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, 2018		77,000,000					1,000
Stockholders' Equity Attributable to Parent at Dec. 31, 2018						$ 2,904	$ 0	$ 2,308	$ 600	$ (4)
Net Income (Loss) Attributable to Parent	$ 622					6			6
Dividends, Common Stock, Cash						(75)			(75)
Balance (shares) at Mar. 31, 2019		77,000,000					1,000
Stockholders' Equity Attributable to Parent at Mar. 31, 2019						$ 2,835	$ 0	2,308	531	(4)
Stockholders' Equity, Other	$ (1)	$ 0	$ 0	$ (1)	$ 0
Balance (shares) at Dec. 31, 2019	77,000,000	77,000,000				1,000	1,000
Stockholders' Equity Attributable to Parent at Dec. 31, 2019	$ 32,449					$ 2,797	$ 0	2,308	493	(4)
Net Income (Loss) Attributable to Parent	$ 670					$ (4)			(4)
Balance (shares) at Mar. 31, 2020	76,000,000	76,000,000				1,000	1,000
Stockholders' Equity Attributable to Parent at Mar. 31, 2020	$ 32,445					$ 2,794	$ 0	$ 2,308	490	$ (4)
Stockholders' Equity, Other	$ (1)	$ 0	$ (1)	$ 0	$ 0	$ 1			$ 1