Transactions with Boeing - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Nov. 30, 2012	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Guarantor Obligations [Line Items]
Maturity period of 364-day line of credit	1 year
Outstanding amount under credit facilities		$ 0		$ 0
Maximum Beneficiary		1,519
Portfolio Assets Totaling		1,859		1,928
Deferred Revenue		31		38
Fees paid to Boeing		(2)	(2)
New Business Volume		20	105
Revolving Credit Line Due Two Thousand Thirteen [Member]
Guarantor Obligations [Line Items]
Bank access to 364-day line credit		750
364-day line credit		2,300
Revolving Credit Line Due Two Thousand Seventeen [Member]
Guarantor Obligations [Line Items]
Bank access to 364-day line credit		750
364-day line credit		$ 2,300