Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities:
Net income (loss)	$ 22.0	$ (230.6)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Impairments	0.0	354.5
Depreciation and amortization	302.9	321.0
Utility credits	(43.8)	0.0
Deferred income tax (benefit) expense	7.9	(22.7)
Non-cash unit-based compensation	12.9	16.2
Amortization of designated cash flow hedge	6.0	0.0
Payments to terminate interest rate swaps	(1.3)	0.0
Non-cash loss on derivatives recognized in net income (loss)	34.2	6.0
Gain on extinguishment of debt	0.0	(32.0)
Amortization of debt issue costs, net discount (premium) of notes	2.5	2.2
Distribution of earnings from unconsolidated affiliates	0.0	1.2
(Income) loss from unconsolidated affiliates	7.6	(1.0)
Other operating activities	(2.8)	4.1
Changes in assets and liabilities:
Accounts receivable, accrued revenue, and other	(61.4)	109.8
Natural gas and NGLs inventory, prepaid expenses, and other	(47.8)	9.3
Accounts payable, accrued product purchases, and other accrued liabilities	163.3	(221.2)
Net cash provided by operating activities	402.2	316.8
Cash flows from investing activities:
Additions to property and equipment	(62.5)	(203.6)
Acquisitions	(55.0)	0.0
Distribution from unconsolidated affiliates in excess of earnings	3.7	0.8
Other investing activities	1.6	0.8
Net cash used in investing activities	(112.2)	(202.0)
Cash flows from financing activities:
Proceeds from borrowings	539.5	490.0
Payments on borrowings	(679.5)	(476.0)
Conversion of restricted units, net of units withheld for taxes	(1.4)	(4.3)
Distribution to members	(93.8)	(139.8)
Distributions to non-controlling interests	(62.0)	(60.6)
Contributions by non-controlling interests	1.9	50.3
Common unit repurchases	(2.0)	0.0
Other financing activities	0.5	0.2
Net cash used in financing activities	(296.8)	(140.2)
Net decrease in cash and cash equivalents	(6.8)	(25.4)
Cash and cash equivalents, beginning of period	39.6	77.4
Cash and cash equivalents, end of period	32.8	52.0
Supplemental disclosures of cash flow information:
Cash paid for interest	97.1	106.6
Cash paid (refunded) for income taxes	0.2	(1.0)
Non-cash investing activities:
Non-cash accrual of property and equipment	6.9	(19.6)
Non-cash acquisitions	16.5	0.0
Right-of-use assets obtained in exchange for operating lease liabilities	10.7	4.8
Non-cash financing activities:
Fair value adjustment related to redeemable non-controlling interest	$ 0.0	$ (4.0)