Receivables - Additional Information Relating to Trouble Debt Restructuring Loan (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Average balance of TDR Loans:
Total average balance of TDR Loans	$ 12,155	$ 15,763	$ 12,629	$ 15,875
Interest income recognized on TDR Loans:
Total interest income recognized on TDR Loans	217	261	671	842
Real estate secured [Member]
Interest income recognized on TDR Loans:
Total interest income recognized on TDR Loans	217	261	671	802
First Lien [Member]
Average balance of TDR Loans:
Total average balance of TDR Loans	11,203	14,634	11,638	14,715
Interest income recognized on TDR Loans:
Total interest income recognized on TDR Loans	193	234	599	719
Second Lien [Member]
Average balance of TDR Loans:
Total average balance of TDR Loans	952	1,129	991	1,160
Interest income recognized on TDR Loans:
Total interest income recognized on TDR Loans	24	27	72	83
Personal non-credit card [Member]
Interest income recognized on TDR Loans:
Total interest income recognized on TDR Loans	$ 0	$ 0	$ 0	$ 40