CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Millions	Total	Common Stock	Capital in Excess of Par Value	Reinvested Earnings	Common Stock in Treasury	Accumulated Other Comprehensive (Loss) Income	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjustment Reinvested Earnings	Cumulative Effect, Period of Adoption, Adjustment Accumulated Other Comprehensive (Loss) Income
Balances, beginning of period at Jun. 30, 2017	$ 1,198.6	$ 276.7	$ 284.8	$ 1,321.8	$ (341.6)	$ (343.1)
Increase (Decrease) in Stockholders' Equity
Net income	188.5			188.5
Pension and postretirement benefits gain (loss), net of tax	78.6					78.6
Marketable securities gain, net of tax	0.0
Net gain (loss) on derivative instruments, net of tax	26.1					26.1
Foreign currency translation	(1.4)					(1.4)
Cash Dividends:
Common	(34.4)			(34.4)
Share-based compensation plans	17.0		14.2		2.8
Stock options exercised	12.9	1.9	11.0
Balances, end of period at Jun. 30, 2018	$ 1,485.9	$ 278.6	310.0	1,475.9	$ (338.8)	(239.8)	$ 0.0	$ 1.0	$ (1.0)
Cash Dividends:
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201712Member
Balances, beginning of period (in shares) at Jun. 30, 2017	46,753,180	55,349,658			8,596,478
Common Shares
Stock options exercised (in shares)	362,571	362,571
Share-based compensation plans (in shares)	75,993				75,993
Balances, end of period (in shares) at Jun. 30, 2018	47,191,744	55,712,229			8,520,485
Increase (Decrease) in Stockholders' Equity
Net income	$ 167.0			167.0
Pension and postretirement benefits gain (loss), net of tax	(72.9)					(72.9)
Marketable securities gain, net of tax	0.3					0.3
Net gain (loss) on derivative instruments, net of tax	(37.6)					(37.6)
Foreign currency translation	(0.8)					(0.8)
Cash Dividends:
Common	(38.6)			(38.6)
Share-based compensation plans	12.9		6.9		$ 6.0
Stock options exercised	3.9	$ 0.4	3.5
Balances, end of period at Jun. 30, 2019	$ 1,520.1	$ 279.0	320.4	1,605.3	$ (332.8)	(351.8)
Common Shares
Stock options exercised (in shares)	96,514	96,514
Share-based compensation plans (in shares)	182,105				182,105
Balances, end of period (in shares) at Jun. 30, 2019	47,470,363	55,808,743			8,338,380
Increase (Decrease) in Stockholders' Equity
Net income	$ 1.5			1.5
Pension and postretirement benefits gain (loss), net of tax	(41.0)					(41.0)
Marketable securities gain, net of tax	0.0
Net gain (loss) on derivative instruments, net of tax	3.7					3.7
Foreign currency translation	(8.9)					(8.9)
Cash Dividends:
Common	(38.8)			(38.8)
Share-based compensation plans	4.8	$ 0.5	(2.7)		$ 7.0
Stock options exercised	4.3	0.6	3.7
Balances, end of period at Jun. 30, 2020	$ 1,445.7	$ 280.1	$ 321.4	$ 1,568.0	$ (325.8)	$ (398.0)
Common Shares
Stock options exercised (in shares)	117,049	117,049
Share-based compensation plans (in shares)	263,056	86,956			176,100
Balances, end of period (in shares) at Jun. 30, 2020	47,850,468	56,012,748			8,162,280