Income Taxes (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended		12 Months Ended	9 Months Ended	12 Months Ended			24 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2013	Sep. 30, 2013 Brazilian Federal Revenue Service [Member] assessment	Dec. 31, 2007 Brazilian Federal Revenue Service [Member]	Dec. 31, 2006 Brazilian Federal Revenue Service [Member]	Dec. 31, 2004 Brazilian Federal Revenue Service [Member]	Jun. 30, 2005 Argentine Tax Authorities [Member]
Income Taxes [Line Items]
Effective income tax rate	32.20%	28.70%	37.60%	30.30%	31.00%	30.00%
Adjusted effective tax rate		30.00%
Income tax effect of discrete items gain loss	$ 12		$ 8
Number of separate tax assessments							3
Tax assessment received consisting of tax, penalty, and interest								79	18	449	48
Estimated further assessments that could be received							$ 97