Subsequent event (Details) - Term Loan Agreement - WBI Energy Transmission - Subsequent Event $ in Millions	Apr. 01, 2024 USD ($)
Subsequent Events [Line Items]
Debt instrument, face amount	$ 60.0
Interest rate, stated percentage	4.52%
Ratio of total debt to total capitalization	65.00%

Face (par) amount of debt instrument at time of issuance.

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Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant