{"cik":52485,"taxonomy":"us-gaap","tag":"CommonStockParOrStatedValuePerShare","label":"Common Stock, Par or Stated Value Per Share","description":"Face amount or stated value per share of common stock.","entityName":"INTERSTATE POWER & LIGHT CO","units":{"USD/shares":[{"end":"2025-12-31","val":0.01,"accn":"0000352541-26-000043","fy":2026,"fp":"Q2","form":"10-Q","filed":"2026-07-31","frame":"CY2025Q4I"},{"end":"2026-06-30","val":0.01,"accn":"0000352541-26-000043","fy":2026,"fp":"Q2","form":"10-Q","filed":"2026-07-31","frame":"CY2026Q2I"}]}}