Consolidated Statements of Changes in Equity - NPC - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) Income, Net [Member]	Nevada Power Company [Member]	Nevada Power Company [Member] Common Stock [Member]	Nevada Power Company [Member] Additional Paid-in Capital [Member]	Nevada Power Company [Member] Retained Earnings [Member]	Nevada 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)	$ 2,797	$ 0	$ 2,308	$ 493	$ (4)
Net Income (Loss) Attributable to Parent	$ 670					(4)			(4)
Stockholders' Equity, Other	(1)	$ 0	$ (1)	$ 0	0	(1)			(1)
Balance (shares) at Mar. 31, 2020							1,000
Balance at Mar. 31, 2020					(2,253)	$ 2,794	$ 0	2,308	490	(4)
Balance (shares) at Dec. 31, 2020						1,000	1,000
Balance at Dec. 31, 2020	43,010				(1,552)	$ 2,939	$ 0	2,308	634	(3)
Net Income (Loss) Attributable to Parent	4					$ 2			2
Stockholders' Equity, Other	$ 3	$ 0	$ 0	$ 1	0
Balance (shares) at Mar. 31, 2021	76,000,000					1,000	1,000
Balance at Mar. 31, 2021	$ 43,089				$ (1,440)	$ 2,941	$ 0	$ 2,308	$ 636	$ (3)