0000052485 2026-08-19 2026-08-19 0000052485 1 2026-08-19 2026-08-19 iso4217:USD pure shares S-3 424B5 EX-FILING FEES 333-276062-01 0000052485 INTERSTATE POWER & LIGHT CO N/A N/A S-3 INTERSTATE POWER & LIGHT CO false Debt 5.100% Senior Debentures due 2031 true 500000000 0.99889 499445000.00 0.0001381 68973.35 499445000.00 68973.35 0.00 0.00 68973.35 Calculated in accordance with Rule 457(o) under the Securities Act of 1933, as amended (the "Securities Act"), based on the proposed maximum aggregate offering price, and Rules 456(b) and 457(r) under the Securities Act, pursuant to which the registrant initially deferred payment of all of the registration fees for the Registration Statement on Form S-3 (Registration No. 333-276062-01), filed with the Securities and Exchange Commission on December 15, 2023. 499445000.00 true