Segment and Related Information (Tables)
9 Months Ended
Sep. 30, 2011
Segment and Related Information [Abstract] 
Segment information
                                 
    2011     2010  
            Operating             Operating  
Three Months   Revenue     Income     Revenue     Income  
S&P
  $ 409.9     $ 169.1     $ 417.5     $ 187.3  
MH Financial
    348.5       112.6       294.3       85.8  
MHE
    937.3       314.7       1,054.7       357.5  
I&M
    228.5       51.3       204.1       43.8  
Intersegment elimination
    (16.2 ) 1     —       (14.4 ) 1     —  
 
                       
Total operating segments
    1,908.0       647.7       1,956.2       674.4  
 
                       
General corporate expense
    —       (40.9 )     —       (44.4 )
 
                       
Total
  $ 1,908.0     $ 606.8     $ 1,956.2     $ 630.0  
 
                       
                                 
    2011     2010  
            Operating             Operating  
Nine Months   Revenue     Income     Revenue     Income  
S&P
  $ 1,333.1     $ 572.2     $ 1,223.8     $ 557.5  
MH Financial
    1,005.9       306.7       866.8       240.3  
MHE
    1,776.6       281.4       1,936.9       347.3  
I&M
    657.6       139.1       590.4       118.0  
Intersegment elimination
    (46.8 )1     —       (41.3 )1     —  
 
                       
Total operating segments
    4,726.4       1,299.4       4,576.6       1,263.1  
 
                       
General corporate expense
    —       (119.3 )     —       (117.7 )
 
                       
Total
  $ 4,726.4     $ 1,180.1     $ 4,576.6     $ 1,145.4  
 
                       
 
1   Revenue for S&P and expenses for MH Financial include an intersegment royalty charged to MH Financial for the rights to use and distribute content and data developed by S&P.
    See Note 2 — Acquisitions and Divestitures, and Note 11 — Restructuring for actions that impacted the segment operating results.