Reclassifications from Accumulated Other Comprehensive Income (Loss) (AOCI) - Schedule of amounts reclassified from AOCI (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Amount reclassified from AOCI
Cost of sales	$ 476.2	$ 390.5	$ 1,272.4	$ 1,098.3
Net sales	572.2	473.6	1,539.7	1,289.9
Interest expense	7.5	7.7	22.0	22.5
Total before tax	37.7	29.1	106.6	32.1
Tax (expense) benefit	(7.5)	(8.4)	39.1	(10.6)
Net income	30.2	20.7	145.7	21.5
Cash flow hedging items
Amount reclassified from AOCI
Net of tax	1.3	(1.7)	(0.7)	(12.4)
Net actuarial loss
Amount reclassified from AOCI
Total before tax	(4.1)	(10.3)	(12.4)	(30.7)
Prior service benefit
Amount reclassified from AOCI
Total before tax	0.8	1.1	2.5	3.6
Curtailment charge
Amount reclassified from AOCI
Total before tax	0.0	0.0	0.0	(0.5)
Pension and other postretirement benefit plan items
Amount reclassified from AOCI
Total before tax	(3.3)	(9.2)	(9.9)	(27.6)
Tax benefit	1.2	3.5	3.2	10.5
Net of tax	(2.1)	(5.7)	(6.7)	(17.1)
Amount Reclassified from AOCI | Cash flow hedging items
Amount reclassified from AOCI
Total before tax	2.1	(2.8)	(1.0)	(20.0)
Tax (expense) benefit	(0.8)	1.1	0.3	7.6
Net income	1.3	(1.7)	(0.7)	(12.4)
Amount Reclassified from AOCI | Commodity contracts | Cash flow hedging items
Amount reclassified from AOCI
Cost of sales	2.5	(3.1)	(0.3)	(21.0)
Amount Reclassified from AOCI | Foreign exchange contracts | Cash flow hedging items
Amount reclassified from AOCI
Net sales	(0.5)	0.2	(1.0)	0.7
Amount Reclassified from AOCI | Forward interest rate swaps | Cash flow hedging items
Amount reclassified from AOCI
Interest expense	$ 0.1	$ 0.1	$ 0.3	$ 0.3