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	$ 2,443		80			80
Dividends, Common Stock, Cash			(46)	$ 0		(46)	0
Balance (shares) at Sep. 30, 2019		77,000,000		1,000
Stockholders' Equity Attributable to Parent at Sep. 30, 2019			1,298	$ 0	1,111	187	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
Net Income (Loss) Attributable to Parent	$ 1,137		44			44
Balance (shares) at Sep. 30, 2019		77,000,000		1,000
Stockholders' Equity Attributable to Parent at Sep. 30, 2019			$ 1,298	$ 0	1,111	187	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	$ 4,628		90			90
Dividends, Common Stock, Cash			$ (20)			(20)
Balance (shares) at Sep. 30, 2020	0	76,000,000	1,000	1,000
Stockholders' Equity Attributable to Parent at Sep. 30, 2020	$ 36,768		$ 1,390	$ 0	1,111	280	(1)
Balance (shares) at Jun. 30, 2020		76,000,000		1,000
Stockholders' Equity Attributable to Parent at Jun. 30, 2020			1,338	$ 0	1,111	228	(1)
Net Income (Loss) Attributable to Parent	$ 2,842		$ 52			52
Balance (shares) at Sep. 30, 2020	0	76,000,000	1,000	1,000
Stockholders' Equity Attributable to Parent at Sep. 30, 2020	$ 36,768		$ 1,390	$ 0	$ 1,111	$ 280	$ (1)