Note 5 – Long-Term Debt

Carrying amounts of the Company’s long-term debt and their related estimated fair values as of June 30, 2013 and December 31, 2012 are disclosed in the following table. The fair values of the revolving credit facility including commercial paper, the NPL revolving credit facility, and the variable-rate Industrial Development Revenue Bonds (“IDRBs”) approximate their carrying values, and are categorized as Level 1 (quoted prices for identical financial instruments) within the three-level fair value hierarchy that ranks the inputs used to measure fair value by their reliability. The market values of debentures (except the 6.1% Notes) and fixed-rate IDRBs are categorized as Level 2. The 6.1% Notes and NPL other debt obligations are categorized as Level 3 (based on significant unobservable inputs to their fair values). Fair values for the debentures, fixed-rate IDRBs, and NPL other debt obligations were determined through a market-based valuation approach, where fair market values are determined based on evaluated pricing data, such as broker quotes and yields for similar securities adjusted for observable differences. Significant inputs used in the valuation generally include benchmark yield curves and issuer spreads. The external credit rating, coupon rate, and maturity of each security are considered in the valuation, as applicable.


	June 30, 2013				December 31, 2012
	Carrying Amount		Market Value		Carrying Amount		Market Value
	Carrying Amount		Market Value		Carrying Amount		Market Value
(Thousands of dollars)
Debentures:
Notes, 4.45%, due 2020	$	125,000	$	134,581	$	125,000	$	141,771
Notes, 6.1%, due 2041		125,000		143,655		125,000		165,779
Notes, 3.875%, due 2022		250,000		261,148		250,000		277,950
8% Series, due 2026		75,000		102,116		75,000		111,501
Medium-term notes, 7.59% series, due 2017		25,000		29,442		25,000		30,710
Medium-term notes, 7.78% series, due 2022		25,000		31,998		25,000		34,637
Medium-term notes, 7.92% series, due 2027		25,000		33,398		25,000		36,953
Medium-term notes, 6.76% series, due 2027		7,500		8,976		7,500		10,058
Unamortized discount		(3,320)				(3,403)

		654,180				654,097

Revolving credit facility and commercial paper		119,000		119,000		111,000		111,000

Industrial development revenue bonds:
Variable-rate bonds:
Tax-exempt Series A, due 2028		50,000		50,000		50,000		50,000
2003 Series A, due 2038		50,000		50,000		50,000		50,000
2008 Series A, due 2038		50,000		50,000		50,000		50,000
2009 Series A, due 2039		50,000		50,000		50,000		50,000
Fixed-rate bonds:
5.55% 1999 Series D, due 2038		8,270		8,314		8,270		8,375
5.45% 2003 Series C, due 2038		-		-		30,000		30,152
5.25% 2003 Series D, due 2038		20,000		20,436		20,000		20,571
5.80% 2003 Series E, due 2038		-		-		15,000		15,102
5.25% 2004 Series A, due 2034		65,000		63,500		65,000		66,955
5.00% 2004 Series B, due 2033		31,200		30,300		31,200		31,655
4.85% 2005 Series A, due 2035		100,000		94,660		100,000		101,184
4.75% 2006 Series A, due 2036		24,855		23,588		24,855		25,189
Unamortized discount		(2,854)				(3,195)

		446,471				491,130

NPL credit facility		-		-		41,562		41,562
NPL other debt obligations		47,687		47,454		20,721		20,991

		1,267,338				1,318,510
Less: current maturities		(11,000)				(50,137)

Long-term debt, less current maturities	$	1,256,338			$	1,268,373

In February 2013, a notice of mandatory tender was sent to holders of the Clark County, Nevada 5.45% Series 2003C and 5.80% Series 2003E IDRBs. These IDRBs (totaling $45 million) were subject to mandatory tender on March 1, 2013 at a price of 100% plus accrued interest, and the Company tendered these IDRBs to the trustee for cancellation immediately following the mandatory tender, thereby extinguishing this debt. The Company facilitated the redemption primarily from borrowings under its $300 million credit facility.