Long-Term Debt (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Sale leaseback financing obligation	$ 100	$ 103
2018 Revolver	158	162
Finance Lease, Liability	29	32
Total debt	3,087	3,097
Less: current maturities	12	11
Less: debt issuance costs	23	26
Long-term debt, net	3,052	3,060
Two Thousand Eighteen Revolver [Member] \| Revolving Credit Agreement [Member]
Debt Instrument [Line Items]
2018 Revolver	$ 158	162
Four Point Eight Seven Five Percentage Senior Notes Due Two Thousand Twenty Three [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.85%
Senior Notes	$ 1,000	1,000
Five Point Five Zero Zero Percentage Senior Notes Due Two Thousand Twenty Six [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.50%
Senior Notes	$ 800	800
Six Percentage Senior Notes Due Two Thousand Twenty Seven [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.00%
Senior Notes	$ 600	600
Five Point Eight Seven Five Percentage Senior Notes Due Two Thousand Twenty Eight [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.875%
Senior Notes	$ 400	$ 400

Contractual interest rate for funds borrowed, under the debt agreement.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Present value of lessee's discounted obligation for lease payments from finance lease.

+ References

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Amount of long-term debt and lease obligation, classified as noncurrent.

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Amount of long-term debt and lease obligation, classified as current.

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Amount of long-term debt and lease obligation, including portion classified as current.

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The carrying value as of the balance sheet date of the noncurrent portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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The liability due as of the balance sheet date for leasebacks accounted for using the deposit method.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

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