Equity-Based Compensation - Equity Units Activity (Details) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2020 USD ($) $ / shares shares
Minimum
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Granted (in dollars per unit)	$ 2.67
Maximum
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Granted (in dollars per unit)	$ 10.13
Performance units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Units Outstanding (in units) | shares	1,393,329
Granted (in units) | shares	933,738	[1]
Vested (in units) | shares	(385,267)	[2]
Forfeited (in units) | shares	(139,024)
Units Outstanding (in units) | shares	1,802,776
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Units Outstanding (in dollars per unit)	$ 19.04
Granted (in dollars per unit)	7.00	[1]
Vested (in dollars per unit)	19.23	[2]
Forfeited (in dollars per unit)	14.57
Units Outstanding (in dollars per unit)	$ 13.11
Aggregate Intrinsic Value of Units Outstanding | $	$ 8
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]
Payout percentage	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]
Payout percentage	200.00%
Performance units | Annual Grant in 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Granted (in units) | shares	376,292
Phantom units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Units Outstanding (in units) | shares	1,392,560
Granted (in units) | shares	947,632	[1]
Vested (in units) | shares	(360,005)	[2]
Forfeited (in units) | shares	(172,016)
Units Outstanding (in units) | shares	1,808,171
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Units Outstanding (in dollars per unit)	$ 14.65
Granted (in dollars per unit)	6.55	[1]
Vested (in dollars per unit)	16.02	[2]
Forfeited (in dollars per unit)	10.49
Units Outstanding (in dollars per unit)	$ 10.53
Aggregate Intrinsic Value of Units Outstanding | $	$ 8

[1] Performance units represents the target number of performance units granted. The actual number of performance units earned, if any, is dependent upon performance and may range from 0% to 200% of the target.

[2] Performance units vested as of June 30, 2020 include 376,292 units from the 2017 annual grant, which were approved by the Board of Directors in 2017 and, based on the level of achievement of a performance goal established by the Board of Directors over the performance period of January 1, 2017 through December 31, 2019, no performance units vested.