Investment Securities - Amortized Costs and Estimated Fair Values (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Available-for-sale securities
Amortized cost	$ 347,859	$ 228,769
Gross unrealized gains	6,200	3,168
Gross unrealized losses	638	1,543
Fair value	353,421	230,394
Held-to-maturity securities
Amortized cost	40,830	31,434
Gross unrealized gains	1,567	239
Gross unrealized losses	20	215
Fair value	42,377	31,458
Total investment securities
Amortized cost	388,689	260,203
Gross unrealized gains	7,767	3,407
Gross unrealized losses	658	1,758
Fair value	395,798	261,852
Total mortgage-backed securities
Available-for-sale securities
Amortized cost	120,887	84,190
Gross unrealized gains	2,993	788
Gross unrealized losses	73	1,158
Fair value	123,807	83,820
Held-to-maturity securities
Amortized cost	35,976	26,610
Gross unrealized gains	1,250	134
Gross unrealized losses	20	200
Fair value	37,206	26,544
Total mortgage-backed securities \| Fannie Mae
Total investment securities
Securities exceeding 10% of total stockholders' equity, Amortized cost	69,800
Securities exceeding 10% of total stockholders' equity, Fair value	72,000
Total mortgage-backed securities \| Freddie Mac
Total investment securities
Securities exceeding 10% of total stockholders' equity, Amortized cost	37,800
Securities exceeding 10% of total stockholders' equity, Fair value	38,800
U.S. GSEs and government agencies
Available-for-sale securities
Amortized cost	103,086	69,026
Gross unrealized gains	2,556	594
Gross unrealized losses	61	974
Fair value	105,581	68,646
Held-to-maturity securities
Amortized cost	35,976	26,610
Gross unrealized gains	1,250	134
Gross unrealized losses	20	200
Fair value	37,206	26,544
Residential: U.S.
Available-for-sale securities
Amortized cost	10,083	5,877
Gross unrealized gains	273	79
Gross unrealized losses	6	31
Fair value	10,350	5,925
Residential: Non-U.S.
Available-for-sale securities
Amortized cost	2,490	2,529
Gross unrealized gains	64	72
Gross unrealized losses	2	6
Fair value	2,552	2,595
Commercial
Available-for-sale securities
Amortized cost	5,228	6,758
Gross unrealized gains	100	43
Gross unrealized losses	4	147
Fair value	5,324	6,654
U.S. Treasury and government agencies
Available-for-sale securities
Amortized cost	141,646	55,771
Gross unrealized gains	376	366
Gross unrealized losses	493	78
Fair value	141,529	56,059
Held-to-maturity securities
Amortized cost	51	0
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Fair value	51	0
Obligations of U.S. states and municipalities
Available-for-sale securities
Amortized cost	28,871	36,221
Gross unrealized gains	2,193	1,582
Gross unrealized losses	0	80
Fair value	31,064	37,723
Held-to-maturity securities
Amortized cost	4,803	4,824
Gross unrealized gains	317	105
Gross unrealized losses	0	15
Fair value	5,120	4,914
Certificates of deposit
Available-for-sale securities
Amortized cost	74	75
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Fair value	74	75
Non-U.S. government debt securities
Available-for-sale securities
Amortized cost	21,644	23,771
Gross unrealized gains	524	351
Gross unrealized losses	10	20
Fair value	22,158	24,102
Corporate debt securities
Available-for-sale securities
Amortized cost	1,596	1,904
Gross unrealized gains	39	23
Gross unrealized losses	1	9
Fair value	1,634	1,918
Asset-backed securities: Collateralized loan obligations
Available-for-sale securities
Amortized cost	27,942	19,612
Gross unrealized gains	18	1
Gross unrealized losses	52	176
Fair value	27,908	19,437
Asset-backed securities: Other
Available-for-sale securities
Amortized cost	5,199	7,225
Gross unrealized gains	57	57
Gross unrealized losses	9	22
Fair value	5,247	7,260
U.S. GSE obligations
Available-for-sale securities
Fair value	78,800	50,700
Held-to-maturity securities
Amortized cost	$ 30,800	$ 20,900

Available-for-sale Securities and Held-to-maturity Securities, Accumulated Gross Unrealized Gain, before Tax

No definition available.

Name:	jpm_AvailableforsaleSecuritiesandHeldtomaturitySecuritiesAccumulatedGrossUnrealizedGainbeforeTax
Namespace Prefix:	jpm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Available-for-sale Securities and Held-to-maturity Securities, Accumulated Gross Unrealized Loss, before Tax

+ References

No definition available.

+ Details

Name:	jpm_AvailableforsaleSecuritiesandHeldtomaturitySecuritiesAccumulatedGrossUnrealizedLossbeforeTax
Namespace Prefix:	jpm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Available-for-sale Securities and Held-to-maturity Securities, Amortized Cost Basis

+ References

No definition available.

+ Details

Name:	jpm_AvailableforsaleSecuritiesandHeldtomaturitySecuritiesAmortizedCostBasis
Namespace Prefix:	jpm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Available-for-sale Securities and Held-to-maturity Securities Exceeding Ten Percent of Total Stockholders' Equity, Amortized Cost Basis

+ References

No definition available.

+ Details

Name:	jpm_AvailableforsaleSecuritiesandHeldtomaturitySecuritiesExceedingTenPercentofTotalStockholdersEquityAmortizedCostBasis
Namespace Prefix:	jpm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Available-for-sale Securities and Held-to-maturity Securities Exceeding Ten Percent of Total Stockholders' Equity, Fair Value

+ References

No definition available.

+ Details

Name:	jpm_AvailableforsaleSecuritiesandHeldtomaturitySecuritiesExceedingTenPercentofTotalStockholdersEquityFairValue
Namespace Prefix:	jpm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Available-for-sale Securities and Held-to-maturity Securities, Fair Value

+ References

No definition available.

+ Details

Name:	jpm_AvailableforsaleSecuritiesandHeldtomaturitySecuritiesFairValue
Namespace Prefix:	jpm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563

+ Details

Name:	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563

+ Details

Name:	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118942338&loc=SL82898722-210454

+ Details

Name:	us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118942338&loc=SL82898722-210454

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118954083&loc=d3e26610-111562

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleAndHeldToMaturityAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118954083&loc=d3e26610-111562

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27232-111563

+ Details

Name:	us-gaap_HeldToMaturitySecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27232-111563

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27232-111563

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value of investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27232-111563

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=jpm_FannieMaeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=jpm_FreddieMacMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=jpm_DomesticMortgagebackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=jpm_ForeignMortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CommercialMortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USTreasuryAndGovernmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CertificatesOfDepositMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ForeignGovernmentDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CollateralizedLoanObligationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_OtherDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: