Financing - Debt (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2023	Dec. 31, 2022
Unsecured Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 3,300.0
Debt, Weighted-Average Interest Rate	4.84%
Debt Instrument, Covenant Compliance	As of March 31, 2023, Boardwalk Pipelines and its operating subsidiaries were in compliance with their debt covenants.
Line of Credit
Line of Credit Facility [Abstract]
Line of Credit Facility, Remaining Borrowing Capacity	$ 1,000.0	$ 1,000.0
Line of Credit Facility, Covenant Compliance	The Company and its subsidiaries were in compliance with all covenant requirements under its revolving credit facility as of March 31, 2023.
Line of Credit \| Amendment No. 3 Credit Agreement - 2021
Line of Credit Facility [Abstract]
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,000.0

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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