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			51 Months Ended	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011	Jun. 30, 2011	Mar. 31, 2012 Brazilian Federal Revenue Service [Member]	Dec. 31, 2007 Brazilian Federal Revenue Service [Member]	Dec. 31, 2006 Brazilian Federal Revenue Service [Member]	Dec. 31, 2004 Brazilian Federal Revenue Service [Member]	Mar. 31, 2012 Brazilian Federal Revenue Service [Member]	Jun. 30, 2005 Argentine Tax Authorities [Member]
Effective rate	28.70%	28.20%	29.70%	27.20%	33.00%
Number of separate tax assessments						3
Tax assessment received consisting of tax, penalty, and interest							$ 83	$ 20	$ 484
Tax assessment received											11
Estimated further assessments that could be received										$ 101