Debt and Credit Arrangements Annual Maturities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Maturities of Long-term Debt [Abstract]
2013	$ 16.1	[1]
2014	352.8
2015	0.1
2016	0.1
2017	913.8
Thereafter	994.5
Total long-term debt	$ 2,277.4		$ 1,615.7

[1] The interest coverage ratio is defined as EBITDA, as defined in the Credit Agreement, to net interest expense plus cash dividends on convertible preferred stock for the four quarters then ended.