Regulatory Matters - Regulatory Liabilities (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Regulatory Liabilities [Line Items]
Regulatory liabilities		$ 402	$ 163
Regulatory liabilities, noncurrent		2,631	2,669
Regulatory Liabilities		3,033	2,832
Removal Costs [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities	[1]	$ 2,167	2,215
Weighted average remaining life	[1]	28 years
Asset Retirement Obligation Costs [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities		$ 147	169
Weighted average remaining life		22 years
Levelized depreciation [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities		$ 199	169
Weighted average remaining life		26 years
Employee benefit plans [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities	[2]	$ 13	20
Weighted average remaining life	[2]	12 years
Regulatory liabilities other [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities		$ 301	259
Weighted average remaining life		Various
Deferred net power costs [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities		$ 206	$ 0
Weighted average remaining life		2 years

[1] Amounts represent estimated costs, as accrued through depreciation rates and exclusive of ARO liabilities, of removing regulated property, plant and equipment in accordance with accepted regulatory practices. Amounts are deducted from rate base or otherwise accrue a carrying cost.

[2] Represents amounts not yet recognized as a component of net periodic benefit cost that are to be returned to customers in future periods when recognized.Utah Mine DispositionDue to quality issues with the coal reserves at PacifiCorp's Deer Creek mine in Utah and rising costs at PacifiCorp's wholly owned subsidiary, Energy West Mining Company, PacifiCorp believes the Deer Creek coal reserves are no longer able to be economically mined. As a result, in December 2014, PacifiCorp filed applications with the Utah Public Service Commission ("UPSC"), the Oregon Public Utility Commission ("OPUC"), the Wyoming Public Service Commission ("WPSC") and the Idaho Public Utilities Commission ("IPUC") seeking certain approvals, prudence determinations and accounting orders to close its Deer Creek mining operations, sell certain Utah mining assets, enter into a replacement coal supply agreement, amend an existing coal supply agreement, withdraw from the United Mine Workers of America ("UMWA") 1974 Pension Plan and settle PacifiCorp's other postretirement benefit obligation for UMWA participants (collectively, the "Utah Mine Disposition"). In April 2015, PacifiCorp filed all-party settlement stipulations with the UPSC and the WPSC finding that the decision to enter into the Utah Mine Disposition transaction was prudent and in the public interest. The UPSC approved the stipulation in April 2015 and the WPSC approved the stipulation in May 2015. In May 2015, the OPUC issued its final order concluding that the Utah Mine Disposition transaction produces net benefits for customers and was in the public interest. The IPUC also issued an order in May 2015, approving the Utah Mine Disposition and ruling that the decision to enter into the transaction was prudent and in the public interest. Accordingly, in June 2015, PacifiCorp sold the specified Utah mining assets and the replacement and amended coal supply agreements became effective. Refer to Note 12 for discussion of the UMWA 1974 Pension Plan withdrawal and the settlement of the other postretirement benefit obligation for UMWA participants. The Deer Creek mine is currently idled and closure activities have begun.In December 2014, PacifiCorp also filed an advice letter with the California Public Utilities Commission ("CPUC"). In July 2015, the CPUC Energy Division issued a letter requiring PacifiCorp to file a formal application for approval of the sale of certain Utah mining assets. Accordingly, in September 2015, PacifiCorp filed an application with the CPUC.