Receivables Held for Sale - Summary of Components of Cumulative Lower of Amortized Cost or Fair Value Adjustment (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012	Jun. 30, 2013		Jun. 30, 2012
Lower of amortized cost or fair value adjustment recorded as a component of:
Lower of amortized cost or fair value adjustment	$ (471)			$ (925)
Real Estate Owned [Member]
Lower of amortized cost or fair value adjustment recorded as a component of:
Lower of amortized cost or fair value adjustment	(16)			(49)
Short Sales [Member]
Lower of amortized cost or fair value adjustment recorded as a component of:
Lower of amortized cost or fair value adjustment	(2)			(11)
Other Income [Member]
Lower of amortized cost or fair value adjustment recorded as a component of:
Provision for credit losses	0		112	0		112
Initial lower of amortized cost or fair value adjustment	99		1,547	99		1,547
Subsequent to initial transfer to held for sale(1)	(471)	[1]		(925)	[1]
Total recorded through other revenues	(372)		1,547	(826)		1,547
Lower of amortized cost or fair value adjustment	(372)		1,659	(826)		1,659
Other Income [Member] | Fair Value [Member]
Lower of amortized cost or fair value adjustment recorded as a component of:
Provision for credit losses	0		112	0		112
Initial lower of amortized cost or fair value adjustment	99		1,547	99		1,547
Subsequent to initial transfer to held for sale(1)	(453)	[1]		(865)	[1]
Total recorded through other revenues	(354)		1,547	(766)		1,547
Lower of amortized cost or fair value adjustment	(354)		1,659	(766)		1,659
Other Income [Member] | Real Estate Owned [Member]
Lower of amortized cost or fair value adjustment recorded as a component of:
Provision for credit losses	0		0	0		0
Initial lower of amortized cost or fair value adjustment	0		0	0		0
Subsequent to initial transfer to held for sale(1)	(16)	[1]		(49)	[1]
Total recorded through other revenues	(16)		0	(49)		0
Lower of amortized cost or fair value adjustment	(16)		0	(49)		0
Other Income [Member] | Short Sales [Member]
Lower of amortized cost or fair value adjustment recorded as a component of:
Provision for credit losses	0		0	0		0
Initial lower of amortized cost or fair value adjustment	0		0	0		0
Subsequent to initial transfer to held for sale(1)	(2)	[1]		(11)	[1]
Total recorded through other revenues	(2)		0	(11)		0
Lower of amortized cost or fair value adjustment	$ (2)		$ 0	$ (11)		$ 0

[1] For the three months ended June 30, 2013, the fair value amount relates to an increase in the relative fair value of real estate secured receivables held for sale. For the six months ended June 30, 2013, the fair value of the lower of amortized cost or fair value adjustment reflects an increase in the relative fair value of $947 million related to real estate secured receivables held for sale and an additional charge of $82 million related to personal non-credit card receivables prior to the sale of t