Long-term Incentive Compensation (Summary of Liability-Classified Restricted Stock Unit Activity) (Details) - Restricted stock units shares in Thousands	6 Months Ended
	Jun. 30, 2020 $ / shares shares
Number of Units
Beginning balance (in shares) | shares	12,992
Granted (in shares) | shares	6,172
Vested (in shares) | shares	(3,946)
Forfeited (in shares) | shares	(2,829)
Ending balance (in shares) | shares	12,389
Weighted Average Fair Value
Beginning balance (in dollars per share) | $ / shares	$ 2.42
Granted (in dollars per share) | $ / shares	1.41
Vested (in dollars per share) | $ / shares	1.42
Forfeited (in dollars per share) | $ / shares	1.56
Ending balance (in dollars per share) | $ / shares	$ 2.56