Supplemental Cash Flow and Noncash Investing Transactions (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Supplemental Cash Flow Information
Interest paid	$ 162.3	[1]	$ 152.7	[1]	$ 152.6	[1]
Income taxes paid (refunded), net	$ 11.1		$ (2.8)		$ 13.0

[1] Interest paid consisted of interest on debt obligations, interest rate swaps (net of interest received) and capital lease interest. Interest expense capitalized as part of the cost of construction of major assets was immaterial for all periods presented.