Unaudited Quarterly Operating Results Unaudited Quarterly Operating Results (Notes)

12 Months Ended

Dec. 31, 2019

Nevada Power Company [Member]

Quarterly Operating Results [Line Items]

Quarterly Financial Information [Text Block]

Unaudited Quarterly Operating Results (in millions)

	Three-Month Periods Ended
	March 31,		June 30,		September 30,		December 31,
	2019		2019		2019		2019
Operating revenues	$	395	$	527	$	806	$	420
Operating income	45		123		244		67
Net income	6		69		165		24
	Three-Month Periods Ended
	March 31,		June 30,		September 30,		December 31,
	2018		2018		2018		2018
Operating revenues	$	395	$	562	$	820	$	407
Operating income	40		122		247		37
Net income	—		64		164		(2		)

Sierra Pacific Power Company [Member]

Quarterly Operating Results [Line Items]

Quarterly Financial Information [Text Block]

Unaudited Quarterly Operating Results (in millions)

	Three-Month Periods Ended
	March 31,		June 30,		September 30,		December 31,
	2019		2019		2019		2019
Regulated electric operating revenue	$	182	$	172	$	232	$	184
Regulated natural gas operating revenue	37		22		16		44
Operating income	37		27		67		40
Net income	22		14		44		23
	Three-Month Periods Ended
	March 31,		June 30,		September 30,		December 31,
	2018		2018		2018		2018
Regulated electric operating revenue	$	181	$	169	$	225	$	177
Regulated natural gas operating revenue	41		19		14		29
Operating income	47		19		56		30
Net income	34		7		35		16