XML 43 R45.htm IDEA: XBRL DOCUMENT v2.4.0.6
Amortized Cost or Cost and Fair Value of Available For Sale Securities (Parenthetical) (Detail) (USD $)
In Millions, unless otherwise specified
Sep. 30, 2012
Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]    
Fair values of financial instruments $ 18,076.2 $ 4,647.0
Equity Securities
   
Schedule of Available-for-sale Securities [Line Items]    
Fair values of financial instruments 1,504.6 871.0
Equity Securities | Common Stock
   
Schedule of Available-for-sale Securities [Line Items]    
Fair values of financial instruments 1,504.6 [1] 871.0 [1]
Equity Securities | Energy Sector Business | Common Stock
   
Schedule of Available-for-sale Securities [Line Items]    
Fair values of financial instruments $ 572.8 $ 573.3
[1] Of the $1,504.6 million and $871.0 million of fair value as of September 30, 2012 and December 31, 2011, respectively, $572.8 million and $573.3 million, respectively, related to certain energy sector businesses.