Credit Loss Reserves - Summarizes Changes in Credit Loss Reserves by Product/Class and Related Receivable Balance by Product (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012		Mar. 31, 2012
Financing Receivable, Allowance for Credit Losses [Line Items]
Write-offs	$ 527	[1],[2]	$ 1,132	[1],[2]	$ 926	[1],[2]	$ 2,111	[1],[2]
Excludes Credit loss reserves for TDR Loans that are carried at the lower of amortized cost or fair value	51				51				41
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	726				726				671
Personal non-credit card [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for credit losses related to amortized cost or fair value attributable to credit for personal non-credit card receivables	112				112
Write-offs	0	[1]	168	[1]	0	[1]	389	[1]
Real Estate Secured Receivable Portfolio [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Write-offs	$ 119		$ 333		$ 119		$ 333

[1] For collateral dependent receivables that are transferred to held for sale, existing credit loss reserves at the time of transfer are recognized as a charge-off. We transferred to held for sale a pool of real estate secured receivables that were carried at the lower of amortized cost or fair value of the collateral less cost and recognized the existing credit loss reserves on these receivables as additional charge-off totaling $119 million during the three and six months ended June 30, 2013 and $333 million during the three and six months ended June 30, 2012. See Note 6, "Receivables Held for Sale," for additional information.

[2] The three and six months ended June 30, 2012 includes $112 million related to the lower of amortized cost or fair value attributable to credit for personal non-credit card receivables transferred to held for sale at June 30, 2012. See Note 6, "Receivables Held for Sale," for additional information.