Reclassifications from Accumulated Other Comprehensive (Loss) Income Schedule of changes in AOCI by component, net of tax (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Changes in the balance of Accumulated Other Comprehensive Income
Balance at the beginning of the period	$ (333.3)	$ (268.3)	$ (328.2)	$ (245.2)
Other comprehensive loss before reclassifications	(14.7)	(19.1)	(29.4)	(43.7)
Amounts reclassified from AOCI	10.4	4.6	20.0	6.1
Other comprehensive loss	(4.3)	(14.5)	(9.4)	(37.6)
Balance at the end of the period	(337.6)	(282.8)	(337.6)	(282.8)
Cash flow hedging items
Changes in the balance of Accumulated Other Comprehensive Income
Balance at the beginning of the period	(34.0)	(10.6)	(28.5)	7.6
Other comprehensive loss before reclassifications	(12.4)	(9.0)	(23.8)	(25.7)
Amounts reclassified from AOCI	6.7	1.7	12.6	0.2
Other comprehensive loss	(5.7)	(7.3)	(11.2)	(25.5)
Balance at the end of the period	(39.7)	(17.9)	(39.7)	(17.9)
Pension and other postretirement benefit plan items
Changes in the balance of Accumulated Other Comprehensive Income
Balance at the beginning of the period	(253.1)	(233.7)	(256.8)	(236.7)
Other comprehensive loss before reclassifications	0.0	0.0	0.0	0.0
Amounts reclassified from AOCI	3.7	2.9	7.4	5.9
Other comprehensive loss	3.7	2.9	7.4	5.9
Balance at the end of the period	(249.4)	(230.8)	(249.4)	(230.8)
Unrealized losses on available-for- sale securities
Changes in the balance of Accumulated Other Comprehensive Income
Balance at the beginning of the period	(0.3)	(0.4)	(0.3)	(0.4)
Other comprehensive loss before reclassifications	0.0	0.0	0.0	0.0
Amounts reclassified from AOCI	0.0	0.0	0.0	0.0
Other comprehensive loss	0.0	0.0	0.0	0.0
Balance at the end of the period	(0.3)	(0.4)	(0.3)	(0.4)
Foreign currency items
Changes in the balance of Accumulated Other Comprehensive Income
Balance at the beginning of the period	(45.9)	(23.6)	(42.6)	(15.7)
Other comprehensive loss before reclassifications	(2.3)	(10.1)	(5.6)	(18.0)
Amounts reclassified from AOCI	0.0	0.0	0.0	0.0
Other comprehensive loss	(2.3)	(10.1)	(5.6)	(18.0)
Balance at the end of the period	$ (48.2)	$ (33.7)	$ (48.2)	$ (33.7)