0001111711 2026-05-18 2026-05-18 false 0001111711 8-K 2026-05-18 NiSource Inc. DE 001-16189 35-2108964 801 East 86th Avenue Merrillville IN 46410 (614) 460-6000 false false false false Common Stock, par value $0.01 per share NI NYSE false