Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities
Net income (loss)	$ 319.9	$ 67.0	$ (166.6)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, amortization and accretion	195.8	168.7	191.7
Amortization of debt-related deferred costs	6.2	6.8	7.2
Unit-based compensation charges	47.0	28.5	25.5
Loss on long-lived assets, net	6.2	28.6	65.6
Gain on acquisition	(209.4)	0.0	0.0
Goodwill impairment	0.0	0.0	38.8
Loss on contingent consideration	0.0	0.0	57.0
Loss on modification/extinguishment of debt	0.0	0.9	37.7
Earnings from unconsolidated affiliates, net, adjusted for cash distributions received	6.9	0.5	(0.1)
Deferred income taxes	0.0	(0.7)	(2.1)
Other	0.0	0.2	0.9
Changes in operating assets and liabilities:
Accounts receivable	42.9	167.8	(170.7)
Inventory	10.9	(24.1)	(9.9)
Prepaid expenses and other current assets	0.1	(3.1)	1.8
Accounts payable, accrued expenses and other liabilities	(23.3)	(138.6)	140.1
Reimbursements of property, plant and equipment	24.8	21.7	19.6
Change in price risk management activities, net	(7.6)	(70.6)	19.4
Net cash provided by operating activities	420.4	253.6	255.9
Investing activities
Acquisition, net of cash acquired (Note 3)	(462.1)	0.0	0.0
Purchases of property, plant and equipment	(455.5)	(305.5)	(188.4)
Investment in unconsolidated affiliates	(61.3)	(64.4)	(58.0)
Capital distributions from unconsolidated affiliates	35.5	49.2	59.9
Net proceeds from sale of assets	0.8	79.5	225.2
Other	(1.1)	0.0	0.0
Net cash provided by (used in) investing activities	(943.7)	(241.2)	38.7
Financing activities
Proceeds from the issuance of long-term debt	2,307.3	2,274.8	2,838.6
Payments on long-term debt	(1,729.5)	(2,015.7)	(2,913.9)
Payments on finance leases	3.5
Payments on capital leases		(1.6)	(2.7)
Payments for deferred financing costs	(9.0)	(5.7)	(1.0)
Redemption of non-controlling interest	0.0	0.0	(202.7)
Net proceeds from issuance of non-controlling interest	235.0	0.0	175.0
Distributions to partners	(172.4)	(170.8)	(167.6)
Distributions to non-controlling partner	(25.0)	(9.9)	(15.2)
Distributions to preferred unitholders	(60.1)	(60.1)	(15.0)
Net proceeds from issuance of common units	0.0	0.0	15.2
Taxes paid for unit-based compensation vesting	(11.0)	(7.4)	(5.5)
Other	0.0	(0.1)	(0.1)
Net cash provided by (used in) financing activities	531.8	3.5	(294.9)
Net change in cash and restricted cash	8.5	15.9	(0.3)
Cash and restricted cash at beginning of period	17.2	1.3	1.6
Cash and restricted cash at end of period	25.7	17.2	1.3
Supplemental disclosure of cash flow information
Cash paid during the period for interest	123.7	97.4	95.1
Cash paid during the period for income taxes	0.6	3.1	3.1
Supplemental schedule of noncash investing activities
Net change to property, plant and equipment through accounts payable and accrued expenses	(27.7)	0.3	(20.4)
CMLP
Operating activities
Net income (loss)	310.6	58.6	(175.5)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, amortization and accretion	209.9	181.4	202.7
Amortization of debt-related deferred costs	6.2	6.8	7.2
Unit-based compensation charges	47.0	28.5	25.5
Loss on long-lived assets, net	6.2	28.6	65.6
Gain on acquisition	(209.4)	0.0	0.0
Goodwill impairment	0.0	0.0	38.8
Loss on contingent consideration	0.0	0.0	57.0
Loss on modification/extinguishment of debt	0.0	0.9	37.7
Earnings from unconsolidated affiliates, net, adjusted for cash distributions received	6.9	0.5	(0.1)
Deferred income taxes	0.2	(0.1)	0.0
Other	0.0	0.2	0.9
Changes in operating assets and liabilities:
Accounts receivable	41.6	169.3	(170.5)
Inventory	10.9	(24.1)	(9.9)
Prepaid expenses and other current assets	0.1	(3.1)	1.8
Accounts payable, accrued expenses and other liabilities	(23.3)	(138.1)	142.0
Reimbursements of property, plant and equipment	24.8	21.7	19.6
Change in price risk management activities, net	(7.6)	(70.6)	19.4
Net cash provided by operating activities	424.1	260.5	262.2
Investing activities
Acquisition, net of cash acquired (Note 3)	(462.1)	0.0	0.0
Purchases of property, plant and equipment	(455.5)	(305.5)	(188.4)
Investment in unconsolidated affiliates	(61.3)	(64.4)	(58.0)
Capital distributions from unconsolidated affiliates	35.5	49.2	59.9
Net proceeds from sale of assets	0.8	79.5	225.2
Other	(1.1)	0.0	0.0
Net cash provided by (used in) investing activities	(943.7)	(241.2)	38.7
Financing activities
Proceeds from the issuance of long-term debt	2,307.3	2,274.8	2,838.6
Payments on long-term debt	(1,729.5)	(2,015.7)	(2,913.9)
Payments on finance leases	3.5
Payments on capital leases		(1.6)	(2.7)
Payments for deferred financing costs	(9.0)	(5.7)	(1.0)
Redemption of non-controlling interest	0.0	0.0	(202.7)
Net proceeds from issuance of non-controlling interest	235.0	0.0	175.0
Distributions to partners	(235.8)	(238.4)	(174.0)
Distributions to non-controlling partner	(25.0)	(9.9)	(15.2)
Taxes paid for unit-based compensation vesting	(11.0)	(7.4)	(5.5)
Other	0.0	0.1	0.2
Net cash provided by (used in) financing activities	528.5	(3.8)	(301.2)
Net change in cash and restricted cash	8.9	15.5	(0.3)
Cash and restricted cash at beginning of period	16.5	1.0	1.3
Cash and restricted cash at end of period	25.4	16.5	1.0
Supplemental disclosure of cash flow information
Cash paid during the period for interest	123.7	97.4	95.1
Cash paid during the period for income taxes	0.6	0.6	0.6
Supplemental schedule of noncash investing activities
Net change to property, plant and equipment through accounts payable and accrued expenses	$ (27.7)	$ 0.3	$ (20.4)