Commitments and Contingencies	6 Months Ended
Commitments and Contingencies	Jun. 30, 2018
Loss Contingencies [Line Items]
Commitments and Contingencies	Commitments and Contingencies Easements During the six-month period ended June 30, 2018, MidAmerican Energy entered into non-cancelable easements with minimum payments totaling $283 million through 2058 for land in Iowa on which some of its wind-powered generating facilities will be located. Legal Matters The Company is party to a variety of legal actions arising out of the normal course of business. Plaintiffs occasionally seek punitive or exemplary damages. The Company does not believe that such normal and routine litigation will have a material impact on its consolidated financial results. The Company is also involved in other kinds of legal actions, some of which assert or may assert claims or seek to impose fines, penalties and other costs in substantial amounts and are described below. Environmental Laws and Regulations The Company is subject to federal, state, local and foreign laws and regulations regarding air and water quality, renewable portfolio standards, emissions performance standards, climate change, coal combustion byproduct disposal, hazardous and solid waste disposal, protected species and other environmental matters that have the potential to impact the Company's current and future operations. The Company believes it is in material compliance with all applicable laws and regulations. Hydroelectric Relicensing PacifiCorp's Klamath hydroelectric system is currently operating under annual licenses with the Federal Energy Regulatory Commission ("FERC"). In February 2010, PacifiCorp, the United States Department of the Interior, the United States Department of Commerce, the state of California, the state of Oregon and various other governmental and non-governmental settlement parties signed the Klamath Hydroelectric Settlement Agreement ("KHSA"). Among other things, the KHSA provided that that United States Department of the Interior would conduct scientific and engineering studies to assess whether removal of the Klamath hydroelectric system's mainstem dams was in the public interest and would advance restoration of the Klamath Basin's salmonid fisheries. If it was determined that dam removal should proceed, dam removal would begin no earlier than 2020. Congress failed to pass legislation needed to implement the original KHSA. In April 2016, the principal parties to the KHSA (PacifiCorp, the states of California and Oregon and the United States Departments of the Interior and Commerce) executed an amendment to the KHSA. Consistent with the terms of the amended KHSA, in September 2016, PacifiCorp and the Klamath River Renewal Corporation ("KRRC"), a private, independent nonprofit 501(c)(3) organization formed by certain signatories of the amended KSHA, jointly filed an application with the FERC to transfer the license for the four mainstem Klamath River hydroelectric generating facilities from PacifiCorp to the KRRC. Also in September 2016, the KRRC filed an application with the FERC to surrender the license and decommission the same four facilities. The KRRC's license surrender application included a request for the FERC to refrain from acting on the surrender application until after the transfer of the license to the KRRC is effective. In March 2018, the FERC issued an order splitting the existing license for the Klamath Project into two licenses: the Klamath Project (P‑2082) contains East Side, West Side, Keno and Fall Creek developments; the new Lower Klamath Project (P‑14803) contains J.C. Boyle, Copco No. 1, Copco No. 2 and Iron Gate developments. In the same order, the FERC deferred consideration of the transfer of the license for the Lower Klamath facilities from PacifiCorp to the KRRC until some point in the future. PacifiCorp is currently the licensee for both the Klamath Project and Lower Klamath Project facilities and will retain ownership of the Klamath Project facilities after the approval and transfer of the Lower Klamath Project facilities. In April 2018, PacifiCorp filed a motion to stay the effective date of the license amendment until transfer is approved. In June 2018, the FERC granted PacifiCorp’s motion to stay the effective date of the Lower Klamath Project license and all related compliance obligations, pending a Commission order on the license transfer. Meanwhile, the FERC continues to assess the KRRC’s capacity to become a project licensee for purposes of dam removal. Under the amended KHSA, PacifiCorp and its customers are protected from uncapped dam removal costs and liabilities. The KRRC must indemnify PacifiCorp from liabilities associated with dam removal. The amended KHSA also limits PacifiCorp's contribution to facilities removal costs to no more than $200 million, of which up to $184 million would be collected from PacifiCorp's Oregon customers with the remainder to be collected from PacifiCorp's California customers. California voters approved a water bond measure in November 2014 from which the state of California's contribution toward facilities removal costs are being drawn. In accordance with this bond measure, additional funding of up to $250 million for facilities removal costs was included in the California state budget in 2016, with the funding effective for at least five years. If facilities removal costs exceed the combined funding that will be available from PacifiCorp's Oregon and California customers and the state of California, sufficient funds would need to be provided by the KRRC or an entity other than PacifiCorp for removal to proceed. If certain conditions in the amended KHSA are not satisfied and the license does not transfer to the KRRC, PacifiCorp will resume relicensing with the FERC. Guarantees The Company has entered into guarantees as part of the normal course of business and the sale of certain assets. These guarantees are not expected to have a material impact on the Company's consolidated financial results.
PacifiCorp [Member]
Loss Contingencies [Line Items]
Commitments and Contingencies	Commitments and Contingencies Commitments During the six-month period ended June 30, 2018, PacifiCorp entered into non-cancelable agreements totaling $613 million through 2021 for the repowering of certain existing wind facilities in Wyoming and Washington and supply of coal. Legal Matters PacifiCorp is party to a variety of legal actions arising out of the normal course of business. Plaintiffs occasionally seek punitive or exemplary damages. PacifiCorp does not believe that such normal and routine litigation will have a material impact on its consolidated financial results. Environmental Laws and Regulations PacifiCorp is subject to federal, state and local laws and regulations regarding air and water quality, renewable portfolio standards, emissions performance standards, climate change, coal combustion byproduct disposal, hazardous and solid waste disposal, protected species and other environmental matters that have the potential to impact PacifiCorp's current and future operations. PacifiCorp believes it is in material compliance with all applicable laws and regulations. Hydroelectric Relicensing PacifiCorp's Klamath hydroelectric system is currently operating under annual licenses with the Federal Energy Regulatory Commission ("FERC"). In February 2010, PacifiCorp, the United States Department of the Interior, the United States Department of Commerce, the state of California, the state of Oregon and various other governmental and non-governmental settlement parties signed the Klamath Hydroelectric Settlement Agreement ("KHSA"). Among other things, the KHSA provided that that United States Department of the Interior would conduct scientific and engineering studies to assess whether removal of the Klamath hydroelectric system's mainstem dams was in the public interest and would advance restoration of the Klamath Basin's salmonid fisheries. If it was determined that dam removal should proceed, dam removal would begin no earlier than 2020. Congress failed to pass legislation needed to implement the original KHSA. In April 2016, the principal parties to the KHSA (PacifiCorp, the states of California and Oregon and the United States Departments of the Interior and Commerce) executed an amendment to the KHSA. Consistent with the terms of the amended KHSA, in September 2016, PacifiCorp and the Klamath River Renewal Corporation ("KRRC"), a private, independent nonprofit 501(c)(3) organization formed by certain signatories of the amended KSHA, jointly filed an application with the FERC to transfer the license for the four mainstem Klamath River hydroelectric generating facilities from PacifiCorp to the KRRC. Also in September 2016, the KRRC filed an application with the FERC to surrender the license and decommission the same four facilities. The KRRC's license surrender application included a request for the FERC to refrain from acting on the surrender application until after the transfer of the license to the KRRC is effective. In March 2018, the FERC issued an order splitting the existing license for the Klamath Project into two licenses: the Klamath Project (P‑2082) contains East Side, West Side, Keno and Fall Creek developments; the new Lower Klamath Project (P‑14803) contains J.C. Boyle, Copco No. 1, Copco No. 2 and Iron Gate developments. In the same order, the FERC deferred consideration of the transfer of the license for the Lower Klamath facilities from PacifiCorp to the KRRC until some point in the future. PacifiCorp is currently the licensee for both the Klamath Project and Lower Klamath Project facilities and will retain ownership of the Klamath Project facilities after the approval and transfer of the Lower Klamath Project facilities. In April 2018, PacifiCorp filed a motion to stay the effective date of the license amendment until transfer is approved. In June 2018, the FERC granted PacifiCorp’s motion to stay the effective date of the Lower Klamath Project license and all related compliance obligations, pending a Commission order on the license transfer. Meanwhile, the FERC continues to assess the KRRC’s capacity to become a project licensee for purposes of dam removal. Under the amended KHSA, PacifiCorp and its customers are protected from uncapped dam removal costs and liabilities. The KRRC must indemnify PacifiCorp from liabilities associated with dam removal. The amended KHSA also limits PacifiCorp's contribution to facilities removal costs to no more than $200 million, of which up to $184 million would be collected from PacifiCorp's Oregon customers with the remainder to be collected from PacifiCorp's California customers. California voters approved a water bond measure in November 2014 from which the state of California's contribution toward facilities removal costs are being drawn. In accordance with this bond measure, additional funding of up to $250 million for facilities removal costs was included in the California state budget in 2016, with the funding effective for at least five years. If facilities removal costs exceed the combined funding that will be available from PacifiCorp's Oregon and California customers and the state of California, sufficient funds would need to be provided by the KRRC or an entity other than PacifiCorp for removal to proceed. If certain conditions in the amended KHSA are not satisfied and the license does not transfer to the KRRC, PacifiCorp will resume relicensing with the FERC. Guarantees PacifiCorp has entered into guarantees as part of the normal course of business and the sale of certain assets. These guarantees are not expected to have a material impact on PacifiCorp's consolidated financial results.
MidAmerican Energy Company [Member]
Loss Contingencies [Line Items]
Commitments and Contingencies	Commitments and Contingencies Easements During the six-month period ended June 30, 2018, MidAmerican Energy entered into non-cancelable easements with minimum payments totaling $283 million through 2058 for land in Iowa on which some of its wind-powered generating facilities will be located. Legal Matters MidAmerican Energy is party to a variety of legal actions arising out of the normal course of business. Plaintiffs occasionally seek punitive or exemplary damages. MidAmerican Energy does not believe that such normal and routine litigation will have a material impact on its financial results. Environmental Laws and Regulations MidAmerican Energy is subject to federal, state and local laws and regulations regarding air and water quality, emissions performance standards, climate change, coal combustion byproduct disposal, hazardous and solid waste disposal, protected species and other environmental matters that have the potential to impact its current and future operations. MidAmerican Energy believes it is in material compliance with all applicable laws and regulations. Transmission Rates MidAmerican Energy's wholesale transmission rates are set annually using FERC-approved formula rates subject to true-up for actual cost of service. Prior to September 2016, the rates in effect were based on a 12.38% return on equity ("ROE"). In November 2013 and February 2015, a coalition of intervenors filed successive complaints with the FERC requesting that the 12.38% ROE no longer be found just and reasonable and sought to reduce the base ROE to 9.15% and 8.67%, respectively. MidAmerican Energy is authorized by the FERC to include a 0.50% adder beyond the base ROE effective January 2015. In September 2016, the FERC issued an order for the first complaint, which reduces the base ROE to 10.32% and required refunds, plus interest, for the period from November 2013 through February 2015. Customer refunds relative to the first complaint occurred in February 2017. It is uncertain when the FERC will rule on the second complaint, covering the period from February 2015 through May 2016. MidAmerican Energy believes it is probable that the FERC will order a base ROE lower than 12.38% in the second complaint and, as of June 30, 2018, has accrued a $10 million liability for refunds under the second complaint of amounts collected under the higher ROE from March 2015 through May 2016. Retail Regulated Rates In December 2017, 2017 Tax Reform was signed into law, reducing the federal tax rate from 35% to 21%. Accumulated deferred income tax balances were re-measured at the 21% rate and regulatory liabilities increased reflective of the probability of such balances being passed back to customers. MidAmerican Energy has made filings or has been in discussions with each of its state rate regulatory bodies proposing either a reduction in retail rates or rate base for all or a portion of the net benefits of 2017 Tax Reform for 2018 and beyond. MidAmerican Energy proposed in Iowa, its largest jurisdiction, to reduce customer revenue via a rider mechanism for the impact of the lower statutory rate on current operations, subject to change depending on actual results, and defer as a regulatory liability the amortization of excess deferred income taxes. The Illinois Commerce Commission approved MidAmerican Energy's Illinois tax reform rate reduction tariff on March 21, 2018, and the Iowa Utilities Board approved MidAmerican Energy's Iowa tax reform rate reduction tariff on April 27, 2018. The approved tax reform rider mechanisms for each jurisdiction function consistent with MidAmerican Energy's other bill riders in that over or under collection from customers at any given time is included in accounts receivable, net, on the Balance Sheets.
MidAmerican Funding, LLC and Subsidiaries [Domain]
Loss Contingencies [Line Items]
Commitments and Contingencies	Commitments and Contingencies MidAmerican Funding is party to a variety of legal actions arising out of the normal course of business. Plaintiffs occasionally seek punitive or exemplary damages. MidAmerican Funding does not believe that such normal and routine litigation will have a material impact on its consolidated financial results. Refer to Note 10 of MidAmerican Energy's Notes to Financial Statements.
Nevada Power Company [Member]
Loss Contingencies [Line Items]
Commitments and Contingencies	Commitments and Contingencies Environmental Laws and Regulations Nevada Power is subject to federal, state and local laws and regulations regarding air and water quality, renewable portfolio standards, emissions performance standards, climate change, coal combustion byproduct disposal, hazardous and solid waste disposal, protected species and other environmental matters that have the potential to impact Nevada Power's current and future operations. Nevada Power believes it is in material compliance with all applicable laws and regulations. Legal Matters Nevada Power is party to a variety of legal actions arising out of the normal course of business. Plaintiffs occasionally seek punitive or exemplary damages. Nevada Power does not believe that such normal and routine litigation will have a material impact on its consolidated financial results.
Sierra Pacific Power Company [Member]
Loss Contingencies [Line Items]
Commitments and Contingencies	Commitments and Contingencies Environmental Laws and Regulations Sierra Pacific is subject to federal, state and local laws and regulations regarding air and water quality, renewable portfolio standards, emissions performance standards, climate change, coal combustion byproduct disposal, hazardous and solid waste disposal, protected species and other environmental matters that have the potential to impact Sierra Pacific's current and future operations. Sierra Pacific believes it is in material compliance with all applicable laws and regulations. Legal Matters Sierra Pacific is party to a variety of legal actions arising out of the normal course of business. Plaintiffs occasionally seek punitive or exemplary damages. Sierra Pacific does not believe that such normal and routine litigation will have a material impact on its consolidated financial results.