Quarterly report pursuant to Section 13 or 15(d)

Commitments and Contingencies - Additional Information (Detail)

v2.4.0.6
Commitments and Contingencies - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2013
Dec. 31, 2012
Minimum [Member]
   
Commitments and Contingencies Disclosure [Line Items]    
Data Processing, Outsourcing Services And Other Agreements, expiration year 2013  
Data Processing, Outsourcing Services And Other Agreements, estimated aggregate contractual obligation   $ 40
Maximum [Member]
   
Commitments and Contingencies Disclosure [Line Items]    
Data Processing, Outsourcing Services And Other Agreements, expiration year 2018  
Data Processing, Outsourcing Services And Other Agreements, estimated aggregate contractual obligation   70
Bvs Commitment [Member]
   
Commitments and Contingencies Disclosure [Line Items]    
Maximum Committed Borrowing Capacity $ 55  
Commitment Maturity Date May 31, 2015