Loans - by Portfolio Segment (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
Loans by Portfolio Segment and Class [Line Items]
Loans retained	$ 735,304,000,000	$ 724,177,000,000	$ 722,471,000,000
Loans held-for-sale	4,339,000,000	12,230,000,000
Loans at fair value	3,614,000,000	2,011,000,000
Total loans	743,257,000,000	738,418,000,000
Loans unearned income, unamortized discounts and premiums, and net deferred loan costs	1,500,000,000	1,900,000,000
Consumer, excluding credit card
Loans by Portfolio Segment and Class [Line Items]
Loans retained	288,379,000,000	288,449,000,000	288,211,000,000
Loans held-for-sale	481,000,000	614,000,000
Loans at fair value	0	0
Total loans	288,860,000,000	289,063,000,000
Credit card
Loans by Portfolio Segment and Class [Line Items]
Loans retained	126,564,000,000	127,465,000,000	123,672,000,000
Loans held-for-sale	395,000,000	326,000,000
Loans at fair value	0	0
Total loans	126,959,000,000	127,791,000,000
Wholesale
Loans by Portfolio Segment and Class [Line Items]
Loans retained	320,361,000,000	308,263,000,000	310,588,000,000
Loans held-for-sale	3,463,000,000	11,290,000,000
Loans at fair value	3,614,000,000	2,011,000,000
Total loans	$ 327,438,000,000	$ 321,564,000,000