Condensed Consolidated Statements of Shareholders' Equity Statement - USD ($) $ in Millions	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings (Accumulated Deficit)	Retirement Benefit Adjustments, net of tax	Hedging Adjustments, net of tax	Foreign Currency Translation Adjustments	Treasury Stock	Noncontrolling Interest
Shareholders' Equity Excluding Noncontrolling Interest, Beginning of period at Sep. 30, 2017		$ 0.0	$ 0.7	$ 3,566.5	$ (376.0)	$ 35.1	$ (11.1)	$ (64.0)	$ (371.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred stock conversion			0.1
Preferred stock dividends declared				(6.8)	(2.0)
Activity under stock and deferred compensation plans				(1.5)
Stock-based compensation expense				23.2
Preferred Stock Conversion				0.0
Net earnings	$ 482.9				482.9
Adoption of Accounting Standards Updates					1.4
Net change in retirement benefits, net of tax						(0.7)
Net change in hedges, net of tax							37.9
Foreign currency translation adjustments								(27.4)		$ 0.0
Purchases of treasury stock									(218.7)
Shareholders' Equity Excluding Noncontrolling Interest, End of period at Jun. 30, 2018	3,068.4	0.0	0.8	3,581.4	106.3	34.4	26.8	(91.4)	(589.9)
Total Shareholders' Equity, Beginning of period at Sep. 30, 2017										9.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings attributable to noncontrolling interest	0.9									0.9
Total Shareholders' Equity, End of period at Jun. 30, 2018	3,079.0									10.6
Shareholders' Equity Excluding Noncontrolling Interest, Beginning of period at Mar. 31, 2018		0.0	0.8	3,574.0	11.8	34.9	(12.0)	19.9	(510.0)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred stock conversion			0.0
Preferred stock dividends declared				0.0	(2.0)
Activity under stock and deferred compensation plans				0.0
Stock-based compensation expense				7.4
Preferred Stock Conversion				0.0
Net earnings	96.5				96.5
Adoption of Accounting Standards Updates					0.0
Net change in retirement benefits, net of tax						(0.5)
Net change in hedges, net of tax							38.8
Foreign currency translation adjustments								(111.3)		0.0
Purchases of treasury stock									(79.9)
Shareholders' Equity Excluding Noncontrolling Interest, End of period at Jun. 30, 2018	3,068.4	0.0	0.8	3,581.4	106.3	34.4	26.8	(91.4)	(589.9)
Total Shareholders' Equity, Beginning of period at Mar. 31, 2018										10.3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings attributable to noncontrolling interest	0.3									0.3
Total Shareholders' Equity, End of period at Jun. 30, 2018	3,079.0									10.6
Shareholders' Equity Excluding Noncontrolling Interest, Beginning of period at Sep. 30, 2018	3,050.4	0.0	0.8	3,590.9	88.0	37.9	37.4	(114.7)	(589.9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred stock conversion			0.0
Preferred stock dividends declared				0.0	(4.0)
Activity under stock and deferred compensation plans				34.2
Stock-based compensation expense				28.4
Preferred Stock Conversion				(0.1)
Net earnings	185.8				185.8
Adoption of Accounting Standards Updates					(0.9)
Net change in retirement benefits, net of tax						(2.7)
Net change in hedges, net of tax							5.1
Foreign currency translation adjustments								(1.4)		0.2
Purchases of treasury stock									(88.7)
Shareholders' Equity Excluding Noncontrolling Interest, End of period at Jun. 30, 2019	3,206.1	0.0	0.8	3,653.4	268.9	35.2	42.5	(116.1)	(678.6)
Total Shareholders' Equity, Beginning of period at Sep. 30, 2018	3,060.5									10.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings attributable to noncontrolling interest	0.9									0.9
Total Shareholders' Equity, End of period at Jun. 30, 2019	3,217.3									11.2
Shareholders' Equity Excluding Noncontrolling Interest, Beginning of period at Mar. 31, 2019		0.0	0.8	3,643.1	252.7	36.1	32.0	(75.1)	(655.7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred stock conversion			0.0
Preferred stock dividends declared				0.0	0.0
Activity under stock and deferred compensation plans				0.0
Stock-based compensation expense				10.3
Preferred Stock Conversion				0.0
Net earnings	16.2				16.2
Adoption of Accounting Standards Updates					0.0
Net change in retirement benefits, net of tax						(0.9)
Net change in hedges, net of tax							10.5
Foreign currency translation adjustments								(41.0)		(0.1)
Purchases of treasury stock									(22.9)
Shareholders' Equity Excluding Noncontrolling Interest, End of period at Jun. 30, 2019	3,206.1	$ 0.0	$ 0.8	$ 3,653.4	$ 268.9	$ 35.2	$ 42.5	$ (116.1)	$ (678.6)
Total Shareholders' Equity, Beginning of period at Mar. 31, 2019										11.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings attributable to noncontrolling interest	0.3									0.3
Total Shareholders' Equity, End of period at Jun. 30, 2019	$ 3,217.3									$ 11.2