Variable interest entities - Municipal Bond Vehicle VIEs (Details) - USD ($) $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2015		Dec. 31, 2014		Sep. 30, 2014
Firm's exposure to nonconsolidated municipal bond VIEs [Abstract]
Total assets	$ 2,417,121	[1]	$ 2,572,773	[1]	$ 2,526,655
Nonconsolidated municipal bond vehicles | Municipal bond vehicles
Firm's exposure to nonconsolidated municipal bond VIEs [Abstract]
Total assets	11,600		11,500
Liquidity facilities	6,500		6,300
Excess/ (deficit)	$ 5,100		$ 5,200
Weighted average expected life of assets (years)	4 years 8 months 12 days		4 years 10 months 24 days
Nonconsolidated municipal bond vehicles | Municipal bond vehicles | Investment-grade AAA to AAA-
Firm's exposure to nonconsolidated municipal bond VIEs [Abstract]
Total assets	$ 2,700		$ 2,700
Nonconsolidated municipal bond vehicles | Municipal bond vehicles | Investment-grade AAplus to AA-
Firm's exposure to nonconsolidated municipal bond VIEs [Abstract]
Total assets	8,200		8,400
Nonconsolidated municipal bond vehicles | Municipal bond vehicles | Investment-grade Aplus to A-
Firm's exposure to nonconsolidated municipal bond VIEs [Abstract]
Total assets	700		400
Nonconsolidated municipal bond vehicles | Municipal bond vehicles | Investment-grade BBBplus to BBB-
Firm's exposure to nonconsolidated municipal bond VIEs [Abstract]
Total assets	0		0
Nonconsolidated municipal bond vehicles | Municipal bond vehicles | Noninvestment-grade BBplus and below
Firm's exposure to nonconsolidated municipal bond VIEs [Abstract]
Total assets	0		0
Nonconsolidated entities | Municipal bond vehicles
Firm's exposure to nonconsolidated municipal bond VIEs [Abstract]
Maximum exposure	$ 6,500		$ 6,300

[1] The following table presents information on assets and liabilities related to VIEs that are consolidated by the Firm at September 30, 2015, and December 31, 2014. The difference between total VIE assets and liabilities represents the Firm’s interests in those entities, which were eliminated in consolidation.(in millions)Sep 30, 2015 Dec 31, 2014Assets Trading assets$4,237 $9,090Loans69,119 68,880All other assets2,109 1,815Total assets$75,465 $79,785Liabilities Beneficial interests issued by consolidated variable interest entities$48,733 $52,362All other liabilities821 949Total liabilities$49,554 $53,311The assets of the consolidated VIEs are used to settle the liabilities of those entities. The holders of the beneficial interests do not have recourse to the general credit of JPMorgan Chase. At both September 30, 2015, and December 31, 2014, the Firm provided limited program-wide credit enhancement of $2.0 billion related to its Firm-administered multi-seller conduits, which are eliminated in consolidation. For further discussion, see Note 15.