Debt (Schedule of Long-term Debt) (Details) € in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2014 EUR (€)
Long-Term Debt
Subtotal	$ 2,563	$ 2,542
Current installments of long-term debt	(58)	(56)
Total	2,487	2,468
Long-term Debt [Member]
Long-Term Debt
Deferred Finance Costs, Net	(18)	(18)
Term C-2 Loan Facility [Member]
Long-Term Debt
Senior credit facilities - Term loans	$ 31	30	€ 28
Credit facility, expiration date	Oct. 15, 2016
Term C-3 Loan Facility [Member]
Long-Term Debt
Senior credit facilities - Term loans	$ 883	878
Credit facility, expiration date	Oct. 15, 2018
Senior Unsecured Notes Due 2019 [Member]
Long-Term Debt
Senior unsecured notes	$ 342	327
Interest rate	3.25%
Date of maturity	Oct. 15, 2019
Senior Unsecured Notes Due 2021 [Member]
Long-Term Debt
Senior unsecured notes	$ 400	400
Interest rate	5.875%
Date of maturity	Jun. 15, 2021
Senior Unsecured Notes Due 2022 [Member]
Long-Term Debt
Senior unsecured notes	$ 500	500
Interest rate	4.625%
Date of maturity	Nov. 15, 2022
Pollution Control and Industrial Revenue Bonds [Member]
Long-Term Debt
Refunding revenue and pollution control debt	$ 0	169
Interest rate, stated percentage range, minimum	5.70%
Interest rate, stated percentage range, maximum	6.70%
Year of maturity, range end	Dec. 31, 2030
Refunding loan for pollution control and industrial revenue bonds [Member]
Long-Term Debt
Refunding revenue and pollution control debt	$ 170	0
Interest rate, stated percentage range, minimum	4.05%
Interest rate, stated percentage range, maximum	5.00%
Year of maturity, range end	Dec. 31, 2030
Obligations Under Capital Leases [Member]
Long-Term Debt
Capital lease obligations	$ 237	$ 238
Year of maturity, range end	Dec. 31, 2054