Investments in Affiliated Companies (Future Debt Maturities) (Details 9) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Schedule of Equity Method Investments [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	$ 485.7
Long-term Debt, Maturities, Repayments of Principal in Year Two	513.6
Long-term Debt, Maturities, Repayments of Principal in Year Three	552.5
Long-term Debt, Maturities, Repayments of Principal in Year Four	626.9
Long-term Debt, Maturities, Repayments of Principal in Year Five	236.2
Long-term Debt, Maturities, Repayments of Principal after Year Five	866.2
Total Debt	3,283.0		3,504.2
RRPF Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	64.2
Long-term Debt, Maturities, Repayments of Principal in Year Two	417.1
Long-term Debt, Maturities, Repayments of Principal in Year Three	622.0
Long-term Debt, Maturities, Repayments of Principal in Year Four	359.7
Long-term Debt, Maturities, Repayments of Principal in Year Five	245.6
Long-term Debt, Maturities, Repayments of Principal after Year Five	288.3
Total Debt	$ 1,996.9	[1]

[1] All debt obligations are nonrecourse to the shareholders.