Investments in Affiliated Companies (Balance Sheet, Affiliates) (Details 6) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Summarized balance sheet for all affiliated companies
Current assets	$ 311.0	$ 404.4
Noncurrent assets	4,781.3	4,724.4
Total assets	5,092.3	5,128.8
Current liabilities	439.7	570.7
Noncurrent liabilities	3,739.6	3,671.9
Shareholders’ equity	913.0	886.2
Total liabilities and shareholders' equity	$ 5,092.3	$ 5,128.8