Condensed Consolidated Statements of Stockholders’ Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)
Balance (in shares) at Jun. 30, 2018		154.5
Balance at Jun. 30, 2018	$ 1,094.3	$ 1.6	$ 1,048.5	$ 1,727.0	$ (1,630.8)	$ (51.9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	288.1			298.8		(10.7)
Stock option exercises	24.2		24.2
Stock-based compensation	46.8		46.8
Treasury stock acquired	(120.3)				(120.3)
Treasury stock reissued	0.0		(11.8)		11.8
Common stock dividends	(168.7)			(168.7)
Balance (in shares) at Mar. 31, 2019		154.5
Balance at Mar. 31, 2019	$ 1,265.6	$ 1.6	1,107.6	1,959.9	(1,739.2)	(64.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury stock acquired (less than) (in shares)	1.1
Treasury stock reissued (in shares)	0.6
Common stock dividends (in dollars per share)	$ 1.455
Balance (in shares) at Dec. 31, 2018		154.5
Balance at Dec. 31, 2018	$ 1,122.6	$ 1.6	1,087.8	1,843.8	(1,741.4)	(69.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	177.2			172.2		5.1
Stock option exercises	4.6		4.6
Stock-based compensation	17.3		17.3
Treasury stock acquired	0.0
Treasury stock reissued	0.0		(2.2)		2.2
Common stock dividends	(56.1)			(56.1)
Balance (in shares) at Mar. 31, 2019		154.5
Balance at Mar. 31, 2019	$ 1,265.6	$ 1.6	1,107.6	1,959.9	(1,739.2)	(64.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury stock acquired (less than) (in shares)	0.1
Treasury stock reissued (in shares)	0.1
Common stock dividends (in dollars per share)	$ 0.485
Balance (in shares) at Jun. 30, 2019	154.5	154.5
Balance at Jun. 30, 2019	$ 1,127.5	$ 1.6	1,109.3	2,087.7	(1,999.8)	(71.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	236.8			232.8		4.0
Stock option exercises	26.7		26.7
Stock-based compensation	47.4		47.4
Treasury stock acquired	(50.5)				(50.5)
Treasury stock reissued	0.0		(14.0)		14.0
Common stock dividends	$ (185.6)			(185.6)
Balance (in shares) at Mar. 31, 2020	154.5	154.5
Balance at Mar. 31, 2020	$ 1,202.5	$ 1.6	1,169.3	2,135.1	(2,036.2)	(67.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury stock acquired (less than) (in shares)	0.4
Treasury stock reissued (in shares)	0.6
Common stock dividends (in dollars per share)	$ 1.62
Balance (in shares) at Dec. 31, 2019		154.5
Balance at Dec. 31, 2019	$ 1,125.4	$ 1.6	1,150.1	2,030.1	(1,988.7)	(67.7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	167.3			166.8		0.5
Stock option exercises	4.8		4.8
Stock-based compensation	17.3		17.3
Treasury stock acquired	(50.5)				(50.5)
Treasury stock reissued	0.0		(2.9)		2.9
Common stock dividends	$ (61.8)			(61.8)
Balance (in shares) at Mar. 31, 2020	154.5	154.5
Balance at Mar. 31, 2020	$ 1,202.5	$ 1.6	$ 1,169.3	$ 2,135.1	$ (2,036.2)	$ (67.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury stock acquired (less than) (in shares)	0.4
Treasury stock reissued (in shares)	0.1
Common stock dividends (in dollars per share)	$ 0.54