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	$ 1,306					75			75
Dividends, Common Stock, Cash						(95)			(95)
Balance (shares) at Jun. 30, 2019		77,000,000					1,000
Stockholders' Equity Attributable to Parent at Jun. 30, 2019						2,884	$ 0	2,308	580	(4)
Stockholders' Equity, Other	(3)	$ 0	$ 0	$ (2)	$ 0
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)
Net Income (Loss) Attributable to Parent	684					69			69
Dividends, Common Stock, Cash						(20)	$ 0	0	(20)	0
Balance (shares) at Jun. 30, 2019		77,000,000					1,000
Stockholders' Equity Attributable to Parent at Jun. 30, 2019						$ 2,884	$ 0	2,308	580	(4)
Stockholders' Equity, Other	$ (2)	$ 0	0	(1)	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					$ 2,797	$ 0	2,308	493	(4)
Net Income (Loss) Attributable to Parent	$ 1,786					79			79
Dividends, Common Stock, Cash						$ (85)			(85)
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					$ 2,792	$ 0	2,308	488	(4)
Stockholders' Equity, Other	(1)	$ 0	$ (1)	$ 0	$ 0	1			1
Balance (shares) at Mar. 31, 2020		76,000,000					1,000
Stockholders' Equity Attributable to Parent at Mar. 31, 2020						2,794	$ 0	2,308	490	(4)
Net Income (Loss) Attributable to Parent	$ 1,116					83			83
Dividends, Common Stock, Cash						$ (85)			(85)
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					$ 2,792	$ 0	$ 2,308	$ 488	$ (4)