Accumulated Other Comprehensive Income - Components of Accumulated Other Comprehensive Income Included in Shareholders' Equity (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated unrealized loss on derivative instruments, net of taxes of $(48), $(39) and $(20), respectively	$ (74)	$ (62)	$ (33)
Accumulated unrealized gain on available-for-sale securities, net of taxes of $3, $1 and $3, respectively	4	2	5
Foreign currency translation adjustments	276	243	261
Funded status of post-retirement benefit obligations, net of taxes of $(11), $(9) and $(4), respectively	(13)	(11)	(3)
Total accumulated other comprehensive income	$ 193	$ 172	$ 230