Receivables Held for Sale - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended					3 Months Ended				0 Months Ended		3 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2014		Dec. 31, 2013		Apr. 01, 2013	Apr. 02, 2013	Jun. 30, 2013	Mar. 31, 2013	Sep. 01, 2013 employee	Dec. 31, 2011
Financing Receivable, Recorded Investment, Past Due [Line Items]
Receivables held for sale	$ 860	[1]	$ 2,047	[1]	$ 6,203	$ 860	[1]	$ 2,047	[1]						$ 0
Period of receivables sold in multiple transactions	15 months
Change in real estate secured receivable balance, including collections	(243)		(711)		(264)
Lower of amortized cost or fair value adjustment	314		748		18
Number of employees transferred to new department (over)														200
Other Income [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Initial lower of amortized cost or fair value adjustment	113		212		1,547
Lower of amortized cost or fair value adjustment					1,641
Real Estate Owned [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Change in real estate secured receivable balance, including collections	182		529		168
Lower of amortized cost or fair value adjustment	(5)		40		50
Real Estate Owned [Member] | Other Income [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Initial lower of amortized cost or fair value adjustment	0		0		0
Lower of amortized cost or fair value adjustment					(50)
Short Sales [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Change in real estate secured receivable balance, including collections	61		182		96
Lower of amortized cost or fair value adjustment	(3)		22		20
Short Sales [Member] | Other Income [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Initial lower of amortized cost or fair value adjustment	0		0		0
Lower of amortized cost or fair value adjustment					(20)
Fair Value [Member] | Other Income [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Initial lower of amortized cost or fair value adjustment	113		212		1,547
Lower of amortized cost or fair value adjustment					1,711
Receivables Held for Sale, Initial Lower of Amortized Cost or Fair Value Adjustment, Including Amount Recorded as Provision for Credit Losses					(1,659)
First Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Receivables held for sale	860		2,047			860		2,047
Threshold, days past due to initiate sale activities for first lien real estate secured receivables	180 days
Aggregate unpaid balance	1,390		3,612
Aggregate carrying balance	1,080		2,506
First Mortgage [Member] | Third-Party Investor [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Aggregate unpaid balance	2,927		5,685			1,383		4,561
Aggregate carrying balance	2,152		3,127			996		2,493
Proceeds from sale of loans held-for-sale	2,242		3,131
Gain (loss) on sales of loans	63		(89)
Personal non-credit card [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Receivables held for sale	0	[1]	0	[1]	3,181	0	[1]	0	[1]						0
Aggregate unpaid balance										3,760
Change in real estate secured receivable balance, including collections	0		0		0
Lower of amortized cost or fair value adjustment	0		(82)		21								(82)
Receivable sales													2,947
Proceeds from sale of loans held-for-sale											2,964
Gain (loss) on sales of loans												(11)
Servicing fees			28
Real Estate Secured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Lower of amortized cost or fair value adjustment	$ (322)		$ (768)

[1] The following table provides a rollforward of our valuation allowance for 2014, 2013 and 2012. At December 31, 2014, the valuation allowance is zero as the fair value of the pool of receivables held for sale at December 31, 2014 exceeds the carrying value as these receivables are carried at the lower of amortized cost or fair value. See Note 20, "Fair Value Measurements," for a discussion of the factors impacting the fair value of these receivables.