Revenues - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	$ 523.0	$ 467.3	$ 1,131.5	$ 968.0
Other operating revenues	11.0	10.2	21.1	20.0
Total operating revenues	534.0	477.5	1,152.6	988.0
Operating Segments
Disaggregation of Revenue [Line Items]
Total operating revenues	546.9	489.8	1,178.5	1,012.7
Operating Segments \| Natural Gas Reportable Segment
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	369.5	325.0	787.3	705.3
Other operating revenues	5.8	5.3	11.7	10.7
Total operating revenues	375.3	330.3	799.0	716.0
Operating Segments \| Natural Gas Liquids Reportable Segment
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	162.1	150.1	361.1	278.0
Other operating revenues	9.5	9.4	18.4	18.7
Total operating revenues	171.6	159.5	379.5	296.7
Intersegment Eliminations
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(8.6)	(7.8)	(16.9)	(15.3)
Other operating revenues	(4.3)	(4.5)	(9.0)	(9.4)
Total operating revenues	(12.9)	(12.3)	(25.9)	(24.7)
Firm Service
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	480.9	404.8	1,027.0	845.0
Firm Service \| Operating Segments \| Natural Gas Reportable Segment
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	347.4	304.5	749.0	666.6
Firm Service \| Operating Segments \| Natural Gas Liquids Reportable Segment
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	141.7	108.1	294.5	193.7
Firm Service \| Intersegment Eliminations
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(8.2)	(7.8)	(16.5)	(15.3)
Interruptible Service
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	20.6	20.1	33.6	32.0
Interruptible Service \| Operating Segments \| Natural Gas Reportable Segment
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	21.0	20.1	34.0	32.0
Interruptible Service \| Operating Segments \| Natural Gas Liquids Reportable Segment
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	0.0	0.0	0.0	0.0
Interruptible Service \| Intersegment Eliminations
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	(0.4)	0.0	(0.4)	0.0
Other revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	21.5	42.4	70.9	91.0
Other revenues \| Operating Segments \| Natural Gas Reportable Segment
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	1.1	0.4	4.3	6.7
Other revenues \| Operating Segments \| Natural Gas Liquids Reportable Segment
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	20.4	42.0	66.6	84.3
Other revenues \| Intersegment Eliminations
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	$ 0.0	$ 0.0	$ 0.0	$ 0.0