Regulatory Matters - General Disclosures (Details) (USD $) In Millions, unless otherwise specified		1 Months Ended		3 Months Ended
	Mar. 31, 2014 Public Utilities Commission, Nevada [Member]	May 31, 2013 Federal Energy Regulatory Commission [Member]	Mar. 31, 2014 Federal Energy Regulatory Commission [Member]	Mar. 31, 2014 MEHC Merger
Public Utilities, General Disclosures [Line Items]
Recovery of loss on revenues				50.00%
Customer refund liability, current	$ 2		$ 1
Requested rate increase (decrease), amended, amount		$ 17