Fair Value Measurements (Details) (Measured on a recurring basis, USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Jun. 30, 2011
Assets and liabilities measured at fair value on a recurring basis
Derivative financial instruments, Assets	$ 2.6	$ 20.0
Total assets	7.6	55.8
Derivative financial instruments, Liabilities	56.5	14.1
Level 1
Assets and liabilities measured at fair value on a recurring basis
Total assets		30.5
Level 2
Assets and liabilities measured at fair value on a recurring basis
Derivative financial instruments, Assets	2.6	20.0
Total assets	7.6	25.3
Derivative financial instruments, Liabilities	56.5	14.1
Government agency bonds
Assets and liabilities measured at fair value on a recurring basis
Marketable securities		13.7
Government agency bonds | Level 1
Assets and liabilities measured at fair value on a recurring basis
Marketable securities		13.7
Corporate bonds
Assets and liabilities measured at fair value on a recurring basis
Marketable securities		15.1
Corporate bonds | Level 1
Assets and liabilities measured at fair value on a recurring basis
Marketable securities		15.1
Commercial paper
Assets and liabilities measured at fair value on a recurring basis
Marketable securities		1.7
Commercial paper | Level 1
Assets and liabilities measured at fair value on a recurring basis
Marketable securities		1.7
Municipal auction rate securities
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	5.0	5.3
Municipal auction rate securities | Level 2
Assets and liabilities measured at fair value on a recurring basis
Marketable securities	$ 5.0	$ 5.3