Fair Value Measurements - Assets and Liabilities Recorded at Fair Value on Non-recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended									3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013 Receivables Held For Sale [Member]	Mar. 31, 2013 Real Estate Owned [Member]		Mar. 31, 2012 Real Estate Owned [Member]		Mar. 31, 2013 Real estate secured [Member] Receivables Held For Sale [Member]	Dec. 31, 2012 Personal non-credit card [Member]	Mar. 31, 2013 Personal non-credit card [Member] Receivables Held For Sale [Member]	Mar. 31, 2013 Level 1	Dec. 31, 2012 Level 1	Mar. 31, 2013 Level 2	Dec. 31, 2012 Level 2	Mar. 31, 2013 Level 3	Dec. 31, 2012 Level 3	Mar. 31, 2012 Non-Recurring Fair Value Measurements [Member]	Mar. 31, 2012 Non-Recurring Fair Value Measurements [Member] Real Estate Owned [Member]		Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Level 1	Mar. 31, 2012 Non-Recurring Fair Value Measurements [Member] Level 1	Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Level 1 Receivables Held For Sale [Member]	Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Level 1 Real Estate Owned [Member]		Mar. 31, 2012 Non-Recurring Fair Value Measurements [Member] Level 1 Real Estate Owned [Member]		Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Level 1 Real estate secured [Member] Receivables Held For Sale [Member]	Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Level 1 Personal non-credit card [Member] Receivables Held For Sale [Member]	Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Level 2	Mar. 31, 2012 Non-Recurring Fair Value Measurements [Member] Level 2	Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Level 2 Receivables Held For Sale [Member]	Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Level 2 Real Estate Owned [Member]		Mar. 31, 2012 Non-Recurring Fair Value Measurements [Member] Level 2 Real Estate Owned [Member]		Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Level 2 Real estate secured [Member] Receivables Held For Sale [Member]	Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Level 2 Personal non-credit card [Member] Receivables Held For Sale [Member]	Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Level 3	Mar. 31, 2012 Non-Recurring Fair Value Measurements [Member] Level 3	Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Level 3 Receivables Held For Sale [Member]	Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Level 3 Real Estate Owned [Member]		Mar. 31, 2012 Non-Recurring Fair Value Measurements [Member] Level 3 Real Estate Owned [Member]		Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Level 3 Real estate secured [Member] Receivables Held For Sale [Member]	Dec. 31, 2012 Non-Recurring Fair Value Measurements [Member] Level 3 Real estate secured [Member] Receivables Held For Sale [Member]	Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Level 3 Personal non-credit card [Member] Receivables Held For Sale [Member]		Dec. 31, 2012 Non-Recurring Fair Value Measurements [Member] Level 3 Personal non-credit card [Member] Receivables Held For Sale [Member]		Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Total	Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Total Receivables Held For Sale [Member]	Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Total Real Estate Owned [Member]		Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Total Real estate secured [Member] Receivables Held For Sale [Member]	Mar. 31, 2013 Non-Recurring Fair Value Measurements [Member] Total Personal non-credit card [Member] Receivables Held For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total receivables held for sale									$ 3,181		$ 0	$ 0	$ 0	$ 0	$ 0	$ 0						$ 0					$ 0	$ 0			$ 2,947					$ 0	$ 2,947			$ 3,407					$ 3,407	$ 3,022	$ 0	[1]	$ 3,181	[1]		$ 6,354			$ 3,407	$ 2,947
Real estate owned																		290	[2]				0	[2]	0	[2]						271	[2]	290	[2]						0	[2]	0	[2]									271	[2]
Total assets at fair value on a non-recurring basis																	290			0	0								3,218	290								3,407	0												6,625
Total Gains (Losses) for the Three Months Ended March 31, 2013	$ 437	$ (26)	$ 454	$ (17)	[2]	$ (26)	[2]	$ 536		$ (82)

[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.

[2] Real estate owned is required to be reported on the balance sheet net of transactions costs. The real estate owned amounts in the table above reflect the fair value of the underlying asset unadjusted for transaction costs.