Receivables - Receivables Classified as Trouble Debt Restructuring Loan (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Receivables classified as Trouble Debt Restructuring Loans
Total	$ 2,723	$ 2,548
First Mortgage [Member]
Receivables classified as Trouble Debt Restructuring Loans
Total	2,202	1,941
Second Mortgage [Member]
Receivables classified as Trouble Debt Restructuring Loans
Total	259	189
Real estate secured [Member]
Receivables classified as Trouble Debt Restructuring Loans
Total	2,461	2,130
Personal non-credit card [Member]
Receivables classified as Trouble Debt Restructuring Loans
Total	$ 262	$ 418