Debt (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Debt
Debt payable within one year	$ 72.4	$ 57.9
Debt payable after one year	13.2	3.3
Debt Subject to Compromise
Bank borrowings	500.0	500.0
Accrued interest on bank borrowings	429.5	407.3
Drawn letters of credit	26.5	26.3
Accrued interest on drawn letters of credit	9.3	8.2
Debt Subject to Compromise	$ 965.3	$ 941.8
Weighted average interest rates on total debt (as a percent)	3.50%	3.50%