Receivables - Additional Information Relating to Trouble Debt Restructuring Loan (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
Average balance of TDR Loans:
Total average balance of TDR Loans	$ 15,208	$ 14,102	$ 15,925	$ 12,704
Interest income recognized on TDR Loans:
Total interest income recognized on TDR Loans	298	212	836	556
First Lien [Member]
Average balance of TDR Loans:
Total average balance of TDR Loans	13,486	11,875	13,738	10,763
Interest income recognized on TDR Loans:
Total interest income recognized on TDR Loans	227	156	628	419
Second Lien [Member]
Average balance of TDR Loans:
Total average balance of TDR Loans	1,152	940	1,146	842
Interest income recognized on TDR Loans:
Total interest income recognized on TDR Loans	27	17	76	45
Real estate secured [Member]
Average balance of TDR Loans:
Total average balance of TDR Loans	14,638	12,815	14,884	11,605
Interest income recognized on TDR Loans:
Total interest income recognized on TDR Loans	254	173	704	464
Personal non-credit card [Member]
Average balance of TDR Loans:
Total average balance of TDR Loans	570	1,287	1,041	1,099
Interest income recognized on TDR Loans:
Total interest income recognized on TDR Loans	$ 44	$ 39	$ 132	$ 92