Securities financing activities - Schedule of secured financing transactions by assets pledged & remaining maturity (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements, gross	$ 325,635	$ 312,525
Securities loaned, gross	20,738	$ 25,927
Remaining maturity, Overnight and continuous
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements, gross	117,879
Securities loaned, gross	9,463
Remaining maturity, Up to 30 days
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements, gross	124,711
Securities loaned, gross	649
Remaining maturity, 30 - 90 days
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements, gross	27,052
Securities loaned, gross	319
Remaining maturity, Greater than 90 days
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements, gross	55,993
Securities loaned, gross	10,307
Mortgage-backed securities
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements, gross	22,060
Securities loaned, gross	0
U.S. Treasury and government agencies
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements, gross	166,522
Securities loaned, gross	223
Obligations of U.S. states and municipalities
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements, gross	1,718
Securities loaned, gross	0
Non-U.S. government debt
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements, gross	89,573
Securities loaned, gross	621
Corporate debt securities
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements, gross	19,580
Securities loaned, gross	110
Asset-backed securities
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements, gross	5,238
Securities loaned, gross	0
Equity securities
Securities Financing Transaction [Line Items]
Securities sold under repurchase agreements, gross	20,944
Securities loaned, gross	$ 19,784

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Amount, before effects of master netting arrangements, of securities loaned to entities in exchange for collateral. Includes liabilities not subject to a master netting arrangement and elected not to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

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Amount, before effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and elected not to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Repurchase Agreement Accounted for as a Collateralized Borrowing

-URI http://asc.fasb.org/extlink&oid=49203159

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

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-Section 50

-Paragraph 3

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-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

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