Inventories, net - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule of Inventory [Line Items]
General and administrative costs included in work-in-process inventories	$ 623,000,000	$ 592,000,000
General and administrative costs incurred and recorded in inventories	2,400,000,000	2,300,000,000	2,300,000,000
General and administrative costs charged to cost of sales from inventories	$ 2,400,000,000	$ 2,200,000,000	$ 2,400,000,000