Income Taxes - Narrative and Unrecognized Tax Benefits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Taxes [Line Items]
Issuance of common units for ENLK public common units related to the Merger	$ 399,000,000.0	$ 399,000,000.0
Valuation allowance	153,300,000	0
Unrecognized tax benefits	0	$ 0
Domestic Tax Authority
Income Taxes [Line Items]
Operating loss carryforwards	2,300,000,000
Deferred tax assets, operating loss carryforwards, domestic	488,300,000
State and Local Jurisdiction
Income Taxes [Line Items]
Operating loss carryforwards	1,100,000,000
Deferred tax assets, operating loss carryforwards, domestic	$ 61,000,000.0