LONG-TERM DEBT (Tables)

12 Months Ended

Dec. 31, 2012

Debt Disclosure [Abstract]

Schedule of Long-term Debt

			2012								2011
					NVE								NVE
			Consolidated		Holding Co.		NPC		SPPC		Consolidated		Holding Co.		NPC		SPPC
Long-Term Debt:
Secured Debt
	General and Refunding Mortgage
	Securities
		6.50% NPC Series I due 2012	$	0	$	0	$	0	$	0	$	130,000		0	$	130,000	$	0
		5.875% NPC Series L due 2015		250,000		0		250,000		0		250,000		0		250,000		0
		5.95% NPC Series M due 2016		210,000		0		210,000		0		210,000		0		210,000		0
		6.65% NPC Series N due 2036		370,000		0		370,000		0		370,000		0		370,000		0
		6.50% NPC Series O due 2018		325,000		0		325,000		0		325,000		0		325,000		0
		6.75% NPC Series R due 2037		350,000		0		350,000		0		350,000		0		350,000		0
		6.50% NPC Series S due 2018		500,000		0		500,000		0		500,000		0		500,000		0
		7.375% NPC Series U due 2014		125,000		0		125,000		0		125,000		0		125,000		0
		7.125% NPC Series V due 2019		500,000		0		500,000		0		500,000		0		500,000		0
		5.375% NPC Series X due 2040		250,000		0		250,000		0		250,000		0		250,000		0
		5.45% NPC Series Y due 2041		250,000		0		250,000		0		250,000		0		250,000		0
		6.00% SPPC Series M due 2016		450,000		0		0		450,000		450,000		0		0		450,000
		6.75% SPPC Series P due 2037		251,742		0		0		251,742		251,742		0		0		251,742
		5.45% SPPC Series Q due 2013		250,000		0		0		250,000		250,000		0		0		250,000
	Variable Rate Debt (Secured by
		General and Refunding Mortgage
		Securities)
		NPC IDRB Series 2000A due 2020		98,100		0		98,100		0		98,100		0		98,100		0
		NPC PCRB Series 2006 due 2036		37,700		0		37,700		0		37,700		0		37,700		0
		NPC PCRB Series 2006A due 2032		37,975		0		37,975		0		37,975		0		37,975		0
		SPPC PCRB Series 2006A due 2031		58,200		0		0		58,200		58,200		0		0		58,200
		SPPC PCRB Series 2006B due 2036		75,000		0		0		75,000		75,000		0		0		75,000
		SPPC PCRB Series 2006C due 2036		81,475		0		0		81,475		81,475		0		0		81,475
Senior Notes
		6.25% NVE Senior Notes due 2020		315,000		315,000		0		0		315,000		315,000		0		0
		2.81% NVE Term Loan due 2014		195,000		195,000		0		0		195,000		195,000		0		0
Obligations under capital leases				44,258		0		42,908		1,350		51,270		0		51,270		0
Unamortized bond premium and discount, net				1,631		0		(9,827)		11,458		(12,546)		0		(25,455)		12,909
Current maturities				(356,283)		0		(106,048)		(250,235)		(139,985)		0		(139,985)		0
Total Long-Term Debt			$	4,669,798	$	510,000	$	3,230,808	$	928,990	$	5,008,931	$	510,000	$	3,319,605	$	1,179,326

Schedule of Maturities of Long-term Debt [Table Text Block]

	NVE		NVE
	Consolidated		Holding Co.		NPC		SPPC
2013(1)	$	354,848	$	0	$	104,613	$	250,235
2014		324,317		195,000		129,142		175
2015		251,746		0		251,567		179
2016		661,854		0		211,677		450,177
2017		1,934		0		1,753		181
		1,594,699		195,000		698,752		700,947
Thereafter		3,429,751		315,000		2,647,931		466,820
		5,024,450		510,000		3,346,683		1,167,767
Unamortized Premium (Discount) Amount		1,631		0		(9,827)		11,458
Total Debt	$	5,026,081	$	510,000	$	3,336,856	$	1,179,225

Schedule of Future Minimum Lease Payments for Capital Leases [Table Text Block]

2013		$	10,156
2014			7,685
2015			5,074
2016			5,136
2017			5,164
Thereafter			56,591
	Total minimum lease payments	$	89,806
	Less amounts representing interest	$	(45,548)
Present value of net minimum lease payments		$	44,258