Employees' Retirement Plans (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2011
Compensation and Retirement Disclosure [Abstract]
Compensation expense under defined contribution profit sharing and savings plan and BRP Plan	$ 15.9	$ 13.0	$ 14.1
Benefit restoration plan [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Deferred compensation liability	78.8	77.0
Current value of segregated assets	59.4	52.9
Net holding gain (loss) on segregated assets	9.9	5.3	6.5
Other Postretirement Benefit Plans, Defined Benefit [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Liability related to unfunded status of defined benefit plans	3.5	5.1
Foreign Postretirement Benefit Plans, Defined Benefit [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Company expenses for international plans	$ 3.6	$ 2.2	$ 3.2