Credit Loss Reserves - Summarizes Changes in Credit Loss Reserves by Product/Class and Related Receivable Balance by Product (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Credit loss reserve analysis:
Credit loss reserve balances at beginning of period	$ 4,608	$ 4,590	$ 5,952	$ 5,512
Provision for credit losses	287	2,182	1,816	3,473
Net charge-offs:
Charge-offs	(488)	(973)	(2,266)	(3,468)
Recoveries	22	112	225	394
Net charge-offs	(466)	(861)	(2,041)	(3,074)
Reserves on receivables transferred to held for sale	(1,298)		(1,298)
Credit loss reserve balance at end of period	4,429	5,911	4,429	5,911
Reserve components:
Collectively evaluated for impairment	750	2,230	750	2,230
Individually evaluated for impairment(1)	3,590	3,236	3,590	3,236
Receivables carried at the lower of amortized cost or fair value of the collateral less cost to sell	83	435	83	435
Loans acquired with deteriorated credit quality	6	10	6	10
Total credit loss reserves	4,429	5,911	4,429	5,911
Receivables:
Collectively evaluated for impairment	20,141	31,991	20,141	31,991
Individually evaluated for impairment(1)	11,966	12,174	11,966	12,174
Receivables carried at the lower of amortized cost or fair value of the collateral less cost to sell	1,840	5,593	1,840	5,593
Receivables acquired with deteriorated credit quality	16	41	16	41
Total receivables	33,963	49,799	33,963	49,799	47,912
First Lien [Member]
Credit loss reserve analysis:
Credit loss reserve balances at beginning of period	3,858	3,002	4,089	3,355
Provision for credit losses	242	1,534	1,392	2,525
Net charge-offs:
Charge-offs	(379)	(578)	(1,444)	(1,941)
Recoveries	3	7	20	26
Net charge-offs	(376)	(571)	(1,424)	(1,915)
Reserves on receivables transferred to held for sale	(333)		(333)
Credit loss reserve balance at end of period	3,724	3,965	3,724	3,965
Reserve components:
Collectively evaluated for impairment	572	786	572	786
Individually evaluated for impairment(1)	3,065	2,737	3,065	2,737
Receivables carried at the lower of amortized cost or fair value of the collateral less cost to sell	82	433	82	433
Loans acquired with deteriorated credit quality	5	9	5	9
Total credit loss reserves	3,724	3,965	3,724	3,965
Receivables:
Collectively evaluated for impairment	17,501	23,996	17,501	23,996
Individually evaluated for impairment(1)	10,854	9,926	10,854	9,926
Receivables carried at the lower of amortized cost or fair value of the collateral less cost to sell	1,775	5,504	1,775	5,504
Receivables acquired with deteriorated credit quality	13	35	13	35
Total receivables	30,143	39,461	30,143	39,461
Second Lien [Member]
Credit loss reserve analysis:
Credit loss reserve balances at beginning of period	750	635	823	832
Provision for credit losses	50	375	271	613
Net charge-offs:
Charge-offs	(109)	(168)	(433)	(636)
Recoveries	14	15	44	48
Net charge-offs	(95)	(153)	(389)	(588)
Credit loss reserve balance at end of period	705	857	705	857
Reserve components:
Collectively evaluated for impairment	178	355	178	355
Individually evaluated for impairment(1)	525	499	525	499
Receivables carried at the lower of amortized cost or fair value of the collateral less cost to sell	1	2	1	2
Loans acquired with deteriorated credit quality	1	1	1	1
Total credit loss reserves	705	857	705	857
Receivables:
Collectively evaluated for impairment	2,640	3,707	2,640	3,707
Individually evaluated for impairment(1)	1,112	933	1,112	933
Receivables carried at the lower of amortized cost or fair value of the collateral less cost to sell	65	89	65	89
Receivables acquired with deteriorated credit quality	3	6	3	6
Total receivables	3,820	4,735	3,820	4,735
Personal non-credit card [Member]
Credit loss reserve analysis:
Credit loss reserve balances at beginning of period		953	1,040	1,325
Provision for credit losses	(5)	273		335
Net charge-offs:
Charge-offs		(227)	(389)	(891)
Recoveries	5	90	161	320
Net charge-offs	5	(137)	(228)	(571)
Reserves on receivables transferred to held for sale	(965)		(965)
Credit loss reserve balance at end of period		1,089		1,089
Reserve components:
Collectively evaluated for impairment		1,089		1,089
Total credit loss reserves		1,089		1,089
Receivables:
Collectively evaluated for impairment		4,285		4,285
Individually evaluated for impairment(1)		1,315		1,315
Total receivables		5,600		5,600
Commercial and Other [Member]
Receivables:
Collectively evaluated for impairment		3		3
Total receivables		$ 3		$ 3