CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Operating Activities:
Net income	$ 266.9	$ 230.3
Adjustments to reconcile net income to cash provided by operations:
Depreciation and amortization	302.9	294.0
Amortization of deferred costs and other	15.7	2.8
Loss on sale of assets and impairments	0.1	7.1
Changes in operating assets and liabilities:
Trade and other receivables	28.5	15.7
Gas transportation and storage receivables and payables	(1.3)	5.9
Prepayments and other assets	(4.6)	(7.3)
Trade and other payables	(5.1)	9.9
Other payables, affiliates	0.1	(0.2)
Accrued liabilities	31.1	25.0
Other liabilities	(5.0)	(1.5)
Net cash provided by operating activities	629.3	581.7
Investing Activities:
Capital expenditures	(231.9)	(208.0)
Proceeds from sale of operating assets	0.2	1.0
Advances to affiliates	0.0	(2.7)
Acquisition of business	(347.6)	0.0
Net cash used in investing activities	(579.3)	(209.7)
Financing Activities:
Proceeds from long-term debt, net of issuance cost	0.0	495.0
Repayment of borrowings from long-term debt	0.0	(300.0)
Payment of financing fees	(0.6)	(0.6)
Principal payment of finance lease obligation	(0.6)	(0.6)
Advances from affiliates	0.6	3.0
Net cash (used in) provided by financing activities	(0.6)	196.8
Increase in cash and cash equivalents	49.4	568.8
Cash and cash equivalents at beginning of period	215.6	39.1
Cash and cash equivalents at end of period	$ 265.0	$ 607.9