CONSOLIDATED BALANCE SHEET (Parenthetical) (USD $) In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2012	Sep. 30, 2011
Treasury Stock	238.1	207.2
Common stock, Class A [Member]
Common stock, par value	0.001	0.001
Common Stock Authorized	375.0	375.0
Common stock, outstanding	51.4	51.4
Common stock, Class B [Member]
Common stock, par value	0.001	0.001
Common Stock Authorized	5,000.0	5,000.0
Common stock, outstanding	478.8	506.9