Loans - Purchased, Sold and Reclassified to Held-for-Sale (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchases	$ 1,553	$ 1,816
Sales	2,424	4,185
Retained loans reclassified to held-for-sale	554	338
Consumer, excluding credit card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchases	1,265	1,608
Sales	760	1,736
Retained loans reclassified to held-for-sale	65	18
Excluded retained loans purchased from correspondents that were originated in accordance with the Firm's underwriting standards	8,700	11,200
Credit card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchases	0	0
Sales	0	0
Retained loans reclassified to held-for-sale	0	0
Wholesale
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchases	288	208
Sales	1,664	2,449
Retained loans reclassified to held-for-sale	$ 489	$ 320