Debt And Credit Facilities (Floating Rate Debt) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Debt And Credit Facilities [Abstract]
Floating debt	$ 2,926	[1]	$ 2,851	[1]
Floating debt, average interest rate	1.50%	[1]	1.60%	[1]
Debt indexed to Brazilian inflation	$ 353		$ 376

[1] Excludes $353 million and $376 million of Brazilian debt at December 31, 2011 and 2010, respectively, that is indexed annually to Brazilian inflation.