Pension and Defined Contribution Plans - Net Periodic Pension Cost and Pension Plan Asset Allocation (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2011
Domestic Plans
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 3.4	$ 2.7	$ 3.1
Interest cost	6.3	6.6	6.5
Expected return on plan assets	(7.1)	(6.5)	(5.9)
Amortization of prior service cost	0.7	0.1	0.1
Curtailment	0	0.1	0
Recognized actuarial loss	4.4	3.2	3.7
Net periodic pension cost	7.7	6.2	7.5
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	4.80%	3.80%
Rate of compensation increase	5.50%	5.50%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	3.80%	5.00%	5.00%
Expected return on plan assets	7.50%	7.50%	7.80%
Rate of compensation increase	5.50%	5.50%	5.50%
Reduction in net periodic pension cost per 100 basis point increase in benefig obligation discount rate	0.8
Additional net periodic pension cost per 100 basis point decrease in expected retun on plan assets rate	1.1
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Pension plan asset allocation, percentage	100.00%	100.00%
Domestic Plans | Equity securities
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Targeted asset allocation, percentage	55.00%
Pension plan asset allocation, percentage	58.80%	57.30%
Domestic Plans | Fixed income securities
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Targeted asset allocation, percentage	40.00%
Pension plan asset allocation, percentage	36.40%	37.80%
Domestic Plans | Multi-strategy investments
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Pension plan asset allocation, percentage	0.00%	0.00%
Domestic Plans | Real estate
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Targeted asset allocation, percentage	5.00%
Pension plan asset allocation, percentage	4.80%	4.90%
International Plans
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	0.1	0.1	0.1
Interest cost	1.7	1.9	1.8
Expected return on plan assets	(1.5)	(1.7)	(1.6)
Amortization of prior service cost	0	0	0
Curtailment	0	0	0
Recognized actuarial loss	1.8	0.9	1.1
Net periodic pension cost	2.1	1.2	1.4
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	4.50%	3.70%
Rate of compensation increase	3.30%	2.50%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	3.70%	5.60%	4.90%
Expected return on plan assets	6.20%	5.50%	6.60%
Rate of compensation increase	2.50%	3.40%	3.10%
Reduction in net periodic pension cost per 100 basis point increase in benefig obligation discount rate	0.1
Additional net periodic pension cost per 100 basis point decrease in expected retun on plan assets rate	$ 0.3
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Pension plan asset allocation, percentage	100.00%	100.00%
International Plans | Equity securities
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Targeted asset allocation, percentage	60.00%
Pension plan asset allocation, percentage	63.40%	70.00%
International Plans | Fixed income securities
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Targeted asset allocation, percentage	25.00%
Pension plan asset allocation, percentage	22.50%	25.00%
International Plans | Multi-strategy investments
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Targeted asset allocation, percentage	10.00%
Pension plan asset allocation, percentage	9.60%	0.00%
International Plans | Real estate
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Targeted asset allocation, percentage	5.00%
Pension plan asset allocation, percentage	4.50%	5.00%