Related Party Transactions (Details) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Kern River [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Purchases from Related Party	$ 68,000,000	$ 68,000,000	$ 66,000,000
Due to Affiliate, Current	5,000,000	5,000,000
BHE [Member]
Related Party Transaction [Line Items]
Due from Affiliate, Current	0	2,000,000
PacifiCorp [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Purchases from Related Party	5,000,000	2,000,000	62,000,000
Due to Affiliate, Current	4,000,000
Revenue from Related Parties	3,000,000	3,000,000	7,000,000
Sierra Pacific Power Company [Member]
Related Party Transaction [Line Items]
Due from Affiliates	7,000,000	3,000,000
Related Party Transaction, Expense Reimbursement	16,000,000	22,000,000	22,000,000
Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party	20,000,000	24,000,000	20,000,000
Sierra Pacific Power Company [Member] \| Electric Distribution [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Purchases from Related Party	8,000,000	1,000,000	1,000,000
Revenue from Related Parties	33,000,000	36,000,000	20,000,000
NV Energy, Inc. [Member]
Related Party Transaction [Line Items]
Due to Affiliate, Current		60,000,000
Related Party Transaction, Expense Reimbursement	19,000,000	45,000,000	27,000,000
Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party	1,000,000	0	1,000,000
Accounts Payable [Member] \| PacifiCorp [Member]
Related Party Transaction [Line Items]
Due to Affiliate		0
Accounts Payable [Member] \| Sierra Pacific Power Company [Member]
Related Party Transaction [Line Items]
Due to Affiliate	0	0
Accounts Payable [Member] \| NV Energy, Inc. [Member]
Related Party Transaction [Line Items]
Due to Affiliate, Current	33,000,000
Accounts Receivable [Member] \| PacifiCorp [Member]
Related Party Transaction [Line Items]
Due from Affiliate, Current	0	0
Accounts Receivable [Member] \| Sierra Pacific Power Company [Member]
Related Party Transaction [Line Items]
Due from Affiliates	$ 5,000,000	$ 6,000,000

Expense reimbursement for charges incurred on behalf of affiliates.

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Amount of receivables due from an entity that is affiliated with the reporting entity by means of direct or indirect ownership, due within 1 year (or 1 business cycle).

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For an unclassified balance sheet, amount of receivables due from an entity that is affiliated with the reporting entity by means of direct or indirect ownership.

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Amount of payable due to an entity that is affiliated with the reporting entity by means of direct or indirect ownership. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Amount of payable due to an entity that is affiliated with the reporting entity by means of direct or indirect ownership.

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Purchases during the period (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

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No definition available.

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Amount of selling, general and administrative expenses resulting from transactions, excluding transactions that are eliminated in consolidated or combined financial statements, with related party.

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Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

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