Significant Accounting Policies - Narrative (Details) - USD ($)	1 Months Ended			12 Months Ended
	Oct. 31, 2019	May 31, 2019	Apr. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2019
Property, Plant and Equipment [Line Items]
Financing receivable, gross		$ 58,000,000.0
Loss on secured term loan receivable				$ 0	$ 52,900,000	$ 0
Property, plant and equipment, disposals				36,400,000	12,400,000	2,100,000
Proceeds from sale of productive assets				27,600,000	14,300,000	1,700,000
Gain (loss) on disposition of assets				(8,800,000)	1,900,000	400,000
Tangible asset impairment charges				$ 168,000,000.0	7,900,000
Intangible asset, useful life				15 years
Lease liability				$ 87,600,000
Other assets, net				59,800,000	80,400,000
Derivative, notional amount			$ 850,000,000.0	350,000,000.0
Derivative, fixed interest rate			2.27825%
Derivative, amount terminated				500,000,000.0
Derivative liability outstanding				10,900,000
Allowance for doubtful accounts receivable				500,000	500,000
Environmental remediation expense				0	0	0
Debt issuance costs, noncurrent, net				32,600,000	29,800,000
Cumulative Effect, Period of Adoption, Adjustment
Property, Plant and Equipment [Line Items]
Lease liability							$ 97,600,000
Other assets, net							75,300,000
Other liabilities							$ 22,600,000
Redeemable Non-Controlling Interest (Temporary Equity)
Property, Plant and Equipment [Line Items]
Partners' capital account, redemptions				4,000,000.0
Louisiana
Property, Plant and Equipment [Line Items]
Loss on secured term loan receivable					0
Tangible asset impairment charges				3,400,000		24,600,000
Crude and Condensate
Property, Plant and Equipment [Line Items]
Tangible asset impairment charges						$ 109,200,000
Cedar Cove JV
Property, Plant and Equipment [Line Items]
Tangible asset impairment charges				$ 31,400,000
Minimum
Property, Plant and Equipment [Line Items]
Intangible asset, useful life				10 years
Maximum
Property, Plant and Equipment [Line Items]
Intangible asset, useful life				20 years
EnLink Midstream Partners, LP
Property, Plant and Equipment [Line Items]
Gas balancing payable				$ 6,100,000	5,700,000
Gas balancing receivable				$ 7,500,000	$ 6,400,000
Delaware Basin JV | NPG
Property, Plant and Equipment [Line Items]
Noncontrolling interest, ownership percentage by parent				49.90%
Ascension JV | Marathon Petroleum and Resources LLC
Property, Plant and Equipment [Line Items]
Noncontrolling interest, ownership percentage by parent				50.00%
White Star
Property, Plant and Equipment [Line Items]
Financing receivable, scheduled payment	$ 10,750,000	$ 9,750,000	$ 19,500,000
Loss on secured term loan receivable				$ 52,900,000
Minimum Volume Contract
Property, Plant and Equipment [Line Items]
Contractual commitments				174,300,000
Contract with customer, liability, revenue recognized				$ 57,200,000