Stock-Based and Other Compensation Plans - Stock Option Activity (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares shares
Options
Outstanding, beginning balance (in shares) | shares	13,852,020
Granted (in shares) | shares	461,311
Forfeited (in shares) | shares	(51,100)
Expired (in shares) | shares	(1,686,478)
Outstanding, ending balance (in shares) | shares	12,575,753
Exercisable (in shares) | shares	11,373,846
Weighted Average Exercise Price
Outstanding, beginning balance (in dollars per share) | $ / shares	$ 44.04
Granted (in dollars per share) | $ / shares	22.15
Forfeited (in dollars per share) | $ / shares	34.72
Expired (in dollars per share) | $ / shares	35.26
Outstanding, ending balance (in dollars per share) | $ / shares	44.62
Exercisable (in dollars per share) | $ / shares	$ 46.11
Weighted Average Remaining Contractual Term and Aggregate Intrinsic Value
Weighted Average Remaining Contractual Term, Outstanding	4 years 2 months 12 days
Weighted Average Remaining Contractual Term, Exercisable	3 years 8 months 12 days
Aggregate Intrinsic Value, Outstanding | $	$ 1
Aggregate Intrinsic Value, Exercisable | $	$ 0