Debt (Schedule of Net Deferred Financing Costs) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Debt Instrument [Line Items]
Deferred Finance Costs, Net		$ 27	[1]	$ 22	[1]	$ 27
Financing costs deferred		1	[2]	13	[3]	0
Accelerated amortization due to refinancing activity		0		(3)	[4]	0
Amortization		(4)		(5)		(5)
Deferred Finance Costs, Net	[1]	24		27		22
New Credit Agreement [Member]
Debt Instrument [Line Items]
Financing costs deferred	[3]			5
Senior Unsecured Notes Due 2023 [Member]
Debt Instrument [Line Items]
Financing costs deferred	[3]			6
Refunding loan for pollution control and industrial revenue bonds [Member]
Debt Instrument [Line Items]
Financing costs deferred	[3]			2
Amended Credit Agreement [Member]
Debt Instrument [Line Items]
Accelerated amortization due to refinancing activity	[4]			(2)
Pollution Control and Industrial Revenue Bonds [Member]
Debt Instrument [Line Items]
Accelerated amortization due to refinancing activity	[4]			(1)
Other Noncurrent Assets [Member] | RevolvingCreditandAccountsReceivableSecuritizationFacilities [Member]
Debt Instrument [Line Items]
Deferred Finance Costs, Net	[1]	6		4
Deferred Finance Costs, Net	[1]	$ 4		$ 6		$ 4

[1] Includes $4 million, $6 million and $4 million as of December 31, 2017, 2016 and 2015, respectively, related to the Company's revolving credit facility and accounts receivables securitization facility, which are included in noncurrent Other assets in the consolidated balance sheets.

[2] Related to the 1.250% Notes, which are being amortized through the term of the 1.250% Notes.

[3] Includes $5 million, $6 million and $2 million related to the Credit Agreement, the 1.125% Notes and the pollution control and industrial revenue bonds, respectively, all of which are being amortized through the term of the respective financing arrangement.

[4] Includes $2 million and $1 million related to the senior secured credit facilities and the pollution control and industrial revenue bonds, respectively, which are included in Refinancing expense in the consolidated statement of operations during the year ended December 31, 2016.