Restructuring - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended			1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Jul. 31, 2012 2012 Restructuring [Member] Areas Employees	Dec. 31, 2012 2012 Restructuring [Member]	Jul. 31, 2011 2011 Restructuring [Member] Employees	Dec. 31, 2011 2011 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Number of areas pre restructuring				22
Number of areas post restructuring				17
Number of employee positions eliminated				700		700
Pre-tax restructuring charges	$ 67	$ 19	$ (2)		$ 67		$ 19
Pre-tax restructuring charges associated with this reorganization related to employee severance and benefit costs					56		18
Number of employees positions eliminated open position						300
Employee severance and benefit cost payments through the balance sheet date	$ 46