Basis of Presentation and Summary of Significant Accounting Policies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) segment	Dec. 31, 2019 USD ($)
Summary of Significant Accounting Policies [Table] [Line Items]
Number of reportable segments | segment	1
Bank overdrafts	$ 0	$ 57
Cash	279
Unamortized issuance costs, senior notes	$ 0	44
Revenue, payment terms	30 days
Exit credit facility | Credit facility
Summary of Significant Accounting Policies [Table] [Line Items]
Unamortized issuance costs	$ 33
Employee
Summary of Significant Accounting Policies [Table] [Line Items]
Vesting period	3 years
Director
Summary of Significant Accounting Policies [Table] [Line Items]
Vesting period	3 years
Other noncurrent assets
Summary of Significant Accounting Policies [Table] [Line Items]
Unamortized issuance costs		$ 27