Debt and Credit Arrangements Annual Maturities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Maturities of Long-term Debt [Abstract]
2012	$ 1.8	[1]
2013	16.0	[2]
2014	354.4
2015	0.1
2016	0.1
Thereafter	1,243.3
Total long-term debt	$ 1,615.7		$ 1,622.2

[1] Holders of our 4.25% Notes may require us to repurchase their notes for cash at par in March 2012. The 4.25% Notes are redeemable in whole or in part at our option beginning March 15, 2012.

[2] Holders of our 4.75% Convertible Senior Notes due 2023 (the “4.75% Notes”) may require us to repurchase their notes for cash, stock or a combination, at our election, at par in March 2013.