Employee Incentive Plans - Restricted and Performance Awards (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended				3 Months Ended
	Jan. 31, 2021	Jul. 31, 2020	Mar. 31, 2020	Jan. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Grant-Date Fair Value (in dollars per share)	$ 4.70	$ 2.33	$ 1.13	$ 7.69
Beginning TSR Price (in dollars per share)	$ 3.71	$ 2.52	$ 1.25	$ 6.13
Risk-free interest rate	0.17%	0.17%	0.42%	1.62%
Volatility factor	71.00%	67.00%	51.00%	37.00%
Unvested restricted units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Non-vested, beginning of period (in shares)	5,350,086				5,350,086
Granted (in shares)					3,622,698
Vested (in shares)					(813,686)
Forfeited (in shares)					(116,444)
Non-vested, end of period (in shares)					8,042,654
Aggregate intrinsic value, end of period					$ 34.5
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Non-vested, beginning of period (in dollars per share)	$ 8.45				$ 8.45
Granted (in dollars per share)					3.72
Vested (in dollars per share)					12.52
Forfeited (in dollars per share)					6.62
Non-vested, end of period (in dollars per share)					$ 5.93
Incentive unit award vesting period					3 years
Units withheld for payroll taxes (in shares)					240,085
Unrecognized compensation cost related to non-vested restricted incentive units					$ 26.6
Unrecognized compensation costs, weighted average period for recognition					1 year 10 months 24 days
Unvested restricted units | ENLC
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Fair value of units vested					$ 10.2	$ 18.9
Aggregate intrinsic value of units vested					$ 3.0	10.1
Performance units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Non-vested, beginning of period (in shares)	2,351,241				2,351,241
Granted (in shares)					1,388,139
Vested (in shares)					(164,553)
Non-vested, end of period (in shares)					3,574,827
Aggregate intrinsic value, end of period					$ 15.3
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Non-vested, beginning of period (in dollars per share)	$ 8.82				$ 8.82
Granted (in dollars per share)					4.70
Vested (in dollars per share)					26.73
Non-vested, end of period (in dollars per share)					$ 6.40
Fair value of units vested					$ 4.4	5.0
Units withheld for payroll taxes (in shares)					63,901
Aggregate intrinsic value of units vested					$ 0.6	$ 0.9
Unrecognized compensation cost related to non-vested restricted incentive units					$ 14.9
Unrecognized compensation costs, weighted average period for recognition					1 year 9 months 18 days
Performance units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Percent of units vesting					0.00%
Performance units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Percent of units vesting					200.00%