Earnings Per Share - Calculation of Average Share Outstanding (Details) - shares shares in Millions		12 Months Ended
	Oct. 15, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Convertible notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of anti-dilutive securities (in shares)	15	0	0	0
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of anti-dilutive securities (in shares)		1	1	9
Stock awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of anti-dilutive securities (in shares)		0	0	0