Loans - Purchased, Sold and Reclassified to Held-for-Sale (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Retained Loans Purchases Sales and Transfer Into Held For Sale By Portfolio Segment [Line Items]
Purchases	$ 5,564	$ 7,433	$ 8,319
Sales	15,107	14,287	14,036
Retained loans reclassified to held-for-sale	2,702	2,235	4,810
Consumer, excluding credit card
Retained Loans Purchases Sales and Transfer Into Held For Sale By Portfolio Segment [Line Items]
Purchases	4,116	5,279	7,434
Sales	6,368	5,099	6,655
Retained loans reclassified to held-for-sale	321	1,514	1,190
Excluded retained loans purchased from correspondents that were originated in accordance with the Firm's underwriting standards	30,400	50,300	15,100
Credit card
Retained Loans Purchases Sales and Transfer Into Held For Sale By Portfolio Segment [Line Items]
Purchases	0	0	0
Sales	0	0	0
Retained loans reclassified to held-for-sale	0	79	3,039
Wholesale
Retained Loans Purchases Sales and Transfer Into Held For Sale By Portfolio Segment [Line Items]
Purchases	1,448	2,154	885
Sales	8,739	9,188	7,381
Retained loans reclassified to held-for-sale	$ 2,381	$ 642	$ 581