Consolidated Statements of Changes in Equity - NPC - USD ($) $ in Millions	Total	Common Stock [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, 2016		77,000,000		1,000
Stockholders' Equity Attributable to Parent at Dec. 31, 2016			$ 2,972	$ 0	$ 2,308	$ 667	$ (3)
Net Income (Loss) Attributable to Parent	$ 556		10			10
Dividends, Common Stock, Cash			75			75
Balance (shares) at Mar. 31, 2017		77,000,000		1,000
Stockholders' Equity Attributable to Parent at Mar. 31, 2017			$ 2,907	$ 0	2,308	602	(3)
Balance (shares) at Dec. 31, 2017	77,000,000	77,000,000	1,000	1,000
Stockholders' Equity Attributable to Parent at Dec. 31, 2017	$ 28,176		$ 2,678	$ 0	2,308	374	(4)
Net Income (Loss) Attributable to Parent	$ 513		$ 0
Balance (shares) at Mar. 31, 2018	77,000,000	77,000,000	1,000	1,000
Stockholders' Equity Attributable to Parent at Mar. 31, 2018	$ 28,667		$ 2,678	$ 0	$ 2,308	$ 374	$ (4)