Nature of Business and Basis of Presentation	3 Months Ended
Nature of Business and Basis of Presentation	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business and Basis of Presentation	Nature of Business and Basis of Presentation General NRG Energy, Inc., or NRG or the Company, sits at the intersection of energy and home services. NRG is a leading energy and home services company fueled by market-leading brands, proprietary technologies, and complementary sales channels. Across the United States and Canada, NRG delivers innovative, sustainable solutions, predominately under brand names such as NRG, Reliant, Direct Energy, Green Mountain Energy and Vivint, while also advocating for competitive energy markets and customer choice. The Company has a customer base that includes approximately 8.0 million residential consumers in addition to commercial, industrial, and wholesale customers, supported by approximately 13 GW of generation as of March 31, 2024. The Company's business is segmented as follows: •Texas, which includes all activity related to customer, plant and market operations in Texas, other than Cottonwood; •East, which includes all activity related to customer, plant and market operations in the East; •West/Services/Other, which includes the following assets and activities: (i) all activity related to customer, plant and market operations in the West and Canada, (ii) the Services businesses (iii) activity related to the Cottonwood facility and other investments; •Vivint Smart Home; and •Corporate activities. The accompanying unaudited interim condensed consolidated financial statements have been prepared in accordance with the SEC's regulations for interim financial information and with the instructions to Form 10-Q. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. The following notes should be read in conjunction with the accounting policies and other disclosures as set forth in the notes to the consolidated financial statements in the Company's 2023 Form 10-K. Interim results are not necessarily indicative of results for a full year. In the opinion of management, the accompanying unaudited interim condensed consolidated financial statements contain all material adjustments consisting of normal and recurring accruals necessary to present fairly the Company's consolidated financial position as of March 31, 2024, and the results of operations, comprehensive income/(loss), cash flows and stockholders' equity for the three months ended March 31, 2024 and 2023. The Company identified an error in the previously issued condensed consolidated financial statements for the period ended March 31, 2023 related to the presentation of cash flows associated with certain borrowings and repayments related to certain credit facilities. The statement of cash flows for the period ended March 31, 2023 has been adjusted to present on a gross basis the certain borrowings from credit facilities of $1.1 billion and the related repayments of $825 million. The change had no impact to the total cash used by financing activities for the period ended March 31, 2023. The Company evaluated the materiality of this error both qualitatively and quantitatively and has concluded it is immaterial to the impacted period. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates. Reclassifications Certain prior period amounts have been reclassified for comparative purposes. The reclassifications did not affect consolidated results of operations, net assets or consolidated cash flows.