Consolidated Statements of Changes in Equity - SPPC - USD ($) $ in Millions	Total	Common Stock [Member]	Sierra Pacific Power Company [Member]	Sierra Pacific Power Company [Member] Common Stock [Member]	Sierra Pacific Power Company [Member] Additional Paid-in Capital [Member]	Sierra Pacific Power Company [Member] Retained Earnings [Member]	Sierra Pacific 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			$ 998	$ 0	$ 1,111	$ (111)	$ (2)
Net Income (Loss) Attributable to Parent	$ 469		19			19
Balance (shares) at Mar. 31, 2015		77,000,000		1,000
Stockholders' Equity Attributable to Parent at Mar. 31, 2015			$ 1,017	$ 0	1,111	(92)	(2)
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		$ 1,076	$ 0	1,111	(35)	0
Net Income (Loss) Attributable to Parent	$ 490		$ 17			17
Balance (shares) at Mar. 31, 2016	77,000,000	77,000,000	1,000	1,000
Stockholders' Equity Attributable to Parent at Mar. 31, 2016	$ 22,990		$ 1,093	$ 0	$ 1,111	$ (18)	$ 0