Fair Value Option - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Fair Value Disclosures [Abstract]
Increased the debt balance	$ 200		$ 200		$ 247
Foreign currency translation gains (losses) recorded in derivatives	(109)	(53)	(28)	31
Offsetting gains (losses) recorded in derivative related income (expense)	109	53	28	(31)
Cumulative increased value of debt through fair value option adjustments	$ 632		$ 632		$ 824