Investment in Lease Financing (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Rental receivable, net of principal and interest on nonrecourse debt	$ 3,543		$ 3,757
Estimated residual value of leased assets	760		772
Initial direct cost, net of amortization	16		16
Gross investment in lease financing	4,319		4,545
Unearned income	(758)		(942)
Net investment in lease financing	$ 3,561	[1]	$ 3,603	[1]

[1] The accumulated allowance for uncollectible minimum lease payments was $67 million and $79 million at December 31, 2012 and 2011, respectively