XML 37 R29.htm IDEA: XBRL DOCUMENT  v2.3.0.11
Fair Value Measurements (Details Textuals) (USD $)
In Millions
6 Months Ended
Jun. 30, 2011
Dec. 31, 2010
Fair Value Measurements (Textuals)    
Restricted cash and investments $ 15.9 $ 16.3
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
   
Fair Value Measurements (Textuals)    
Cash equivalents 169.5 426.3
Restricted cash and investments 15.9 16.3
Trading securities, included in other assets $ 14.4 $ 13.5
Average Maturity period of investment in AAA-rated money market mutual funds, days less than 90 days