Loans - Purchased, Sold and Reclassified to Held-for-Sale (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchases	$ 2,395	$ 2,257	$ 5,812	$ 6,283
Sales	2,986	3,659	12,723	10,581
Retained loans reclassified to held-for-sale	99	468	1,806	1,994
Consumer, excluding credit card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchases	1,196	1,945	3,918	5,694
Sales	1,130	1,573	4,073	3,816
Retained loans reclassified to held-for-sale	0	232	1,272	1,034
Excluded retained loans purchased from correspondents that were originated in accordance with the Firm's underwriting standards	14,400	4,100	39,800	8,200
Credit card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchases	0	0	0	0
Sales	0	272	1,269	272
Retained loans reclassified to held-for-sale	79	186	79	401
Wholesale
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchases	1,199	312	1,894	589
Sales	1,856	1,814	7,381	6,493
Retained loans reclassified to held-for-sale	$ 20	$ 50	$ 455	$ 559