Receivables - Aging Analysis of Past Due Loans (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Apr. 30, 2013 platform	Mar. 31, 2013 platform	Sep. 30, 2012	Sep. 30, 2013 Real estate secured [Member]		Dec. 31, 2012 Real estate secured [Member]		Sep. 30, 2013 First Lien [Member]		Dec. 31, 2012 First Lien [Member]		Sep. 30, 2013 Second Lien [Member]		Dec. 31, 2012 Second Lien [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, 30 - 89 days past due					$ 2,925	[1]	$ 3,075	[1]	$ 2,661		$ 2,759		$ 264		$ 316
Financing Receivable, 90 plus days past due					1,775	[1]	2,987	[1]	1,577		2,748		198		239
Financing Receivable, Past Due, Total					4,700	[1]	6,062	[1]	4,238		5,507		462		555
Financing Receivable, Current					23,144	[1],[2]	26,877	[1],[2]	20,444	[2]	23,794	[2]	2,700	[2]	3,083	[2]
Total receivables	$ 27,844			$ 33,963	$ 27,844	[1],[3]	$ 32,939	[1],[3]	$ 24,682	[3]	$ 29,301	[3]	$ 3,162	[3]	$ 3,638	[3]
Number of mortgage loan servicing platforms		1	2

[1] Our real estate secured receivables have historically been maintained on two mortgage loan servicing platforms which resulted in differences relating to how contractual delinquency was determined. In April 2013, we moved all closed-end real estate secured receivables onto one platform which resulted in the substantial majority of our real estate secured receivables utilizing the same platform. As a result of this move, we have experienced an increase in dollars of two-months-and-over contractual delinquency, although much of the increase has been offset by improvements in credit quality in other parts of our real estate secured receivable portfolio.

[2] Receivables less than 30 days past due are presented as current.

[3] The receivable balances included in this table reflects the principal amount outstanding on the loan and certain basis adjustments to the loan such as deferred fees and costs on originated loans, purchase accounting fair value adjustments and premiums or discounts on purchased loans. However, these basis adjustments on the loans are excluded in other presentations of dollars of two-months-and-over contractual delinquency and nonperforming receivable account balances.