Revenues - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	$ 602.8	$ 530.5	$ 1,776.3	$ 1,662.0
Other operating revenues	10.8	10.4	32.7	31.5
Total operating revenues	613.6	540.9	1,809.0	1,693.5
Natural Gas Reportable Segment
Disaggregation of Revenue [Line Items]
Total operating revenues	417.1	358.7	1,246.1	1,131.8
Natural Gas Liquids Reportable Segment
Disaggregation of Revenue [Line Items]
Total operating revenues	196.5	182.2	562.9	561.7
Operating Segments
Disaggregation of Revenue [Line Items]
Total operating revenues	613.6	540.9	1,809.0	1,693.5
Operating Segments \| Natural Gas Reportable Segment
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	415.8	357.6	1,241.1	1,128.0
Other operating revenues	1.3	1.1	5.0	3.8
Total operating revenues	417.1	358.7	1,246.1	1,131.8
Operating Segments \| Natural Gas Liquids Reportable Segment
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	187.0	172.9	535.2	534.0
Other operating revenues	9.5	9.3	27.7	27.7
Total operating revenues	196.5	182.2	562.9	561.7
Firm Service
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	526.9	489.3	1,552.1	1,516.3
Firm Service \| Operating Segments \| Natural Gas Reportable Segment
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	372.6	341.3	1,134.6	1,073.8
Firm Service \| Operating Segments \| Natural Gas Liquids Reportable Segment
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	154.3	148.0	417.5	442.5
Interruptible Service
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	15.5	15.9	57.2	49.5
Interruptible Service \| Operating Segments \| Natural Gas Reportable Segment
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	15.5	15.9	57.2	49.5
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
Other revenues
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	60.4	25.3	167.0	96.2
Other revenues \| Operating Segments \| Natural Gas Reportable Segment
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	27.7	0.4	49.3	4.7
Other revenues \| Operating Segments \| Natural Gas Liquids Reportable Segment
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	$ 32.7	$ 24.9	$ 117.7	$ 91.5