Stock Option Plans (Narrative) (Details) (USD $)	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance, years	3 years
Performance award expense	$ (10,000)
Pretax compensation expense associated with stock options	7,800,000	6,500,000	6,900,000
Tax benefit associated with stock options	2,500,000	2,100,000	2,400,000
Weighted average fair value for options granted, per share	$ 9.37	$ 8.63	$ 6.62
Intrinsic value of options exercised	29,500,000	34,200,000	19,500,000
Shares reserved	15,288,416
Aggregate intrinsic value of options outstanding	116,700,000
Aggregate intrinsic value of shares exercisable	109,400,000
Total fair value of shares vested	19,500,000	10,500,000	8,000,000
Unrecognized compensation cost related to non-vested stock options granted	8,100,000
2010 Master Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance award expense	$ 1,900,000	$ 1,800,000
Shares reserved	9,200,000
2010 Master Stock Incentive Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercisable from date of the grant, in years	10 years
Fiscal 2002 To Fiscal 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, years	3 years
Fiscal 2012 And Fiscal 2011 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, years	3 years
Fiscal 2004, 2006, And 2007 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, years	3 years