Consolidated Statements of Changes in Equity - SPPC - USD ($) $ in Millions	Total	Common Stock [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, 2018		77,000,000		1,000
Stockholders' Equity Attributable to Parent at Dec. 31, 2018			$ 1,264	$ 0	$ 1,111	$ 153	$ 0
Net Income (Loss) Attributable to Parent	$ 1,306		36			36
Dividends, Common Stock, Cash			(46)	$ 0		(46)	0
Balance (shares) at Jun. 30, 2019		77,000,000		1,000
Stockholders' Equity Attributable to Parent at Jun. 30, 2019			1,254	$ 0	1,111	143	0
Balance (shares) at Mar. 31, 2019		77,000,000		1,000
Stockholders' Equity Attributable to Parent at Mar. 31, 2019			1,286	$ 0	1,111	175	0
Net Income (Loss) Attributable to Parent	$ 684		14			14
Dividends, Common Stock, Cash			(46)	$ 0		(46)	0
Balance (shares) at Jun. 30, 2019		77,000,000		1,000
Stockholders' Equity Attributable to Parent at Jun. 30, 2019			$ 1,254	$ 0	1,111	143	0
Balance (shares) at Dec. 31, 2019	0	77,000,000	1,000	1,000
Stockholders' Equity Attributable to Parent at Dec. 31, 2019	$ 32,449		$ 1,320	$ 0	1,111	210	(1)
Net Income (Loss) Attributable to Parent	$ 1,786		38			38
Dividends, Common Stock, Cash			$ (20)			(20)
Balance (shares) at Jun. 30, 2020	0	76,000,000	1,000	1,000
Stockholders' Equity Attributable to Parent at Jun. 30, 2020	$ 33,684		$ 1,338	$ 0	1,111	228	(1)
Balance (shares) at Mar. 31, 2020		76,000,000		1,000
Stockholders' Equity Attributable to Parent at Mar. 31, 2020			1,345	$ 0	1,111	235	(1)
Net Income (Loss) Attributable to Parent	$ 1,116		13			13
Dividends, Common Stock, Cash			$ (20)			(20)
Balance (shares) at Jun. 30, 2020	0	76,000,000	1,000	1,000
Stockholders' Equity Attributable to Parent at Jun. 30, 2020	$ 33,684		$ 1,338	$ 0	$ 1,111	$ 228	$ (1)