Debt - Debt Issuances (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Finance lease obligations	$ 17,000,000	$ 20,000,000
Other Long-term Debt	4,000,000	4,000,000
Principal debt balance	1,493,000,000	1,528,000,000
Debt issuance costs and unamortized discounts	(16,000,000)	(18,000,000)
Less: current maturities	(89,000,000)	(90,000,000)
Total Long-term Debt	1,388,000,000	1,420,000,000
Line of Credit Facility [Line Items]
Letters of Credit Outstanding, Amount	7,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	750,000,000
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	750,000,000
Line of Credit Facility, Remaining Borrowing Capacity	743,000,000
Term Loan A due 2022
Debt Instrument [Line Items]
Long-term debt, gross	624,000,000	654,000,000
Term Loan B due 2023
Debt Instrument [Line Items]
Long-term debt, gross	814,000,000	816,000,000
Senior Notes due 2024
Debt Instrument [Line Items]
Long-term debt, gross	$ 34,000,000	$ 34,000,000