Fair Value Measurements - Quantitative Information for Non-Recurring Fair Value Measurements (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013		Dec. 31, 2012
Real estate secured [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Valuation Techniques	Third party appraisal valuation based on estimated loss severities, including collateral values, cash flows and market discount rate
Personal non-credit card [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Valuation Techniques	Third party appraisal valuation based on estimated loss rates, cash flows and market discount rate
Receivables held for sale carried at fair value:			3,181
Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Receivables held for sale carried at fair value:	0		0
Level 3 | Real estate secured [Member] | Third Party Appraisal Valuation [Member] | Collateral Severity Rates [Member] | Minimum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs	0.00%	[1]	0.00%	[1]
Level 3 | Real estate secured [Member] | Third Party Appraisal Valuation [Member] | Collateral Severity Rates [Member] | Maximum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs	97.00%	[1]	92.00%	[1]
Level 3 | Real estate secured [Member] | Third Party Appraisal Valuation [Member] | Expenses Incurred through Collateral Disposition [Member] | Minimum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs	5.00%		5.00%
Level 3 | Real estate secured [Member] | Third Party Appraisal Valuation [Member] | Expenses Incurred through Collateral Disposition [Member] | Maximum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs	10.00%		10.00%
Level 3 | Real estate secured [Member] | Third Party Appraisal Valuation [Member] | Market Discount Rate [Member] | Minimum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs	6.00%		10.00%
Level 3 | Real estate secured [Member] | Third Party Appraisal Valuation [Member] | Market Discount Rate [Member] | Maximum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs	10.00%		15.00%
Level 3 | Personal non-credit card [Member] | Third Party Appraisal Valuation [Member] | Collateral Severity Rates [Member] | Minimum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs			13.00%
Level 3 | Personal non-credit card [Member] | Third Party Appraisal Valuation [Member] | Collateral Severity Rates [Member] | Maximum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs			19.00%
Level 3 | Personal non-credit card [Member] | Third Party Appraisal Valuation [Member] | Market Discount Rate [Member] | Minimum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs			10.00%
Level 3 | Personal non-credit card [Member] | Third Party Appraisal Valuation [Member] | Market Discount Rate [Member] | Maximum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs			15.00%
Receivables Held For Sale [Member] | Non-Recurring Fair Value Measurements [Member] | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Receivables held for sale carried at fair value:	3,407
Receivables Held For Sale [Member] | Non-Recurring Fair Value Measurements [Member] | Level 3 | Real estate secured [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Receivables held for sale carried at fair value:	3,407		3,022
Receivables Held For Sale [Member] | Non-Recurring Fair Value Measurements [Member] | Level 3 | Personal non-credit card [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Receivables held for sale carried at fair value:	0	[1]	3,181	[1]

[1] The majority of the real estate secured receivables held for sale consider collateral value, among other items, in determining fair value. Collateral values are based on the most recently available broker's price opinion and the collateral loss severity rate averaged 36 percent and 37 percent at March 31, 2013 and December 31, 2012, respectively.