Summary of Significant Accounting Policies - Shares Used in Computing Basic and Diluted Earnings Per Share (Details) - shares shares in Thousands		12 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Accounting Policies [Abstract]
Average common shares outstanding for basic computation		173,115	172,733	170,885
Incremental shares issuable for stock options and common stock awards	[1]	2,552	2,498	2,397
Average common shares outstanding for diluted computation		175,667	175,231	173,282
Antidilutive securities excluded from computation of earnings per share		1,274	0	132

[1] For Fiscal 2015, Fiscal 2014 and Fiscal 2013, there were 1,274 shares, 0 shares and 132 shares, respectively, associated with outstanding stock option awards that were not included in the computation of diluted earnings per share above because their effect was antidilutive.