Receivables - Receivables Classified as Trouble Debt Restructuring Loan (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Receivables classified as Trouble Debt Restructuring Loans
Total	$ 397	$ 1,034
First Mortgage [Member]
Receivables classified as Trouble Debt Restructuring Loans
Total	340	821
Second Mortgage [Member]
Receivables classified as Trouble Debt Restructuring Loans
Total	36	85
Real estate secured [Member]
Receivables classified as Trouble Debt Restructuring Loans
Total	376	906
Personal non-credit card [Member]
Receivables classified as Trouble Debt Restructuring Loans
Total	$ 21	$ 128