Long-term Incentive Compensation (Summary of Liability-Classified Performance Cash Awards ) (Details) - Performance units shares in Thousands	6 Months Ended
	Jun. 30, 2020 $ / shares shares
Number of Units
Beginning balance (in shares) | shares	5,142
Granted (in shares) | shares	6,172
Vested (in shares) | shares	0
Forfeited (in shares) | shares	(2,124)
Ending balance (in shares) | shares	9,190
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	0
Forfeited (in dollars per share) | $ / shares	3.10
Ending balance (in dollars per share) | $ / shares	$ 2.56