CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
OPERATING ACTIVITIES:
Net income	$ 594.7	$ 510.9	$ 386.0
Adjustments to reconcile net income to cash provided by operations:
Depreciation and amortization	438.9	424.8	408.7
Amortization of deferred costs and other	16.2	13.8	18.5
Loss (gain) on sale of assets, impairments and other	0.2	(5.5)	0.3
Interest income from short-term investments	(1.3)	(19.8)	0.0
Changes in operating assets and liabilities:
Trade and other receivables	(16.0)	(2.8)	(7.8)
Gas transportation receivables, storage assets and other product inventory	(31.4)	(15.2)	70.6
Prepayments and other assets	(8.4)	(7.7)	3.1
Trade and other payables	14.2	11.9	11.5
Other payables, affiliates	0.0	0.1	0.1
Gas transportation payables	10.9	(8.6)	(20.8)
Accrued liabilities	12.4	17.1	7.4
Regulatory assets and liabilities	11.1	2.7	(40.3)
Other liabilities	1.1	(21.2)	(19.9)
Net cash provided by operating activities	1,042.6	900.5	817.4
INVESTING ACTIVITIES:
Capital expenditures	(353.9)	(392.4)	(382.4)
Proceeds from sale of operating assets	1.0	0.5	0.3
Acquisition of business	0.0	0.0	(355.0)
Purchases of short-term investments	(350.0)	(1,102.2)	0.0
Proceeds from the maturity of short-term investments	0.0	1,122.0	0.0
Net cash used in investing activities	(702.9)	(372.1)	(737.1)
FINANCING ACTIVITIES:
Proceeds from long-term debt, net of issuance cost	544.0	593.5	0.0
Repayment of borrowings from long-term debt	0.0	(600.0)	0.0
Proceeds from borrowings on revolving credit facility	0.0	170.0	155.0
Repayments of borrowings on revolving credit facility, including financing fees	(2.9)	(195.0)	(130.6)
Principal payment of finance lease obligation	(0.9)	(0.9)	(0.9)
Advances from affiliates	1.4	1.8	0.7
Distributions paid	(500.0)	(400.0)	(300.0)
Net cash provided by (used in) financing activities	41.6	(430.6)	(275.8)
Increase (decrease) in cash and cash equivalents	381.3	97.8	(195.5)
Cash and cash equivalents at beginning of period	117.9	20.1	215.6
Cash and cash equivalents at end of period	$ 499.2	$ 117.9	$ 20.1