Regulatory Matters	9 Months Ended
Sep. 30, 2026
Regulated Operations [Abstract]
Regulatory Matters	2. REGULATORY MATTERS Regulatory Rate Review On June 17, 2026, the IURC issued an order (the “2026 Base Rate Order”) approving in part the Stipulation and Settlement Agreement that AES Indiana entered into on October 15, 2025 with most parties in AES Indiana’s base rate case filing. Among other things, the 2026 Base Rate Order establishes a revenue requirement of $1,979.7 million for AES Indiana’s 2027 electric service base rates, provides for a return on common equity of 9.50% using the capital structure of 49.47% common equity and 50.53% long-term debt and cost of long-term debt of 5.34%, and establishes a rate base of $5.5 billion for AES Indiana’s 2027 electric service base rates. In addition, the 2026 Base Rate Order includes a commitment to not implement additional base rate increases, following the implementation of new basic rates and charges under the 2026 Base Rate Order, until at least January of 2030 and to not start a second TDSIC Plan before January of 2028. On July 7, 2026, the OUCC and CAC (parties to the regulatory rate review) each filed a petition for reconsideration and rehearing with the IURC. On July 17, 2026, the OUCC also filed a notice of appeal with the Court of Appeals of Indiana. Following the petitions for reconsideration, on September 2, 2026, the IURC granted (i) the OUCC's request to reconsider the 2026 Base Rate Order based on the IURC's weighing of the five pillars of electric utility service and (ii) the CAC's request to reopen the record for the limited capacity of gathering any new evidence applicable to the rate case concerning the Google Monrovia data center project and the pending AES Merger. A preliminary hearing was held on September 17, 2026 establishing a procedural schedule on this case, and the IURC has set an evidentiary hearing to begin on March 11, 2027. AES Indiana will implement new basic rates and charges authorized under the 2026 Base Rate Order in two phases. Phase one rates and charges became effective on July 27, 2026. Phase two rates and charges are anticipated to be effective in the first quarter of 2027. New basic rates and charges are subject to refund pending resolution of the regulatory petitions and legal appeal processes. HEA 1007 - Large Load Customer Project Filing On April 22, 2026, AES Indiana filed a petition and case in chief seeking IURC approval related to certain generation resources and energy infrastructure investments required to serve increasing demand in AES Indiana's service territory, primarily driven by the anticipated demand for a new data center campus to be located in Monrovia, Indiana, which is being developed by a subsidiary of Alphabet, Inc. (the “Customer”). This energy infrastructure and generation resources primarily required to serve the Customer is referred to as the “Monrovia Project.” AES Indiana is also seeking approval of various accounting and ratemaking requests associated with the Monrovia Project. As part of developing this comprehensive plan, AES Indiana has incorporated certain protections for existing and future customers that ensure the costs of the generation resources and energy infrastructure upgrades required benefit all customers, are fairly allocated, and follow cost causation/beneficiary pays regulatory principles. The petition includes AES Indiana's plan to serve this increasing demand through the acquisition and development of additional generation resources, including solar and energy storage projects, sufficient to provide 390 MW of new load by the end of 2029. AES Indiana is seeking approval to acquire two development-stage renewables projects located in Indiana, including i) Crosstrack, a 130 MW solar and 130 MW (520 MWh) energy storage project in Pike County with a planned in-service date in late 2028 and ii) Foundry Works, a 200 MW (800 MWh) energy storage project in Lake County with a planned in-service date in mid-2028. Additionally, AES Indiana is seeking approval to develop and construct a 130 MW (520 MWh) energy storage project at its existing Hardy Hills renewable facility in Clinton County with a planned in-service date in March 2029. The petition also includes AES Indiana's plan to develop and construct specific transmission network upgrades and enhancements required to serve the increasing demand, including seeking approval of a construction service agreement executed with the Customer. AES Indiana is also seeking approval of an electric services agreement ("ESA") executed with the Customer to provide high-voltage retail electric service to the new data center campus, which includes financial assurances, minimum demand commitments, and exit provisions as protections for existing customers. The rates and charges that the Customer will pay under these agreements will be sufficient to reimburse AES Indiana for the incremental annual revenue requirement associated with the Monrovia Project. On October 7, 2026, the IURC issued an order approving AES Indiana's petition and plan to serve the Monrovia Project.

On June 17, 2026, the IURC issued an order (the “2026 Base Rate Order”) approving in part the Stipulation and Settlement Agreement that AES Indiana entered into on October 15, 2025 with most parties in AES Indiana’s base rate case filing. Among other things, the 2026 Base Rate Order establishes a revenue requirement of $1,979.7 million for AES Indiana’s 2027 electric service base rates, provides for a return on common equity of 9.50% using the capital structure of 49.47% common equity and 50.53% long-term debt and cost of long-term debt of 5.34%, and establishes a rate base of $5.5 billion for AES Indiana’s 2027 electric service base rates. In addition, the 2026 Base Rate Order includes a commitment to not implement additional base rate increases, following the implementation of new basic rates and charges under the 2026 Base Rate Order, until at least January of 2030 and to not start a second TDSIC Plan before January of 2028.

On July 7, 2026, the OUCC and CAC (parties to the regulatory rate review) each filed a petition for reconsideration and rehearing with the IURC. On July 17, 2026, the OUCC also filed a notice of appeal with the Court of Appeals of Indiana. Following the petitions for reconsideration, on September 2, 2026, the IURC granted (i) the OUCC's request to reconsider the 2026 Base Rate Order based on the IURC's weighing of the five pillars of electric utility service and (ii) the CAC's request to reopen the record for the limited capacity of gathering any new evidence applicable to the rate case concerning the Google Monrovia data center project and the pending AES Merger. A preliminary hearing was held on September 17, 2026 establishing a procedural schedule on this case, and the IURC has set an evidentiary hearing to begin on March 11, 2027.

AES Indiana will implement new basic rates and charges authorized under the 2026 Base Rate Order in two phases. Phase one rates and charges became effective on July 27, 2026. Phase two rates and charges are anticipated to be effective in the first quarter of 2027. New basic rates and charges are subject to refund pending resolution of the regulatory petitions and legal appeal processes.

On April 22, 2026, AES Indiana filed a petition and case in chief seeking IURC approval related to certain generation resources and energy infrastructure investments required to serve increasing demand in AES Indiana's service territory, primarily driven by the anticipated demand for a new data center campus to be located in Monrovia, Indiana, which is being developed by a subsidiary of Alphabet, Inc. (the “Customer”). This energy infrastructure and generation resources primarily required to serve the Customer is referred to as the “Monrovia Project.” AES Indiana is also seeking approval of various accounting and ratemaking requests associated with the Monrovia Project. As part of developing this comprehensive plan, AES Indiana has incorporated certain protections for existing and future customers that ensure the costs of the generation resources and energy infrastructure upgrades required benefit all customers, are fairly allocated, and follow cost causation/beneficiary pays regulatory principles.

The petition includes AES Indiana's plan to serve this increasing demand through the acquisition and development of additional generation resources, including solar and energy storage projects, sufficient to provide 390 MW of new load by the end of 2029. AES Indiana is seeking approval to acquire two development-stage renewables projects located in Indiana, including i) Crosstrack, a 130 MW solar and 130 MW (520 MWh) energy storage project in Pike County with a planned in-service date in late 2028 and ii) Foundry Works, a 200 MW (800 MWh) energy storage project in Lake County with a planned in-service date in mid-2028. Additionally, AES Indiana is seeking approval to develop and construct a 130 MW (520 MWh) energy storage project at its existing Hardy Hills renewable facility in Clinton County with a planned in-service date in March 2029.

The petition also includes AES Indiana's plan to develop and construct specific transmission network upgrades and enhancements required to serve the increasing demand, including seeking approval of a construction service agreement executed with the Customer. AES Indiana is also seeking approval of an electric services agreement ("ESA") executed with the Customer to provide high-voltage retail electric service to the new data center campus, which includes financial assurances, minimum demand commitments, and exit provisions as protections for existing customers. The rates and charges that the Customer will pay under these agreements will be sufficient to reimburse AES Indiana for the incremental annual revenue requirement associated with the Monrovia Project.