Long-Term Incentive Compensation (Summary of Liability-Classified Performance Unit Activity) (Details) - Liability-Classified Performance Units - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Number of Units
Number of Shares/Units, Unvested shares/units at January 1 (in shares)	8,699,000	5,142,000	2,803,000
Number of Shares/Units, Granted (in shares)	3,580,000	6,172,000	2,757,000
Number of Shares/Units, Vested (in shares)	(2,020,000)	0	(43,000)
Number of Shares/Units, Forfeited (in shares)	(744,000)	(2,615,000)	(375,000)
Number of Shares/Units, Unvested shares/units at December 31 (in shares)	9,515,000	8,699,000	5,142,000
Weighted Average Fair Value
Weighted Average Fair Value, Unvested shares/units at January 1 (in dollars per share)	$ 2.57	$ 2.42	$ 3.41
Weighted Average Fair Value, Granted (in dollars per share)	4.14	1.41	4.34
Weighted Average Fair Value, Vested (in dollars per share)	4.05	0	2.42
Weighted Average Fair Value, Forfeited (in dollars per share)	3.40	3.05	3.12
Weighted Average Fair Value, Unvested shares/units at December 31 (in dollars per share)	$ 2.88	$ 2.57	$ 2.42
Workforce Reduction
Number of Units
Number of Shares/Units, Forfeited (in shares)		(518,450)	(375,086)