Fair Value Measurements - Assets and Liabilities Recorded at Fair Value on Non-recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended				9 Months Ended				3 Months Ended				9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Real Estate Secured [Member]	Sep. 30, 2013 Real Estate Secured [Member]	Sep. 30, 2014 Real Estate Secured [Member]	Sep. 30, 2013 Real Estate Secured [Member]	Sep. 30, 2013 Personal non-credit card [Member]	Sep. 30, 2013 Personal non-credit card [Member]		Sep. 30, 2013 Receivables Held For Sale [Member]	Sep. 30, 2013 Receivables Held For Sale [Member]	Sep. 30, 2014 Receivables Held-for-Investment [Member]		Sep. 30, 2013 Receivables Held-for-Investment [Member]		Sep. 30, 2014 Receivables Held-for-Investment [Member]		Sep. 30, 2013 Receivables Held-for-Investment [Member]		Sep. 30, 2014 Real Estate Owned [Member]		Sep. 30, 2013 Real Estate Owned [Member]		Sep. 30, 2014 Real Estate Owned [Member]		Sep. 30, 2013 Real Estate Owned [Member]		Sep. 30, 2014 Level 1 [Member]	Dec. 31, 2013 Level 1 [Member]	Sep. 30, 2014 Level 2 [Member]	Dec. 31, 2013 Level 2 [Member]	Sep. 30, 2014 Level 3 [Member]	Dec. 31, 2013 Level 3 [Member]	Sep. 30, 2014 Non-Recurring Fair Value Measurements [Member] Level 1 [Member]	Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Level 1 [Member]	Sep. 30, 2014 Non-Recurring Fair Value Measurements [Member] Level 1 [Member] Real Estate Secured [Member]	Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Level 1 [Member] Real Estate Secured [Member]	Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Level 1 [Member] Personal non-credit card [Member]		Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Level 1 [Member] Receivables Held For Sale [Member]	Sep. 30, 2014 Non-Recurring Fair Value Measurements [Member] Level 1 [Member] Receivables Held-for-Investment [Member]		Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Level 1 [Member] Receivables Held-for-Investment [Member]		Sep. 30, 2014 Non-Recurring Fair Value Measurements [Member] Level 1 [Member] Real Estate Owned [Member]		Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Level 1 [Member] Real Estate Owned [Member]		Sep. 30, 2014 Non-Recurring Fair Value Measurements [Member] Level 2 [Member]	Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Level 2 [Member]	Sep. 30, 2014 Non-Recurring Fair Value Measurements [Member] Level 2 [Member] Real Estate Secured [Member]	Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Level 2 [Member] Real Estate Secured [Member]	Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Level 2 [Member] Personal non-credit card [Member]		Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Level 2 [Member] Receivables Held For Sale [Member]	Sep. 30, 2014 Non-Recurring Fair Value Measurements [Member] Level 2 [Member] Receivables Held-for-Investment [Member]		Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Level 2 [Member] Receivables Held-for-Investment [Member]		Sep. 30, 2014 Non-Recurring Fair Value Measurements [Member] Level 2 [Member] Real Estate Owned [Member]		Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Level 2 [Member] Real Estate Owned [Member]		Sep. 30, 2014 Non-Recurring Fair Value Measurements [Member] Level 3 [Member]	Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Level 3 [Member]	Sep. 30, 2014 Non-Recurring Fair Value Measurements [Member] Level 3 [Member] Real Estate Secured [Member]	Dec. 31, 2013 Non-Recurring Fair Value Measurements [Member] Level 3 [Member] Real Estate Secured [Member]	Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Level 3 [Member] Real Estate Secured [Member]	Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Level 3 [Member] Personal non-credit card [Member]		Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Level 3 [Member] Receivables Held For Sale [Member]	Sep. 30, 2014 Non-Recurring Fair Value Measurements [Member] Level 3 [Member] Receivables Held-for-Investment [Member]		Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Level 3 [Member] Receivables Held-for-Investment [Member]		Sep. 30, 2014 Non-Recurring Fair Value Measurements [Member] Level 3 [Member] Real Estate Owned [Member]		Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Level 3 [Member] Real Estate Owned [Member]		Sep. 30, 2014 Non-Recurring Fair Value Measurements [Member] Total [Member]	Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Total [Member]	Sep. 30, 2014 Non-Recurring Fair Value Measurements [Member] Total [Member] Real Estate Secured [Member]	Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Total [Member] Real Estate Secured [Member]	Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Total [Member] Personal non-credit card [Member]		Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Total [Member] Receivables Held For Sale [Member]	Sep. 30, 2014 Non-Recurring Fair Value Measurements [Member] Total [Member] Receivables Held-for-Investment [Member]		Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Total [Member] Receivables Held-for-Investment [Member]		Sep. 30, 2014 Non-Recurring Fair Value Measurements [Member] Total [Member] Real Estate Owned [Member]		Sep. 30, 2013 Non-Recurring Fair Value Measurements [Member] Total [Member] Real Estate Owned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total receivables held for sale																														$ 0	$ 0	$ 1,031	$ 0	$ 873	$ 2,047			$ 0	$ 0	$ 0	[1]	$ 0											$ 998	$ 901	$ 0	[1]	$ 901											$ 842	$ 2,047	$ 3,816	$ 0	[1]	$ 3,816											$ 1,840	$ 4,717	$ 0	[1]	$ 4,717
Receivables held for investment																																											0	[2]	0	[2]												690	[2]	883	[2]													0	[2]	0	[2]												690	[2]	883	[2]
Real estate owned																																															0	[3]	0	[3]												178	[3]	392	[3]													0	[3]	0	[3]												178	[3]	392	[3]
Total assets at fair value on a non-recurring basis																																				0	0														1,866	2,176														842	3,816															2,708	5,992
Total Gains (Losses)	$ (13)	$ (157)	$ (70)	$ 129	$ 84	$ 66	$ 292	$ 974	$ 0	$ (82)	[1]	$ 66	$ 892	$ (86)	[2]	$ (203)	[2]	$ (319)	[2]	$ (708)	[2]	$ (11)	[3]	$ (20)	[3]	$ (43)	[3]	$ (55)	[3]

[1] Our personal non-credit card portfolio was sold on April 1, 2013 as discussed more fully in Note 7, "Receivables Held for Sale," in our 2013 Form 10-K.

[2] Total gains (losses) for the three and nine months ended September 30, 2014 and 2013 includes amounts recorded on receivables that were subsequently transferred to held for sale.

[3] 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.