Quarterly report pursuant to Section 13 or 15(d)

Fair Value of Financial Instruments (Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation) (Details)

 v2.3.0.11
Fair Value of Financial Instruments (Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation) (Details) (USD $)
In Millions
3 Months Ended 6 Months Ended
Jun. 30, 2011
Jun. 30, 2010
Jun. 30, 2011
Jun. 30, 2010
Fair Value of Financial Instruments        
Beginning balance - January 1 $ 68.1 $ 171.0 $ 45.6 $ 63.2
Total gains (losses)        
Included in earnings 46.5 437.7 91.1 799.8
Included in other comprehensive income        
Settlements (30.6) (369.8) (52.7) (624.1)
Transfers out of Level 3 (20.0)   (20.0)  
Ending balance - March 31 64.0 238.9 64.0 238.9
Total gains (losses) for the period included in earnings attributable to the change in unrealized gains or losses on assets and liabilities still held at the reporting date $ 46.5 $ 400.9 $ 91.1 $ 639.8