Credit Loss Reserves - Summarizes Changes in Credit Loss Reserves by Product/Class and Related Receivable Balance by Product (Parenthetical) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Financing Receivable, Allowance for Credit Losses [Line Items]
Excludes Credit loss reserves for TDR Loans that are carried at the lower of amortized cost or fair value	$ 94,000,000		$ 143,000,000		$ 27,000,000
Provision for credit losses related to adoption of new accountin guidance for TDR	2,224,000,000	[1],[2]	4,418,000,000	[3]	5,346,000,000
TDR [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Excludes TDR Loans that are carried at the lower of amortized cost or fair value	1,500,000,000		2,500,000,000		1,500,000,000
Provision for credit losses related to adoption of new accountin guidance for TDR			$ 925,000,000

[1] Provision for credit losses during 2012 includes $112 million related to the portion of the lower of amortized cost or fair value adjustment that was attributable to credit for personal non-credit card receivables transferred to held for sale during the second quarter of 2012. See Note 7, “Receivables Held for Sale,” for additional information. This amount was recorded as a provision for credit losses and included in the total of reserves on receivables transferred to held for sale. There was no lower of cost or fair value adjustment allocated to credit for the real estate secured receivables as these receivables were previously carried at the lower of amortized cost or fair value of the collateral less cost to sell prior to the transfer of the loans to held for sale.

[2] Provision for credit losses during 2012 includes $112 million related to the portion of the lower of amortized cost or fair value that was attributable to credit for personal non-credit card receivables transferred to held for sale during the second quarter of 2012. See Note 7, “Receivables Held for Sale,” for additional information. This amount was recorded as a provision for credit losses and included in the total of reserves on receivables transferred to held for sale. There was no lower of cost or fair value adjustment allocated to credit for the real estate secured receivables as these receivables were previously carried at the lower of amortized cost or fair value of the collateral less cost to sell prior to the transfer of the loans to held for sale.

[3] Provision for credit losses during 2011 included approximately $925 million related to the adoption of new accounting guidance for TDR Loans in the third quarter of 2011 as discussed above.