Significant Accounting Policies - Components of Property and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property and equipment	$ 11,544.2	$ 11,330.5
Accumulated depreciation	(5,137.2)	(4,774.5)
Property and equipment, net of accumulated depreciation	6,407.0	6,556.0
Transmission assets
Property, Plant and Equipment [Line Items]
Property and equipment	$ 1,459.5	1,452.0
Transmission assets | Minimum
Property, Plant and Equipment [Line Items]
Useful life	20 years
Transmission assets | Maximum
Property, Plant and Equipment [Line Items]
Useful life	25 years
Gathering systems
Property, Plant and Equipment [Line Items]
Property and equipment	$ 5,472.4	5,370.0
Gathering systems | Minimum
Property, Plant and Equipment [Line Items]
Useful life	20 years
Gathering systems | Maximum
Property, Plant and Equipment [Line Items]
Useful life	25 years
Natural gas processing plants and fractionation facilities
Property, Plant and Equipment [Line Items]
Property and equipment	$ 4,279.1	4,237.8
Natural gas processing plants and fractionation facilities | Minimum
Property, Plant and Equipment [Line Items]
Useful life	20 years
Natural gas processing plants and fractionation facilities | Maximum
Property, Plant and Equipment [Line Items]
Useful life	25 years
Other property and equipment
Property, Plant and Equipment [Line Items]
Property and equipment	$ 90.1	165.0
Other property and equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Other property and equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life	25 years
Construction in process
Property, Plant and Equipment [Line Items]
Property and equipment	$ 243.1	$ 105.7