Debt (Schedule of Long-term Debt) (Details) - USD ($) $ in Millions		Mar. 31, 2018	Dec. 31, 2017	Jul. 15, 2016
Long-Term Debt
Subtotal		$ 3,424	$ 3,398
Unamortized debt issuance costs	[1]	(19)	(20)
Current installments of long-term debt		(62)	(63)
Total		3,343	3,315
Senior Unsecured Term Loan Due 2021 [Member]
Long-Term Debt
Senior unsecured debt	[2]	$ 488	494	$ 500
Date of maturity		Jul. 15, 2021
Senior Unsecured Notes Due 2019 [Member]
Long-Term Debt
Senior unsecured debt		$ 370	360
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		$ 922	897
Interest rate		1.125%
Date of maturity		Sep. 26, 2023
Senior Unsecured Notes Due 2025 [Member]
Long-Term Debt
Senior unsecured debt		$ 369	359
Interest rate		1.25%
Date of maturity		Dec. 11, 2025
Refunding loan for pollution control and industrial revenue bonds [Member]
Long-Term Debt
Other long-term debt		$ 169	$ 169
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	[3]	$ 12	$ 11
Date of maturity		Dec. 31, 2026
Obligations Under Capital Leases [Member]
Long-Term Debt
Capital lease obligations		$ 194	$ 208
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%
London Interbank Offered Rate (LIBOR) [Member] | Senior Unsecured Term Loan Due 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.50%

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

[2] The margin for borrowings under the senior unsecured term loan due 2021 was 1.5% above LIBOR at current Company credit ratings.

[3] The weighted average interest rate was 1.3% and 1.3% as of March 31, 2018 and December 31, 2017, respectively.