Commitments and Contingent Liabilities - Narrative (Details) gal in Millions, $ in Millions	6 Months Ended
Jun. 30, 2026 USD ($) gal
NJWSA Untreated Water Agreement
Loss Contingencies [Line Items]
Average purchase of gallons a day under agreement (in mgd)	27.0
NJWSA Untreated Water Agreement \| Maximum
Loss Contingencies [Line Items]
Average purchase of gallons a day under agreement (in mgd)	47.0
NJBPU Treated Water Agreement \| Minimum
Loss Contingencies [Line Items]
Average purchase of gallons a day under agreement (in mgd)	3.0
Treated Water
Loss Contingencies [Line Items]
Average purchase of gallons	75.0
Construction Agreement
Loss Contingencies [Line Items]
Estimated future expenditure obligation \| $	$ 52.8

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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