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, 2014		77,000,000					1,000
Stockholders' Equity Attributable to Parent at Dec. 31, 2014						$ 2,888	$ 0	$ 2,308	$ 583	$ (3)
Net Income (Loss) Attributable to Parent	$ 1,901					271			271
Balance (shares) at Sep. 30, 2015		77,000,000					1,000
Stockholders' Equity Attributable to Parent at Sep. 30, 2015						3,145	$ 0	2,308	840	(3)
Dividends, Common Stock, Cash						13			13
Stockholders' Equity, Other	$ (12)	$ 0	$ (8)	$ 0	$ 0	$ (1)			(1)
Balance (shares) at Dec. 31, 2015	77,000,000	77,000,000				1,000	1,000
Stockholders' Equity Attributable to Parent at Dec. 31, 2015	$ 22,401					$ 3,163	$ 0	2,308	858	(3)
Net Income (Loss) Attributable to Parent	$ 2,062					$ 257			257
Balance (shares) at Sep. 30, 2016	77,000,000	77,000,000				1,000	1,000
Stockholders' Equity Attributable to Parent at Sep. 30, 2016	$ 24,354					$ 3,054	$ 0	$ 2,308	749	$ (3)
Dividends, Common Stock, Cash						365			365
Stockholders' Equity, Other	$ 9	$ 0	$ 1	$ 0	$ 0	$ (1)			$ (1)