Commitments and contingent liabilities - Significant Industry Concentrations Related to Credit Exposure (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	$ 64,458	$ 63,703
Financial institutions
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	14,689	15,899
Unfunded commitments	33,700
Total exposure	48,400
Financial institutions \| Securities industry
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	3,800
Unfunded commitments	19,200
Total exposure	23,000
Financial institutions \| Banks
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	7,900
Unfunded commitments	2,000
Total exposure	9,900
Financial institutions \| Asset managers
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	1,500
Unfunded commitments	6,200
Total exposure	7,700
Financial institutions \| Insurance
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	100
Unfunded commitments	3,800
Total exposure	3,900
Financial institutions \| Government
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	100
Unfunded commitments	900
Total exposure	1,000
Financial institutions \| Other
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	1,300
Unfunded commitments	1,600
Total exposure	2,900
Commercial
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	2,617	$ 2,342
Unfunded commitments	17,500
Total exposure	20,100
Commercial \| Manufacturing
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	1,100
Unfunded commitments	6,700
Total exposure	7,800
Commercial \| Commercial portfolio exposure (in billions)
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	600
Unfunded commitments	4,300
Total exposure	4,900
Commercial \| Energy and utilities
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	600
Unfunded commitments	4,700
Total exposure	5,300
Commercial \| Media and telecom
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	300
Unfunded commitments	1,800
Total exposure	$ 2,100

The sum of loans outstanding and unfunded credit commitments

No definition available.

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- Definition

Credit commitments to extend credit to a counterparty under certain terms and conditions.

+ References

No definition available.

+ Details

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- Definition

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.

+ References

No definition available.

+ Details

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- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65884687&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5074-111524

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