Retirement Plan and Postretirement Benefits Retirement Plan and Postretirement Benefits (Tables)

12 Months Ended

Dec. 31, 2015

Nevada Power Company [Member]

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

Schedule of Amounts Recognized in Balance Sheet [Table Text Block]

Amounts receivable from (payable to) NV Energy are included on the Consolidated Balance Sheets and consist of the following as of December 31(in millions):

	2015			2014
Qualified Pension Plan -
Other long-term liabilities	$	(38	)	$	(23	)
Non-Qualified Pension Plans:
Other current liabilities	(1		)	(1		)
Other long-term liabilities	(9		)	(9		)
Other Postretirement Plans -
Other long-term liabilities	(5		)	1

Sierra Pacific Power Company [Member]

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

Schedule of Amounts Recognized in Balance Sheet [Table Text Block]

Amounts payable to NV Energy are included on the Consolidated Balance Sheets and consist of the following as of December 31(in millions):

	2015			2014
Qualified Pension Plan -
Other long-term liabilities	$	(29	)	$	(13	)
Non-Qualified Pension Plans:
Other current liabilities	(1		)	(1		)
Other long-term liabilities	(9		)	(10		)
Other Postretirement Plans -
Other long-term liabilities	(32		)	(33		)

Domestic Pension Plans [Member]

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

Schedule of Net Benefit Costs [Table Text Block]

Net periodic benefit cost for the plans included the following components for the years ended December 31 (in millions):

	Pension									Other Postretirement
	2015			2014			2013			2015			2014			2013
Service cost	$	33		$	36		$	24		$	11		$	14		$	14
Interest cost	121			131			87			31			46			33
Expected return on plan assets	(169		)	(164		)	(119		)	(45		)	(53		)	(44		)
Net amortization	53			44			58			(11		)	(3		)	6
Net periodic benefit cost (credit)	$	38		$	47		$	50		$	(14	)	$	4		$	9