CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Revision of Prior Period, Accounting Standards Update, Adjustment	Common Stock	Common Stock Revision of Prior Period, Accounting Standards Update, Adjustment	Additional Paid-In Capital	Additional Paid-In Capital Revision of Prior Period, Accounting Standards Update, Adjustment	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings Revision of Prior Period, Accounting Standards Update, Adjustment	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss) Revision of Prior Period, Accounting Standards Update, Adjustment	Common Stock in Treasury, at Cost	Common Stock in Treasury, at Cost Revision of Prior Period, Accounting Standards Update, Adjustment
Balance at Sep. 30, 2017	$ 2,307.4			$ 0.9		$ 802.2		$ 2,399.8			$ (125.0)			$ (770.5)
Net income	471.9							471.9
Employee pension and postretirement benefits, net of tax	35.3										35.3
Currency translation adjustments	(17.6)										(17.6)
Cash dividends	(71.2)							(71.2)
Repurchases of Common Stock	(249.3)													(249.3)
Exercise of stock options	16.6					(5.1)								21.7
Stock-based compensation expense	26.7					26.7
Payment of stock-based restricted and performance shares						(9.4)								9.4
Shares tendered for taxes on stock-based compensation	(7.7)													(7.7)
Retirement of treasury stock				(0.2)				(792.6)						792.8
Other	1.4					0.4					0.5			0.5
Balance at Sep. 30, 2018	2,513.5		$ 2,497.6	0.7	$ 0.7	814.8	$ 814.8	2,007.9		$ 2,001.1	(106.8)		$ (115.9)	(203.1)	$ (203.1)
Balance (Accounting Standards Update 2014-09) at Sep. 30, 2018		$ (60.4)							$ (60.4)
Balance (Accounting Standards Update 2016-16) at Sep. 30, 2018		$ 44.5							44.5
Balance (Accounting Standards Update 2018-02) at Sep. 30, 2018									$ 9.1			$ (9.1)
Net income	579.4							579.4
Employee pension and postretirement benefits, net of tax	(49.4)										(49.4)
Currency translation adjustments	(36.3)										(36.3)
Cash dividends	(75.5)							(75.5)
Repurchases of Common Stock	(350.1)													(350.1)
Exercise of stock options	11.3					(10.4)								21.7
Stock-based compensation expense	29.0					29.0
Payment of stock-based restricted and performance shares						(24.6)								24.6
Shares tendered for taxes on stock-based compensation	(7.3)													(7.3)
Other	1.1					(0.3)								1.4
Balance at Sep. 30, 2019	2,599.8			0.7		808.5		2,505.0			(201.6)			(512.8)
Net income	324.5							324.5
Employee pension and postretirement benefits, net of tax	(26.5)										(26.5)
Currency translation adjustments	30.4										30.4
Cash dividends	(81.8)							(81.8)
Repurchases of Common Stock	(40.8)													(40.8)
Exercise of stock options	26.1					(11.6)								37.7
Stock-based compensation expense	29.3					29.3
Payment of stock-based restricted and performance shares						(23.0)								23.0
Shares tendered for taxes on stock-based compensation	(10.7)													(10.7)
Other	0.4					(2.3)					(0.7)			3.4
Balance at Sep. 30, 2020	$ 2,850.7			$ 0.7		$ 800.9		$ 2,747.7			$ (198.4)			$ (500.2)