Receivables Held for Sale - Summary of Receivables Held for Sale (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Financing Receivable, Allowance for Credit Losses [Line Items]
Receivables held-for-sale, Amount, Total	$ 6,203	[1]	$ 0	[1]	$ 4	[1]	$ 3
First Mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Receivables held-for-sale, Amount, Total	3,022		0
Personal non-credit card [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Receivables held-for-sale, Amount, Total	$ 3,181		$ 0

[1] Net of a valuation allowance of $1.5 billion at December 31, 2012