Basis of Presentation and Summary of Significant Accounting Policies (Revenue Recognition) (Details) - USD ($) $ in Millions		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Apr. 09, 2019
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment		$ 3,612.5	$ 2,598.1
Revenues		3,181.9	3,654.1	$ 3,880.9
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		0.7
ASC 606 Accounts Receivable		$ 225.0	209.7
Revenue, remaining performance obligations, expected timing of satisfaction, period		17 years
Contract with Customer, Asset, Gross, Noncurrent		$ 1.2	1.0
Deferred revenue		8.8	12.0
Contract liabilities		144.7	65.4
Contract with Customer, Liability, Revenue Recognized		13.3
Depreciation, amortization and accretion		195.8	168.7	191.7
Earnings from unconsolidated affiliates, net		32.8	53.3	47.8
Net income (loss)		319.9	67.0	(166.6)
Less: accumulated depreciation		703.4	568.4
Investments in unconsolidated affiliates		980.4	1,188.2
Accrued expenses and other liabilities		161.7	112.4
Other long-term liabilities		301.6	173.6
Partners' capital		1,320.8	1,240.5
Total CEQP/CMLP partners’ capital		1,932.8	1,852.5
Property, plant and equipment, net		2,909.1	2,029.7
Accounting Standards Update 2014-09
Summary Of Significant Accounting Policies [Line Items]
Deferred Revenue	$ 69.1
Property, plant and equipment, net	87.6
Product
Summary Of Significant Accounting Policies [Line Items]
Revenues		2,755.3	3,309.7	3,462.2
Product and service costs		2,469.7	2,950.5	3,309.5
Service
Summary Of Significant Accounting Policies [Line Items]
Revenues		426.6	344.4	418.7
Product and service costs		29.8	44.2	49.9
Gathering and Processing Segment | Product
Summary Of Significant Accounting Policies [Line Items]
Revenues		455.8	670.5	1,369.1
Gathering and Processing Segment | Service
Summary Of Significant Accounting Policies [Line Items]
Revenues		380.0	276.1	317.3
Marketing Supply and Logistics
Summary Of Significant Accounting Policies [Line Items]
Revenues			2,690.3
Marketing Supply and Logistics | Product
Summary Of Significant Accounting Policies [Line Items]
Revenues		2,296.6	2,639.2	2,093.1
Marketing Supply and Logistics | Service
Summary Of Significant Accounting Policies [Line Items]
Revenues		26.2	50.2	62.4
CMLP
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment		3,942.6	2,928.2
Revenues		3,181.9	3,654.1	3,880.9
Deferred revenue		8.8	12.0
Depreciation, amortization and accretion		209.9	181.4	202.7
Earnings from unconsolidated affiliates, net		32.8	53.3	47.8
Net income (loss)		310.6	58.6	(175.5)
Less: accumulated depreciation		875.1	725.9
Investments in unconsolidated affiliates		980.4	1,188.2
Accrued expenses and other liabilities		160.4	111.3
Other long-term liabilities		295.6	171.0
Total CEQP/CMLP partners’ capital		2,099.3	2,028.2
Property, plant and equipment, net		3,067.5	2,202.3
CMLP | Product
Summary Of Significant Accounting Policies [Line Items]
Revenues		2,755.3	3,309.7	3,462.2
Product and service costs		2,469.7	2,950.5	3,309.5
CMLP | Service
Summary Of Significant Accounting Policies [Line Items]
Revenues		426.6	344.4	418.7
Product and service costs		29.8	44.2	49.9
CMLP | Gathering and Processing Segment | Product
Summary Of Significant Accounting Policies [Line Items]
Revenues		455.8	670.5	1,369.1
CMLP | Gathering and Processing Segment | Service
Summary Of Significant Accounting Policies [Line Items]
Revenues		380.0	276.1	317.3
CMLP | Marketing Supply and Logistics | Product
Summary Of Significant Accounting Policies [Line Items]
Revenues		2,296.6	2,639.2	2,093.1
CMLP | Marketing Supply and Logistics | Service
Summary Of Significant Accounting Policies [Line Items]
Revenues		26.2	50.2	62.4
Jackalope Gas Gathering Services, LLC
Summary Of Significant Accounting Policies [Line Items]
Earnings from unconsolidated affiliates, net		3.7	18.1	$ 10.5
Investments in unconsolidated affiliates		0.0	$ 210.2		$ 226.7
Jackalope Gas Gathering Services, LLC | Accounting Standards Update 2014-09
Summary Of Significant Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	9.5
New Accounting Pronouncement, Equity Earnings Decrease		$ 9.7
Capital Reimbursements [Member] | Accounting Standards Update 2014-09
Summary Of Significant Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	18.5
Contracts with Increasing (Decreasing) Rates per Unit [Member] | Accounting Standards Update 2014-09
Summary Of Significant Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 1.5