Related Party Transactions - Fees Received and Paid (Detail) (HSBC USA, Inc. [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
HSBC USA, Inc. [Member]
Related Party Transaction [Line Items]
Fees received from HSBC Bank USA	$ 1	$ 1	$ 3	$ 3
Fees paid to HSBC Bank USA		$ 1		$ 3