Commitments and Contingencies	6 Months Ended
Commitments and Contingencies	Jun. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Contingencies FERC Return on Equity (ROE). In November 2013 and February 2015, customers filed complaints with the Federal Energy Regulatory Commission (FERC) seeking to reduce the ROE component of the transmission rates that MISO transmission owners, including OTP, may collect under the MISO tariff rate. FERC's most recent order, issued on November 19, 2020, adopted a revised ROE methodology and set the base ROE at 10.02% (10.52% with an adder) effective for the fifteen-month period from November 2013 to February 2015 and on a prospective basis beginning in September 2016. The order also dismissed any complaints covering the period from February 2015 to May 2016. On August 9, 2022, the U.S. Court of Appeals for the District of Columbia Circuit vacated the FERC order citing a lack of reasoned explanation by FERC in its adoption of its revised ROE methodology as outlined in its November 2020 order and remanded the matter to FERC to reopen the proceedings. In July 2024, FERC counsel indicated that the FERC plans to act within 120 days on the U.S. Court of Appeals remand and that the expectation is there will be no further briefings on the matter; rather, FERC intends to issue an order based on the record developed to date to resolve the ROE matter and remand proceedings. Although FERC has indicated they will act on the remand before the end of the year, uncertainty remains as to what specific actions FERC will take in their final order. As a result, we have continued to defer recognition of certain revenues and recognize a refund liability related to this matter. The balance of the recorded refund liability was $2.9 million as of June 30, 2024, which is included in other current liabilities on the consolidated balance sheets. This refund liability reflects our best estimate of amounts previously collected from customers under the MISO tariff rate that may be required to be refunded to customers once all regulatory and judicial proceedings are complete and a final ROE is established for the periods outlined above. Regional Haze Rule (RHR). The RHR was adopted in an effort to improve visibility in national parks and wilderness areas. The RHR requires states, in coordination with the Environmental Protection Agency (EPA) and other governmental agencies, to develop and implement plans to achieve natural visibility conditions. The second RHR implementation period covers the years 2018-2028. States are required to submit a state implementation plan to assess reasonable progress with the RHR and determine what additional emission reductions are appropriate, if any. Coyote Station, OTP's jointly owned coal-fired power plant in North Dakota, is subject to assessment in the second implementation period under the North Dakota state implementation plan. The North Dakota Department of Environmental Quality (NDDEQ) submitted its state implementation plan to the EPA for approval in August 2022. In its plan, the NDDEQ concluded it is not reasonable to require additional emission controls during this planning period. In June 2023, a coalition of environmental organizations filed a lawsuit against the EPA for failing to enforce the RHR. In response, the EPA proposed, through a consent decree filed in the U.S. District Court for the District of Columbia in March 2024, a timeline for it to act on 34 outstanding state implementation plans. Under the consent decree, which was issued on July 12, 2024, the EPA would approve, deny, partially approve or issue a federal implementation plan at assigned dates between 2024 and 2026, including a final decision on the North Dakota state implementation plan by November 2024. In July 2024, the EPA published its proposed rule for North Dakota’s state implementation plan, in which the EPA proposed to approve certain aspects of the state implementation plan and disapprove of other aspects of the plan. The EPA proposes to find that North Dakota failed to submit a long-term strategy that includes enforceable emissions limitations, compliance schedules, and other measures necessary to make reasonable progress on national visibility goals. Specific to Coyote Station, the EPA contends North Dakota relied on non-statutory visibility modeling to reject the installation of emission controls. The EPA also proposes to find the North Dakota plan does not adequately demonstrate that existing limits for NOx and SO2 at Coyote Station are sufficient to ensure progress towards the national visibility goals. The proposed rule remains subject to a 30-day comment period. We continue to anticipate final EPA action by November 2024. We cannot predict with certainty the final resolution of regional haze compliance in North Dakota and specifically the impact, if any, on the operations of Coyote Station. However, significant emission control investments could be required and the recovery of such costs from customers would require regulatory approval. Alternatively, investments in emission control equipment may prove to be uneconomic and result in the early retirement, or sale, of our interest in Coyote Station, which would be subject to regulatory approval. We cannot estimate the ultimate financial effects such a retirement or sale may have on our consolidated operating results, financial position or cash flows, but such amounts could be material and the recovery of such costs in rates would be subject to regulatory approval. Self-Funding of Transmission Upgrades for Generator Interconnections. The FERC has granted transmission owners within MISO the unilateral authority to determine the funding mechanism for interconnection transmission upgrades that are necessary to accommodate new generation facilities connecting to the electrical grid. Under existing FERC orders, transmission owners can unilaterally determine whether the generator pays the transmission owner in advance for the transmission upgrade or, alternatively, the transmission owner can elect to fund the upgrade and recover over time from the generator the cost of and a return on the upgrade investment (a self-funding). FERC’s orders granting transmission owners this unilateral funding authority have been judicially contested on the basis that transmission owners may be motivated to discriminate among generators in making funding determinations. In the most recent judicial proceedings, the petitioners argued to the U.S. Court of Appeals for the District of Columbia that FERC did not comply with a previous judicial order to fully develop a record regarding the risk of discrimination and the financial risk absorbed by transmission owners for generator-funded upgrades. In December 2022, the Court of Appeals ruled in favor of the petitioners remanding the matter to FERC, instructing the agency to adequately explain the basis of its orders. The Court of Appeals decision did not vacate transmission owners’ unilateral funding authority. On June 13, 2024, FERC issued an Order to Show Cause proceeding against four Regional Transmission Organizations (RTOs), including MISO. Within its order, FERC indicates that the transmission tariffs of the RTOs appear to be unjust, unreasonable, and unduly discriminatory or preferential because they allow transmission owners to unilaterally elect transmission owner self-funding, which may increase costs, impose barriers to transmission interconnection and result in undue discrimination among interconnection customers. The order requires each RTO to submit filings to either 1) show cause as to why the transmission tariff remains just and reasonable and not duly discriminatory or preferential, or 2) to explain what changes to the tariff it believes would remedy the identified concerns. The RTO filings are due 90 days after the order was issued and interested entities may file within 30 days thereafter to address the RTOs filings. The order also stipulates that if no final decision is reached by the conclusion of a 180-day period from the issuance of the order, FERC shall state the reasons why it did not act and provide its best estimate when it expects to issue a decision. FERC contemporaneously issued an order suspending the pending remand on the related case. On July 15, 2024, a group of utilities, not including OTP, submitted to FERC a request for rehearing of the order on the basis of the legal and statutory authority of the order. In the alternative, the utilities also requested FERC rescind or withdraw the order. OTP, as a transmission owner in MISO, has exercised its authority and elected to self-fund previous transmission upgrades necessary to accommodate new system generation. Under such an election, OTP is recovering the cost of the transmission upgrade and a return on that investment from the generator over a contractual period of time. Should the resolution of this matter eliminate transmission owners’ unilateral funding authority on either a prospective or retrospective basis, our financial results would be impacted. We cannot at this time reasonably predict the outcome of this matter given the uncertainty as to how FERC may ultimately decide on the matter after RTO's filings in response to the Order to Show Cause. Other Contingencies. We are party to litigation and regulatory matters arising in the normal course of business. We regularly analyze relevant information and, as necessary, estimate and record accrued liabilities for legal, regulatory enforcement and other matters in which a loss is probable of occurring and can be reasonably estimated. We believe the effect on our consolidated operating results, financial position and cash flows, if any, for the disposition of all matters pending as of June 30, 2024, other than those discussed above, will not be material.