Loans - TDR - Subsequent Payment Defaults of Completed TDR Modifications (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013 Contract	Sep. 30, 2012 Contract	Sep. 30, 2013 Contract	Sep. 30, 2012 Contract
Financing Receivable, Modifications [Line Items]
Number of Contracts	25,140	25,368	72,059	70,608
Total Loans	$ 88	$ 77	$ 247	$ 258
Domestic Credit Card [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	10,114	12,314	28,957	30,484
Total Loans	16	22	53	61
International Credit Card [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	12,641	11,903	35,769	36,956
Total Loans	36	40	104	127
Credit Card and Installment Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	22,755	24,217	64,726	67,440
Total Loans	52	62	157	188
Consumer Banking [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	2,369	1,147	7,302	3,148
Total Loans	21	13	56	43
Consumer Banking [Member] | Auto [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	2,321	1,121	7,178	2,986
Total Loans	17	10	49	27
Consumer Banking [Member] | Home Loan [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	7	12	25	79
Total Loans	1	1	2	7
Consumer Banking [Member] | Retail Banking [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	41	14	99	83
Total Loans	3	2	5	9
Commercial Banking [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	16	4	31	20
Total Loans	15	2	34	27
Commercial Banking [Member] | Commercial and Multifamily Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	3	0	10	5
Total Loans	4	0	15	8
Commercial Banking [Member] | Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	13	4	20	12
Total Loans	11	2	19	17
Commercial Banking [Member] | Total Commercial Lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	16	4	30	17
Total Loans	15	2	34	25
Commercial Banking [Member] | Small-Ticket Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	0	0	1	3
Total Loans	$ 0	$ 0	$ 0	$ 2