Regulatory Matters (Details) - USD ($) $ in Millions		3 Months Ended		12 Months Ended			36 Months Ended
Regulatory Matters (Details) - USD ($) $ in Millions	Aug. 01, 2023	Jun. 30, 2025	Mar. 31, 2025	Sep. 30, 2027	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2027	Nov. 01, 2025
NEW YORK \| Forecast
Regulatory Matters [Line Items]
Rate plan period							3 years
Approved Return on Equity (as a percent)							9.70%
Increase in annual revenue requirement in first year						$ 57.3
Additional increase in annual revenue requirement in second year					$ 15.8
Additional increase in annual revenue requirement in third year				$ 12.7
Reduction to annual revenue requirement for actuarial projections of pension and other-post retirement benefit income expected to be recognized				$ 14.0	$ 14.0	$ 14.0
PENNSYLVANIA
Regulatory Matters [Line Items]
Public utilities authorized rate increase, amount	$ 23.0
Public utilities distribution system improvement charge recovered from customers		$ 0.3	$ 0.2
Empire \| Forecast
Regulatory Matters [Line Items]
FERC estimated annual reduction of revenue amount								$ 0.5