S. Government Bonds	25,238			1,216			14,149			7,217			2,656
The Company recognizes impairment losses on certain of its securities deemed to be other than temporary. In accordance with FASB guidance, these impairment losses are recognized in net income, and a lower cost basis is established for these securities. For the twelve months ended December 31, 2013, 2012, and 2011 the Company recognized other than temporary impairment losses on its available-for-sale securities as follows (in thousands):
	2013			2012			2011
Unrealized holding losses included in pre-tax income	$	—		$	(479	)	$	(2,116	)
The Company’s marketable securities in its decommissioning trust funds are sold from time to time and the Company uses the specific identification basis to determine the amount to reclassify out of accumulated other comprehensive income and into net income. The proceeds from the sale of these securities during the twelve months ended December 31, 2013, 2012, and 2011 and the related effects on pre-tax income are as follows (in thousands):
	2013			2012			2011
Proceeds from sales or maturities of available-for-sale securities	$	56,148		$	98,542		$	82,926
Gross realized gains included in pre-tax income	$	986		$	1,478		$	1,479
Gross realized losses included in pre-tax income	(433		)	(2,041		)	(721		)
Gross unrealized losses included in pre-tax income	—			(479		)	(2,116		)
Net gains (losses) in pre-tax income	$	553		$	(1,042	)	$	(1,358	)
Net unrealized holding gains included in accumulated other comprehensive income	$	17,699		$	9,927		$	1,570
Net (gains) losses reclassified out of accumulated other comprehensive income	(553		)	1,042			1,358
Net gains in other comprehensive income	$	17,146		$	10,969		$	2,928
Fair Value Measurements. FASB guidance requires the Company to provide expanded quantitative disclosures for financial assets and liabilities recorded on the balance sheet at fair value. Financial assets carried at fair value include the Company's decommissioning trust investments and investments in debt securities which are included in deferred charges and other assets on the balance sheets. The Company has no liabilities that are measured at fair value on a recurring basis. The FASB guidance establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three levels as follows:
•	Level 1 - Observable inputs that reflect quoted market prices for identical assets and liabilities in active markets. Financial assets utilizing Level 1 inputs include the nuclear decommissioning trust investments in active exchange-traded equity securities, mutual funds and U.S. Treasury securities that are in a highly liquid and active market.
•	Level 2 - Inputs other than quoted market prices included in Level 1 that are observable for the asset or liability either directly or indirectly. Financial assets utilizing Level 2 inputs include the nuclear decommissioning trust investments in fixed income securities. The fair value of these financial instruments is based on evaluated prices that reflect observable market information, such as actual trade information of similar securities, adjusted for observable differences.
•	Level 3 - Unobservable inputs using data that is not corroborated by market data and primarily based on internal Company analysis using models and various other analyses. Financial assets utilizing Level 3 inputs include the Company's investments in debt securities.
The securities in the Company’s decommissioning trust funds are valued using prices and other relevant information generated by market transactions involving identical or comparable securities. FASB guidance identifies this valuation technique as the "market approach" with observable inputs. The Company analyzes available-for-sale securities to determine if losses are other than temporary.
The fair value of the Company’s decommissioning trust funds and investments in debt securities, at December 31, 2013 and 2012, and the level within the three levels of the fair value hierarchy defined by FASB guidance are presented in the table below (in thousands):
Description of Securities		Fair Value as  of			Quoted Prices			Significant			Significant
		December 31,			in Active			Other			Unobservable
		2013			Markets for			Observable			Inputs
					Identical Assets			Inputs			(Level 3)
					(Level 1)			(Level 2)
Trading Securities:
Investments in Debt Securities		$	1,555		$	—		$	—		$	1,555
Available for sale:
U.S. Government Bonds		$	25,238		$	25,238		$	—		$	—
Federal Agency Mortgage Backed Securities		17,794			—			17,794			—
Municipal Obligations		28,851			—			28,851			—
Corporate Obligations		13,373			—			13,373			—
Subtotal, Debt Securities		85,256			25,238			60,018			—
Common Stock		106,113			106,113			—			—
Equity Mutual Funds		16,802			16,802			—			—
Cash and Cash Equivalents		5,924			5,924			—			—
Total available for sale		$	214,095		$	154,077		$	60,018		$	—
Description of Securities	Fair Value as  of			Quoted Prices			Significant			Significant
	December 31,			in Active			Other			Unobservable
	2012			Markets for			Observable			Inputs
				Identical Assets			Inputs			(Level 3)
				(Level 1)			(Level 2)
Trading Securities:
Investments in Debt Securities	$	1,295		$	—		$	—		$	1,295
Available for sale:
U.S. Government Bonds	$	24,385		$	24,385		$	—		$	—
Federal Agency Mortgage Backed Securities	19,497			—			19,497			—
Municipal Obligations	33,863			—			33,863			—
Corporate Obligations	12,830			—			12,830			—
Subtotal, Debt Securities	90,575			24,385			66,190			—
Common Stock	76,813			76,813			—			—
Equity Mutual Funds	15,194			15,194			—			—
Cash and Cash Equivalents	4,471			4,471			—			—
Total available for sale	$	187,053		$	120,863		$	66,190		$	—
Below is a reconciliation of the beginning and ending balance of the fair value of the investment in debt securities (in thousands):
	2013			2012
Balance at January 1	$	1,295		$	1,120
Net unrealized gains in fair value recognized in income (a)	260			175
Balance at December 31	$	1,555		$	1,295
_____________________
(a) These amounts are reflected in the Company's statement of operations as investment and interest income.
There were no transfers in or out of Level 1 and Level 2 fair value measurements categories due to changes in observable inputs during the twelve month periods ending December 31, 2013 and 2012. There were no purchases, sales, issuances, and settlements related to the assets in the Level 3 fair value measurement category during the twelve month periods ending December 31, 2013 and 2012.

Supplemental_Statements_of_Cas

Supplemental Statements of Cash Flows Disclosures	12 Months Ended
	Dec. 31, 2013
Supplemental Statements of Cash Flow Disclosures [Abstract]	'
Cash Flow, Supplemental Disclosures	'
	Supplemental Statements of Cash Flows Disclosures
		Years Ended December 31,
		2013		2012		2011
		(In thousands)
	Cash paid (received) for:
	Interest on long-term debt and borrowing under the revolving credit facility	$	53,752	$	50,189	$	48,797
	Income taxes paid (refund), net	244		5,031		(6,260		)
	Non-cash financing activities:
	Grants of restricted shares of common stock	3,224		2,411		3,268
	Issuance of performance shares	849		1,193		628
	Acquisition of treasury stock for options exercised	—		—		500

Selected_Quarterly_Financial_D

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2013
Selected Quarterly Financial Data	'
Quarterly Financial Information	'
	Selected Quarterly Financial Data (Unaudited)
	The following table summarizes the Company’s unaudited results of operations on a quarterly basis. The quarterly earnings per share amounts for a year will not add to the earnings per share for that year due to the weighting of shares used in calculating per share data.
		2013 Quarters								2012 Quarters
		4th		3rd		2nd		1st		4th		3rd		2nd		1st
						(In thousands except for share data)
	Operating revenues (1)	$	190,297	$	282,661	$	240,114	$	177,290	$	188,802	$	267,249	$	228,252	$	168,578
	Operating income	6,050		85,896		54,344		19,345		13,708		86,396		56,512		12,042
	Net income	1,191		50,565		29,193		7,634		4,819		51,789		30,894		3,344
	Basic earnings per share:
	Net income	0.03		1.26		0.73		0.19		0.12		1.29		0.77		0.08
	Diluted earnings per share:
	Net income	0.03		1.26		0.72		0.19		0.12		1.29		0.77		0.08
	Dividends declared per share of common stock	0.265		0.265		0.265		0.25		0.25		0.25		0.25		0.22
	________________
	-1	Operating revenues are seasonal in nature, with the peak sales periods generally occurring during the summer months. Comparisons among quarters of a year may not represent overall trends and changes in operations.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Use of Estimates	'
	Use of Estimates. The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Basis of Presentation, Policy	'
	Basis of Presentation. The Company maintains its accounts in accordance with the Uniform System of Accounts prescribed by the Federal Energy Regulatory Commission (the "FERC").
Application of FASB Guidance for Regulated Operations	'
	Application of FASB Guidance for Regulated Operations. Regulated electric utilities typically prepare their financial statements in accordance with the Financial Accounting Standards Board ("FASB") guidance for regulated operations. FASB guidance for regulated operations requires the Company to include an allowance for equity and borrowed funds used during construction ("AEFUDC" and "ABFUDC") as a cost of construction of electric plant in service. AEFUDC is recognized as income and ABFUDC is shown as capitalized interest charges in the Company’s statement of operations. FASB guidance for regulated operations also requires the Company to show certain recoverable costs as either assets or liabilities on a utility’s balance sheet if the regulator provides assurance that these costs will be charged to and collected from the utility’s customers (or has already permitted such cost recovery) or will be credited or refunded to the utility’s customers. The resulting regulatory assets or liabilities are amortized in subsequent periods based upon the respective amortization periods reflected in a utility’s regulated rates. See Note D. The Company applies FASB guidance for regulated operations for all three of the jurisdictions in which it operates.
Comprehensive Income	'
	Comprehensive Income. Certain gains and losses that are not recognized currently in the statements of operations are reported as other comprehensive income in accordance with FASB guidance for reporting comprehensive income.
Utility plant	'
	Utility Plant. Utility plant is generally reported at cost. The cost of renewals and betterments are capitalized and the costs of repairs and minor replacements are charged to the appropriate operating expense accounts. Depreciation is provided on a straight-line basis over the estimated remaining lives of the assets (ranging in average from 5 to 48 years). The average composite depreciation rate utilized in 2013, 2012 and 2011 was 2.61%, 2.64%, and 2.80%, respectively. When property subject to composite depreciation is retired or otherwise disposed of in the normal course of business, its cost – together with the cost of removal, less salvage – is charged to accumulated depreciation. For other property dispositions, the applicable cost and accumulated depreciation is removed from the balance sheet accounts and a gain or loss is recognized.
	The cost of nuclear fuel is amortized to fuel expense on a units-of-production basis. A provision for spent fuel disposal costs is charged to expense based on the funding requirements of the Department of Energy (the "DOE") for disposal cost of approximately one-tenth of one cent on each kWh generated. The Company is also amortizing its share of costs associated with on-site spent fuel storage casks at Palo Verde over the burn period of the fuel that will necessitate the use of the storage casks. See Note E.
Impairment of Long-Lived Assets	'
	Impairment of Long-Lived Assets. Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated undiscounted future cash flows, an impairment charge is recognized for the amount by which the carrying amount of the asset exceeds the fair value of the asset.
AFUDC and Capitalized Interest	'
	AFUDC and Capitalized Interest. The Company capitalizes interest ("ABFUDC") and common equity ("AEFUDC") costs to construction work in progress and capitalizes interest to nuclear fuel in process in accordance with the FERC Uniform System of Accounts as provided for in FASB guidance. AFUDC is a non-cash component of income and is calculated monthly and charged to all new eligible construction and capital improvement projects. AFUDC is compounded on a semi-annual basis. The AFUDC rates used in 2013, 2012 and 2011 were 8.10%, 8.53% and 8.54%, respectively.
Asset Retirement Obligation	'
	Asset Retirement Obligation. FASB guidance sets forth accounting requirements for the recognition and measurement of liabilities associated with the retirement of tangible long-lived assets. An asset retirement obligation ("ARO") associated with long-lived assets included within the scope of FASB guidance is that for which a legal obligation exists under enacted laws, statutes, written or oral contracts, including obligations arising under the doctrine of promissory estoppel and legal obligations to perform an asset retirement activity even if the timing and/or settlement are conditioned on a future event that may or may not be within the control of an entity. See Note F. Under FASB guidance, these liabilities are recognized as incurred if a reasonable estimate of fair value can be established and are capitalized as part of the cost of the related tangible long-lived assets. The Company records the increase in the ARO due to the passage of time as an operating expense (accretion expense).
Cash and Cash Equivalents	'
	Cash and Cash Equivalents. All temporary cash investments with an original maturity of three months or less are considered cash equivalents.
Investments	'
	Investments. The Company’s marketable securities, included in decommissioning trust funds in the balance sheets, are reported at fair value and consist of cash, equity securities and municipal, federal and corporate bonds in trust funds established for decommissioning of its interest in Palo Verde. Such marketable securities are classified as "available-for-sale" securities and, as such, unrealized gains and losses are included in accumulated other comprehensive loss as a separate component of common stock equity. However, if declines in fair value of marketable securities below original cost basis are determined to be other than temporary, then the declines are reported as losses in the statement of operations and a new cost basis is established for the affected securities at fair value. Gains and losses are determined using the cost of the security based on the specific identification basis. See Note O.
Derivative Accounting	'
	Derivative Accounting. Accounting for derivative instruments and hedging activities requires the recognition of derivatives as either assets or liabilities in the balance sheet with measurement of those instruments at fair value. Any changes in the fair value of these instruments are recorded in earnings or other comprehensive income. See Note O.
Inventories	'
	Inventories. Inventories, primarily parts, materials, supplies, fuel oil and natural gas are stated at average cost not to exceed recoverable cost.
Operating Revenues Net of Energy Expenses	'
	Operating Revenues Net of Energy Expenses. The Company accrues revenues for services rendered, including unbilled electric service revenues. Energy expenses are stated at actual cost incurred. The Company’s Texas retail customers are billed under base rates and a fixed fuel factor approved by the Public Utility Commission of Texas ("PUCT"). The Company’s New Mexico retail customers and its sales for resale customer are billed under base rates and a fuel adjustment clause which is adjusted monthly, as approved by the New Mexico Public Regulation Commission ("NMPRC") and the FERC. The Company’s recovery of energy expenses is subject to periodic reconciliations of actual energy expenses incurred to actual fuel revenues collected. The difference between energy expenses incurred and fuel revenues charged to customers is reflected as over/undercollection of fuel revenues in the balance sheets. See Note C.
	Revenues. Revenues related to the sale of electricity are generally recorded when service is rendered or electricity is delivered to customers. The billing of electricity sales to retail customers is based on the reading of their meters, which occurs on a systematic basis throughout the month. Unbilled revenues are estimated based on monthly generation volumes and by applying an average revenue/kWh to the number of estimated kWhs delivered but not billed. Accounts receivable included accrued unbilled revenues of $19.8 million and $17.9 million at December 31, 2013 and 2012, respectively. The Company presents revenues net of sales taxes in its statements of operations.
Allowance for Doubtful Accounts	'
	Allowance for Doubtful Accounts. The allowance for doubtful accounts represents the Company’s estimate of existing accounts receivable that will ultimately be uncollectible. The allowance is calculated by applying estimated write-off factors to various classes of outstanding receivables. The write-off factors used to estimate uncollectible accounts are based upon consideration of both historical collections experience and management’s best estimate of future collections success given the existing collections environment. Additions, deductions and balances for allowance for doubtful accounts for 2013, 2012 and 2011 are as follows (in thousands):
		2013		2012		2011
	Balance at beginning of year	$	2,906	$	3,015	$	2,885
	Additions:
	Charged to costs and expense	2,098		3,087		6,209
	Recovery of previous write-offs	1,929		2,041		2,034
	Uncollectible receivables written off	4,672		5,237		8,113
	Balance at end of year	$	2,261	$	2,906	$	3,015
Income Taxes	'
	Income Taxes. The Company accounts for federal and state income taxes under the asset and liability method of accounting for income taxes. Deferred income taxes are recognized for the estimated future tax consequences of "temporary differences" by applying enacted statutory tax rates for each taxable jurisdiction applicable to future years to differences between the financial statement carrying amounts and the tax basis of existing assets and liabilities. Certain temporary differences are accorded flow-through treatment by the Company's regulators and impact the Company's effective tax rate. FASB guidance requires that rate-regulated companies record deferred income taxes for temporary differences accorded flow-through treatment at the direction of the regulatory commission. The resulting deferred tax assets and liabilities are recorded at the expected cash flow to be reflected in future rates. Because the Company's regulators have consistently permitted the recovery of tax effects previously flowed-through earnings, the Company has recorded regulatory liabilities and assets offsetting such deferred tax assets and liabilities. The effect on deferred tax assets and liabilities of a change in tax rate is recognized in income in the period that includes the enactment date. The Company recognizes tax assets and liabilities for uncertain tax positions in accordance with the recognition and measurement criteria of FASB guidance for uncertainty in income taxes. See Note J.
Earnings Per Share	'
	Earnings per Share. The Company’s restricted stock awards are participating securities and earnings per share must be calculated using the two-class method in both the basic and diluted earnings per share calculations. For the basic earnings per share calculation, net income is allocated to the weighted average number of restricted stock awards and to the weighted average number of shares outstanding. The net income allocated to the weighted average number of shares outstanding is then divided by the weighted average number of shares outstanding to derive the basic earnings per share. For the diluted earnings per share, net income is allocated to the weighted average number of restricted stock awards and to the weighted average number of shares and dilutive potential shares outstanding. The Company’s dilutive potential shares outstanding amount is calculated using the treasury stock method for the unvested performance shares and outstanding stock options. Net income allocated to the weighted average number of shares and dilutive potential shares is then divided by the weighted average number of shares and dilutive potential shares outstanding to derive the diluted earnings per share. See Note G.
Stock-Based Compensation	'
	Stock-Based Compensation. The Company has a stock-based long-term incentive plan. The Company is required under FASB guidance to measure the cost of employee services received in exchange for an award of equity instruments based on the grant-date fair value of the award. Such costs are recognized over the period during which an employee is required to provide service in exchange for the award (the "requisite service period") which typically is the vesting period. Compensation cost is not recognized for anticipated forfeitures prior to vesting of equity instruments. See Note G.
Reclassifications	'
	Reclassification. Certain amounts in the financial statements for 2012 and 2011 have been reclassified to conform with the 2013 presentation.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Allowance for Doubtful Accounts Receivable	'
	Additions, deductions and balances for allowance for doubtful accounts for 2013, 2012 and 2011 are as follows (in thousands):
		2013		2012		2011
	Balance at beginning of year	$	2,906	$	3,015	$	2,885
	Additions:
	Charged to costs and expense	2,098		3,087		6,209
	Recovery of previous write-offs	1,929		2,041		2,034
	Uncollectible receivables written off	4,672		5,237		8,113
	Balance at end of year	$	2,261	$	2,906	$	3,015

Regulation_Tables

Regulation (Tables)	12 Months Ended
	Dec. 31, 2013
Public Utilities, General Disclosures [Abstract]	'
Refund Fuel Cost Over Recoveries	'
	Docket	Date Filed	Date Approved	Recovery Period	Refund Period	Refund
	No.					Amount Authorized (In Thousands)
	40622	3-Aug-12	28-Sep-12	January 2011- June 2012	Sep-12	$	6,600
Revised Fixed Fuel Factor	'
	Docket	Date Filed	Date Approved	Increase (Decrease) in	Effective Billing
	No.			Fuel Factor	Month
	40302	April 12, 2012	April 25, 2012	-18.50%	May-12
	41803	September 9, 2013	September 23, 2013	12.20%	Oct-13

Regulatory_Assets_and_Liabilit1

Regulatory Assets and Liabilities Regulatory Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2013
Regulatory Assets and Liabilities Disclosure [Abstract]	'
Schedule of Regulatory Assets	'
	Regulatory assets and liabilities reflected in the Company's balance sheets are presented below (in thousands):
		Amortization	December 31, 2013		December 31, 2012
		Period Ends
	Regulatory assets
	Regulatory tax assets (a)	(b)	$	61,772	$	57,551
	Loss on reacquired debt (c)	May-35	18,338		19,191
	Final coal reclamation (f)	Jul-16	4,290		5,473
	Nuclear fuel postload daily financing charge	(d)	4,141		3,833
	Unrecovered issuance costs due to reissuance of PCBs (c)	Aug-42	893		926
	Texas energy efficiency	(e)	—		536
	Texas 2012 rate case costs (f)	Apr-14	581		2,335
	Texas military base discount and recovery factor	(h)	759		2,116
	New Mexico procurement plan costs	(g)	139		139
	New Mexico renewable energy credits	(g)	4,833		4,033
	New Mexico 2010 FPPCAC audit	(g)	433		433
	New Mexico Palo Verde deferred depreciation	(b)	4,871		5,024
	Total regulatory assets		$	101,050	$	101,590
	Regulatory liabilities
	Regulatory tax liabilities (a)	(b)	$	17,752	$	16,666
	Accumulated deferred investment tax credit (i)	(b)	4,656		4,587
	New Mexico energy efficiency	(e)	3,646		926
	Texas energy efficiency	(e)	362		—
	Total regulatory liabilities		$	26,416	$	22,179
	________________
	(a)	No specific return on investment is required since related assets and liabilities offset.
	(b)	The amortization period for this asset is based upon the life of the associated assets or liabilities.
	(c)	This item is recovered as a component of the weighted cost of debt and amortized over the life of the related debt issuance.
	(d)	This item is recovered through fuel recovery mechanisms.
	(e)	This item is recovered or credited through a recovery factor that is set annually.
	(f)	This item is included in rate base which earns a return on investment.
	(g)	Amortization period is anticipated to be established in next general rate case.
	(h)	This item represents the net asset related to the military discount which is recovered from non-military customers through a recovery factor.
	(i)	This item is excluded from rate base.
Schedule of Regulatory Liabilities	'
	Regulatory assets and liabilities reflected in the Company's balance sheets are presented below (in thousands):
		Amortization	December 31, 2013		December 31, 2012
		Period Ends
	Regulatory assets
	Regulatory tax assets (a)	(b)	$	61,772	$	57,551
	Loss on reacquired debt (c)	May-35	18,338		19,191
	Final coal reclamation (f)	Jul-16	4,290		5,473
	Nuclear fuel postload daily financing charge	(d)	4,141		3,833
	Unrecovered issuance costs due to reissuance of PCBs (c)	Aug-42	893		926
	Texas energy efficiency	(e)	—		536
	Texas 2012 rate case costs (f)	Apr-14	581		2,335
	Texas military base discount and recovery factor	(h)	759		2,116
	New Mexico procurement plan costs	(g)	139		139
	New Mexico renewable energy credits	(g)	4,833		4,033
	New Mexico 2010 FPPCAC audit	(g)	433		433
	New Mexico Palo Verde deferred depreciation	(b)	4,871		5,024
	Total regulatory assets		$	101,050	$	101,590
	Regulatory liabilities
	Regulatory tax liabilities (a)	(b)	$	17,752	$	16,666
	Accumulated deferred investment tax credit (i)	(b)	4,656		4,587
	New Mexico energy efficiency	(e)	3,646		926
	Texas energy efficiency	(e)	362		—
	Total regulatory liabilities		$	26,416	$	22,179
	________________
	(a)	No specific return on investment is required since related assets and liabilities offset.
	(b)	The amortization period for this asset is based upon the life of the associated assets or liabilities.
	(c)	This item is recovered as a component of the weighted cost of debt and amortized over the life of the related debt issuance.
	(d)	This item is recovered through fuel recovery mechanisms.
	(e)	This item is recovered or credited through a recovery factor that is set annually.
	(f)	This item is included in rate base which earns a return on investment.
	(g)	Amortization period is anticipated to be established in next general rate case.
	(h)	This item represents the net asset related to the military discount which is recovered from non-military customers through a recovery factor.
	(i)	This item is excluded from rate base.

Utility_Plant_Palo_Verde_and_O1

Utility Plant, Palo Verde and Other Jointly-Owned Utility Plant Utility Plant, Palo Verde and Other Jointly-Owned Utility Plant (Tables)	12 Months Ended
	Dec. 31, 2013
Utility Plant, Palo Verde and Other Jointly-Owned Utility Plant [Abstract]	'
Schedule of Property, Plant and Equipment and Finite-Lived Intangible Assets By Major Class	'
	The table below presents the balance of each major class of depreciable assets at December 31, 2013 (in thousands):
		Gross			Accumulated			Net
		Plant			Depreciation			Plant
	Nuclear production	$	817,665		$	(271,173	)	$	546,492
	Steam and other	668,666			(264,019		)	404,647
	Total production	1,486,331			(535,192		)	951,139
	Transmission	432,674			(246,175		)	186,499
	Distribution	965,674			(337,513		)	628,161
	General	122,209			(58,231		)	63,978
	Intangible	69,661			(36,977		)	32,684
	Total	$	3,076,549		$	(1,214,088	)	$	1,862,461
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	'
	The table below presents the actual and estimated amortization expense for intangible plant for the previous three years and for the next five years (in thousands):
	2011	$	6,668
	2012	7,183
	2013	7,683
	2014 (estimated)	7,372
	2015 (estimated)	6,540
	2016 (estimated)	5,980
	2017 (estimated)	5,326
	2018 (estimated)	3,713
Schedule of Jointly Owned Utility Plants	'
	A summary of the Company’s investment in jointly-owned utility plant, excluding fuel inventories, at December 31, 2013 and 2012 is as follows (in thousands):
		December 31, 2013						December 31, 2012
		Palo Verde			Other			Palo Verde			Other
	Electric plant in service	$	817,665		$	217,137		$	795,259		$	213,155
	Accumulated depreciation	(271,173		)	(173,819		)	(257,540		)	(168,569		)
	Construction work in progress	75,040			2,347			64,623			2,401
	Total	$	621,532		$	45,665		$	602,342		$	46,987

Accounting_for_Asset_Retiremen1

Accounting for Asset Retirement Obligations Accounting for Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2013
Accounting for Asset Retirement Obligations [Abstract]	'
Changes In Estimated Probabilities Assumptions	'
	The assumptions used to calculate the Palo Verde ARO liability are as follows:
		Escalation			Credit-Risk
		Rate			Adjusted
					Discount Rate
	Original ARO liability	3.6	%		9.5	%
	Incremental ARO liability	3.6	%		6.2	%
Schedule of Asset Retirement Obligations	'
		2013				2012			2011
	ARO liability at beginning of year	$	62,784			$	56,140		$	92,911
	Liabilities incurred	—				—			—
	Liabilities settled	(36		)		(450		)	(793		)
	Revisions to estimate	(3,401		)		1,929			(41,670		)
	Accretion expense	5,867				5,165			5,692
	ARO liability at end of year	$	65,214			$	62,784		$	56,140

Common_Stock_Tables

Common Stock (Tables)	12 Months Ended
	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Schedule of Treasury Stock by Class	'
	Detail regarding the Company's stock repurchase program are presented below:
		Since 1999				Authorized
		(a)				Shares
	Shares repurchased (b)	25,406,184
	Cost, including commission (in thousands)	$	423,647
	Total remaining shares available for repurchase at December 31, 2013					393,816
	______________________
	(a)	Represents repurchased shares and cost since inception of the stock repurchase program in 1999.
	(b)	Shares repurchased does not include 86,735 treasury shares related to employee compensation arrangements outside of the Company's repurchase programs.
Schedule of Earnings Per Share, Basic and Diluted	'
	The Company awards unvested restricted stock which qualifies as a participating security. The basic and diluted earnings per share are presented below:
		Years Ended December 31,
		2013				2012				2011
	Weighted average number of common shares outstanding:
	Basic number of common shares outstanding	40,114,594				39,974,022				41,349,883
	Dilutive effect of unvested performance awards	12,053				66,756				206,658
	Dilutive effect of stock options	—				14,803				30,518
	Diluted number of common shares outstanding	40,126,647				40,055,581				41,587,059
	Basic net income per common share:
	Net income	$	88,583			$	90,846			$	103,539
	Income allocated to participating restricted stock	(254		)		(256		)		(471		)
	Net income available to common shareholders	$	88,329			$	90,590			$	103,068
	Diluted net income per common share:
	Net income	$	88,583			$	90,846			$	103,539
	Income reallocated to participating restricted stock	(254		)		(256		)		(469		)
	Net income available to common shareholders	$	88,329			$	90,590			$	103,070
	Basic net income per common share:
	Distributed earnings	$	1.045			$	0.97			$	0.66
	Undistributed earnings	1.155				1.3				1.83
	Basic net income per common share	$	2.2			$	2.27			$	2.49
	Diluted net income per common share:
	Distributed earnings	$	1.045			$	0.97			$	0.66
	Undistributed earnings	1.155				1.29				1.82
	Diluted net income per common share	$	2.2			$	2.26			$	2.48
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	'
	The amount of restricted stock awards and performance shares at 100% performance level excluded from the calculation of the diluted number of common shares outstanding because their effect was antidilutive is presented below:
			Year Ended December 31,
			2013			2012			2011
	Restricted stock awards		51,189			45,178			81,653
	Performance shares (a)		115,044			57,625			—
	_____________________
	(a)	Certain performance shares were excluded from the computation of diluted earnings per share as no payouts would have been required based upon performance at the end of each corresponding period.
Restricted Stock	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Schedule of Expense, Deferred Tax Benefit, and Current Tax Expense Related to Restricted Stock Awards	'
	The expense, deferred tax benefit, and current tax expense recognized related to restricted stock awards in 2013, 2012 and 2011 is presented below (in thousands):
			2013				2012				2011
	Expense (a)		$	2,458			$	1,508			$	2,258
	Deferred tax benefit		860				528				790
	Current tax benefit recognized		109				94				518
	_____________________
	(a) Any capitalized costs related to these expenses is less than $0.1 million for all years.
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity	'
	The aggregate intrinsic value and fair value at grant date of restricted stock which vested in 2013, 2012 and 2011 is presented below (in thousands):
			2013				2012				2011
	Aggregated intrinsic value		$	2,077			$	2,242			$	3,279
	Fair value at grant date		1,765				1,973				1,799
Schedule of Nonvested Restricted Stock Units Activity	'
	The unvested restricted stock transactions for 2013 are presented below:
		Total			Weighted				Unrecognized Compensation Expense (a)				Aggregate Intrinsic Value
		Shares			Average
					Grant Date
					Fair Value
									(In thousands)				(In thousands)
	Restricted shares outstanding at December 31, 2012	84,446			$	31.26
	Restricted stock awards	96,279			35.48
	Vested	(58,642	)		30.1
	Forfeitures	(1,549	)		31.28
	Restricted shares outstanding at December 31, 2013	120,534			35.19				$	1,976			$	4,232
	_______________________
	(a) The unrecognized compensation expense is expected to be recognized over the weighted average remaining contractual term of the outstanding restricted stock of approximately one year.
Schedule of Share-based Compensation Award, Restricted Stock, Grants in Period, Weighted Average Grant Date Fair Value	'
	The weighted average fair value per share at grant date for restricted stock awarded during 2013, 2012 and 2011 were:
		2013				2012				2011
	Weighted average fair value per share	$	35.48			$	32.45			$	28.98
Performance Shares	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Schedule of Share-based Compensation Award, Performance-Based Units, Vested and Expected to Vest	'
	Detail of performance shares vested follows:
	Date Vested		Payout Ratio			Performance Shares Awarded			Compensation Costs Expensed				Period Compensation Costs Expensed		Aggregated Intrinsic Value
									(In thousands)						(In thousands)
	February 18, 2014		0	%		0			$	954			2011-2013		$	—
	January 29, 2013		150	%		64,275			849				2010-2012		2,176
	January 1, 2012		175	%		174,038			1,193				2009-2011		6,029
	September 3, 2011		112.5	%		3,825			40				2008-2011		129
	July 9, 2011		112.5	%		2,250			23				2008-2011		75
Schedule of Share-based Compensation Arrangements by Share-based Payment Award	'
	The outstanding performance share awards at the 100% performance level is summarized below:
		Number			Weighted				Unrecognized Compensation Expense (a)				Aggregate Intrinsic Value
		Outstanding			Average
					Grant Date
					Fair Value
									(In thousands)				(In thousands)
	Performance shares outstanding at December 31, 2012	128,033			$	26.48
	Performance share awards	39,814			34.69
	Performance shares vested	(42,850	)		19.82
	Performance shares outstanding at December 31, 2013	124,997			31.38				$	1,452			$	4,389
	_______________________
	(a) The unrecognized compensation expense is expected to be recognized over the weighted average remaining contractual term of the awards of approximately one year.
Schedule of Share-based Compensation, Performance Stock Activity	'
	A summary of information related to performance shares for 2013, 2012 and 2011 is presented below:
		2013				2012				2011
	Weighted average per share grant date fair value per share of performance shares awarded	$	34.69			$	32.74			$	23.45
	Fair value of performance shares vested (in thousands)	849				1,193				628
	Intrinsic value of performance shares vested (in thousands) (a)	1,450				3,464				1,032
	Compensation expense (in thousands) (b)	1,188				170				1,573
	Deferred tax benefit related to compensation expense (in thousands)	416				59				551
	_____________________
	(a) Based on a 100% performance level.
	(b) Includes adjustments for forfeiture of performance share awards by certain executives.

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]	'
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	'
	Changes in Accumulated Other Comprehensive Income (Loss) (net of tax) by component which are presented below (in thousands):
			Years Ended December 31, 2013
			Unrecognized Pension and Postretirement Benefit Costs				Net Unrealized Gains (Losses) on Marketable Securities			Net Losses on Cash Flow Hedges			Accumulated Other Comprehensive Income (Loss)
	Balance at December 31, 2012		$	(75,737	)		$	22,194		$	(12,541	)	$	(66,084	)
		Other comprehensive income before reclassifications	51,371				14,482			—			65,853
		Amounts reclassified from accumulated other comprehensive income (loss)	3,036				(436		)	243			2,843
	Balance at December 31, 2013		$	(21,330	)		$	36,240		$	(12,298	)	$	2,612
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]	'
	Amounts reclassified from accumulated other comprehensive income (loss) for the twelve months ended December 31, 2013 are as follows ( in thousands):
	Details about Accumulated Other Comprehensive Income (Loss) Components			2013				Affected Line Item in the Statement of Operations
	Amortization of pension and postretirement benefit costs:
		Prior service benefit		$	5,560			(a)
		Net loss		(10,472		)		(a)
				(4,912		)		(a)
		Income tax effect		1,876
				(3,036		)		(a)
	Marketable securities:
		Net realized gain on sale of securities		553				Investment and interest income, net
				553				Income before income taxes
				(117		)		Income tax expense
				436				Net income
	Loss on cash flow hedge:
		Amortization of loss		(411		)		Interest on long-term debt and revolving credit facility
				(411		)		Income before income taxes
				168				Income tax expense
				(243		)		Net income
		Total reclassifications		$	(2,843	)
	(a) These items are included in the computation of net periodic benefit cost. See Note M, Employee Benefits, for additional information.

LongTerm_Debt_and_Financing_Ob1

Long-Term Debt and Financing Obligations (Tables)	12 Months Ended
	Dec. 31, 2013
Long-Term Debt and Financing Obligations [Abstract]	'
Schedule of Debt	'
	Outstanding long-term debt and financing obligations are as follows:
		December 31,
		2013			2012
		(In thousands)
	Long-Term Debt:
	Pollution Control Bonds (1):
	7.25% 2009 Series A refunding bonds, due 2040 (7.46% effective interest rate)	$	63,500		$	63,500
	4.50% 2012 Series A refunding bonds, due 2042 (4.63% effective interest rate)	59,235			59,235
	7.25% 2009 Series B refunding bonds, due 2040 (7.49% effective interest rate)	37,100			37,100
	1.875% 2012 Series A refunding bonds, due 2032 (2.35% effective interest rate)	33,300			33,300
	Total Pollution Control Bonds	193,135			193,135
	Senior Notes (2):
	6.00% Senior Notes, net of discount, due 2035 (7.12% effective interest rate)	397,976			397,934
	7.50% Senior Notes, net of discount, due 2038 (7.67% effective interest rate)	148,800			148,783
	3.30% Senior Notes, net of discount, due 2022 (3.43% effective interest rate)	149,709			149,683
	Total Senior Notes	696,485			696,400
	RGRT Senior Notes (3):
	3.67% Senior Notes, Series A, due 2015 (3.87% effective interest rate)	15,000			15,000
	4.47% Senior Notes, Series B, due 2017 (4.62% effective interest rate)	50,000			50,000
	5.04% Senior Notes, Series C, due 2020 (5.16% effective interest rate)	45,000			45,000
	Total RGRT Senior Notes	110,000			110,000
	Total long-term debt	999,620			999,535
	Financing Obligations:
	Revolving Credit Facility ($14,352 due in 2014) (4)	14,352			22,155
	Total long-term debt and financing obligations	1,013,972			1,021,690
	Current Portion (amount due within one year):
	Short-term borrowings under the revolving credit facility	(14,352		)	(22,155		)
		$	999,620		$	999,535
	_____________________
	-1	Pollution Control Bonds ("PCBs")
	The Company has four series of tax exempt unsecured PCBs in aggregate principal amount of $193.1 million. The 1.875% 2012 Series A (El Paso Electric Company Four Corners Project) Pollution Control Refunding Revenue Bonds with an aggregate principal amount of $33.3 million are subject to mandatory tender for purchase in September 2017.
	-2	Senior Notes
	The Senior Notes are unsecured obligations of the Company. They were issued pursuant to bond covenants that provide limitations on the Company’s ability to enter into certain transactions. The 6.00% senior notes have an aggregate principal amount of $400.0 million and were issued in May 2005. The proceeds, net of a $2.3 million discount, were used to fund the retirement of the Company's first mortgage bonds. The Company amortizes the loss associated with a cash flow hedge recorded in accumulated other comprehensive income to earnings as interest expense over the life of the 6.00% senior notes. See Note O, "Financial Instruments and Investments - Treasury Rate Locks". This amortization is included in the effective interest rate of the 6.00% senior notes.
	The 7.50% senior notes have an aggregate principal amount of $150.0 million and were issued in June 2008. The proceeds, net of a $1.3 million discount, were used to repay short-term borrowings of $44.0 million, fund capital expenditures and for other general corporate purposes.
	The 3.30% senior notes have an aggregate principal amount of $150.0 million and were issued in December 2012. The proceeds, net of a $0.3 million discount, were used to fund construction expenditures and for working capital and general corporate purposes.
	-3	RGRT Senior Notes
	In 2010, the Company and RGRT, a Texas grantor trust through which the Company finances its portion of fuel for Palo Verde, entered into a note purchase agreement with various institutional purchasers. Under the terms of the Agreement, RGRT sold to the purchasers $110 million aggregate principal amount of senior notes (the "Notes"). The Company guarantees the payment of principal and interest on the Notes. In the Company’s financial statements, the assets and liabilities of the RGRT are reported as assets and liabilities of the Company.
	RGRT will pay interest on the Notes on February 15, and August 15 of each year until maturity. RGRT may redeem the Notes, in whole or in part, at any time at a redemption price equal to 100% of the principal amount to be redeemed together with the interest on such principal amount accrued to the date of redemption, plus a make-whole amount based on the prevailing market interest rates. The agreement requires compliance with certain
	covenants, including a total debt to capitalization ratio. The Company was in compliance with these requirements throughout 2013.
	The sale of the Notes was made by RGRT in reliance on a private placement exemption from registration under the Securities Act of 1933, as amended.
	The proceeds of $109.4 million, net of issuance costs, from the sale of the Notes was used by RGRT to repay amounts borrowed under the revolving credit facility and will enable future nuclear fuel financing requirements of RGRT to be met with a combination of the Notes and amounts borrowed from the revolving credit facility.
	-4	Revolving Credit Facility
	On January 14, 2014, the Company and RGRT entered into a second amended and restated credit agreement related to the RCF with JP Morgan Chase Bank, N.A., as administrative agent and issuing bank, and Union Bank, N.A., as syndication agent, and various lending banks party thereto. Under the terms of the agreement, the Company has available $300 million and the ability to increase the RCF by up to $100 million (up to a total of $400 million) upon the satisfaction of certain conditions, more fully set forth in the agreement, including obtaining commitments from lenders or third party financial institutions. The RCF has a term ending January 2019. The Company may extend the maturity date up to two times, in each case for an additional one year period upon the satisfaction of certain conditions.
	The RCF provides that amounts borrowed by the Company may be used for, among other things, working capital and general corporate purposes. Any amounts borrowed by RGRT may be used, among other things, to finance the acquisition and processing of nuclear fuel. Amounts borrowed by RGRT are guaranteed by the Company and the balance borrowed under the RCF is recorded as short-term borrowings on the balance sheet. The RCF is unsecured. The RCF requires compliance with certain covenants, including a total debt to capitalization ratio. The Company was in compliance with these requirements throughout 2013. As of December 31, 2013, the total amount borrowed by RGRT was $14.4 million for nuclear fuel under the RCF. As of December 31, 2013, no borrowings were outstanding under this facility for working capital and general corporate purposes. The weighted average interest rate on the RCF was 1.4% as of December 31, 2013.
Schedule of Maturities of Long-term Debt	'
	As of December 31, 2013, the scheduled maturities for the next five years of long-term debt are as follows (in thousands):
	2014	$	—
	2015	15,000
	2016	—
	2017	83,300
	2018	—

Income_Taxes_Income_Taxes_Tabl

Income Taxes Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Taxes [Abstract]	'
Schedule of Deferred Tax Assets and Liabilities	'
	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and liabilities at December 31, 2013 and 2012 are presented below (in thousands):
		December 31,
		2013			2012
	Deferred tax assets:
	Benefit of tax loss carryforwards	$	17,709		$	7,798
	Alternative minimum tax credit carryforward	21,638			21,599
	Pensions and benefits	54,652			86,816
	Asset retirement obligation	23,727			21,710
	Deferred fuel	—			1,951
	Other	14,485			14,115
	Total gross deferred tax assets	132,211			153,989
	Deferred tax liabilities:
	Plant, principally due to depreciation and basis differences	(511,847		)	(457,127		)
	Decommissioning	(35,489		)	(29,416		)
	Deferred fuel	(2,171		)	—
	Other	(5,664		)	(5,828		)
	Total gross deferred tax liabilities	(555,171		)	(492,371		)
	Net accumulated deferred income taxes	$	(422,960	)	$	(338,382	)
Schedule of Components of Income Tax Expense (Benefit)	'
	The Company recognized income tax expense for 2013, 2012 and 2011 as follows (in thousands):
		Years Ended December 31,
		2013			2012			2011
	Income tax expense:
	Federal:
	Current	$	(2,877	)	$	1,487		$	5,084
	Deferred	45,024			43,187			46,864
	Total federal income tax	42,147			44,674			51,948
	State:
	Current	1,854			1,931			2,936
	Deferred	(414		)	697			(924		)
	Total state income tax	1,440			2,628			2,012
	Generation (amortization) of accumulated investment tax credits	68			(323		)	(252		)
	Total income tax expense	$	43,655		$	46,979		$	53,708
Schedule of Effective Income Tax Rate Reconciliation	'
	Income tax provisions differ from amounts computed by applying the statutory federal income tax rate of 35% to book income before federal income tax as follows (in thousands):
		Years Ended December 31,
		2013			2012			2011
	Federal income tax expense computed on income at statutory rate	$	46,283		$	48,239		$	55,036
	Difference due to:
	State taxes, net of federal benefit	936			1,708			1,308
	AEFUDC	(2,149		)	(1,845		)	(2,295		)
	Permanent tax differences	(1,153		)	(604		)	(303		)
	Other	(262		)	(519		)	(38		)
	Total income tax expense	$	43,655		$	46,979		$	53,708
	Effective income tax rate	33		%	34.1		%	34.2		%
Summary of Income Tax Contingencies	'
	A reconciliation of the December 31, 2013, 2012 and 2011 amount of unrecognized tax benefits is as follows (in thousands):
		2013			2012			2011
	Balance at January 1	$	9,800		$	9,500		$	7,300
	Additions for tax positions related to the current year	600			1,600			2,200
	Reductions for tax positions related to the current year	—			(900		)	—
	Additions for tax positions of prior years	1,700			1,400			—
	Reductions for tax positions of prior years	(4,900		)	(1,800		)	—
	Balance at December 31	$	7,200		$	9,800		$	9,500

Commitments_Contingencies_and_1

Commitments, Contingencies and Uncertainties Commitments, Contingencies and Uncertainties (Tables)	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Long-term Purchase Commitment	'
	The Company had entered into the following significant agreements with various counterparties for forward purchases and sales of electricity:
								Commercial
								Operation
	Type of Contract		Counterparty	Quantity			Term	Date
	Power Purchase and Sale Agreement		Freeport		125	MW	December 2008 through December 2014	N/A
	Power Purchase and Sale Agreement		Freeport		100	MW	January 2015 through December 2021	N/A
	Power Purchase Agreement		Shell	Up to	40	MW	January 2011 through September 2014	N/A
	Power Purchase Agreement		NRG		20	MW	August 2011 through August 2031	Aug-11
	Power Purchase Agreement		Sun Edison 1		10	MW	June 2012 through June 2037	Jun-12
	Power Purchase Agreement		Sun Edison 2		12	MW	May 2012 through May 2037	May 2012
	Power Purchase Agreement		Hatch Solar Energy Center I, LLC		5	MW	July 2011 through June 2036	Jul-11
	Power Purchase Agreement		Macho Springs Solar, LLC		50	MW	20 years after operational start date	Expected May 1, 2014
	Power Purchase Agreement		Newman Solar, LLC		10	MW	30 years after operational start date	Expected December 31, 2014
Schedule of Future Minimum Rental Payments for Operating Leases	'
	As of December 31, 2013, the Company’s minimum future rental payments for the next five years are as follows (in thousands):
	2014	$	1,081
	2015	1,028
	2016	600
	2017	442
	2018	408

Employee_Benefits_Employee_Ben

Employee Benefits Employee Benefits (Tables)	12 Months Ended
	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]	'
Schedule of Net Benefit Costs	'
	The components of net periodic benefit cost are presented below (in thousands):
		Years Ended December 31,
		2013								2012								2011
		Retirement				Non-Qualified				Retirement				Non-Qualified				Retirement				Non-Qualified
		Income				Retirement				Income				Retirement				Income				Retirement
		Plan				Plans				Plan				Plans				Plan				Plans
	Service cost	$	9,137			$	190			$	8,530			$	299			$	6,590			$	260
	Interest cost	12,742				872				12,594				963				12,871				1,116
	Expected return on plan assets	(17,108		)		—				(14,443		)		—				(14,095		)		—
	Amortization of:
	Net loss	10,437				661				10,729				627				6,190				354
	Prior service cost	3				94				21				94				21				94
	Net periodic benefit cost	$	15,211			$	1,817			$	17,431			$	1,983			$	11,577			$	1,824
Fair Value, Measurement Inputs, Disclosure	'
	The fair value of the Company’s Retirement Plan assets at December 31, 2013 and 2012, and the level within the three levels of the fair value hierarchy defined by FASB guidance on fair value measurements are presented in the table below (in thousands):
	Description of Securities	Fair Value as of				Quoted Prices				Significant				Significant
		December 31,				in Active				Other				Unobservable
		2013				Markets for				Observable				Inputs
						Identical Assets				Inputs				(Level 3)
						(Level 1)				(Level 2)
	Cash and Cash Equivalents	$	940			$	940			$	—			$	—
	Guaranteed Investment Contract	1,126				—				1,126				—
	Common Collective Trusts (a)
	Equity funds	142,960				—				142,960				—
	Fixed income funds	103,948				—				103,948				—
	Total Common Collective Trusts	246,908				—				246,908				—
	Limited Partnership Interest in Real Estate (b)	8,857				—				—				8,857
	Total Plan Investments	$	257,831			$	940			$	248,034			$	8,857
	Description of Securities	Fair Value as of				Quoted Prices				Significant				Significant
		December 31,				in Active				Other				Unobservable
		2012				Markets for				Observable				Inputs
						Identical Assets				Inputs				(Level 3)
						(Level 1)				(Level 2)
	Cash and Cash Equivalents	$	9,163			$	9,163			$	—			$	—
	U.S. Treasury Securities	24,854				24,854				—				—
	Guaranteed Investment Contract	1,059				—				1,059				—
	Common Stock	52,149				52,149				—				—
	Mutual Funds - Fixed Income	59,150				59,150				—				—
	Mutual Funds - Equity	65,634				65,634				—				—
	Limited Partnership Interest in Real Estate (b)	8,559				—				—				8,559
	Total Plan Investments	$	220,568			$	210,950			$	1,059			$	8,559
	_____________________
	(a)	The Common Collective Trusts are invested in equity or fixed income securities, or a combination thereof. The investment objective of each trust is to produce returns in excess of, or commensurate with, its predefined index.
	(b)	This investment is a commercial real estate partnership that purchases land, develops limited infrastructure, and sells it for commercial development. The Company is restricted from selling its partnership interest during the life of the partnership which is generally 5-7 years. Return on investment is realized as land is sold. The fair value of the limited partnership interest in real estate is based on the NAV of the partnership which reflects the appraised value of the land.
Changes in Fair Value of Investments in Real Estate	'
	The table below reflects the changes in the fair value of investments in real estate during the period (in thousands):
		Fair Value of
		Investments in
		Real Estate
	Balances at December 31, 2011	$	8,511
	Unrealized gain in fair value	48
	Balances at December 31, 2012	8,559
	Unrealized gain in fair value	298
	Balances at December 31, 2013	$	8,857
Schedule of Accumulated Other Comprehensive Income (Loss)	'
	Changes in Accumulated Other Comprehensive Income (Loss) (net of tax) by component which are presented below (in thousands):
				Years Ended December 31, 2013
				Unrecognized Pension and Postretirement Benefit Costs				Net Unrealized Gains (Losses) on Marketable Securities				Net Losses on Cash Flow Hedges				Accumulated Other Comprehensive Income (Loss)
	Balance at December 31, 2012			$	(75,737	)		$	22,194			$	(12,541	)		$	(66,084	)
		Other comprehensive income before reclassifications		51,371				14,482				—				65,853
		Amounts reclassified from accumulated other comprehensive income (loss)		3,036				(436		)		243				2,843
	Balance at December 31, 2013			$	(21,330	)		$	36,240			$	(12,298	)		$	2,612
Retirement Plans	'
Defined Benefit Plan Disclosure [Line Items]	'
Schedule of Net Funded Status	'
	The obligations and funded status of the plans are presented below (in thousands):
		December 31,
		2013								2012
		Retirement				Non-Qualified				Retirement				Non-Qualified
		Income				Retirement				Income				Retirement
		Plan				Plans				Plan				Plans
	Change in projected benefit obligation:
	Benefit obligation at end of prior year	$	320,846			$	27,241			$	296,293			$	26,547
	Service cost	9,137				190				8,530				299
	Interest cost	12,742				872				12,594				963
	Actuarial (gain) loss	(15,373		)		(533		)		12,417				1,338
	Benefits paid	(9,537		)		(1,872		)		(8,988		)		(1,906		)
	Benefit obligation at end of year	317,815				25,898				320,846				27,241
	Change in plan assets:
	Fair value of plan assets at end of prior year	220,568				—				191,369				—
	Actual return on plan assets	31,800				—				20,187				—
	Employer contribution	15,000				1,872				18,000				1,906
	Benefits paid	(9,537		)		(1,872		)		(8,988		)		(1,906		)
	Fair value of plan assets at end of year	257,831				—				220,568				—
	Funded status at end of year	$	(59,984	)		$	(25,898	)		$	(100,278	)		$	(27,241	)
Schedule of Amounts Recognized in Balance Sheet	'
	Amounts recognized in the Company's balance sheets consist of the following (in thousands):
		December 31,
		2013								2012
		Retirement				Non-Qualified				Retirement				Non-Qualified
		Income				Retirement				Income				Retirement
		Plan				Plans				Plan				Plans
	Current liabilities	$	—			$	(1,870	)		$	—			$	(1,829	)
	Noncurrent liabilities	(59,984		)		(24,028		)		(100,278		)		(25,412		)
	Total	$	(59,984	)		$	(25,898	)		$	(100,278	)		$	(27,241	)
Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets	'
	The accumulated benefit obligation in excess of plan assets is as follows (in thousands):
		December 31,
		2013								2012
		Retirement				Non-Qualified				Retirement				Non-Qualified
		Income				Retirement				Income				Retirement
		Plan				Plans				Plan				Plans
	Projected benefit obligation	$	(317,815	)		$	(25,898	)		$	(320,846	)		$	(27,241	)
	Accumulated benefit obligation	(275,555		)		(25,077		)		(274,890		)		(26,363		)
	Fair value of plan assets	257,831				—				220,568				—
Schedule of Amounts Recognized in Other Comprehensive Income (Loss)	'
	Amounts recognized in accumulated other comprehensive income consist of the following (in thousands):
		Years Ended December 31,
		2013								2012
		Retirement				Non-Qualified				Retirement				Non-Qualified
		Income				Retirement				Income				Retirement
		Plan				Plans				Plan				Plans
	Net loss	$	85,261			$	8,508			$	125,763			$	9,701
	Prior service cost	—				219				3				314
	Total	$	85,261			$	8,727			$	125,766			$	10,015
Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss)	'
	The changes in benefit obligations recognized in other comprehensive income are presented below (in thousands):
		Years Ended December 31,
		2013								2012								2011
		Retirement				Non-Qualified				Retirement				Non-Qualified				Retirement				Non-Qualified
		Income				Retirement				Income				Retirement				Income				Retirement
		Plan				Plans				Plan				Plans				Plan				Plans
	Net (gain) loss	$	(30,065	)		$	(533	)		$	6,672			$	1,337			$	40,181			$	2,980
	Amortization of:
	Net loss	(10,437		)		(661		)		(10,729		)		(627		)		(6,190		)		(354		)
	Prior service cost	(3		)		(94		)		(21		)		(94		)		(21		)		(94		)
	Total recognized in other comprehensive income	$	(40,505	)		$	(1,288	)		$	(4,078	)		$	616			$	33,970			$	2,532
Schedule of Recognized Net Periodic Benefit Obligation and Other Comprehensive Income	'
	The total amount recognized in net periodic benefit costs and other comprehensive income are presented below (in thousands):
		Years Ended December 31,
		2013								2012								2011
		Retirement				Non-Qualified				Retirement				Non-Qualified				Retirement				Non-Qualified
		Income				Retirement				Income				Retirement				Income				Retirement
		Plan				Plans				Plan				Plans				Plan				Plans
	Total recognized in net periodic benefit cost and other comprehensive income	$	(25,294	)		$	529			$	13,353			$	2,599			$	45,547			$	4,356
Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year	'
	The following are amounts in accumulated other comprehensive income that are expected to be recognized as components of net periodic benefit cost during 2014 (in thousands):
		Retirement				Non-Qualified
		Income				Retirement
		Plan				Plans
	Net loss	$	6,270			$	570
	Prior service cost	—				90
Schedule of Allocation of Plan Assets	'
	The expected long-term rate of return is based on the weighted average of the expected returns on investments based upon the target asset allocation of the pension fund. The Company’s target allocations for the plan’s assets are presented below:
			December 31, 2013
	Equity securities		55	%
	Fixed income		40	%
	Alternative investments		5	%
	Total		100	%
Schedule of Expected Benefit Payments	'
	The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid (in thousands):
		Retirement				Non-Qualified
		Income				Retirement
		Plan				Plans
	2014	$	10,902			$	1,870
	2015	12,015				1,818
	2016	13,180				1,772
	2017	14,440				1,829
	2018	15,807				1,715
	2019-2023	96,510				9,447
Retirement Plans | Net Periodic Benefit Costs	'
Defined Benefit Plan Disclosure [Line Items]	'
Schedule of Assumptions Used	'
	The following are the weighted-average actuarial assumptions used to determine the net periodic benefit cost for the twelve months ended December 31:
		2013									2012									2011
					Non-Qualified									Non-Qualified									Non-Qualified
		Retirement			Supplemental Retirement			Excess			Retirement			Supplemental Retirement			Excess			Retirement			Supplemental Retirement		Excess
		Income			Plan			Benefit			Income			Plan			Benefit			Income			Plan		Benefit
		Plan						Plan			Plan						Plan			Plan					Plan
	Discount rate	4	%		3.1	%		4	%		4.3	%		3.6	%		4.1	%		5.4	%		4.6	%	5.3	%
	Expected long-term return on plan assets	7.5	%		N/A			N/A			7.5	%		N/A			N/A			7.5	%		N/A		N/A
	Rate of compensation increase	4.75	%		N/A			4.75	%		5	%		N/A			5	%		5	%		N/A		5	%
Retirement Plans | Benefit Obligations	'
Defined Benefit Plan Disclosure [Line Items]	'
Schedule of Assumptions Used	'
	The following are the weighted-average actuarial assumptions used to determine the benefit obligations:
		December 31,
		2013									2012
					Non-Qualified									Non-Qualified
		Retirement			Supplemental			Excess			Retirement			Supplemental			Excess
		Income			Retirement			Benefit			Income			Retirement			Benefit
		Plan			Plan			Plan			Plan			Plan			Plan
	Discount rate	4.9	%		3.9	%		4.9	%		4	%		3.1	%		4	%
	Rate of compensation increase	4.75	%		N/A			4.75	%		4.75	%		N/A			4.75	%
Other Postretirement Benefit Plans, Defined Benefit	'
Defined Benefit Plan Disclosure [Line Items]	'
Schedule of Net Funded Status	'
	The following table contains a reconciliation of the change in the benefit obligation, the fair value of plan assets, and the funded status of the plan (in thousands):
		December 31,
		2013				2012
	Change in benefit obligation:
	Benefit obligation at end of prior year	$	135,680			$	133,272
	Service cost	3,843				4,378
	Interest cost	5,156				5,651
	Actuarial gain	(48,778		)		(5,009		)
	Amendment (a)	(97		)		—
	Benefits paid	(4,013		)		(3,929		)
	Retiree contributions	1,056				1,086
	Medicare Part D subsidy	—				231
	Benefit obligation at end of year	92,847				135,680
	Change in plan assets:
	Fair value of plan assets at end of prior year	36,510				32,817
	Actual return on plan assets	5,539				2,605
	Employer contribution	3,100				3,700
	Benefits paid	(4,013		)		(3,929		)
	Retiree contributions	1,056				1,086
	Medicare Part D subsidy	—				231
	Fair value of plan assets at end of year	42,192				36,510
	Funded status (b)	$	(50,655	)		$	(99,170	)
	_____________________
	(a)	Amendment relates to modification of the Company's Other Postretirement Benefit Plan which limits the Company's premium contribution. The amendment became effective October 3, 2013 and resulted in a remeasurement of the plan.
	(b)	These amounts are recognized in the Company’s balance sheets as a non-current liability.
Schedule of Net Benefit Costs	'
	Net periodic benefit cost is made up of the components listed below (in thousands):
		Years Ended December 31,
		2013				2012				2011
	Service cost	$	3,843			$	4,378			$	2,988
	Interest cost	5,156				5,651				5,379
	Expected return on plan assets	(1,951		)		(1,714		)		(1,823		)
	Amortization of:
	Prior service benefit	(5,657		)		(5,877		)		(5,927		)
	Net (gain) loss	(626		)		615				(39		)
	Net periodic benefit cost	$	765			$	3,053			$	578
Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss)	'
	The changes in benefit obligations recognized in other comprehensive income are presented below (in thousands):
		Years Ended December 31,
		2013				2012				2011
	Net (gain) loss	$	(52,366	)		$	(5,900	)		$	34,517
	Prior service benefit	(97		)		—				—
	Amortization of:
	Prior service benefit	5,657				5,877				5,927
	Net gain (loss)	626				(615		)		39
	Total recognized in other comprehensive income	$	(46,180	)		$	(638	)		$	40,483
Schedule of Recognized Net Periodic Benefit Obligation and Other Comprehensive Income	'
	The total recognized in net periodic benefit cost and other comprehensive income are presented below (in thousands):
		Years Ended December 31,
		2013				2012				2011
	Total recognized in net periodic benefit cost and other comprehensive income	$	(45,415	)		$	2,415			$	41,061
Schedule of Allocation of Plan Assets	'
	The Company’s target allocations for the plan’s assets are presented below:
			December 31, 2013
	Equity securities		65	%
	Fixed income		30	%
	Alternative investments		5	%
	Total		100	%
Fair Value, Measurement Inputs, Disclosure	'
	The fair value of the Company’s Other Postretirement Benefits Plan assets at December 31, 2013 and 2012, and the level within the three levels of the fair value hierarchy defined by FASB guidance on fair value measurements are presented in the table below (in thousands):
	Description of Securities	Fair Value as of				Quoted Prices				Significant				Significant
		December 31,				in Active				Other				Unobservable
		2013				Markets for				Observable				Inputs
						Identical Assets				Inputs				(Level 3)
						(Level 1)				(Level 2)
	Cash and Cash Equivalents	$	33			$	33			$	—			$	—
	Common Collective Trusts (a)
	Equity funds	28,077				—				28,077				—
	Fixed income funds	12,421				—				12,421				—
	Total Common Collective Trusts	40,498				—				40,498				—
	Limited Partnership Interest in Real Estate (b)	1,661				—				—				1,661
	Total Plan Investments	$	42,192			$	33			$	40,498			$	1,661
	Description of Securities	Fair Value as of				Quoted Prices				Significant				Significant
		December 31,				in Active				Other				Unobservable
		2012				Markets for				Observable				Inputs
						Identical Assets				Inputs				(Level 3)
						(Level 1)				(Level 2)
	Cash and Cash Equivalents	$	2,075			$	2,075			$	—			$	—
	Municipal Securities – Tax Exempt	12,811				—				12,811				—
	Common Stock	14,397				14,397				—				—
	Mutual Funds – Equity	5,622				5,622				—				—
	Limited Partnership Interest in Real Estate (b)	1,605				—				—				1,605
	Total Plan Investments	$	36,510			$	22,094			$	12,811			$	1,605
	___________________
	(a)	The Common Collective Trusts are invested in equity or fixed income securities, or a combination thereof. The investment objective of each trust is to produce returns in excess of, or commensurate with, its predefined index.
	(b)	This investment is a commercial real estate partnership that purchases land, develops limited infrastructure, and sells it for commercial development. The Company is restricted from selling its partnership interest during the life of the partnership which is generally 5-7 years. Return of investment is realized as land is sold. The fair value of the limited partnership interest in real estate is based on the NAV of the partnership which reflects the appraised value of the land.
Changes in Fair Value of Investments in Real Estate	'
	The table below reflects the changes in the fair value of the investments in real estate during the period (in thousands):
		Fair Value of
		Investments  in
		Real Estate
	Balance at December 31, 2011	$	1,596
	Unrealized gain in fair value	9
	Balance at December 31, 2012	1,605
	Unrealized gain in fair value	56
	Balance at December 31, 2013	$	1,661
Schedule of Expected Benefit Payments	'
	The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid (in thousands):
	2014	$	3,024
	2015	3,414
	2016	3,810
	2017	4,230
	2018	4,639
	2019-2023	28,238
Schedule of Accumulated Other Comprehensive Income (Loss)	'
	Amounts recognized in accumulated other comprehensive income that have not been recognized as a component of net periodic cost consist of the following (in thousands):
		December 31,
		2013				2012
	Net (gain) loss	$	(38,110	)		$	13,630
	Prior service credit	(19,210		)		(24,770		)
		$	(57,320	)		$	(11,140	)
Other Postretirement Benefit Plans, Defined Benefit | Net Periodic Benefit Costs	'
Defined Benefit Plan Disclosure [Line Items]	'
Schedule of Assumptions Used	'
	The following are the weighted-average actuarial assumptions used to determine the net periodic benefit cost for the twelve months ended December 31:
		2013 (a)			2012			2011
	Discount rate at beginning of year	4.1	%		4.3	%		5.5	%
	Expected long-term return on plan assets	5.2	%		5.2	%		5.2	%
	Health care cost trend rates:
	Initial	7.75	%		8	%		8.5	%
	Ultimate	4.5	%		4.5	%		5	%
	Year ultimate reached	2026			2026			2018
Other Postretirement Benefit Plans, Defined Benefit | Accrued Postretirement Benefit	'
Defined Benefit Plan Disclosure [Line Items]	'
Schedule of Assumptions Used	'
	The following are the weighted-average actuarial assumptions used to determine the accrued postretirement benefit obligations:
		December 31,
		2013			2012
	Discount rate at end of year	4.9	%		4.1	%
	Health care cost trend rates:
	Initial	7.5	%		7.75	%
	Ultimate	4.5	%		4.5	%
	Year ultimate reached	2026			2026

Franchises_and_Significant_Cus1

Franchises and Significant Customers Franchises and Significant Customers (Tables)	12 Months Ended
	Dec. 31, 2013
Franchises and Significant Customers [Abstract]	'
Schedule of Franchise Fee Agreements	'
	The franchise arrangements held between the Company and the cities of El Paso and Las Cruces are detailed below:
	City	Period	Franchise Fee	(a)
	El Paso	August 1, 2010 - Present	4.00%	(b)
	Las Cruces	February 1, 2000 - Present	2.00%
	_________________
	(a) Based on a percentage of revenue.
	(b) 0.75% of the El Paso franchise fee is to be placed in a restricted fund to be used solely for economic development and renewable energy purposes.

Recovered_Sheet1

Financial Instruments And Investments (Tables)	12 Months Ended
	Dec. 31, 2013
Financial Instruments And Investments [Abstract]	'
Fair Values Of Long-Term Debt And Short-Term Borrowings Under the RCF	'
	Long-Term Debt and Short-Term Borrowings Under the RCF. The fair values of the Company's long-term debt and short-term borrowings under the RCF are based on estimated market prices for similar issues and are presented below (in thousands):
		December 31,
		2013						2012
		Carrying			Estimated			Carrying			Estimated
		Amount			Fair Value			Amount			Fair Value
	Pollution Control Bonds	$	193,135		$	193,990		$	193,135		$	215,228
	Senior Notes	696,485			734,515			696,400			823,497
	RGRT Senior Notes (1)	110,000			115,850			110,000			120,985
	RCF (1)	14,352			14,352			22,155			22,155
	Total	$	1,013,972		$	1,058,707		$	1,021,690		$	1,181,865
	__________________
	-1	Nuclear fuel financing as of December 31, 2013 and December 31, 2012 is funded through the $110 million RGRT Senior Notes and $14.4 million and $22.2 million, respectively under the RCF. As of December 31, 2013 and 2012, no amount was outstanding under the RCF for working capital or general corporate purposes. The interest rate on the Company’s borrowings under the RCF is reset throughout the period reflecting current market rates. Consequently, the carrying value approximates fair value.
Unrecognized Gross Unrealized Gains (Losses) And the Fair Value	'
	The tables below present the gross unrealized losses and the fair value of these securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position (in thousands):
		December 31, 2013
		Less than 12 Months						12 Months or Longer						Total
		Fair			Unrealized			Fair			Unrealized			Fair		Unrealized
		Value			Losses			Value			Losses			Value		Losses
	Description of Securities (1):
	Federal Agency Mortgage Backed Securities	$	6,444		$	(169	)	$	1,421		$	(119	)	$	7,865	$	(288	)
	U.S. Government Bonds	8,114			(245		)	10,866			(840		)	18,980		(1,085		)
	Municipal Obligations	12,286			(335		)	7,782			(479		)	20,068		(814		)
	Corporate Obligations	3,284			(96		)	901			(54		)	4,185		(150		)
	Total Debt Securities	30,128			(845		)	20,970			(1,492		)	51,098		(2,337		)
	Common Stock	2,305			(126		)	—			—			2,305		(126		)
	Total Temporarily Impaired Securities	$	32,433		$	(971	)	$	20,970		$	(1,492	)	$	53,403	$	(2,463	)
	____________________
	-1	Includes approximately 122 securities.
		December 31, 2012
		Less than 12 Months						12 Months or Longer						Total
		Fair			Unrealized			Fair			Unrealized			Fair		Unrealized
		Value			Losses			Value			Losses			Value		Losses
	Description of Securities (2):
	Federal Agency Mortgage Backed Securities	$	1,792		$	(5	)	$	416		$	(9	)	$	2,208	$	(14	)
	U.S. Government Bonds	6,633			(79		)	4,457			(114		)	11,090		(193		)
	Municipal Obligations	5,306			(39		)	5,760			(241		)	11,066		(280		)
	Corporate Obligations	452			(11		)	—			—			452		(11		)
	Total Debt Securities	14,183			(134		)	10,633			(364		)	24,816		(498		)
	Common stock	3,603			(409		)	—			—			3,603		(409		)
	Total Temporarily Impaired Securities	$	17,786		$	(543	)	$	10,633		$	(364	)	$	28,419	$	(907	)
	______________________
	-2	Includes approximately 65 securities.
	The Company monitors the length of time the security trades below its cost basis along with the amount and percentage of the unrealized loss in determining if a decline in fair value of marketable securities below recorded cost is considered to be other than temporary. In addition, the Company will research the future prospects of individual securities as necessary. As a result of these factors, as well as the Company’s intent and ability to hold these securities until their market price recovers, these securities are considered temporarily impaired. The Company does not anticipate expending monies held in trust before 2044 or a later period when the Company begins to decommission Palo Verde.
	The reported fair values also include gross unrealized gains on marketable securities which have not been recognized in the Company’s net income. The table below presents the unrecognized gross unrealized gains and the fair value of these securities, aggregated by investment category (in thousands):
		December 31, 2013						December 31, 2012
		Fair			Unrealized			Fair			Unrealized
		Value			Gains			Value			Gains
	Description of Securities:
	Federal Agency Mortgage Backed Securities	$	9,929		$	433		$	17,289		$	1,036
	U.S. Government Bonds	6,258			126			13,295			678
	Municipal Obligations	8,783			450			22,797			1,531
	Corporate Obligations	9,188			506			12,378			1,134
	Total Debt Securities	34,158			1,515			65,759			4,379
	Common Stock	103,808			43,145			73,210			22,839
	Equity Mutual Funds	16,802			3,081			15,194			1,821
	Cash and Cash Equivalents	5,924			—			4,471			—
	Total	$	160,692		$	47,741		$	158,634		$	29,039
Contractual Year For Maturity Of Available-For-Sale Securities	'
	The contractual year for maturity for these available-for-sale securities as of December 31, 2013 is as follows (in thousands):
		Total			2014			2015			2019 through 2023			2024 and Beyond
								through
								2018
	Municipal Debt Obligations	$	28,851		$	1,486		$	13,311		$	10,920		$	3,134
	Corporate Debt Obligations	13,373			321			3,711			5,525			3,816
	U.S. Government Bonds	25,238			1,216			14,149			7,217			2,656
Unrealized Holding Losses Included In Pre-Tax Income	'
	For the twelve months ended December 31, 2013, 2012, and 2011 the Company recognized other than temporary impairment losses on its available-for-sale securities as follows (in thousands):
		2013			2012			2011
	Unrealized holding losses included in pre-tax income	$	—		$	(479	)	$	(2,116	)
Sale of Securities And The Related Effects On Pre-Tax Income	'
	The proceeds from the sale of these securities during the twelve months ended December 31, 2013, 2012, and 2011 and the related effects on pre-tax income are as follows (in thousands):
		2013			2012			2011
	Proceeds from sales or maturities of available-for-sale securities	$	56,148		$	98,542		$	82,926
	Gross realized gains included in pre-tax income	$	986		$	1,478		$	1,479
	Gross realized losses included in pre-tax income	(433		)	(2,041		)	(721		)
	Gross unrealized losses included in pre-tax income	—			(479		)	(2,116		)
	Net gains (losses) in pre-tax income	$	553		$	(1,042	)	$	(1,358	)
	Net unrealized holding gains included in accumulated other comprehensive income	$	17,699		$	9,927		$	1,570
	Net (gains) losses reclassified out of accumulated other comprehensive income	(553		)	1,042			1,358
	Net gains in other comprehensive income	$	17,146		$	10,969		$	2,928
Fair Value, Measurement Inputs, Disclosure	'
	The fair value of the Company’s decommissioning trust funds and investments in debt securities, at December 31, 2013 and 2012, and the level within the three levels of the fair value hierarchy defined by FASB guidance are presented in the table below (in thousands):
	Description of Securities		Fair Value as  of			Quoted Prices			Significant			Significant
			December 31,			in Active			Other			Unobservable
			2013			Markets for			Observable			Inputs
						Identical Assets			Inputs			(Level 3)
						(Level 1)			(Level 2)
	Trading Securities:
	Investments in Debt Securities		$	1,555		$	—		$	—		$	1,555
	Available for sale:
	U.S. Government Bonds		$	25,238		$	25,238		$	—		$	—
	Federal Agency Mortgage Backed Securities		17,794			—			17,794			—
	Municipal Obligations		28,851			—			28,851			—
	Corporate Obligations		13,373			—			13,373			—
	Subtotal, Debt Securities		85,256			25,238			60,018			—
	Common Stock		106,113			106,113			—			—
	Equity Mutual Funds		16,802			16,802			—			—
	Cash and Cash Equivalents		5,924			5,924			—			—
	Total available for sale		$	214,095		$	154,077		$	60,018		$	—
	Description of Securities	Fair Value as  of			Quoted Prices			Significant			Significant
		December 31,			in Active			Other			Unobservable
		2012			Markets for			Observable			Inputs
					Identical Assets			Inputs			(Level 3)
					(Level 1)			(Level 2)
	Trading Securities:
	Investments in Debt Securities	$	1,295		$	—		$	—		$	1,295
	Available for sale:
	U.S. Government Bonds	$	24,385		$	24,385		$	—		$	—
	Federal Agency Mortgage Backed Securities	19,497			—			19,497			—
	Municipal Obligations	33,863			—			33,863			—
	Corporate Obligations	12,830			—			12,830			—
	Subtotal, Debt Securities	90,575			24,385			66,190			—
	Common Stock	76,813			76,813			—			—
	Equity Mutual Funds	15,194			15,194			—			—
	Cash and Cash Equivalents	4,471			4,471			—			—
	Total available for sale	$	187,053		$	120,863		$	66,190		$	—
Trading Securities (and Certain Trading Assets)	'
	Below is a reconciliation of the beginning and ending balance of the fair value of the investment in debt securities (in thousands):
		2013			2012
	Balance at January 1	$	1,295		$	1,120
	Net unrealized gains in fair value recognized in income (a)	260			175
	Balance at December 31	$	1,555		$	1,295
	_____________________
	(a) These amounts are reflected in the Company's statement of operations as investment and interest income.

Supplemental_Statements_of_Cas1

Supplemental Statements of Cash Flows Disclosures Supplemental Statements of Cash Flows Disclosures (Tables)	12 Months Ended
	Dec. 31, 2013
Supplemental Statements of Cash Flow Disclosures [Abstract]	'
Schedule of Cash Flow, Supplemental Disclosures	'
		Years Ended December 31,
		2013		2012		2011
		(In thousands)
	Cash paid (received) for:
	Interest on long-term debt and borrowing under the revolving credit facility	$	53,752	$	50,189	$	48,797
	Income taxes paid (refund), net	244		5,031		(6,260		)
	Non-cash financing activities:
	Grants of restricted shares of common stock	3,224		2,411		3,268
	Issuance of performance shares	849		1,193		628
	Acquisition of treasury stock for options exercised	—		—		500

Selected_Quarterly_Financial_D1

Selected Quarterly Financial Data (Unaudited) Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Schedule of Quarterly Financial Information	'
	The quarterly earnings per share amounts for a year will not add to the earnings per share for that year due to the weighting of shares used in calculating per share data.
		2013 Quarters								2012 Quarters
		4th		3rd		2nd		1st		4th		3rd		2nd		1st
						(In thousands except for share data)
	Operating revenues (1)	$	190,297	$	282,661	$	240,114	$	177,290	$	188,802	$	267,249	$	228,252	$	168,578
	Operating income	6,050		85,896		54,344		19,345		13,708		86,396		56,512		12,042
	Net income	1,191		50,565		29,193		7,634		4,819		51,789		30,894		3,344
	Basic earnings per share:
	Net income	0.03		1.26		0.73		0.19		0.12		1.29		0.77		0.08
	Diluted earnings per share:
	Net income	0.03		1.26		0.72		0.19		0.12		1.29		0.77		0.08
	Dividends declared per share of common stock	0.265		0.265		0.265		0.25		0.25		0.25		0.25		0.22
	________________
	-1	Operating revenues are seasonal in nature, with the peak sales periods generally occurring during the summer months. Comparisons among quarters of a year may not represent overall trends and changes in operations.

Summary_of_Significant_Account3

Summary of Significant Accounting Policies (General) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013
General [Abstract]	'
Area of Services, in Square Miles	10,000
MiraSol Energy Services, Inc	'
Subsidiary or Equity Method Investee [Line Items]	'
Disposal Date	3-Dec-13
Net Assets and Stockholders' Equity at Wholly Owned Subsidiary	$0.10

Summary_of_Significant_Account4

Summary of Significant Accounting Policies (Utility Plant) (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Significant Accounting Policies [Line Items]	'	'	'
Average composite depreciation rate	2.61%	2.64%	2.80%
AFUDC rate	8.10%	8.53%	8.54%
Minimum	'	'	'
Significant Accounting Policies [Line Items]	'	'	'
Public Utilities Property, Plant and Equipment, Useful Life	'5 years	'	'
Maximum	'	'	'
Significant Accounting Policies [Line Items]	'	'	'
Public Utilities Property, Plant and Equipment, Useful Life	'48 years	'	'

Summary_of_Significant_Account5

Summary of Significant Accounting Policies (Revenues) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Accounting Policies [Abstract]	'	'
Accrued unbilled revenues	$19.80	$17.90

Summary_of_Significant_Account6

Summary of Significant Accounting Policies (Allowance For Doubtful Accounts) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounts Receivable, Net [Abstract]	'	'	'
Balance at beginning of year	$2,906	$3,015	$2,885
Additions:	'	'	'
Charged to costs and expense	2,098	3,087	6,209
Recovery of previous write-offs	1,929	2,041	2,034
Uncollectible receivables written off	4,672	5,237	8,113
Balance at end of year	$2,261	$2,906	$3,015

Regulation_Narrative_Details

Regulation (Narrative) (Details) (USD $)

0 Months Ended

27 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

0 Months Ended

0 Months Ended

12 Months Ended

0 Months Ended

0 Months Ended

12 Months Ended

0 Months Ended

1-May-12

Sep. 30, 2011

Dec. 31, 2013

Sep. 07, 2013

Dec. 31, 2013

Sep. 27, 2013

Oct. 30, 2013

Jan. 14, 2014

Oct. 29, 2013

Sep. 07, 2013

Dec. 31, 2013

Nov. 21, 2012

Oct. 01, 2013

Sep. 30, 2013

Sep. 28, 2013

Jan. 31, 2013

Apr. 15, 2013

Apr. 15, 2013

Apr. 15, 2013

Sep. 24, 2013

Jan. 14, 2014

Oct. 30, 2013

Sep. 30, 2013

Dec. 31, 2013

Dec. 31, 2013

Sep. 07, 2013

Sep. 07, 2013

2012 Texas Retail Rate Case

2012 Texas Retail Rate Case

PUCT

PUCT

PUCT

PUCT Docket No. 41852

NMPRC

NMPRC

NMPRC

NMPRC

NMPRC

NMPRC

FERC

FERC

FERC

FERC

MPS to Caliente Transmission Line

MPS In & Out Transmission Line

Caliente - Coyote Transmission Line

MPS To Montwood Transmission Line

Subsequent Event

Nuclear Fuel Financing

Nuclear Fuel Financing

Phase I of Construction

Phase I of Construction

Phase II of Construction

Phase II of Construction

Montana Power Station

Montana Power Station

Montana Power Station

Montana Power Station

Macho Springs Solar

PUCT Docket No. 41360

PUCT Docket No. 41359

PUCT Docket No. 41359

PUCT Docket No. 41809

NMPRC

NMPRC

FERC

PUCT

NMPRC

PUCT

NMPRC

MW

MW

MW

kV

kV

kV

kV

Montana Power Station

Montana Power Station

Montana Power Station

Montana Power Station

Line of Credit renewal term, year

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'1 year

'

'

'

'

'

'

Line of Credit Facility, Maximum Borrowing Capacity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$400,000,000

'

'

'

'

'

'

Line of Credit renewal option, renewal times

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2

'

'

'

'

'

'

Reconcilable Fuel Expense

'

356,500,000

'

'

'

545,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fuel Reconciliation Period

'

'

'

'

'

'45 months

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Rewards For Operations Requested

'

'

'

'

'

3,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Annual Nonfuel Base Rate reduction

15,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Reduction In Depreciation Expense

4,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Return on Equity

10.13%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of years rate case expenses amortized

'2 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fuel over and under materiality threshold percentage

'

'

4.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Electric capacity

'

'

'

88

'

'

'

'

'

88

'

50

'

'

'

'

115

115

115

115

'

'

'

'

'

'

'

Refund Related to Dispute

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,900,000

'

'

'

'

'

'

'

'

'

'

'

Line of Credit Facility, Current Borrowing Capacity

'

'

'

'

'

'

400,000,000

300,000,000

300,000,000

'

'

'

'

400,000,000

300,000,000

'

'

'

'

'

'

'

'

'

'

'

'

Line of Credit Facility, Increase (Decrease), Net

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100,000,000

'

'

'

'

'

'

Line of Credit Facility, Expiration Period

'

'

'

'

'

'

'4 years

'

'

'

'

'

'4 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Face Amount

'

'

'

'

'

'

$300,000,000

'

'

'

'

'

'

$300,000,000

'

'

'

'

'

'

'

$50,000,000

$50,000,000

'

'

'

'

Number Of Power Generation Units

'

'

'

'

4

'

'

'

'

'

4

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2

2

Number of power generation units authorized to be constructed

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2

2

'

'

Number Of Transmission Lines

'

'

3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Regulation_Refund_Fuel_Cost_Ov

Regulation (Refund Fuel Cost Over Recoveries) (Details) (Puct Docket No. 40622, USD $)	Aug. 03, 2012
In Thousands, unless otherwise specified
Puct Docket No. 40622	'
Refund Amount Authorized	$6,600

Regulation_Revised_Fixed_Fuel_

Regulation (Revised Fixed Fuel Factor) (Details)	Apr. 12, 2012	Sep. 09, 2013
	Puct Docket Number 40302	PUCT Docket No. 41803
Increase (Decrease) in Fuel Factor	-18.50%	12.20%

Regulatory_Assets_and_Liabilit2

Regulatory Assets and Liabilities Regulatory Assets and Liabilities (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Regulatory Assets and Liabilities [Line Items]	'		'
Total regulatory assets	$101,050		$101,590
Total regulatory liabilities	26,416		22,179
Regulatory tax assets or liabilities	'		'
Regulatory Assets and Liabilities [Line Items]	'		'
Total regulatory liabilities	17,752	[1],[2]	16,666	[1],[2]
Accumulated Deferred Investment Tax Credit	'		'
Regulatory Assets and Liabilities [Line Items]	'		'
Total regulatory liabilities	4,656	[1],[3]	4,587	[1],[3]
New Mexico energy efficiency	'		'
Regulatory Assets and Liabilities [Line Items]	'		'
Total regulatory liabilities	3,646	[4]	926	[4]
Texas energy efficiency	'		'
Regulatory Assets and Liabilities [Line Items]	'		'
Total regulatory liabilities	362	[4]	0	[4]
Regulatory tax assets or liabilities	'		'
Regulatory Assets and Liabilities [Line Items]	'		'
Total regulatory assets	61,772	[1],[2]	57,551	[1],[2]
Loss on reacquired debt	'		'
Regulatory Assets and Liabilities [Line Items]	'		'
Total regulatory assets	18,338	[5]	19,191	[5]
Final coal reclamation	'		'
Regulatory Assets and Liabilities [Line Items]	'		'
Total regulatory assets	4,290	[6]	5,473	[6]
Nuclear fuel postload daily financing charge	'		'
Regulatory Assets and Liabilities [Line Items]	'		'
Total regulatory assets	4,141	[7]	3,833	[7]
Unrecovered issuance costs due to reissuance of PCBs	'		'
Regulatory Assets and Liabilities [Line Items]	'		'
Total regulatory assets	893	[5]	926	[5]
Texas energy efficiency	'		'
Regulatory Assets and Liabilities [Line Items]	'		'
Total regulatory assets	0	[4]	536	[4]
Texas 2012 rate case costs	'		'
Regulatory Assets and Liabilities [Line Items]	'		'
Total regulatory assets	581	[6]	2,335	[6]
Texas military base discount and recovery factor	'		'
Regulatory Assets and Liabilities [Line Items]	'		'
Total regulatory assets	759	[8]	2,116	[8]
New Mexico procurement plan costs	'		'
Regulatory Assets and Liabilities [Line Items]	'		'
Total regulatory assets	139	[9]	139	[9]
New Mexico renewable energy credits	'		'
Regulatory Assets and Liabilities [Line Items]	'		'
Total regulatory assets	4,833	[9]	4,033	[9]
New Mexico 2010 FPPCAC audit	'		'
Regulatory Assets and Liabilities [Line Items]	'		'
Total regulatory assets	433	[9]	433	[9]
New Mexico Palo Verde deferred depreciation	'		'
Regulatory Assets and Liabilities [Line Items]	'		'
Total regulatory assets	$4,871	[1]	$5,024	[1]
[1]	The amortization period for this asset is based upon the life of the associated assets or liabilities.
[2]	No specific return on investment is required since related assets and liabilities offset.
[3]	This item is excluded from rate base.
[4]	This item is recovered or credited through a recovery factor that is set annually.
[5]	This item is recovered as a component of the weighted cost of debt and amortized over the life of the related debt issuance.
[6]	This item is included in rate base which earns a return on investment.
[7]	This item is recovered through fuel recovery mechanisms.
[8]	This item represents the net asset related to the military discount which is recovered from non-military customers through a recovery factor.
[9]	Amortization period is anticipated to be established in next general rate case.

Utility_Plant_Palo_Verde_and_O2

Utility Plant, Palo Verde and Other Jointly-Owned Utility Plant (Depreciable Assets By Each Major Class) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Property, Plant and Equipment and Finite-Lived Intangible Assets [Line Items]	'	'
Gross Plant	$3,076,549	$2,857,913
Accumulated Depreciation	-1,214,088	-1,162,483
Net plant in service	1,862,461	'
Intangible Plant Software	'	'
Property, Plant and Equipment and Finite-Lived Intangible Assets [Line Items]	'	'
Gross Plant	69,661	'
Accumulated Depreciation	-36,977	'
Net plant in service	32,684	'
Energy Equipment | Nuclear production	'	'
Property, Plant and Equipment and Finite-Lived Intangible Assets [Line Items]	'	'
Gross Plant	817,665	'
Accumulated Depreciation	-271,173	'
Net plant in service	546,492	'
Energy Equipment | Steam and other	'	'
Property, Plant and Equipment and Finite-Lived Intangible Assets [Line Items]	'	'
Gross Plant	668,666	'
Accumulated Depreciation	-264,019	'
Net plant in service	404,647	'
Energy Equipment | Total production	'	'
Property, Plant and Equipment and Finite-Lived Intangible Assets [Line Items]	'	'
Gross Plant	1,486,331	'
Accumulated Depreciation	-535,192	'
Net plant in service	951,139	'
Energy Equipment | Transmission	'	'
Property, Plant and Equipment and Finite-Lived Intangible Assets [Line Items]	'	'
Gross Plant	432,674	'
Accumulated Depreciation	-246,175	'
Net plant in service	186,499	'
Energy Equipment | Distribution	'	'
Property, Plant and Equipment and Finite-Lived Intangible Assets [Line Items]	'	'
Gross Plant	965,674	'
Accumulated Depreciation	-337,513	'
Net plant in service	628,161	'
Energy Equipment | General	'	'
Property, Plant and Equipment and Finite-Lived Intangible Assets [Line Items]	'	'
Gross Plant	122,209	'
Accumulated Depreciation	-58,231	'
Net plant in service	$63,978	'

Utility_Plant_Palo_Verde_and_O3

Utility Plant, Palo Verde and Other Jointly-Owned Utility Plant (Amortization of Intangible Plant Assets - Software) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment and Finite-Lived Intangible Assets [Line Items]	'	'	'
Number of years amortization expense prior reporting year	'3 years	'	'
Number of years amortization expense after reporting year	'5 years	'	'
Intangible	'	'	'
Property, Plant and Equipment and Finite-Lived Intangible Assets [Line Items]	'	'	'
Finite-Lived Intangible Assets, Amortization Expense	$7,683	$7,183	$6,668
Future Amortization Expense, 2014 (estimated)	7,372	'	'
Future Amortization Expense, 2015 (estimated)	6,540	'	'
Future Amortization Expense, 2016 (estimated)	5,980	'	'
Future Amortization Expense, 2017 (estimated)	5,326	'	'
Future Amortization Expense, 2018 (estimated)	$3,713	'	'
Minimum | Intangible	'	'	'
Property, Plant and Equipment and Finite-Lived Intangible Assets [Line Items]	'	'	'
Finite-Lived Intangible Assets, Useful Life	'5 years	'	'
Maximum | Intangible	'	'	'
Property, Plant and Equipment and Finite-Lived Intangible Assets [Line Items]	'	'	'
Finite-Lived Intangible Assets, Useful Life	'10 years	'	'

Utility_Plant_Palo_Verde_and_O4

Utility Plant, Palo Verde and Other Jointly-Owned Utility Plant (Summary of Jointly Owned Utility Plants) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Palo Verde	'	'
Jointly Owned Utility Plant Interests [Line Items]	'	'
Electric plant in service	$817,665	$795,259
Accumulated depreciation	-271,173	-257,540
Construction work in progress	75,040	64,623
Total	621,532	602,342
Other Jointly Owned Utlity Plant	'	'
Jointly Owned Utility Plant Interests [Line Items]	'	'
Electric plant in service	217,137	213,155
Accumulated depreciation	-173,819	-168,569
Construction work in progress	2,347	2,401
Total	$45,665	$46,987

Utility_Plant_Palo_Verde_and_O5

Utility Plant, Palo Verde and Other Jointly-Owned Utility Plant (Narrative) (Details) (USD $)

0 Months Ended

12 Months Ended

12 Months Ended

1 Months Ended

Mar. 30, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Apr. 21, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Oct. 31, 2010

Oct. 31, 2010

Palo Verde Generating Station

Palo Verde Participants

Four Corners Generating Station

Four Corners Coal Plant Participants

Other Jointly Owned Utlity Plant

Suit Against Department of Energy for Spent Fuel

Suit Against Department of Energy for Spent Fuel

utilityplantunit

utilityplantunit

APS and Palo Verde Participants

Jointly Owned Utility Plant Interests [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Jointly Owned Utility Plant, Proportionate Ownership Share

'

'

'

'

'

15.80%

'

7.00%

'

'

'

'

Jointly Owned Plant, Number of Participants

'

'

'

'

'

'

6

'

'

'

'

'

Jointly Owned Utility Plant, Number of Units

'

'

'

'

'

3

'

2

'

'

'

'

Number of Units With Renewed Operating Licenses

'

'

'

'

3

'

'

'

'

'

'

'

Decommissioning Fund Investments

'

$214,095,000

$187,053,000

'

'

'

'

'

'

'

'

'

Third Party Decommission Cost Estimates Study Period, in Years

'

'3 years

'

'

'

'

'

'

'

'

'

'

Estimated Decommissioning Costs

380,700,000

'

'

'

'

'

'

'

'

'

'

'

Decommission cost increase

23,300,000

'

'

'

'

'

'

'

'

'

'

'

Asset Retirement Obligation, Revision of Estimate

'

3,401,000

-1,929,000

41,670,000

'

'

'

'

'

'

'

'

Litigation Settlement, Gross

'

'

'

'

'

'

'

'

'

'

'

30,000,000

Proceeds from Legal Settlements

'

'

'

'

'

'

'

'

'

'

4,800,000

'

NRC Enhancements

'

15,800,000

'

'

'

'

100,000,000

'

'

'

'

'

Nuclear Energy Hazards Full Limit Of Liability Under Federal Law

'

'

'

'

'

'

13,600,000,000

'

'

'

'

'

Nuclear Energy Hazards Potential Liability

'

'

'

'

'

'

375,000,000

'

'

'

'

'

Maximum Assesment Per Reactor Nuclear Energy Incident

'

'

'

'

'

60,400,000

127,300,000

'

'

'

'

'

Maximum Assesment Per Reactor Nuclear Energy Incident Annual Limit

'

'

'

'

'

9,000,000

19,000,000

'

'

'

'

'

Aggregate Amount of Insurance for Decontamination and Property Damage

'

'

'

'

'

'

2,800,000,000

'

'

'

'

'

Retrospective Premium Adjustments Due to Nuclear Facility Losses

'

$9,800,000

'

'

'

'

'

'

'

'

'

'

Participation agreement expiration date

'

'

'

'

'

'

'

'

6-Jul-16

'

'

'

Date participation is ceased

'

'

'

'

'

'

'

6-Jul-16

'

'

'

'

Long Term Coal Supply Agreement, Expiration Date

'

'

'

'

'

'

'

'

'

31-Dec-31

'

'

Accounting_for_Asset_Retiremen2

Accounting for Asset Retirement Obligations Accounting for Asset Retirement Obligations (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Accounting For Asset Retirement Obligations [Line Items]	'	'
Number of External Trust Funds with Independent Trustee with Legal Restrictions To Settling ARO	6	'
Decommissioning Fund Investments	$214,095	$187,053

Accounting_for_Asset_Retiremen3

Accounting for Asset Retirement Obligations (Changes in Estimated Probabilities Assumptions) (Details)	12 Months Ended
	Dec. 31, 2013
Original ARO Liability [Member]	'
Accounting For Asset Retirement Obligations [Line Items]	'
Escalation Rate	3.60%
Credit-Risk Adjusted Discount Rate	9.50%
Incremental ARO Liability [Member]	'
Accounting For Asset Retirement Obligations [Line Items]	'
Escalation Rate	3.60%
Credit-Risk Adjusted Discount Rate	6.20%

Accounting_for_Asset_Retiremen4

Accounting for Asset Retirement Obligations (Schedule of Asset Retirement Obligations) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Asset Retirement Obligation, Roll Forward Analysis	'	'	'
ARO liability at beginning of year	$62,784	$56,140	$92,911
Liabilities incurred	0	0	0
Liabilities settled	-36	-450	-793
Revisions to estimate	-3,401	1,929	-41,670
Accretion expense	5,867	5,165	5,692
ARO liability at end of year	$65,214	$62,784	$56,140

Common_Stock_Common_Stock_Deta

Common Stock Common Stock (Details) (USD $)

0 Months Ended

3 Months Ended

12 Months Ended

12 Months Ended

0 Months Ended

In Thousands, except Share data, unless otherwise specified

Dec. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

2-May-07

Dec. 31, 2013

Dec. 31, 2013

Jan. 23, 2014

Mar. 31, 2014

Mar. 14, 2014

Jan. 23, 2014

Restricted Stock

Restricted Stock

Subsequent Event

Scenario, Forecast

Scenario, Forecast

Scenario, Forecast

Minimum

Maximum

Common Stock [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period

'

'

'

'

'

'

'

'

'

'

'

'

'

'1 year

'3 years

'

'

'

'

Dividends, Common Stock, Cash

$10,700

'

'

'

'

'

'

'

'

$42,049

$38,889

$27,223

'

'

'

'

'

'

'

Dividends Payable, Date Declared

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

23-Jan-14

'

'

'

Common Stock, Dividends, Per Share, Declared

'

$0.27

$0.27

$0.27

$0.25

$0.25

$0.25

$0.25

$0.22

$1.04

$0.97

$0.66

'

'

'

'

'

'

$0.27

Dividends Payable, Date to be Paid

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

31-Mar-14

'

'

Dividends Payable, Date of Record

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

14-Mar-14

'

Common Stock, Par or Stated Value Per Share

'

$1

'

'

'

$1

'

'

'

$1

$1

'

'

'

'

'

'

'

'

Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized

'

'

'

'

'

'

'

'

'

'

'

'

1,000,000

'

'

'

'

'

'

Common_Stock_ShareBased_Compen

Common Stock (Share-Based Compensation Options) (Details) (Stock Options, USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock Options	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock Options, Expiration Date	'10 years	'	'
Stock options outstanding, in shares	0	15,000	'
Stock options exercised (in shares)	15,000	'	'
Cash received	$200,000	'	'
Weighted Average Exercise Price, options exercised	$12.78	'	'
Realized Current Tax Benefits	100,000	'	'
Intrinsic value of stock options exercised	300,000	600,000	1,000,000
Stock Options forfeited, vested and expired in period	0	0	0
Share-based Compensation Expense	$0	$0	$0

Common_Stock_Schedule_of_Restr

Common Stock (Schedule of Restricted Stock Tax Expense and Deferred Tax) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'		'
Deferred tax benefit	$44,678,000		$43,561,000		$45,688,000
Capitalized Costs Related to Restricted Stock Award or Unit Expense	100,000		100,000		100,000
Restricted Stock	'		'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'		'
Share-based Compensation Expense	2,458,000	[1]	1,508,000	[1]	2,258,000	[1]
Deferred tax benefit	860,000		528,000		790,000
Current tax expense (benefit) recognized	$109,000		$94,000		$518,000
[1]	Any capitalized costs related to these expenses is less than $0.1 million for all years.

Common_Stock_Vested_Restricted

Common Stock (Vested Restricted Stock Aggregate Intrinsic Value And Grant Date Fair Value) (Details) (Restricted Stock, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restricted Stock	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Restricted shares vested - Aggregated Intrinsic Value	$2,077	$2,242	$3,279
Fair value at grant date	$1,765	$1,973	$1,799

Common_Stock_Schedule_of_Unves

Common Stock (Schedule of Unvested Restricted Stock) (Details) (Restricted Stock, USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Restricted Stock	'		'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]	'		'	'
Share based compensation, outstanding at beginning of period (in shares)	84,446		'	'
Total restricted stock awards (in shares)	96,279		'	'
Total vested (in shares)	-58,642		'	'
Total forfeitures (in shares)	-1,549		'	'
Share based compensation, outstanding at end of period (in shares)	120,534		84,446	'
Shares outstanding, Weighted Average Grant Date Fair Value, Beginning of Period	$31.26		'	'
Weighted average fair value per share	$35.48		$32.45	$28.98
Weighted average fair value vested	$30.10		'	'
Weighted average fair value forfeitures	$31.28		'	'
Shares outstanding, Weighted Average Grant Date Fair Value, End of Period	$35.19		$31.26	'
Unrecognized compensation expense expected to be recognized for the weighted average contractual term of the restricted shares outstanding at end of period	$1,976	[1]	'	'
Aggregated intrinsic value for restricted stock oustanding at end of period	$4,232		'	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'1 year		'	'
[1]	The unrecognized compensation expense is expected to be recognized over the weighted average remaining contractual term of the outstanding restricted stock of approximately one year.

Common_Stock_Weighted_Average_

Common Stock (Weighted Average Fair Value Per Share) (Details) (Restricted Stock, USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restricted Stock	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Weighted average fair value per share	$35.48	$32.45	$28.98

Common_Stock_Performance_Share

Common Stock (Performance Shares) (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'		'
The Number of Simulations on Fair Value of Average Payout	1,000,000		'		'
Minimum	'		'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'		'
Performance Shares Payout Level	0.00%		'		'
Maximum	'		'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'		'
Performance Shares Payout Level	200.00%		'		'
Performance Shares	'		'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'		'
Performance shares vested - Aggregated Intrinsic Value	$1,450	[1]	$3,464	[1]	$1,032	[1]
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period	'3 years		'		'
Performance Shares Payout Level	100.00%		'		'
Performance Shares | Minimum	'		'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'		'
Performance shares vested - Performance Shares Awarded	0		'		'
Performance Shares | Maximum	'		'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'		'
Performance shares vested - Performance Shares Awarded	181,894		'		'
February 18, 2014 | Performance Shares	'		'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'		'
Performance shares vested - Payout Ratio	0.00%		'		'
Performance shares vested - Performance Shares Awarded	0		'		'
Performance shares vested - Compensation Costs Expensed	954		'		'
Performance shares vested - Aggregated Intrinsic Value	0		'		'
January 29, 2013 | Performance Shares	'		'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'		'
Performance shares vested - Payout Ratio	150.00%		'		'
Performance shares vested - Performance Shares Awarded	64,275		'		'
Performance shares vested - Compensation Costs Expensed	849		'		'
Performance shares vested - Aggregated Intrinsic Value	2,176		'		'
January 1, 2012 | Performance Shares	'		'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'		'
Performance shares vested - Payout Ratio	175.00%		'		'
Performance shares vested - Performance Shares Awarded	174,038		'		'
Performance shares vested - Compensation Costs Expensed	1,193		'		'
Performance shares vested - Aggregated Intrinsic Value	6,029		'		'
September 3, 2011 | Performance Shares	'		'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'		'
Performance shares vested - Payout Ratio	112.50%		'		'
Performance shares vested - Performance Shares Awarded	3,825		'		'
Performance shares vested - Compensation Costs Expensed	40		'		'
Performance shares vested - Aggregated Intrinsic Value	129		'		'
July 9, 2011 | Performance Shares	'		'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'		'
Performance shares vested - Payout Ratio	112.50%		'		'
Performance shares vested - Performance Shares Awarded	2,250		'		'
Performance shares vested - Compensation Costs Expensed	23		'		'
Performance shares vested - Aggregated Intrinsic Value	$75		'		'
[1]	Based on a 100% performance level.

Common_Stock_Outstanding_Perfo

Common Stock (Outstanding Performance Share Awards) (Details) (Performance Shares, USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Performance Shares	'		'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'	'
Performance Shares Payout Level	100.00%		'	'
Share based compensation, outstanding at beginning of period (in shares)	128,033		'	'
Performance shares awards, Number Outstanding	39,814		'	'
Performance shares vested, Number Outstanding	-42,850		'	'
Share based compensation, outstanding at end of period (in shares)	124,997		128,033	'
Shares outstanding, Weighted Average Grant Date Fair Value, Beginning of Period	$26.48		'	'
Performance shares awards, Weighted Average Grant Date Fair Value	$34.69		$32.74	$23.45
Performance shares vested, Weighted Average Grant Date Fair Value	$19.82		'	'
Shares outstanding, Weighted Average Grant Date Fair Value, End of Period	$31.38		$26.48	'
Performance shares outstanding, Unrecognized Compensation Expense	$1,452	[1]	'	'
Performance shares outstanding, Aggregate Intrinsic Value	$4,389		'	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'1 year		'	'
[1]	The unrecognized compensation expense is expected to be recognized over the weighted average remaining contractual term of the awards of approximately one year.

Common_Stock_Performance_Share1

Common Stock (Performance Share Summary) (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Minimum	'		'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'		'
Performance Shares Payout Level	0.00%		'		'
Maximum	'		'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'		'
Performance Shares Payout Level	200.00%		'		'
Performance Shares	'		'		'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'		'
Weighted average per share grant date fair value per share of performance shares awarded	$34.69		$32.74		$23.45
Fair value of performance shares vested	$849		$1,193		$628
Performance shares vested - Aggregated Intrinsic Value	1,450	[1]	3,464	[1]	1,032	[1]
Share-based Compensation Expense	1,188	[2]	170	[2]	1,573	[2]
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	$416		$59		$551
Performance Shares Payout Level	100.00%		'		'
[1]	Based on a 100% performance level.
[2]	Includes adjustments for forfeiture of performance share awards by certain executives.

Common_Stock_Common_Stock_Repu

Common Stock (Common Stock Repurchase Program) (Details) (USD $)	12 Months Ended		180 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2011	Dec. 31, 2013
Equity, Class of Treasury Stock [Line Items]	'	'	'
Shares repurchased	0	'	25,406,184	[1],[2]
Cost, including commission	'	$87,008	$423,647	[1]
Total remaining shares available for repurchase at December 31, 2013	393,816	'	393,816
Treasury shares acquired outside of repurchase programs	'	'	86,735
[1]	Represents repurchased shares and cost since inception of the stock repurchase program in 1999.
[2]	Shares repurchased does not include 86,735 treasury shares related to employee compensation arrangements outside of the Company's repurchase programs.

Common_Stock_Basic_and_Diluted

Common Stock (Basic and Diluted Earnings Per Share) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Class of Stock Disclosures [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Basic number of common shares outstanding	'	'	'	'	'	'	'	'	40,114,594	39,974,022	41,349,883
Dilutive effect of unvested performance awards	'	'	'	'	'	'	'	'	12,053	66,756	206,658
Dilutive effect of stock options	'	'	'	'	'	'	'	'	0	14,803	30,518
Diluted number of common shares outstanding	'	'	'	'	'	'	'	'	40,126,647	40,055,581	41,587,059
Net income	$1,191	$50,565	$29,193	$7,634	$4,819	$51,789	$30,894	$3,344	$88,583	$90,846	$103,539
Income allocated to participating restricted stock	'	'	'	'	'	'	'	'	-254	-256	-471
Net income available to common shareholders basic	'	'	'	'	'	'	'	'	88,329	90,590	103,068
Income reallocated to participating restricted stock	'	'	'	'	'	'	'	'	-254	-256	-469
Net income available to common shareholders diluted	'	'	'	'	'	'	'	'	$88,329	$90,590	$103,070
Earnings Per Share, Basic, Distributed	'	'	'	'	'	'	'	'	$1.04	$0.97	$0.66
Earnings Per Share, Basic, Undistributed	'	'	'	'	'	'	'	'	$1.16	$1.30	$1.83
Basic net income per common share	$0.03	$1.26	$0.73	$0.19	$0.12	$1.29	$0.77	$0.08	$2.20	$2.27	$2.49
Earnings Per Share, Diluted, Distributed	'	'	'	'	'	'	'	'	$1.04	$0.97	$0.66
Earnings Per Share, Diluted, Undistributed	'	'	'	'	'	'	'	'	$1.16	$1.29	$1.82
Diluted net income per common share	$0.03	$1.26	$0.72	$0.19	$0.12	$1.29	$0.77	$0.08	$2.20	$2.26	$2.48

Common_Stock_Antidilutive_Shar

Common Stock (Antidilutive Shares and Options) (Details)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Restricted Stock	'		'		'
Common Stock [Line Items]	'		'		'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	51,189		45,178		81,653
Performance Shares	'		'		'
Common Stock [Line Items]	'		'		'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	115,044	[1]	57,625	[1]	0	[1]
Performance shares payout based upon performance	0		0		0
Performance Shares Payout Level	100.00%		100.00%		100.00%
[1]	Certain performance shares were excluded from the computation of diluted earnings per share as no payouts would have been required based upon performance at the end of each corresponding period.

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income by Component (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]	'
Accumulated Other Comprehensive Income (Loss), beginning balance	($66,084)
Other Comprehensive Income Loss before Reclassifications	65,853
Amount Reclassified from Accumulated Other Comprehensive Loss	2,843
Accumulated Other Comprehensive Income (Loss), ending balance	2,612
Accumulated Defined Benefit Plans Adjustment	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'
Accumulated Other Comprehensive Income (Loss), beginning balance	-75,737
Other Comprehensive Income Loss before Reclassifications	51,371
Amount Reclassified from Accumulated Other Comprehensive Loss	3,036
Accumulated Other Comprehensive Income (Loss), ending balance	-21,330
Accumulated Net Unrealized Investment Gain (Loss)	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'
Accumulated Other Comprehensive Income (Loss), beginning balance	22,194
Other Comprehensive Income Loss before Reclassifications	14,482
Amount Reclassified from Accumulated Other Comprehensive Loss	-436
Accumulated Other Comprehensive Income (Loss), ending balance	36,240
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'
Accumulated Other Comprehensive Income (Loss), beginning balance	-12,541
Other Comprehensive Income Loss before Reclassifications	0
Amount Reclassified from Accumulated Other Comprehensive Loss	243
Accumulated Other Comprehensive Income (Loss), ending balance	($12,298)

Accumulated_Other_Comprehensiv3

Accumulated Other Comprehensive Income Amounts Reclassified (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Prior service benefit	$5,560	$5,762	$5,812
Interest on long-term debt and revolving credit facility	-47,712	-44,937	-45,079
Income tax expense	43,655	46,979	53,708
Net income (loss)	88,329	90,590	103,068
Reclassification out of Accumulated Other Comprehensive Income	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Net income (loss)	-2,843	'	'
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Defined Benefit Plans Adjustment	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Prior service benefit	5,560	'	'
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax	-10,472	'	'
Income (Loss) before income tax	-4,912	'	'
Income tax expense	1,876	'	'
Net income (loss)	-3,036	'	'
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Net Unrealized Investment Gain (Loss)	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Net Realized Gain on Sale of Securities	553	'	'
Income (Loss) before income tax	553	'	'
Income tax expense	-117	'	'
Net income (loss)	436	'	'
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Interest on long-term debt and revolving credit facility	-411	'	'
Income (Loss) before income tax	-411	'	'
Income tax expense	168	'	'
Net income (loss)	($243)	'	'

LongTerm_Debt_and_Financing_Ob2

Long-Term Debt and Financing Obligations Outstanding Balance (Details) (USD $)

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Jun. 29, 2008

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Aug. 28, 2012

Dec. 31, 2013

Dec. 31, 2012

2-May-05

Dec. 31, 2013

Dec. 31, 2012

1-May-05

Jun. 02, 2008

Dec. 31, 2013

Dec. 31, 2012

Jun. 01, 2008

Dec. 06, 2012

Dec. 31, 2013

Dec. 31, 2012

Aug. 18, 2010

Aug. 31, 2010

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Jan. 14, 2014

In Thousands, unless otherwise specified

Nuclear Fuel Financing

Nuclear Fuel Financing

Working Capital and General Purpose

Working Capital and General Purpose

Revolving Credit Facility

Revolving Credit Facility

Revolving Credit Facility

Short Term Borrowing

Bonds and Notes

Bonds and Notes

Pollution Control Bonds

Pollution Control Bonds

Pollution Control Bonds

Pollution Control Bonds

Pollution Control Bonds

Pollution Control Bonds

Pollution Control Bonds

Pollution Control Bonds

Pollution Control Bonds

Pollution Control Bonds

Pollution Control Bonds

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

RGRT Senior Notes

RGRT Senior Notes

RGRT Senior Notes

RGRT Senior Notes

RGRT Senior Notes

RGRT Senior Notes

RGRT Senior Notes

RGRT Senior Notes

RGRT Senior Notes

RGRT Senior Notes

Financing Obligations

Financing Obligations

Subsequent Event

Nuclear Fuel Financing

Working Capital and General Purpose

7.25% 2009 Series A Refunding Bonds, due 2040

7.25% 2009 Series A Refunding Bonds, due 2040

4.50% 2012 Series A Refunding Bonds, due 2042

4.50% 2012 Series A Refunding Bonds, due 2042

7.25% 2009 Series B Refunding Bonds, due 2040

7.25% 2009 Series B Refunding Bonds, due 2040

1.875% 2012 Series A Refunding Bonds, due 2032

1.875% 2012 Series A Refunding Bonds, due 2032

1.875% 2012 Series A Refunding Bonds, due 2032

6.00% Senior Notes, Net of Discount, due 2035

6.00% Senior Notes, Net of Discount, due 2035

6.00% Senior Notes, Net of Discount, due 2035

6.00% Senior Notes, Net of Discount, due 2035

7.50% Senior Notes, Net of Discount, due 2038

7.50% Senior Notes, Net of Discount, due 2038

7.50% Senior Notes, Net of Discount, due 2038

7.50% Senior Notes, Net of Discount, due 2038

3.30% Senior Notes, Net of Discount, due 2022

3.30% Senior Notes, Net of Discount, due 2022

3.30% Senior Notes, Net of Discount, due 2022

3.67% Senior Notes, Series A, due 2015

3.67% Senior Notes, Series A, due 2015

4.47% Senior Notes, Series B, due 2017

4.47% Senior Notes, Series B, due 2017

5.04% Senior Notes, Series C, due 2020

5.04% Senior Notes, Series C, due 2020

Revolving Credit Facility

Revolving Credit Facility

Revolving Credit Facility Expiring January 2019

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term Debt

$1,013,972

$1,021,690

'

'

'

'

'

'

'

'

$999,620

$999,535

$193,135

[1]

$193,135

[1]

$63,500

[1]

$63,500

[1]

$59,235

[1]

$59,235

[1]

$37,100

[1]

$37,100

[1]

$33,300

[1]

$33,300

[1]

'

$696,485

[2]

$696,400

[2]

'

$397,976

[2]

$397,934

[2]

'

'

$148,800

[2]

$148,783

[2]

'

'

$149,709

[2]

$149,683

[2]

'

'

$110,000

[3]

$110,000

[3]

$15,000

[3]

$15,000

[3]

$50,000

[3]

$50,000

[3]

$45,000

[3]

$45,000

[3]

'

'

'

Long-term Line of Credit

'

'

'

'

'

'

14,352

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

14,352

[4]

22,155

[4]

'

Line of Credit, Current

-14,352

-22,155

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt

999,620

999,535

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Interest Rate, Effective Percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

7.46%

7.46%

4.63%

4.63%

7.49%

7.49%

2.35%

2.35%

'

'

'

'

7.12%

7.12%

'

'

7.67%

7.67%

'

'

3.43%

3.43%

'

'

'

'

3.87%

3.87%

4.62%

4.62%

5.16%

5.16%

'

'

'

Debt Instrument, Interest Rate, Stated Percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

7.25%

7.25%

4.50%

4.50%

7.25%

7.25%

1.88%

1.88%

1.88%

'

'

'

6.00%

6.00%

6.00%

'

7.50%

7.50%

7.50%

3.30%

3.30%

3.30%

'

'

'

'

3.67%

3.67%

4.47%

4.47%

5.04%

5.04%

'

'

'

Number of tax exempt bond series

'

'

'

'

'

'

'

'

'

'

'

'

4

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument Remarketed Date, Year

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

30-Sep-17

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of Credit Facility, Expiration Date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

14-Jan-19

Line of Credit renewal option, renewal times

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2

Line of Credit renewal term, year

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'1 year

Debt Instrument, Face Amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

33,300

'

'

'

'

'

'

'

400,000

'

'

'

150,000

150,000

'

'

110,000

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Issuance Date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1-May-05

'

'

'

1-Jun-08

'

'

'

6-Dec-12

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Unamortized Discount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2,300

'

'

'

1,300

300

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Repayments of Short-term Debt

'

'

'

'

'

'

'

'

'

44,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Redemption Price of Notes Equal to Principal Amount, Percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100.00%

'

'

'

'

'

'

'

'

'

'

'

'

Proceeds from Issuance of Long-term Debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

109,400

'

'

'

'

'

'

'

'

'

'

'

Line of Credit Facility, Current Borrowing Capacity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

300,000

Line of Credit Facility, Maximum Borrowing Capacity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

400,000

Line of Credit Facility, Increase (Decrease), Net

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100,000

Line of Credit Facility, Amount Outstanding

'

'

$14,400

$22,200

$0

$0

'

$14,400

$0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of Credit Weighted Average Interest Rate

'

'

'

'

'

'

1.40%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

[1]

Pollution Control Bonds ("PCBs")The Company has four series of tax exempt unsecured PCBs in aggregate principal amount of $193.1 million. The 1.875% 2012 Series A (El Paso Electric Company Four Corners Project) Pollution Control Refunding Revenue Bonds with an aggregate principal amount of $33.3 million are subject to mandatory tender for purchase in September 2017.

[2]

Senior NotesThe Senior Notes are unsecured obligations of the Company. They were issued pursuant to bond covenants that provide limitations on the Companybs ability to enter into certain transactions. The 6.00% senior notes have an aggregate principal amount of $400.0 million and were issued in May 2005. The proceeds, net of a $2.3 million discount, were used to fund the retirement of the Company's first mortgage bonds. The Company amortizes the loss associated with a cash flow hedge recorded in accumulated other comprehensive income to earnings as interest expense over the life of the 6.00% senior notes. See Note O, "Financial Instruments and Investments - Treasury Rate Locks". This amortization is included in the effective interest rate of the 6.00% senior notes. The 7.50% senior notes have an aggregate principal amount of $150.0 million and were issued in June 2008. The proceeds, net of a $1.3 million discount, were used to repay short-term borrowings of $44.0 million, fund capital expenditures and for other general corporate purposes.The 3.30% senior notes have an aggregate principal amount of $150.0 million and were issued in December 2012. The proceeds, net of a $0.3 million discount, were used to fund construction expenditures and for working capital and general corporate purposes.

[3]

RGRT Senior NotesIn 2010, the Company and RGRT, a Texas grantor trust through which the Company finances its portion of fuel for PaloB Verde, entered into a note purchase agreement with various institutional purchasers. Under the terms of the Agreement, RGRT sold to the purchasers $110 million aggregate principal amount of senior notes (the "Notes"). The Company guarantees the payment of principal and interest on the Notes. In the Companybs financial statements, the assets and liabilities of the RGRT are reported as assets and liabilities of the Company.RGRT will pay interest on the Notes on February 15, and AugustB 15 of each year until maturity. RGRT may redeem the Notes, in whole or in part, at any time at a redemption price equal to 100% of the principal amount to be redeemed together with the interest on such principal amount accrued to the date of redemption, plus a make-whole amount based on the prevailing market interest rates. The agreement requires compliance with certain covenants, including a total debt to capitalization ratio. The Company was in compliance with these requirements throughout 2013.The sale of the Notes was made by RGRT in reliance on a private placement exemption from registration under the Securities Act of 1933, as amended.The proceeds of $109.4 million, net of issuance costs, from the sale of the Notes was used by RGRT to repay amounts borrowed under the revolving credit facility and will enable future nuclear fuel financing requirements of RGRT to be met with a combination of the Notes and amounts borrowed from the revolving credit facility.

[4]

Revolving Credit FacilityOn January 14, 2014, the Company and RGRT entered into a second amended and restated credit agreement related to the RCF with JPB Morgan Chase Bank, N.A., as administrative agent and issuing bank, and Union Bank, N.A., as syndication agent, and various lending banks party thereto. Under the terms of the agreement, the Company has available $300 million and the ability to increase the RCF by up to $100 million (up to a total of $400 million) upon the satisfaction of certain conditions, more fully set forth in the agreement, including obtaining commitments from lenders or third party financial institutions. The RCF has a term ending January 2019. The Company may extend the maturity date up to two times, in each case for an additional one year period upon the satisfaction of certain conditions.The RCF provides that amounts borrowed by the Company may be used for, among other things, working capital and general corporate purposes. Any amounts borrowed by RGRT may be used, among other things, to finance the acquisition and processing of nuclear fuel. Amounts borrowed by RGRT are guaranteed by the Company and the balance borrowed under the RCF is recorded as short-term borrowings on the balance sheet. The RCF is unsecured. The RCF requires compliance with certain covenants, including a total debt to capitalization ratio. The Company was in compliance with these requirements throughout 2013. As of DecemberB 31, 2013, the total amount borrowed by RGRT was $14.4 million for nuclear fuel under the RCF. As of DecemberB 31, 2013, no borrowings were outstanding under this facility for working capital and general corporate purposes. The weighted average interest rate on the RCF was 1.4% as of DecemberB 31, 2013.

LongTerm_Debt_and_Financing_Ob3

Long-Term Debt and Financing Obligations Long-term Debt Maturities (Details) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Instrument [Line Items]	'
Long-term Debt, Maturities, Repayments of Principal in Year One	$0
Long-term Debt, Maturities, Repayments of Principal in Year Two	15,000
Long-term Debt, Maturities, Repayments of Principal in Year Three	0
Long-term Debt, Maturities, Repayments of Principal in Year Four	83,300
Long-term Debt, Maturities, Repayments of Principal in Year Five	0
Nuclear Fuel Financing | Revolving Credit Facility	'
Debt Instrument [Line Items]	'
Long-term Debt, Maturities, Repayments of Principal in Year One	$14,400

Income_Taxes_Deferred_Tax_Asse

Income Taxes (Deferred Tax Assets and Liabilities) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Deferred tax assets:	'	'
Benefit of tax loss carryforwards	$17,709	$7,798
Alternative minimum tax credit carryforward	21,638	21,599
Pensions and benefits	54,652	86,816
Asset retirement obligation	23,727	21,710
Deferred fuel	0	1,951
Other	14,485	14,115
Total gross deferred tax assets	132,211	153,989
Deferred tax liabilities:	'	'
Plant, principally due to depreciation and basis differences	-511,847	-457,127
Decommissioning	-35,489	-29,416
Deferred fuel	-2,171	0
Other	-5,664	-5,828
Total gross deferred tax liabilities	-555,171	-492,371
Net accumulated deferred income taxes	($422,960)	($338,382)

Income_Taxes_Recognized_Income

Income Taxes (Recognized Income Tax Expense) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Federal:	'	'	'
Current	($2,877)	$1,487	$5,084
Deferred	45,024	43,187	46,864
Total federal income tax	42,147	44,674	51,948
State:	'	'	'
Current	1,854	1,931	2,936
Deferred	-414	697	-924
Total state income tax	1,440	2,628	2,012
Generation & Amortization of accumulated investment tax credit	68	-323	-252
Total income tax expense	$43,655	$46,979	$53,708

Income_Taxes_Income_Tax_Provis

Income Taxes (Income Tax Provisions) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Examination [Line Items]	'	'	'
Federal income tax expense computed on income at statutory rate	$46,283	$48,239	$55,036
Difference due to:	'	'	'
State taxes, net of federal benefit	936	1,708	1,308
AEFUDC	-2,149	-1,845	-2,295
Permanent tax differences	-1,153	-604	-303
Other	-262	-519	-38
Total income tax expense	$43,655	$46,979	$53,708
Effective income tax rate	33.00%	34.10%	34.20%

Income_Taxes_Unrecognized_Tax_

Income Taxes (Unrecognized Tax Benefits)[Roll Forward] (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]	'	'	'
Balance at beginning of period	$9,800	$9,500	$7,300
Additions/(reductions) based on tax positions related to the current year	600	1,600	2,200
Unrecognized Tax Benefits, Decreases Resulting from Current Period Tax Positions	0	-900	0
Additions for tax positions for prior years	1,700	1,400	0
Reductions for tax positions of prior years	-4,900	-1,800	0
Balance at end of period	$7,200	$9,800	$9,500

Income_Taxes_Details

Income Taxes (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax [Line Items]	'	'	'
Period of Average Annual Book Income Before Taxes	'3 years	'	'
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax	$21,638	$21,599	'
Federal statutory tax rate	35.00%	35.00%	35.00%
Unrecognized tax benefits, Increase (Decrease) resulting from tax positions taken in prior and current period tax returns.	500	1,400	'
Unrecognized tax benefits that would impact effective tax rate	2,500	'	'
Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions	600	1,600	2,200
Unrecognized tax benefits, interest on income taxes expense / (benefits)	200	-300	200
Unrecognized tax benefits, income tax penalties and interest accrued	400	100	'
Internal Revenue Service (IRS)	'	'	'
Income Tax [Line Items]	'	'	'
Unrecognized Tax Benefits Resulting in Net Operating Loss Carryforward	17,300	'	'
Tax Year Closed	'2009	'	'
State and Local Jurisdiction	'	'	'
Income Tax [Line Items]	'	'	'
Unrecognized Tax Benefits Resulting in Net Operating Loss Carryforward	400	'	'
Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions	1,800	'	'
NEW MEXICO	'	'	'
Income Tax [Line Items]	'	'	'
Tax Year Closed	'2009	'	'
Minimum | Internal Revenue Service (IRS)	'	'	'
Income Tax [Line Items]	'	'	'
Operating Loss Carryforwards, Expiration Date	31-Dec-31	'	'
Minimum | State and Local Jurisdiction	'	'	'
Income Tax [Line Items]	'	'	'
Operating Loss Carryforwards, Expiration Date	31-Dec-16	'	'
Minimum | TEXAS	'	'	'
Income Tax [Line Items]	'	'	'
Income Tax Examination, Year under Examination	'2007	'	'
Minimum | Year 1998 through year 2003 | ARIZONA	'	'	'
Income Tax [Line Items]	'	'	'
Open Tax Year	'1998	'	'
Minimum | Year 2006 through year 2007 | ARIZONA	'	'	'
Income Tax [Line Items]	'	'	'
Open Tax Year	'2006	'	'
Maximum | Internal Revenue Service (IRS)	'	'	'
Income Tax [Line Items]	'	'	'
Operating Loss Carryforwards, Expiration Date	31-Dec-33	'	'
Maximum | State and Local Jurisdiction	'	'	'
Income Tax [Line Items]	'	'	'
Operating Loss Carryforwards, Expiration Date	31-Dec-18	'	'
Maximum | TEXAS	'	'	'
Income Tax [Line Items]	'	'	'
Income Tax Examination, Year under Examination	'2011	'	'
Maximum | Year 1998 through year 2003 | ARIZONA	'	'	'
Income Tax [Line Items]	'	'	'
Open Tax Year	'2003	'	'
Maximum | Year 2006 through year 2007 | ARIZONA	'	'	'
Income Tax [Line Items]	'	'	'
Open Tax Year	'2007	'	'
Change in Accounting Method Accounted for as Change in Estimate	'	'	'
Income Tax [Line Items]	'	'	'
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities	4,500	'	'
Tax credit taken | ARIZONA	'	'	'
Income Tax [Line Items]	'	'	'
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities	400	'	'
Unrecognized tax position of prior years recorded, net of decrease	$1,300	'	'

Commitments_Contingencies_and_2

Commitments, Contingencies and Uncertainties (Power Purchase and Sale Agreement) (Details)	12 Months Ended
	Dec. 31, 2013
	MW
Freeport Agreement 2 - 100 MW	'
Long-term Purchase Commitment [Line Items]	'
Long-Term Sale Commitment, Minimum Quantity Required	100
Long-term Purchase Commitment, Minimum Quantity Required	100
Long-term Purchase Commitment, Time Period	'P7Y
Long-Term Sale Commitment, Time Period	'P7Y
Freeport Agreement 1 - 125 MW	'
Long-term Purchase Commitment [Line Items]	'
Long-Term Sale Commitment, Minimum Quantity Required	125
Long-term Purchase Commitment, Minimum Quantity Required	125
Long-term Purchase Commitment, Time Period	'P6Y
Long-Term Sale Commitment, Time Period	'P6Y
Long-term Contract for Purchase of Electric Power, Date of Contract Expiration	31-Dec-14
Long-Term Contract For Sale Of Electric Power Date Of Contract Expiration	31-Dec-14
Shell	'
Long-term Purchase Commitment [Line Items]	'
Long-Term Purchase commitment, Maximum Quantity	40
Long-term Purchase Commitment, Time Period	'P3Y9M
Long-Term Contract For Purchase Of Electric Power, Contract Start Date	1-Jan-11
Long-term Contract for Purchase of Electric Power, Date of Contract Expiration	30-Sep-14
NRG	'
Long-term Purchase Commitment [Line Items]	'
Long-Term Purchase commitment, Maximum Quantity	20
Long-term Purchase Commitment, Time Period	'P20Y1M
Plant Commercial Operation Date	1-Aug-11
Sun Edison 1 and Sun Edison 2	'
Long-term Purchase Commitment [Line Items]	'
Solar Photovoltaic Projects, Number of Units	2
Sun Edison 1	'
Long-term Purchase Commitment [Line Items]	'
Long-Term Purchase commitment, Maximum Quantity	10
Long-term Purchase Commitment, Time Period	'P25Y1M
Plant Commercial Operation Date	25-Jun-12
Sun Edison 2	'
Long-term Purchase Commitment [Line Items]	'
Long-Term Purchase commitment, Maximum Quantity	12
Long-term Purchase Commitment, Time Period	'P25Y1M
Plant Commercial Operation Date	2-May-12
Hatch Solar Energy Center I	'
Long-term Purchase Commitment [Line Items]	'
Long-Term Purchase commitment, Maximum Quantity	5
Long-term Purchase Commitment, Time Period	'P25Y
Plant Commercial Operation Date	1-Jul-11
Macho Springs Solar	'
Long-term Purchase Commitment [Line Items]	'
Plant Capacity	50
Long-Term Purchase commitment, Maximum Quantity	50
Long-term Purchase Commitment, Time Period	'P20Y
Projected Plant Commercial Operation Date	1-May-14
Newman Solar	'
Long-term Purchase Commitment [Line Items]	'
Plant Capacity	10
Long-Term Purchase commitment, Maximum Quantity	10
Long-term Purchase Commitment, Time Period	'P30Y
Projected Plant Commercial Operation Date	31-Dec-14
FERC | Freeport Agreement 1 - 125 MW	'
Long-term Purchase Commitment [Line Items]	'
Long-term Contract for Purchase of Electric Power, Date of Contract Expiration	31-Dec-21
Long-Term Contract For Sale Of Electric Power Date Of Contract Expiration	31-Dec-21

Commitments_Contingencies_and_3

Commitments, Contingencies and Uncertainties (Narrative) (Details) (USD $)	12 Months Ended	0 Months Ended				0 Months Ended	12 Months Ended	0 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	23-May-13	23-May-13	Dec. 31, 2013	Dec. 31, 2013	Feb. 14, 2014	Dec. 31, 2013	Feb. 14, 2014
		Four Corners Coal Plant Participants	Four Corners Generating Station	Minimum	Four Corners Generating Station	Four Corners Generating Station	Four Corners Generating Station	Scenario, Forecast
								Four Corners Generating Station
Mercury and Air Toxics Standards Required Compliance Period, in Years	'	'	'	'3 years	'	'	'	'
Cost of Pollution Control Equipment	'	'	'	'	$39	'	'	'
Accrual for Environmental Loss Contingencies	0.5	'	'	'	'	'	'	'
Public Utilities, Assessed Coal Severance Surtax Penalty and Interest	'	$30	$1.50	'	'	'	'	'
Number of criteria emissions established under the Clear Air Act	6	'	'	'	'	'	'	'
Frequency of Review by Environmental Protection Agency	'5 years	'	'	'	'	'	'	'
Date participation is ceased	'	'	'	'	'	'	6-Jul-16	'
GHG Emission Level	17.00%	'	'	'	'	'	'	'
Comment period	'60 days	'	'	'	'	'	'	'
Stay Of Judicial Proceeding Period	'	'	'	'	'	'30 days	'	'
Stay Of Judicial Proceeding, Due Date	'	'	'	'	'	'	'	17-Mar-14

Commitments_Contingencies_and_4

Commitments, Contingencies and Uncertainties (Future Minimum Payments For Operating Leases) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Leased Assets [Line Items]	'	'	'
Operating Leases, Rent Expense	$1,200,000	$1,300,000	$1,100,000
2014	1,081,000	'	'
2015	1,028,000	'	'
2016	600,000	'	'
2017	442,000	'	'
2018	$408,000	'	'
Newman Land Lease	'	'	'
Operating Leased Assets [Line Items]	'	'	'
Lessee Leasing Arrangements, Operating Leases, Renewal Term	'25 years	'	'
Lease Expiration Date	30-Jun-33	'	'
Warehouse Facilities	'	'	'
Operating Leased Assets [Line Items]	'	'	'
Lease Expiration Date	31-Dec-15	'	'
Other Property	'	'	'
Operating Leased Assets [Line Items]	'	'	'
Lessee Leasing Arrangements, Operating Leases, Term of Contract	'P4Y	'	'

Commitments_Contingencies_and_5

Commitments, Contingencies and Uncertainties (Union Matters) (Details)	12 Months Ended
	Dec. 31, 2013	Sep. 03, 2015	Sep. 03, 2014	Sep. 03, 2013
	employees
Commitments and Contingencies Disclosure [Abstract]	'	'	'	'
Entity Number of Employees	1,000	'	'	'
Number of Employees Cover by Collective Bargaining Arrangements, Percent	40.00%	'	'	'
Term of Collective Bargaining Agreement, Year	'P3Y	'	'	'
Collective Bargaining Agreement Expiration Date	2-Sep-16	'	'	'
Collective Bargaining Agreement Effective Date	3-Sep-13	'	'	'
Pay increase, percentage	'	2.25%	3.00%	3.00%

Employee_Benefits_Obligations_

Employee Benefits (Obligations and Funded Status of the Plan) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Retirement Plans	'	'	'
Change in plan assets:	'	'	'
Fair value of plan assets at end of year	$257,831	$220,568	'
Retirement Income Plan	'	'	'
Change in projected benefit obligation:	'	'	'
Benefit obligation at end of prior year	320,846	296,293	'
Service cost	9,137	8,530	6,590
Interest cost	12,742	12,594	12,871
Actuarial (gain) loss	-15,373	12,417	'
Benefits paid	-9,537	-8,988	'
Benefit obligation at end of year	317,815	320,846	296,293
Change in plan assets:	'	'	'
Fair value of plan assets at end of prior year	220,568	191,369	'
Actual return on plan assets	31,800	20,187	'
Employer contribution	15,000	18,000	'
Benefits paid	-9,537	-8,988	'
Fair value of plan assets at end of year	257,831	220,568	191,369
Funded status at end of year	-59,984	-100,278	'
Non-Qualified Retirement Plans	'	'	'
Change in projected benefit obligation:	'	'	'
Benefit obligation at end of prior year	27,241	26,547	'
Service cost	190	299	260
Interest cost	872	963	1,116
Actuarial (gain) loss	-533	1,338	'
Benefits paid	-1,872	-1,906	'
Benefit obligation at end of year	25,898	27,241	26,547
Change in plan assets:	'	'	'
Fair value of plan assets at end of prior year	0	0	'
Actual return on plan assets	0	0	'
Employer contribution	1,872	1,906	'
Benefits paid	-1,872	-1,906	'
Fair value of plan assets at end of year	0	0	0
Funded status at end of year	($25,898)	($27,241)	'

Employee_Benefits_Defined_Bene

Employee Benefits (Defined Benefit Plan, Amounts Recognized in Balance Sheet) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Retirement Income Plan	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'
Current liabilities	$0	$0
Noncurrent liabilities	-59,984	-100,278
Total liabilities	-59,984	-100,278
Non-Qualified Retirement Plans	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'
Current liabilities	-1,870	-1,829
Noncurrent liabilities	-24,028	-25,412
Total liabilities	($25,898)	($27,241)

Employee_Benefits_Accumulated_

Employee Benefits (Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Retirement Income Plan	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'
Projected benefit obligation	($317,815)	($320,846)
Accumulated benefit obligation	-275,555	-274,890
Fair value of plan assets	257,831	220,568
Non-Qualified Retirement Plans	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'
Projected benefit obligation	-25,898	-27,241
Accumulated benefit obligation	-25,077	-26,363
Fair value of plan assets	$0	$0

Employee_Benefits_Amounts_Reco

Employee Benefits (Amounts Recognized in Accumulated Other Comprehensive Income (Loss)) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Retirement Income Plan	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'
Net loss	$85,261	$125,763
Prior service cost	0	3
Total	85,261	125,766
Non-Qualified Retirement Plans	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'
Net loss	8,508	9,701
Prior service cost	219	314
Total	$8,727	$10,015

Employee_Benefits_WeightedAver

Employee Benefits (Weighted-Average Actuarial Assumptions for Benefit Obligations - Retirement Plans) (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
	Retirement Plans	Retirement Income Plan	Retirement Income Plan	Supplement Retirement Plan	Supplement Retirement Plan	Excess Benefit Plan	Excess Benefit Plan
		Benefit Obligations	Benefit Obligations	Benefit Obligations	Benefit Obligations	Benefit Obligations	Benefit Obligations
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'	'	'	'	'
Discount rate	'	4.90%	4.00%	3.90%	3.10%	4.90%	4.00%
Rate of compensation increase	'	4.75%	4.75%	'	'	4.75%	4.75%
Defined Benefit Plan, Effect of One Percentage Point Increase on Discount Rate	1.00%	'	'	'	'	'	'
Defined Benefit Plan, Decrease in Projected Benefit Obiligation, Percentage	12.50%	'	'	'	'	'	'
Defined Benefit Plan, Effect of One Percentage Point Decrease on Discount Rate	1.00%	'	'	'	'	'	'
Defined Benefit Plan, Increase in Projected Benefit Obiligation, Percentage	15.50%	'	'	'	'	'	'

Employee_Benefits_Net_Periodic

Employee Benefits (Net Periodic Benefit Costs) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Retirement Income Plan	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'
Service cost	$9,137	$8,530	$6,590
Interest cost	12,742	12,594	12,871
Expected return on plan assets	-17,108	-14,443	-14,095
Amortization of:	'	'	'
Net loss	10,437	10,729	6,190
Prior service cost (benefit)	3	21	21
Net periodic benefit cost	15,211	17,431	11,577
Non-Qualified Retirement Plans	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'
Service cost	190	299	260
Interest cost	872	963	1,116
Expected return on plan assets	0	0	0
Amortization of:	'	'	'
Net loss	661	627	354
Prior service cost (benefit)	94	94	94
Net periodic benefit cost	$1,817	$1,983	$1,824

Employee_Benefits_Other_Compre

Employee Benefits (Other Comprehensive Income - Retirement Plans) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'
Net (gain) loss	($82,964)	$2,109	$77,678
Amortization of:	'	'	'
Net loss	-10,472	-11,971	-6,505
Prior service benefit (cost)	5,560	5,762	5,812
Retirement Income Plan	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'
Net (gain) loss	-30,065	6,672	40,181
Amortization of:	'	'	'
Net loss	-10,437	-10,729	-6,190
Prior service benefit (cost)	-3	-21	-21
Total recognized in other comprehensive income	-40,505	-4,078	33,970
Non-Qualified Retirement Plans	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'
Net (gain) loss	-533	1,337	2,980
Amortization of:	'	'	'
Net loss	-661	-627	-354
Prior service benefit (cost)	-94	-94	-94
Total recognized in other comprehensive income	($1,288)	$616	$2,532

Employee_Benefits_Recognized_i

Employee Benefits (Recognized in Other Comprehensive Income and Net Periodic Benefit Costs - Retirement Plans) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Retirement Income Plan	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'
Total recognized in net periodic benefit cost and other comprehensive income	($25,294)	$13,353	$45,547
Non-Qualified Retirement Plans	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'
Total recognized in net periodic benefit cost and other comprehensive income	$529	$2,599	$4,356

Employee_Benefits_Accumulated_1

Employee Benefits (Accumulated Other Comprehensive Income Recognized in Net Periodic Benefit Cost in Next Fiscal Year) (Details) (Scenario, Forecast, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013
Retirement Income Plan	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'
Net loss	$6,270
Prior service cost	0
Non-Qualified Retirement Plans	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'
Net loss	570
Prior service cost	$90

Employee_Benefits_Weighted_Ave

Employee Benefits (Weighted Average Assumptions Used to Calculate Net Period Benefit Costs- Retirement Plans) (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Retirement Income Plan	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'
Expected long-term return on plan assets	7.50%	'	'
Net Periodic Benefit Costs | Retirement Income Plan	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'
Discount rate	4.00%	4.30%	5.40%
Expected long-term return on plan assets	7.50%	7.50%	7.50%
Rate of compensation increase	4.75%	5.00%	5.00%
Net Periodic Benefit Costs | Supplement Retirement Plan	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'
Discount rate	3.10%	3.60%	4.60%
Net Periodic Benefit Costs | Excess Benefit Plan	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'
Discount rate	4.00%	4.10%	5.30%
Rate of compensation increase	4.75%	5.00%	5.00%

Employee_Benefits_Target_Asset

Employee Benefits (Target Asset Allocation of Pension Fund) (Details) (Retirement Plans)	12 Months Ended
	Dec. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'
Defined Benefit Plan, Assets, Target Allocations Total	100.00%
Equity Securities	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'
Defined Benefit Plan, Assets, Target Allocations	55.00%
Fixed Income Investments	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'
Defined Benefit Plan, Assets, Target Allocations	40.00%
Alternative Investments	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'
Defined Benefit Plan, Assets, Target Allocations	5.00%

Employee_Benefits_Fair_Value_M

Employee Benefits (Fair Value Measurement Inputs) (Details) (Retirement Plans, USD $)

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Cash and Cash Equivalents

Cash and Cash Equivalents

US Treasury Securities

Common Collective Trusts

Investment Contracts

Investment Contracts

Common Stock

Mututal Funds - Fixed Income

Equity Mutual Funds

Limited Partnership Interest in Real Estate

Limited Partnership Interest in Real Estate

Limited Partnership Interest in Real Estate

Fair Value, Inputs, Level 1

Fair Value, Inputs, Level 1

Fair Value, Inputs, Level 1

Fair Value, Inputs, Level 1

Fair Value, Inputs, Level 1

Fair Value, Inputs, Level 1

Fair Value, Inputs, Level 1

Fair Value, Inputs, Level 1

Fair Value, Inputs, Level 1

Fair Value, Inputs, Level 1

Fair Value, Inputs, Level 1

Fair Value, Inputs, Level 1

Fair Value, Inputs, Level 1

Fair Value, Inputs, Level 2

Fair Value, Inputs, Level 2

Fair Value, Inputs, Level 2

Fair Value, Inputs, Level 2

Fair Value, Inputs, Level 2

Fair Value, Inputs, Level 2

Fair Value, Inputs, Level 2

Fair Value, Inputs, Level 2

Fair Value, Inputs, Level 2

Fair Value, Inputs, Level 2

Fair Value, Inputs, Level 2

Fair Value, Inputs, Level 2

Fair Value, Inputs, Level 2

Fair Value, Inputs, Level 3

Fair Value, Inputs, Level 3

Fair Value, Inputs, Level 3

Fair Value, Inputs, Level 3

Fair Value, Inputs, Level 3

Fair Value, Inputs, Level 3

Fair Value, Inputs, Level 3

Fair Value, Inputs, Level 3

Fair Value, Inputs, Level 3

Fair Value, Inputs, Level 3

Fair Value, Inputs, Level 3

Fair Value, Inputs, Level 3

Fair Value, Inputs, Level 3

Common Collective Trusts

Common Collective Trusts

Common Collective Trusts

Common Collective Trusts

Common Collective Trusts

Common Collective Trusts

Common Collective Trusts

Common Collective Trusts

Cash and Cash Equivalents

Cash and Cash Equivalents

US Treasury Securities

Common Collective Trusts

Investment Contracts

Investment Contracts

Common Stock

Mututal Funds - Fixed Income

Equity Mutual Funds

Limited Partnership Interest in Real Estate

Limited Partnership Interest in Real Estate

Cash and Cash Equivalents

Cash and Cash Equivalents

US Treasury Securities

Common Collective Trusts

Investment Contracts

Investment Contracts

Common Stock

Mututal Funds - Fixed Income

Equity Mutual Funds

Limited Partnership Interest in Real Estate

Limited Partnership Interest in Real Estate

Cash and Cash Equivalents

Cash and Cash Equivalents

US Treasury Securities

Common Collective Trusts

Investment Contracts

Investment Contracts

Common Stock

Mututal Funds - Fixed Income

Equity Mutual Funds

Limited Partnership Interest in Real Estate

Limited Partnership Interest in Real Estate

Equity Funds

Fixed Income Funds

Fair Value, Inputs, Level 1

Fair Value, Inputs, Level 1

Fair Value, Inputs, Level 2

Fair Value, Inputs, Level 2

Fair Value, Inputs, Level 3

Fair Value, Inputs, Level 3

Equity Funds

Fixed Income Funds

Equity Funds

Fixed Income Funds

Equity Funds

Fixed Income Funds

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

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Fair value of plan assets at end of year

$257,831,000

$220,568,000

$940,000

$9,163,000

$24,854,000

$246,908,000

[1]

$1,126,000

$1,059,000

$52,149,000

$59,150,000

$65,634,000

$8,857,000

[2]

$8,559,000

[2]

$8,511,000

$940,000

$210,950,000

$940,000

$9,163,000

$24,854,000

$0

[1]

$0

$0

$52,149,000

$59,150,000

$65,634,000

$0

[2]

$0

[2]

$248,034,000

$1,059,000

$0

$0

$0

$246,908,000

[1]

$1,126,000

$1,059,000

$0

$0

$0

$0

[2]

$0

[2]

$8,857,000

$8,559,000

$0

$0

$0

$0

[1]

$0

$0

$0

$0

$0

$8,857,000

[2]

$8,559,000

[2]

$142,960,000

[1]

$103,948,000

[1]

$0

[1]

$0

[1]

$142,960,000

[1]

$103,948,000

[1]

$0

[1]

$0

[1]

Restriction Period To Sell Partnership Interest Minimum

'5 years

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Restriction Period To Sell Partnership Interest Maximum

'7 years

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Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, Sales, Issuances, Settlements

$0

$0

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[1]

The Common Collective Trusts are invested in equity or fixed income securities, or a combination thereof. The investment objective of each trust is to produce returns in excess of, or commensurate with, its predefined index.

[2]

This investment is a commercial real estate partnership that purchases land, develops limited infrastructure, and sells it for commercial development. The Company is restricted from selling its partnership interest during the life of the partnership which is generally 5-7 years. Return on investment is realized as land is sold. The fair value of the limited partnership interest in real estate is based on the NAV of the partnership which reflects the appraised value of the land.

Employee_Benefits_Fair_Value_C

Employee Benefits (Fair Value Change in Investment in Real Estate) (Details) (Retirement Plans, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'
Fair value of plan assets at end of year	$257,831		$220,568
Limited Partnership Interest in Real Estate	'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'
Fair value of plan assets at end of prior year	8,559	[1]	8,511
Unrealized gain in fair value	298		48
Fair value of plan assets at end of year	$8,857	[1]	$8,559	[1]
[1]	This investment is a commercial real estate partnership that purchases land, develops limited infrastructure, and sells it for commercial development. The Company is restricted from selling its partnership interest during the life of the partnership which is generally 5-7 years. Return on investment is realized as land is sold. The fair value of the limited partnership interest in real estate is based on the NAV of the partnership which reflects the appraised value of the land.

Employee_Benefits_Expected_Fut

Employee Benefits (Expected Future Benefit Payments) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013
Retirement Income Plan	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	$13,900
2014	10,902
2015	12,015
2016	13,180
2017	14,440
2018	15,807
2019-2023	96,510
Non-Qualified Retirement Plans	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'
2014	1,870
2015	1,818
2016	1,772
2017	1,829
2018	1,715
2019-2023	$9,447

Employee_Benefits_Changes_in_F

Employee Benefits (Changes in Funded Status of Plan - Other Postretirment Benefit Plans) (Details) (Other Postretirement Benefit Plans, Defined Benefit, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Other Postretirement Benefit Plans, Defined Benefit	'		'		'
Change in projected benefit obligation:	'		'		'
Benefit obligation at end of prior year	$135,680		$133,272		'
Service cost	3,843		4,378		2,988
Interest cost	5,156		5,651		5,379
Actuarial gain	-48,778		-5,009		'
Amendment	-97	[1]	0	[1]	'
Benefits paid	-4,013		-3,929		'
Retiree contributions	1,056		1,086		'
Medicare Part D subsidy	0		231		'
Benefit obligation at end of year	92,847		135,680		133,272
Change in plan assets:	'		'		'
Fair value of plan assets at end of prior year	36,510		32,817		'
Actual return on plan assets	5,539		2,605		'
Employer contribution	3,100		3,700		'
Benefits paid	-4,013		-3,929		'
Retiree contributions	1,056		1,086		'
Medicare Part D subsidy	0		231		'
Fair value of plan assets at end of year	42,192		36,510		32,817
Funded status	($50,655)	[2]	($99,170)	[2]	'
Defined Benefit Plan Amendment Effective Date	3-Oct-13		'		'
[1]	Amendment relates to modification of the Company's Other Postretirement Benefit Plan which limits the Company's premium contribution. The amendment became effective OctoberB 3, 2013 and resulted in a remeasurement of the plan.
[2]	These amounts are recognized in the Companybs balance sheets as a non-current liability.

Employee_Benefits_Components_o

Employee Benefits (Components of Accumulated Other Comprehensive Income) (Details) (Other Postretirement Benefit Plans, Defined Benefit, USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Other Postretirement Benefit Plans, Defined Benefit	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'
Net (gain) loss	($38,110)	$13,630
Prior service cost	-19,210	-24,770
Total	($57,320)	($11,140)

Employee_Benefits_Weighted_Ave1

Employee Benefits (Weighted Average Assumptions- Accrued Postretirement Benefits - Other Postretirment Benefit Plans) (Details) (Other Postretirement Benefit Plans, Defined Benefit)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'
Defined Benefit Plan, Measurement Date	'October 3, 2013	'
Accrued Postretirement Benefit	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'
Discount rate	4.90%	4.10%
Initial	7.50%	7.75%
Ultimate	4.50%	4.50%
Year ultimate reached	'2026	'2026
Defined Benefit Plan, Effect of One Percentage Point Increase on Discount Rate	1.00%	'
Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation, Percentage	12.80%	'
Defined Benefit Plan, Effect of One Percentage Point Decrease on Discount Rate	1.00%	'
Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation, Percentage	16.10%	'

Employee_Benefits_Net_Periodic1

Employee Benefits (Net Periodic Benefit Cost) (Details) (Other Postretirement Benefit Plans, Defined Benefit, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Other Postretirement Benefit Plans, Defined Benefit	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'
Service cost	$3,843	$4,378	$2,988
Interest cost	5,156	5,651	5,379
Expected return on plan assets	-1,951	-1,714	-1,823
Prior service benefit	5,657	5,877	5,927
Net (gain) loss	-626	615	-39
Net periodic benefit cost	$765	$3,053	$578

Employee_Benefits_Other_Compre1

Employee Benefits (Other Comprehensive Income, Other Postretirement Benefit Plans) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'
Net (gain) loss	($82,964)	$2,109	$77,678
Prior service benefit, arising during period	-97	0	0
Prior service benefit (cost)	5,560	5,762	5,812
Net gain (loss)	-10,472	-11,971	-6,505
Other Postretirement Benefit Plans, Defined Benefit	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'
Net (gain) loss	-52,366	-5,900	34,517
Prior service benefit, arising during period	-97	0	0
Prior service benefit (cost)	5,657	5,877	5,927
Net gain (loss)	626	-615	39
Total recognized in other comprehensive income	($46,180)	($638)	$40,483

Employee_Benefits_Recognized_N

Employee Benefits (Recognized Net Periodic Benefit Costs and Other Comprehensive Income -Other Postretirement Benefit Plans) (Details) (Other Postretirement Benefit Plans, Defined Benefit, USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Other Postretirement Benefit Plans, Defined Benefit	'	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'
Total recognized in net periodic benefit cost and other comprehensive income	($45,415,000)	$2,415,000	$41,061,000
Net Gain that Will be Amortized from Accumulated Other Comprehensive Income (Loss)	2,600,000	'	'
Defined Benefit Plan, Future Amortization of Prior Service Cost (Credit)	$4,800,000	'	'

Employee_Benefits_Weighted_Ave2

Employee Benefits (Weighted Average Assumptions - Net Periodic Benefit Cost) (Details) (Other Postretirement Benefit Plans, Defined Benefit, USD $)	0 Months Ended	12 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Jan. 03, 2013	Dec. 31, 2013	Dec. 31, 2013		Oct. 02, 2013		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
			Net Periodic Benefit Costs		Net Periodic Benefit Costs		Net Periodic Benefit Costs	Net Periodic Benefit Costs	Net Periodic Benefit Costs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'		'		'	'	'
Discount rate	'	'	4.90%	[1]	4.10%	[1]	'	4.30%	5.50%
Expected long-term return on plan assets	5.20%	'	'		'		5.20%	5.20%	5.20%
Initial	'	'	'		'		7.75%	8.00%	8.50%
Ultimate	'	'	'		'		4.50%	4.50%	5.00%
Year ultimate reached	'	'	'2026		'		'2026	'2026	'2018
Annual Rate Increase of Covered Health Care Benefits	'	7.75%	'		'		'	'	'
Percentage of Gradual Decrease of Health Care Benefit Rates	'	4.50%	'		'		'	'	'
Defined Benefit Plan, One Percentage Point Change, Increase or Decrease	'	1.00%	'		'		'	'	'
Defined Benefit Plan, Effect of One Percentage Point Increase on Benefit Obligations	'	$14.30	'		'		'	'	'
Defined Benefit Plan, Effect of One Percentage Point Decrease on Benefit Obligations	'	10.8	'		'		'	'	'
Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components	'	2.1	'		'		'	'	'
Defined Benefit Plan, Effect of One Percentage Point Decrease on Service and Interest Cost Components	'	$1.20	'		'		'	'	'
[1]	The Other Postretirement Benefits Plan was remeasured at OctoberB 3, 2013 due to a plan amendment. The discount rate increased from 4.1% as of January 1, 2013 to 4.9%

Employee_Benefits_Target_Alloc

Employee Benefits (Target Allocations - Other Postretirment Benefit Plans) (Details) (Other Postretirement Benefit Plans, Defined Benefit)	12 Months Ended
	Dec. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'
Defined Benefit Plan, Assets, Target Allocations Total	100.00%
Equity Securities	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'
Defined Benefit Plan, Assets, Target Allocations	65.00%
Fixed Income Investments	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'
Defined Benefit Plan, Assets, Target Allocations	30.00%
Alternative Investments	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'
Defined Benefit Plan, Assets, Target Allocations	5.00%

Employee_Benefits_Fair_Value_M1

Employee Benefits (Fair Value Measurements- Other Postretirement Benefits) (Details) (Other Postretirement Benefit Plans, Defined Benefit, USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	$42,192,000		$36,510,000		$32,817,000
Restriction Period To Sell Partnership Interest Minimum	'5 years		'		'
Restriction Period To Sell Partnership Interest Maximum	'7 years		'		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, Sales, Issuances, Settlements	0		'		'
Cash and Cash Equivalents	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	33,000		2,075,000		'
Common Collective Trusts	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	40,498,000	[1]	'		'
Municipal Securities Tax Exempt	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	'		12,811,000		'
Common Stock	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	'		14,397,000		'
Equity Mutual Funds	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	'		5,622,000		'
Limited Partnership Interest in Real Estate	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	1,661,000	[2]	1,605,000	[2]	1,596,000
Fair Value, Inputs, Level 1	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	33,000		22,094,000		'
Fair Value, Inputs, Level 1 | Cash and Cash Equivalents	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	33,000		2,075,000		'
Fair Value, Inputs, Level 1 | Common Collective Trusts	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	'		'
Fair Value, Inputs, Level 1 | Municipal Securities Tax Exempt	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	'		0		'
Fair Value, Inputs, Level 1 | Common Stock	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	'		14,397,000		'
Fair Value, Inputs, Level 1 | Equity Mutual Funds	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	'		5,622,000		'
Fair Value, Inputs, Level 1 | Limited Partnership Interest in Real Estate	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	0	[2]	0	[2]	'
Fair Value, Inputs, Level 2	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	40,498,000		12,811,000		'
Fair Value, Inputs, Level 2 | Cash and Cash Equivalents	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	0		0		'
Fair Value, Inputs, Level 2 | Common Collective Trusts	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	40,498,000	[1]	'		'
Fair Value, Inputs, Level 2 | Municipal Securities Tax Exempt	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	'		12,811,000		'
Fair Value, Inputs, Level 2 | Common Stock	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	'		0		'
Fair Value, Inputs, Level 2 | Equity Mutual Funds	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	'		0		'
Fair Value, Inputs, Level 2 | Limited Partnership Interest in Real Estate	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	0	[2]	0	[2]	'
Fair Value, Inputs, Level 3	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	1,661,000		1,605,000		'
Fair Value, Inputs, Level 3 | Cash and Cash Equivalents	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	0		0		'
Fair Value, Inputs, Level 3 | Common Collective Trusts	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	'		'
Fair Value, Inputs, Level 3 | Municipal Securities Tax Exempt	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	'		0		'
Fair Value, Inputs, Level 3 | Common Stock	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	'		0		'
Fair Value, Inputs, Level 3 | Equity Mutual Funds	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	'		0		'
Fair Value, Inputs, Level 3 | Limited Partnership Interest in Real Estate	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	1,661,000	[2]	1,605,000	[2]	'
Common Collective Trusts | Equity Funds	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	28,077,000	[1]	'		'
Common Collective Trusts | Fixed Income Funds	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	12,421,000	[1]	'		'
Common Collective Trusts | Fair Value, Inputs, Level 1 | Equity Funds	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	'		'
Common Collective Trusts | Fair Value, Inputs, Level 1 | Fixed Income Funds	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	'		'
Common Collective Trusts | Fair Value, Inputs, Level 2 | Equity Funds	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	28,077,000	[1]	'		'
Common Collective Trusts | Fair Value, Inputs, Level 2 | Fixed Income Funds	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	12,421,000	[1]	'		'
Common Collective Trusts | Fair Value, Inputs, Level 3 | Equity Funds	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	'		'
Common Collective Trusts | Fair Value, Inputs, Level 3 | Fixed Income Funds	'		'		'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'		'		'
Defined Benefit Plan, Fair Value of Plan Assets	$0	[1]	'		'
[1]	The Common Collective Trusts are invested in equity or fixed income securities, or a combination thereof. The investment objective of each trust is to produce returns in excess of, or commensurate with, its predefined index.
[2]	This investment is a commercial real estate partnership that purchases land, develops limited infrastructure, and sells it for commercial development. The Company is restricted from selling its partnership interest during the life of the partnership which is generally 5-7 years. Return of investment is realized as land is sold. The fair value of the limited partnership interest in real estate is based on the NAV of the partnership which reflects the appraised value of the land.

Employee_Benefits_Changes_in_F1

Employee Benefits (Changes in Fair Value Investment Real Estate - Other Postretirement Benefit Plans) (Details) (Other Postretirement Benefit Plans, Defined Benefit, USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified				Limited Partnership Interest in Real Estate		Limited Partnership Interest in Real Estate
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'	'	'		'
Fair value of plan assets at end of prior year	$42,192	$36,510	$32,817	$1,605	[1]	$1,596
Unrealized gain in fair value	'	'	'	56		9
Fair value of plan assets at end of year	$42,192	$36,510	$32,817	$1,661	[1]	$1,605	[1]
[1]	This investment is a commercial real estate partnership that purchases land, develops limited infrastructure, and sells it for commercial development. The Company is restricted from selling its partnership interest during the life of the partnership which is generally 5-7 years. Return of investment is realized as land is sold. The fair value of the limited partnership interest in real estate is based on the NAV of the partnership which reflects the appraised value of the land.

Employee_Benefits_Expected_Fut1

Employee Benefits (Expected Future Benefit Payments - Other Postretirement Benefit Plans) (Details) (Other Postretirement Benefit Plans, Defined Benefit, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013
Other Postretirement Benefit Plans, Defined Benefit	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'
Defined Benefit Plan, Measurement Date	'October 3, 2013
2014	$3,024
2015	3,414
2016	3,810
2017	4,230
2018	4,639
2019-2023	$28,238

Employee_Benefits_Employee_Ben1

Employee Benefits Employee Benefits (Details) (USD $)

12 Months Ended

0 Months Ended

3 Months Ended

0 Months Ended

12 Months Ended

0 Months Ended

In Millions, unless otherwise specified

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Apr. 02, 2014

Mar. 31, 2014

Mar. 31, 2014

Apr. 02, 2014

Dec. 31, 2013

Apr. 02, 2014

Defined Contribution Plans

Defined Contribution Plans

Defined Contribution Plans

Scenario, Forecast

Scenario, Forecast

Scenario, Forecast

Scenario, Forecast

Maximum

Maximum

Retirement Plans

Retirement Plans

Retirement Plans

Defined Contribution Plans

Defined Contribution Plans

Scenario, Forecast

Defined Contribution Plans

Employee Benefit Plans and Other Postretirement Benefit Plans [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Number of Non-Qualified Retirement Plans

2

'

'

'

'

'

'

'

'

'

'

'

Defined Contribution Plan, Employer Contribution Amount

'

'

'

$1.90

$1.80

$1.70

'

'

'

'

'

'

Defined benefit plan implementation effective date

'

'

'

'

'

'

1-Apr-14

'

'

'

'

'

Pension benefit earned by employee is frozen, date.

'

'

'

'

'

'

'

31-Mar-14

'

'

'

'

Defined Benefit Plan, Measurement Date

'

'

'

'

'

'

'

'

'March 31, 2014

'

'

'

Defined Contribution Plan, Employer Matching Contribution, Percent

'

'

'

'

'

'

'

'

'

'

6.00%

6.00%

Defined contribution plan implementations effective date

'

'

'

'

'

'

'

'

'

1-Apr-14

'

'

Defined Contribution Plan, Employer Matching Contribution, Percent of Match

'

'

'

50.00%

'

'

'

'

'

100.00%

'

'

Short Term Incentive Plan Payout

$4

$7.90

$7.30

'

'

'

'

'

'

'

'

'

Franchises_and_Significant_Cus2

Franchises and Significant Customers Franchises and Significant Customers (Details)	12 Months Ended
	Dec. 31, 2013
Franchises and Significant Customers [Line Items]	'
Percentage of Revenue Additional Franchise Fees, Restricted	0.75%
Las Cruces	'
Franchises and Significant Customers [Line Items]	'
Retail Electric Service Contract, Expiration Date	'4/30/2009
Holloman [Member]	'
Franchises and Significant Customers [Line Items]	'
Retail Electric Service Contract, Expiration Date	'January 2016
Contract Term to Provide Retail Electric Service	'10 years
August 1, 2010 through Present | El Paso	'
Franchises and Significant Customers [Line Items]	'
Franchise Fee, Percent	4.00%	[1],[2]
February 1, 2000 through Present | Las Cruces	'
Franchises and Significant Customers [Line Items]	'
Franchise Fee, Percent	2.00%	[2]
Sales Revenue, Services, Net | Military Bases	'
Franchises and Significant Customers [Line Items]	'
Concentration Risk, Percentage	5.00%
[1]	0.75% of the El Paso franchise fee is to be placed in a restricted fund to be used solely for economic development and renewable energy purposes.
[2]	Based on a percentage of revenue.

Financial_Instruments_and_Inve1

Financial Instruments and Investments Financial Instruments and Investments (Carrying Amount and Fair Value Amounts) (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Carrying (Reported) Amount, Fair Value Disclosure	'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'
Debt Instrument, Fair Value Disclosure	$1,013,972		$1,021,690
Estimate of Fair Value, Fair Value Disclosure	'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'
Debt Instrument, Fair Value Disclosure	1,058,707		1,181,865
Pollution Control Bonds | Carrying (Reported) Amount, Fair Value Disclosure	'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'
Debt Instrument, Fair Value Disclosure	193,135		193,135
Pollution Control Bonds | Estimate of Fair Value, Fair Value Disclosure	'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'
Debt Instrument, Fair Value Disclosure	193,990		215,228
Senior Notes | Carrying (Reported) Amount, Fair Value Disclosure	'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'
Debt Instrument, Fair Value Disclosure	696,485		696,400
Senior Notes | Estimate of Fair Value, Fair Value Disclosure	'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'
Debt Instrument, Fair Value Disclosure	734,515		823,497
RGRT Senior Notes | Carrying (Reported) Amount, Fair Value Disclosure	'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'
Debt Instrument, Fair Value Disclosure	110,000	[1]	110,000	[1]
RGRT Senior Notes | Estimate of Fair Value, Fair Value Disclosure	'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'
Debt Instrument, Fair Value Disclosure	115,850	[1]	120,985	[1]
Revolving Credit Facility | Carrying (Reported) Amount, Fair Value Disclosure	'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'
Debt Instrument, Fair Value Disclosure	14,352	[1]	22,155	[1]
Revolving Credit Facility | Estimate of Fair Value, Fair Value Disclosure	'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'
Debt Instrument, Fair Value Disclosure	$14,352	[1]	$22,155	[1]
[1]	Nuclear fuel financing as of DecemberB 31, 2013 and DecemberB 31, 2012 is funded through the $110 million RGRT Senior Notes and $14.4 million and $22.2 million, respectively under the RCF. As of DecemberB 31, 2013 and 2012, no amount was outstanding under the RCF for working capital or general corporate purposes. The interest rate on the Companybs borrowings under the RCF is reset throughout the period reflecting current market rates. Consequently, the carrying value approximates fair value.

Recovered_Sheet2

Financial Instruments And Investments (Long-Term Debt And Short-Term Borrowings - Narratives) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Aug. 18, 2010	Dec. 31, 2013	Dec. 31, 2012	1-May-05
			Nuclear Fuel Financing	Nuclear Fuel Financing	Working Capital and General Purpose	Working Capital and General Purpose	RGRT Senior Notes	Senior Notes	Senior Notes	Senior Notes
								6.00% Senior Notes, Net of Discount, due 2035	6.00% Senior Notes, Net of Discount, due 2035	6.00% Senior Notes, Net of Discount, due 2035
Financial Instruments and Investments [Line Items]	'	'	'	'	'	'	'	'	'	'
Debt Instrument, Face Amount	'	'	'	'	'	'	$110,000,000	'	'	$400,000,000
Line of Credit Facility, Amount Outstanding	'	'	14,400,000	22,200,000	0	0	'	'	'	'
Debt Instrument, Interest Rate, Stated Percentage	'	'	'	'	'	'	'	6.00%	6.00%	6.00%
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	400,000	'	'	'	'	'	'	'	'	'
Decommissioning Fund Investments	$214,095,000	$187,053,000	'	'	'	'	'	'	'	'

Financial_Instruments_And_Inve2

Financial Instruments And Investments (Marketable Securities Fair Value And Unrealized Losses) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
	securities		securities
Financial Instruments and Investments [Line Items]	'		'
Marketable Securities Fair Value, Less than 12 Months	$32,433	[1]	$17,786	[2]
Marketable Securities Unrealized Losses Less Than 12 Months	-971	[1]	-543	[2]
Marketable Securities Fair Value 12 Months or Longer	20,970	[1]	10,633	[2]
Marketable Securities Unrealized Losses 12 Months or Longer	-1,492	[1]	-364	[2]
Marketable Securities Fair Value, Total	53,403	[1]	28,419	[2]
Marketable Securities Unrealized Losses, Total	-2,463	[1]	-907	[2]
Number of securities	122		65
Collateralized Mortgage Backed Securities	'		'
Financial Instruments and Investments [Line Items]	'		'
Marketable Securities Fair Value, Less than 12 Months	6,444	[1]	1,792	[2]
Marketable Securities Unrealized Losses Less Than 12 Months	-169	[1]	-5	[2]
Marketable Securities Fair Value 12 Months or Longer	1,421	[1]	416	[2]
Marketable Securities Unrealized Losses 12 Months or Longer	-119	[1]	-9	[2]
Marketable Securities Fair Value, Total	7,865	[1]	2,208	[2]
Marketable Securities Unrealized Losses, Total	-288	[1]	-14	[2]
U.S. Government Bonds	'		'
Financial Instruments and Investments [Line Items]	'		'
Marketable Securities Fair Value, Less than 12 Months	8,114	[1]	6,633	[2]
Marketable Securities Unrealized Losses Less Than 12 Months	-245	[1]	-79	[2]
Marketable Securities Fair Value 12 Months or Longer	10,866	[1]	4,457	[2]
Marketable Securities Unrealized Losses 12 Months or Longer	-840	[1]	-114	[2]
Marketable Securities Fair Value, Total	18,980	[1]	11,090	[2]
Marketable Securities Unrealized Losses, Total	-1,085	[1]	-193	[2]
Municipal Bonds	'		'
Financial Instruments and Investments [Line Items]	'		'
Marketable Securities Fair Value, Less than 12 Months	12,286	[1]	5,306	[2]
Marketable Securities Unrealized Losses Less Than 12 Months	-335	[1]	-39	[2]
Marketable Securities Fair Value 12 Months or Longer	7,782	[1]	5,760	[2]
Marketable Securities Unrealized Losses 12 Months or Longer	-479	[1]	-241	[2]
Marketable Securities Fair Value, Total	20,068	[1]	11,066	[2]
Marketable Securities Unrealized Losses, Total	-814	[1]	-280	[2]
Corporate Debt Securities	'		'
Financial Instruments and Investments [Line Items]	'		'
Marketable Securities Fair Value, Less than 12 Months	3,284	[1]	452	[2]
Marketable Securities Unrealized Losses Less Than 12 Months	-96	[1]	-11	[2]
Marketable Securities Fair Value 12 Months or Longer	901	[1]	0	[2]
Marketable Securities Unrealized Losses 12 Months or Longer	-54	[1]	0	[2]
Marketable Securities Fair Value, Total	4,185	[1]	452	[2]
Marketable Securities Unrealized Losses, Total	-150	[1]	-11	[2]
Debt Securities	'		'
Financial Instruments and Investments [Line Items]	'		'
Marketable Securities Fair Value, Less than 12 Months	30,128	[1]	14,183	[2]
Marketable Securities Unrealized Losses Less Than 12 Months	-845	[1]	-134	[2]
Marketable Securities Fair Value 12 Months or Longer	20,970	[1]	10,633	[2]
Marketable Securities Unrealized Losses 12 Months or Longer	-1,492	[1]	-364	[2]
Marketable Securities Fair Value, Total	51,098	[1]	24,816	[2]
Marketable Securities Unrealized Losses, Total	-2,337	[1]	-498	[2]
Equity Securities	'		'
Financial Instruments and Investments [Line Items]	'		'
Marketable Securities Fair Value, Less than 12 Months	2,305	[1]	3,603	[2]
Marketable Securities Unrealized Losses Less Than 12 Months	-126	[1]	-409	[2]
Marketable Securities Fair Value 12 Months or Longer	0	[1]	0	[2]
Marketable Securities Unrealized Losses 12 Months or Longer	0	[1]	0	[2]
Marketable Securities Fair Value, Total	2,305	[1]	3,603	[2]
Marketable Securities Unrealized Losses, Total	($126)	[1]	($409)	[2]
[1]	Includes approximately 122 securities.
[2]	Includes approximately 65 securities.

Financial_Instruments_And_Inve3

Financial Instruments And Investments (Unrecognized Gross Unrealized Gains And The Fair Value) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Financial Instruments and Investments [Line Items]	'	'
Available-for-sale Securities, Unrealized Gain Position, Fair Value	$160,692	$158,634
Available For Sale Debt Securities Gross Unrealized Gain Accumulated In Investments	47,741	29,039
Collateralized Mortgage Backed Securities	'	'
Financial Instruments and Investments [Line Items]	'	'
Available-for-sale Securities, Unrealized Gain Position, Fair Value	9,929	17,289
Available For Sale Debt Securities Gross Unrealized Gain Accumulated In Investments	433	1,036
U.S. Government Bonds	'	'
Financial Instruments and Investments [Line Items]	'	'
Available-for-sale Securities, Unrealized Gain Position, Fair Value	6,258	13,295
Available For Sale Debt Securities Gross Unrealized Gain Accumulated In Investments	126	678
Municipal Bonds	'	'
Financial Instruments and Investments [Line Items]	'	'
Available-for-sale Securities, Unrealized Gain Position, Fair Value	8,783	22,797
Available For Sale Debt Securities Gross Unrealized Gain Accumulated In Investments	450	1,531
Corporate Debt Securities	'	'
Financial Instruments and Investments [Line Items]	'	'
Available-for-sale Securities, Unrealized Gain Position, Fair Value	9,188	12,378
Available For Sale Debt Securities Gross Unrealized Gain Accumulated In Investments	506	1,134
Debt Securities	'	'
Financial Instruments and Investments [Line Items]	'	'
Available-for-sale Securities, Unrealized Gain Position, Fair Value	34,158	65,759
Available For Sale Debt Securities Gross Unrealized Gain Accumulated In Investments	1,515	4,379
Equity Securities	'	'
Financial Instruments and Investments [Line Items]	'	'
Available-for-sale Securities, Unrealized Gain Position, Fair Value	103,808	73,210
Available For Sale Debt Securities Gross Unrealized Gain Accumulated In Investments	43,145	22,839
Equity Mutual Funds	'	'
Financial Instruments and Investments [Line Items]	'	'
Available-for-sale Securities, Unrealized Gain Position, Fair Value	16,802	15,194
Available For Sale Debt Securities Gross Unrealized Gain Accumulated In Investments	3,081	1,821
Cash and Cash Equivalents	'	'
Financial Instruments and Investments [Line Items]	'	'
Available-for-sale Securities, Unrealized Gain Position, Fair Value	5,924	4,471
Available For Sale Debt Securities Gross Unrealized Gain Accumulated In Investments	$0	$0

Financial_Instruments_And_Inve4

Financial Instruments And Investments (Contractual Year For Maturity Of Available-For-Sale Securities ) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013
Financial Instruments and Investments [Line Items]	'
Contractual Maturity Due For, Mortgaged Backed Securities	'10 years
Municipal Bonds	'
Financial Instruments and Investments [Line Items]	'
Total	28,851
2014	1,486
2015 through 2018	13,311
2019 through 2022	10,920
2023 and Beyond	3,134
Corporate Debt Securities	'
Financial Instruments and Investments [Line Items]	'
Total	13,373
2014	321
2015 through 2018	3,711
2019 through 2022	5,525
2023 and Beyond	3,816
U.S. Government Bonds	'
Financial Instruments and Investments [Line Items]	'
Total	25,238
2014	1,216
2015 through 2018	14,149
2019 through 2022	7,217
2023 and Beyond	2,656
Maximum	'
Financial Instruments and Investments [Line Items]	'
Debt Instrument, Expected Weighted Average Maturity Year	'8 years
Minimum	'
Financial Instruments and Investments [Line Items]	'
Debt Instrument, Expected Weighted Average Maturity Year	'3 years

Financial_Instruments_And_Inve5

Financial Instruments And Investments (Unrealized Holding Losses Included In Pre-Tax Income) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Financial Instruments And Investments [Abstract]	'	'	'
Unrealized losses included in pre-tax income	$0	($479)	($2,116)

Financial_Instruments_And_Inve6

Financial Instruments And Investments (Sale Of Securities And The Related Effects On Pre-Tax Income ) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Investment [Line Items]	'	'	'
Proceeds from sales of available-for-sale securities	$56,148	$98,542	$82,926
Gross realized gains included in pre-tax income	986	1,478	1,479
Gross realized losses included in pre-tax income	-433	-2,041	-721
Other than Temporary Impairment Losses, Investments, Recognized in Earnings, before Tax, Available-for-sale Securities	0	-479	-2,116
Net unrealized holding gains (losses) included in accumulated other comprehensive income	17,699	9,927	1,570
Net gains (losses) in pre-tax income	-553	1,042	1,358
Net gains (losses) in other comprehensive income	$17,146	$10,969	$2,928

Financial_Instruments_And_Inve7

Financial Instruments And Investments (Company's Decommissioning Trust Funds And Investments In Debt Securities) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Decommissioning Fund Investments	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	$214,095	$187,053	'
Decommissioning Fund Investments | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	154,077	120,863	'
Decommissioning Fund Investments | Significant Other Observable Inputs (Level 2)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	60,018	66,190	'
Decommissioning Fund Investments | Significant Unobservable Inputs (Level 3)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	0	0	'
Debt Securities	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Investments in Debt Securities	1,555	1,295	1,120
Debt Securities | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Investments in Debt Securities	0	0	'
Debt Securities | Significant Other Observable Inputs (Level 2)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Investments in Debt Securities	0	0	'
Debt Securities | Significant Unobservable Inputs (Level 3)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Investments in Debt Securities	1,555	1,295	'
Debt Securities | Decommissioning Fund Investments	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	85,256	90,575	'
Debt Securities | Decommissioning Fund Investments | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	25,238	24,385	'
Debt Securities | Decommissioning Fund Investments | Significant Other Observable Inputs (Level 2)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	60,018	66,190	'
Debt Securities | Decommissioning Fund Investments | Significant Unobservable Inputs (Level 3)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	0	0	'
U.S. Government Bonds | Decommissioning Fund Investments	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	25,238	24,385	'
U.S. Government Bonds | Decommissioning Fund Investments | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	25,238	24,385	'
U.S. Government Bonds | Decommissioning Fund Investments | Significant Other Observable Inputs (Level 2)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	0	0	'
U.S. Government Bonds | Decommissioning Fund Investments | Significant Unobservable Inputs (Level 3)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	0	0	'
Collateralized Mortgage Backed Securities | Decommissioning Fund Investments	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	17,794	19,497	'
Collateralized Mortgage Backed Securities | Decommissioning Fund Investments | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	0	0	'
Collateralized Mortgage Backed Securities | Decommissioning Fund Investments | Significant Other Observable Inputs (Level 2)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	17,794	19,497	'
Collateralized Mortgage Backed Securities | Decommissioning Fund Investments | Significant Unobservable Inputs (Level 3)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	0	0	'
Municipal Bonds | Decommissioning Fund Investments	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	28,851	33,863	'
Municipal Bonds | Decommissioning Fund Investments | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	0	0	'
Municipal Bonds | Decommissioning Fund Investments | Significant Other Observable Inputs (Level 2)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	28,851	33,863	'
Municipal Bonds | Decommissioning Fund Investments | Significant Unobservable Inputs (Level 3)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	0	0	'
Corporate Debt Securities | Decommissioning Fund Investments	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	13,373	12,830	'
Corporate Debt Securities | Decommissioning Fund Investments | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	0	0	'
Corporate Debt Securities | Decommissioning Fund Investments | Significant Other Observable Inputs (Level 2)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	13,373	12,830	'
Corporate Debt Securities | Decommissioning Fund Investments | Significant Unobservable Inputs (Level 3)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	0	0	'
Equity Securities | Decommissioning Fund Investments	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	106,113	76,813	'
Equity Securities | Decommissioning Fund Investments | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	106,113	76,813	'
Equity Securities | Decommissioning Fund Investments | Significant Other Observable Inputs (Level 2)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	0	0	'
Equity Securities | Decommissioning Fund Investments | Significant Unobservable Inputs (Level 3)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	0	0	'
Equity Mutual Funds | Decommissioning Fund Investments	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	16,802	15,194	'
Equity Mutual Funds | Decommissioning Fund Investments | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	16,802	15,194	'
Equity Mutual Funds | Decommissioning Fund Investments | Significant Other Observable Inputs (Level 2)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	0	0	'
Equity Mutual Funds | Decommissioning Fund Investments | Significant Unobservable Inputs (Level 3)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	0	0	'
Cash and Cash Equivalents | Decommissioning Fund Investments	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	5,924	4,471	'
Cash and Cash Equivalents | Decommissioning Fund Investments | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	5,924	4,471	'
Cash and Cash Equivalents | Decommissioning Fund Investments | Significant Other Observable Inputs (Level 2)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	0	0	'
Cash and Cash Equivalents | Decommissioning Fund Investments | Significant Unobservable Inputs (Level 3)	'	'	'
Financial Instruments and Investments [Line Items]	'	'	'
Available-for-sale Securities	$0	$0	'

Recovered_Sheet3

Financial Instruments and Investments Financial Instruments and Investments (Reconciliation) (Details) (Debt Securities, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Debt Securities	'		'
Fair Value in Investment in Debt Securities [Roll Forward]	'		'
Balance at January 1	$1,295		$1,120
Net unrealized gains (losses) in fair value recognized in income on debt securities still held	260	[1]	175	[1]
Balance at December 31	$1,555		$1,295
[1]	These amounts are reflected in the Company's statement of operations as investment and interest income.

Supplemental_Statements_of_Cas2

Supplemental Statements of Cash Flows Disclosures Supplemental Statements of Cash Flows Disclosures (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Supplemental Statements of Cash Flow Disclosures [Abstract]	'	'	'
Interest on long-term debt and borrowing under the revolving credit facility	$53,752	$50,189	$48,797
Income taxes paid (refund), net	244	5,031	-6,260
Grants of restricted shares of common stock	3,224	2,411	3,268
Issuance of performance shares	849	1,193	628
Acquisition of treasury stock for options exercised	$0	$0	$500

Selected_Quarterly_Financial_D2

Selected Quarterly Financial Data (Unaudited) Selected Quarterly Financial Data (Unaudited) (Details) (USD $)	3 Months Ended																12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Selected Quarterly Financial Data	'		'		'		'		'		'		'		'		'	'	'
Operating revenues	$190,297	[1]	$282,661	[1]	$240,114	[1]	$177,290	[1]	$188,802	[1]	$267,249	[1]	$228,252	[1]	$168,578	[1]	$890,362	$852,881	$918,013
Operating income	6,050		85,896		54,344		19,345		13,708		86,396		56,512		12,042		165,635	168,658	190,803
Net income	$1,191		$50,565		$29,193		$7,634		$4,819		$51,789		$30,894		$3,344		$88,583	$90,846	$103,539
Basic earnings per share:	'		'		'		'		'		'		'		'		'	'	'
Net income	$0.03		$1.26		$0.73		$0.19		$0.12		$1.29		$0.77		$0.08		$2.20	$2.27	$2.49
Diluted earnings per share:	'		'		'		'		'		'		'		'		'	'	'
Net income	$0.03		$1.26		$0.72		$0.19		$0.12		$1.29		$0.77		$0.08		$2.20	$2.26	$2.48
Dividends declared per share of common stock	$0.27		$0.27		$0.27		$0.25		$0.25		$0.25		$0.25		$0.22		$1.04	$0.97	$0.66
[1]	Operating revenues are seasonal in nature, with the peak sales periods generally occurring during the summer months. Comparisons among quarters of a year may not represent overall trends and changes in operations.