Debt (Schedule of Long-term Debt) (Details) - USD ($) $ in Millions		Jun. 30, 2019	Dec. 31, 2018
Long-Term Debt
Finance Lease, Liability		$ 156	$ 167
Subtotal		3,490	3,355
Unamortized debt issuance costs	[1]	(20)	(18)
Current installments of long-term debt		(26)	(367)
Total		3,444	2,970
Senior Unsecured Notes Due 2019 [Member]
Long-Term Debt
Senior unsecured debt		$ 0	343
Interest rate		3.25%
Date of maturity		Oct. 15, 2019
Senior Unsecured Notes Due 2021 [Member]
Long-Term Debt
Senior unsecured debt		$ 400	400
Interest rate		5.875%
Date of maturity		Jun. 15, 2021
Senior Unsecured Notes Due 2022 [Member]
Long-Term Debt
Senior unsecured debt		$ 500	500
Interest rate		4.625%
Date of maturity		Nov. 15, 2022
Senior Unsecured Notes Due 2023 [Member]
Long-Term Debt
Senior unsecured debt		$ 852	857
Interest rate		1.125%
Date of maturity		Sep. 26, 2023
Senior Unsecured Notes Due 2024 [Member]
Long-Term Debt
Senior unsecured debt		$ 499	0
Interest rate		3.50%
Date of maturity		May 08, 2024
Senior Unsecured Notes Due 2025 [Member]
Long-Term Debt
Senior unsecured debt		$ 341	343
Interest rate		1.25%
Date of maturity		Dec. 11, 2025
Senior Unsecured Notes Due 2027 [Member]
Long-Term Debt
Senior unsecured debt		$ 565	568
Interest rate		2.125%
Date of maturity		Mar. 01, 2027
Refunding loan for pollution control and industrial revenue bonds [Member]
Long-Term Debt
Other long-term debt		$ 167	$ 167
Date of maturity		Dec. 31, 2030
Nylon compounding division of Nilit Group [Member]
Debt Instrument [Line Items]
Long-term Debt, Weighted Average Interest Rate, at Point in Time		1.30%	1.30%
Long-Term Debt
Other long-term debt	[2]	$ 10	$ 10
Date of maturity		Dec. 31, 2026
Obligations Under Capital Leases [Member]
Long-Term Debt
Date of maturity		Dec. 31, 2054
Minimum [Member] | Refunding loan for pollution control and industrial revenue bonds [Member]
Long-Term Debt
Interest rate		4.05%
Maximum [Member] | Refunding loan for pollution control and industrial revenue bonds [Member]
Long-Term Debt
Interest rate		5.00%

[1] Related to the Company's long-term debt, excluding obligations under finance leases.

[2] The weighted average interest rate was 1.3% and 1.3% as of June 30, 2019 and December 31, 2018, respectively.