Receivables - Additional Information Relating to Trouble Debt Restructuring Loan (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Average balance of TDR Loans:
Total average balance of TDR Loans	$ 16,801	[1]	$ 13,512	[1]	$ 10,270	[1]
Interest income recognized on TDR Loans:
Total interest income recognized on TDR Loans	1,149		785		493
First Mortgage [Member]
Average balance of TDR Loans:
Total average balance of TDR Loans	14,657	[1]	11,450	[1]	8,832	[1]
Interest income recognized on TDR Loans:
Total interest income recognized on TDR Loans	871		590		407
Second Mortgage [Member]
Average balance of TDR Loans:
Total average balance of TDR Loans	1,219	[1]	901	[1]	702	[1]
Interest income recognized on TDR Loans:
Total interest income recognized on TDR Loans	104		62		39
Real estate secured [Member]
Average balance of TDR Loans:
Total average balance of TDR Loans	15,876	[1]	12,351	[1]	9,534	[1]
Interest income recognized on TDR Loans:
Total interest income recognized on TDR Loans	975		652		446
Personal non-credit card [Member]
Average balance of TDR Loans:
Total average balance of TDR Loans	925	[1]	1,161	[1]	736	[1]
Interest income recognized on TDR Loans:
Total interest income recognized on TDR Loans	$ 174		$ 133		$ 47

[1] The increase in the average balance of TDR Loans during 2011 reflects, in part, the higher levels of receivables considered to be TDR Loans as a result of the adoption of the new accounting guidance as discussed above. These averages assume the new guidelines were adopted January 1, 2011.