Awards Granted to Company Employees and Non-employee Directors Under the 2007 Equity Incentive Compensation Plan (Detail) (USD $)	6 Months Ended
	Mar. 31, 2012
Nonqualified Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted	432,144
Weighted Average Grant Date Fair Value	$ 29.54
Weighted Average Exercise Price	$ 92.70	[1]
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted	906,499
Weighted Average Grant Date Fair Value	$ 94.32
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted	418,716
Weighted Average Grant Date Fair Value	$ 96.10
Performance-Based Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted	66,114	[1]
Weighted Average Grant Date Fair Value	$ 97.84	[1]

[1] The ultimate number of performance shares to be earned will be between zero and 132,227, depending on a combination of service, performance and market conditions.