CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating Activities:
Net income	$ 183.8	$ 139.4
Adjustments to reconcile net income to cash provided by operations:
Depreciation and amortization	171.8	167.7
Amortization of deferred costs and other	5.5	6.1
Gain on sale of assets and impairments	(0.8)	(0.5)
Changes in operating assets and liabilities:
Trade and other receivables	35.6	7.3
Gas receivables and storage assets	(13.6)	(0.2)
Costs recoverable from customers	13.5	(8.0)
Other assets	(5.5)	(3.8)
Trade and other payables	(8.4)	(2.6)
Gas payables	(0.4)	1.3
Accrued liabilities	(3.9)	(3.9)
Other liabilities	(0.3)	2.7
Net cash provided by operating activities	377.3	305.5
Investing Activities:
Capital expenditures	(179.7)	(228.9)
Proceeds from sale of operating assets	2.2	0.6
Advances to affiliates	(3.1)	0.0
Net cash used in investing activities	(180.6)	(228.3)
Financing Activities:
Proceeds from long-term debt, net of issuance cost	495.2	0.0
Repayment of borrowings from long-term debt	0.0	(185.0)
Proceeds from borrowings on revolving credit agreement	165.0	365.0
Repayment of borrowings on revolving credit agreement	(745.0)	(215.0)
Principal payment of finance lease obligation	(0.3)	(0.3)
Advances from affiliates	3.1	0.1
Distributions paid	(51.1)	(51.1)
Net cash used in financing activities	(133.1)	(86.3)
Increase (decrease) in cash and cash equivalents	63.6	(9.1)
Cash and cash equivalents at beginning of period	3.6	17.6
Cash and cash equivalents at end of period	$ 67.2	$ 8.5