Consolidated Statements of Changes in Equity - SPPC - USD ($) $ in Millions	Total	Accumulated Other Comprehensive (Loss) Income, Net [Member]	Sierra Pacific Power Company [Member]	Sierra Pacific Power Company [Member] Common Stock [Member]	Sierra Pacific Power Company [Member] Additional Paid-in Capital [Member]	Sierra Pacific Power Company [Member] Retained Earnings [Member]	Sierra Pacific Power Company [Member] Accumulated Other Comprehensive (Loss) Income, Net [Member]
Balance (shares) at Dec. 31, 2019				1,000
Balance at Dec. 31, 2019		$ (1,706)	$ 1,320	$ 0	$ 1,111	$ 210	$ (1)
Net Income (Loss) Attributable to Parent	$ 670		25			25
Balance (shares) at Mar. 31, 2020				1,000
Balance at Mar. 31, 2020		(2,253)	$ 1,345	$ 0	1,111	235	(1)
Balance (shares) at Dec. 31, 2020			1,000	1,000
Balance at Dec. 31, 2020	43,010	(1,552)	$ 1,411	$ 0	1,111	301	(1)
Net Income (Loss) Attributable to Parent	$ 4		$ 28			28
Balance (shares) at Mar. 31, 2021	76,000,000		1,000	1,000
Balance at Mar. 31, 2021	$ 43,089	$ (1,440)	$ 1,439	$ 0	$ 1,111	$ 329	$ (1)