Credit Loss Reserves - Summarizes Changes in Credit Loss Reserves by Product/Class and Related Receivable Balance by Product - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended										9 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012		Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Sep. 30, 2011	Sep. 30, 2012	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
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	$ 38				$ 94							$ 38		$ 94		$ 143
Provision for credit losses	(152)	(160)	267	24	408	[1]	287	738	791	925		(21)		2,224	[2]	4,418	[3]
Write-offs												1,521	[4]	3,021	[4]	4,481
Increase in credit loss reserve					350					1,308				40
Roll Rate Migration Analysis, Loss Coverage Period					12 months						7 months	12 months
Roll rate migration analysis, IFRST			12 months		10 months
Provision for Loan and Lease Losses [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for credit losses														(112)
Provision for Loan and Lease Losses [Member] | Fair Value [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for credit losses														(112)
Personal non-credit card [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for credit losses												(50)		15	[2]	433	[3]
Write-offs												0	[4]	389	[4]	1,127
Real Estate Secured Receivable Portfolio [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Write-offs												164		333
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	$ 604				$ 1,488							$ 604		$ 1,488		$ 2,526

[1] The provision for credit losses during the fourth quarter of 2012 included $350 million related to changes in the loss emergence period used in our roll rate migration analysis. See Note 6, "Credit Loss Reserves," in the accompanying consolidated financial statements for further discussion of the adoption of this new accounting guidance.

[2] Provision for credit losses during 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 7, "Receivables Held for Sale," for additional information.

[3] Provision for credit losses for 2011 includes $925 million related to the adoption of new accounting guidance for TDR Loans in the third quarter of 2011 as discussed more fully in Note 5, "Receivables."

[4] 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 certain real estate secured receivables during 2013 and 2012 that were carried at the lower of amortized cost or fair value of the collateral less cost to sell and recognized the existing credit loss reserves on these receivables as additional charge-off totaling $164 million during 2013 and $333 million during 2012.