Employee Benefit Plans (Details) (NV Energy [Member], USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Qualified Pension Plans [Member] | Other assets [Member]
Amounts Recognized in Balance Sheet [Abstract]
Other assets	$ 16	$ 18
Non-Qualified Pension Plans [Member] | Customer deposits and other [Member]
Amounts Recognized in Balance Sheet [Abstract]
Customer deposits and other	(1)	(1)
Non-Qualified Pension Plans [Member] | Other long-term liabilities [Member]
Amounts Recognized in Balance Sheet [Abstract]
Other long-term liabilities	(10)	(11)
Other Postretirement Plans [Member] | Other long-term liabilities [Member]
Amounts Recognized in Balance Sheet [Abstract]
Other long-term liabilities	$ (39)	$ (38)