Fair Value Measurements Fair Value on a Nonrecurring Basis (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012
Level 1
Fair value assets and liabilities measured on recurring and nonrecurring basis
Total long-term debt	$ 0
Level 2
Fair value assets and liabilities measured on recurring and nonrecurring basis
Total long-term debt	1,526.9
Level 3
Fair value assets and liabilities measured on recurring and nonrecurring basis
Total long-term debt	59.9
Fair Value, Total
Fair value assets and liabilities measured on recurring and nonrecurring basis
Total long-term debt	$ 1,586.8