Condensed Consolidated Statements of Stockholders’ Equity - USD ($) shares in Millions, $ in Millions	Total	Cumulative effect of changes in accounting principles		Common Stock	Additional Paid-In Capital	Retained Earnings	Retained Earnings Cumulative effect of changes in accounting principles	[1]	Treasury Stock	Accumulated Other Comprehensive Income (Loss)
Balance (in shares) at Jun. 30, 2019				154.5
Balance at Jun. 30, 2019	$ 1,127.5	$ 0.2	[1]	$ 1.6	$ 1,109.3	$ 2,087.7	$ 0.2		$ (1,999.8)	$ (71.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	47.6					55.9				(8.3)
Stock option exercises	18.2				18.2
Stock-based compensation	11.7				11.7
Treasury stock acquired	0.0
Treasury stock reissued	0.0				(8.2)				8.2
Common stock dividends	(61.8)					(61.8)
Balance (in shares) at Sep. 30, 2019				154.5
Balance at Sep. 30, 2019	$ 1,143.4			$ 1.6	1,131.1	2,082.0			(1,991.6)	(79.5)
Balance (in shares) at Jun. 30, 2020	154.5			154.5
Balance at Jun. 30, 2020	$ 1,346.5	$ 0.2		$ 1.6	1,178.5	2,302.6			(2,035.7)	(100.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	103.4					65.8				37.6
Stock option exercises	20.7				20.7
Stock-based compensation	10.3				10.3
Treasury stock acquired	(0.8)								(0.8)
Treasury stock reissued	0.0				(11.0)				11.0
Common stock dividends	$ (66.4)					(66.4)
Balance (in shares) at Sep. 30, 2020	154.5			154.5
Balance at Sep. 30, 2020	$ 1,413.8			$ 1.6	$ 1,198.5	$ 2,302.1			$ (2,025.5)	$ (62.9)

[1] Primarily reflects the adoption of accounting standards as described in Note 2, “New Accounting Pronouncements.”