Regulatory Matters	12 Months Ended
Regulatory Matters	Dec. 31, 2024
Regulated Operations [Abstract]
Regulatory Matters	Regulatory Matters Environmental regulatory matters are discussed within Note 24, Environmental Matters. NRG operates in a highly regulated industry and is subject to regulation by various federal, state and provincial agencies. As such, NRG is affected by regulatory developments at the federal, state and provincial levels and in the regions in which NRG operates. In addition, NRG is subject to the market rules, procedures, and protocols of the various ISO and RTO markets in which NRG participates. These power markets are subject to ongoing legislative and regulatory changes that may impact NRG's wholesale and retail operations. In addition to the regulatory proceedings noted below, NRG and its subsidiaries are parties to other regulatory proceedings arising in the ordinary course of business or have other regulatory exposure. In management's opinion, the disposition of these ordinary course matters will not materially adversely affect NRG's consolidated financial position, results of operations, or cash flows. California Station Power — As the result of unfavorable final and non-appealable litigation, the Company accrued a liability associated with consumption of station power at the Company's Encina power plant facility in California after August 30, 2010. The Company has established an appropriate accrual pending potential regulatory action by San Diego Gas & Electric regarding the Company's Encina facility. Federal Trade Commission Investigation — In 2019, Vivint Smart Home received a civil investigative demand from the staff of the Federal Trade Commission (“FTC”) concerning potential violations of the Fair Credit Reporting Act and the “Red Flags Rule” thereunder, and the FTC Act. In April 2021, Vivint Smart Home entered into a settlement with the FTC that resolved this investigation. As part of this settlement, Vivint Smart Home paid $20 million and agreed to implement various additional compliance related measures ("Stipulated Order"). The Company is engaged in ongoing discussions with the staff of the FTC regarding the Company’s compliance with the terms of the Stipulated Order. Under the terms of the Stipulated Order, Vivint Smart Home is required to undertake biennial assessments by an independent third-party assessor (the "Assessor"), which reviews Vivint Smart Home’s compliance program and provides a report on Vivint Smart Home’s ongoing compliance with the Stipulated Order. Since its inception until December 31, 2023, Vivint Smart Home has completed its initial assessment and its first biennial assessment as required by the Stipulated Order. In addition, Vivint Smart Home has voluntarily undertaken nine quarterly audits by the appointed Assessor. In all the assessments, Vivint Smart Home received a report from the Assessor with no findings of non-compliance of any kind. New York State Public Service Commission ("NYSPSC") - Notice of Apparent Violation — The NYSPSC issued an order referred to as the Retail Reset Order in December 2019 that limited ESCO's offers for electric and natural gas to three compliant products: guaranteed savings from the utility default rate, a fixed rate commodity product that is priced at no more than 5% greater than the trailing 12-month average utility supply rate or New York-sourced renewable energy that is at least 50% greater than the prevailing New York Renewable Energy Standard for load serving entities. The order effectively limited ESCO offers to natural gas customers to only the guaranteed savings and capped fixed term compliant products because no equivalent renewable energy product exists for natural gas. NRG took action to comply with the order when it became effective April 16, 2021. On January 8, 2024, the NYSPSC notified eight of NRG's retail energy suppliers (serving both electricity and natural gas) of alleged non-compliance with New York regulatory requirements. Among other items, the notices allege that the NRG suppliers did not transition existing residential customers to one of the three compliant products authorized by the NYSPSC following the effective date of the order. NRG responded to the notices in February 2024. The Company believes it has complied with the Retail Reset Order and does not agree with the NYSPSC's assertions made in the notice. The outcome of this process has the potential to negatively impact the retail business in New York.