Variable Interest Entities - Firm Sponsored VIEs (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Total assets held by securitization VIEs	$ 189,403	$ 182,272
Retained securitization interests, risk-rated 'A' or better, at fair value	71.00%	73.00%
Corporate & Investment Bank
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Senior securities purchased in connection with CIB's secondary market-making activities	$ 149	$ 105
Subordinated securities purchased in connection with CIB's secondary market-making activities	81	40
Residential mortgage \| Investment-grade
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Fair value of retained interests	933	1,300
Residential mortgage \| Noninvestment-grade
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Fair value of retained interests	46	41
Residential mortgage \| Prime / Alt-A & option ARMs
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Total assets held by securitization VIEs	48,866	49,644
Residential mortgage \| Subprime
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Total assets held by securitization VIEs	11,923	12,896
Commercial and other
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Total assets held by securitization VIEs	128,614	119,732
Commercial and other \| Investment-grade
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Fair value of retained interests	2,200	2,000
Commercial and other \| Noninvestment-grade
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Fair value of retained interests	824	753
VIEs consolidated by the Firm
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Assets held in consolidated securitization VIEs	1,386	1,739
VIEs consolidated by the Firm \| Residential mortgage \| Prime / Alt-A & option ARMs
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Assets held in consolidated securitization VIEs	1,356	1,693
VIEs consolidated by the Firm \| Residential mortgage \| Subprime
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Assets held in consolidated securitization VIEs	30	46
VIEs consolidated by the Firm \| Commercial and other
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Assets held in consolidated securitization VIEs	0	0
Nonconsolidated entities
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Assets held in nonconsolidated securitization VIEs with continuing involvement	142,927	145,770
Interest in securitized assets in nonconsolidated VIEs	4,042	4,073
Nonconsolidated entities \| Trading assets
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Interest in securitized assets in nonconsolidated VIEs	1,379	1,538
Nonconsolidated entities \| Investment securities
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Interest in securitized assets in nonconsolidated VIEs	2,350	2,273
Nonconsolidated entities \| Other financial assets
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Interest in securitized assets in nonconsolidated VIEs	313	262
Nonconsolidated entities \| Residential mortgage \| Prime / Alt-A & option ARMs
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Assets held in nonconsolidated securitization VIEs with continuing involvement	40,906	41,265
Interest in securitized assets in nonconsolidated VIEs	979	1,298
Nonconsolidated entities \| Residential mortgage \| Subprime
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Assets held in nonconsolidated securitization VIEs with continuing involvement	10,982	12,154
Interest in securitized assets in nonconsolidated VIEs	1	9
Nonconsolidated entities \| Residential mortgage \| Trading assets \| Prime / Alt-A & option ARMs
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Interest in securitized assets in nonconsolidated VIEs	511	574
Nonconsolidated entities \| Residential mortgage \| Trading assets \| Subprime
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Interest in securitized assets in nonconsolidated VIEs	1	9
Nonconsolidated entities \| Residential mortgage \| Investment securities \| Prime / Alt-A & option ARMs
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Interest in securitized assets in nonconsolidated VIEs	449	724
Nonconsolidated entities \| Residential mortgage \| Investment securities \| Subprime
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Interest in securitized assets in nonconsolidated VIEs	0	0
Nonconsolidated entities \| Residential mortgage \| Other financial assets \| Prime / Alt-A & option ARMs
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Interest in securitized assets in nonconsolidated VIEs	19	0
Nonconsolidated entities \| Residential mortgage \| Other financial assets \| Subprime
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Interest in securitized assets in nonconsolidated VIEs	0	0
Nonconsolidated entities \| Commercial and other
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Assets held in nonconsolidated securitization VIEs with continuing involvement	91,039	92,351
Interest in securitized assets in nonconsolidated VIEs	3,062	2,766
Nonconsolidated entities \| Commercial and other \| Trading assets
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Interest in securitized assets in nonconsolidated VIEs	867	955
Nonconsolidated entities \| Commercial and other \| Investment securities
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Interest in securitized assets in nonconsolidated VIEs	1,901	1,549
Nonconsolidated entities \| Commercial and other \| Other financial assets
Firm sponsored mortgage and other consumer securitization trusts [Abstract]
Interest in securitized assets in nonconsolidated VIEs	$ 294	$ 262

Firm-sponsored mortgage and other consumer securitization trusts.

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- Definition

Percent of retained securitization interests rated A or better.

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No definition available.

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- Definition

Senior securities purchased in connection with IB secondary market making activities. These securities are excluded from entity interest in securitized assets in nonconsolidated VIEs.

+ References

No definition available.

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- Definition

Subordinated securities purchased in connection with IB secondary market making Activities. These securities are excluded from entity interest in securitized assets in nonconsolidated VIEs.

+ References

No definition available.

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- Definition

Principal amount of transferred financial assets in which the transferor has continuing involvement with the assets underlying the transaction. Continuing involvement includes, but is not limited to, servicing, recourse, and restrictions on transferor's interests in transferred financial assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
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Amount of transferred financial assets in which the transferor has continuing involvement with the assets underlying the transaction that have been derecognized. Continuing involvement includes, but is not limited to, servicing, recourse, and restrictions on transferor's interests in transferred financial assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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The carrying amount (fair value) as of the balance sheet date of the transferor's interests in transferred financial assets (typically securitized receivables, generally not involved in the collection of principal) following transfer of significant portions of such financial instruments to other parties. Such interests could be ancillary cash flows and interest-only strips.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
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+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=121570589&loc=d3e107314-111719

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