Commitments and Contingent Liabilities - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Settlement fees attributable to related parties	$ 4
Notional amount of future obligations under Chubb Financial Solutions' (CFS) derivative contracts	90	340
Fair value of future obligations under Chubb Financial Solutions' derivative contracts	2	2
Aggregate principal commitments related to a reinsurance contract for which a property and casualty insurance subsidiary was contingently liable	400
Year of expiration of principal commitments related to a reinsurance contract written by a property and casualty subsidiary	2023
Year through which office facilities under lease agreements will expire	2029
Office facility leases renewal options in years, Lower end of range	2 years
Office facility leases renewal options in years, Higher end of range	10 years
Commitments to fund limited partnership investments	$ 580
Period for which commitments can be called by the partnerships	5 years or less