Net-of-Tax Components of AOCI (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Accumulated Other Comprehensive Income Loss Net Of Tax
CTA	$ (1,227)	$ (1,129)	$ (934)
Pension and other employee benefits	(1,619)	(1,508)	(1,245)
Hedging activities	(5)	2	(3)	3
Other	41	44	43
Accumulated other comprehensive loss	$ (2,810)	$ (2,591)	$ (2,139)