Securities Financing Activities - Schedule of securities sold under repurchase agreements, netting & securities loaned (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements with an appropriate legal opinion, Gross liability	$ 277,415	$ 290,529
Amounts netted on the Consolidated balance sheets	(156,258)	(142,719)
Securities sold under repurchase agreements with an appropriate legal opinion, Net liability	121,157	147,810
Securities sold under repurchase agreements where an appropriate legal opinion has not been either sought or obtained(a)	12,629	21,996
Total securities sold under repurchase agreements, Gross liability balance	290,044	312,525
Total securities sold under repurchase agreements, net liability balance	133,786	169,806
Securities loaned including not subject to master netting arrangement	22,556	25,927
Securities loaned where an appropriate legal opinion has not been either sought or obtained	45	271
Securities-For-Securities Borrow Versus Pledge Transactions
Securities Financing Transaction [Line Items]
Securities loaned	4,400	4,100
Securities Financing Transaction, Fair Value
Securities Financing Transaction [Line Items]
Total securities sold under repurchase agreements, net liability balance	$ 3,500	$ 3,000