Stock Repurchase Program (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	12 Months Ended		0 Months Ended
	May 25, 2011	Oct. 31, 2011	Sep. 30, 2011	Sep. 30, 2011 Accelerated Share Repurchase Agreement [Member]
Stock Repurchase Program [Line Items]
Stock repurchase program authorized amount	$ 500.0	$ 500.0		$ 75.0
Stock repurchase program remaining authorized repurchase amount		312.4
Initial number of shares received from accelerated share repurchase agreements				1,710,376
Initial share value			41.7
Equity forward contract		$ 33.3