Stock Repurchase Program (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	3 Months Ended			3 Months Ended
	May 25, 2011	Jan. 31, 2012	Jan. 31, 2012 Accelerated Share Repurchase Agreement [Member]	Oct. 31, 2011 Accelerated Share Repurchase Agreement [Member]	Jan. 31, 2012 Accelerated Share Repurchase Agreement [Member]	Oct. 31, 2011 Accelerated Share Repurchase Agreement [Member]	Jan. 06, 2012 Accelerated Share Repurchase Agreement [Member]	Sep. 30, 2011 Accelerated Share Repurchase Agreement [Member]
Stock Repurchase Program [Line Items]
Accelerated share repurchase agreement amount							$ 40.0	$ 75.0
Stock repurchase program authorized amount	500.0	500.0
Stock repurchase program prepayment							40.0	75.0
Stock repurchase program remaining authorized repurchase amount		272.4
Initial number of shares received from accelerated share repurchase agreements			744,325			1,710,376
Number of shares to settle Equity Forward contract			1,105,457
Initial share value			20.0			41.7
Remaining balance of value or shares to be settled			$ 20.0	$ 33.3
Additional accelerated share repurchase agreement entered date					Jan. 06, 2012