Variable Interest Entities - Municipal Bond Vehicle VIEs (Details 2a) (USD $)						3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Mar. 31, 2013 JPMorgan Chase & Co Municipal Bonds	Dec. 31, 2012 JPMorgan Chase & Co Municipal Bonds	Mar. 31, 2013 Nonconsolidated Municipal Bond Vehicles Municipal Bonds	Dec. 31, 2012 Nonconsolidated Municipal Bond Vehicles Municipal Bonds	Mar. 31, 2013 Nonconsolidated Municipal Bond Vehicles Municipal Bonds Investment Grade AAA to AAA-	Dec. 31, 2012 Nonconsolidated Municipal Bond Vehicles Municipal Bonds Investment Grade AAA to AAA-	Mar. 31, 2013 Nonconsolidated Municipal Bond Vehicles Municipal Bonds Investment Grade AAplus to AA-	Dec. 31, 2012 Nonconsolidated Municipal Bond Vehicles Municipal Bonds Investment Grade AAplus to AA-	Mar. 31, 2013 Nonconsolidated Municipal Bond Vehicles Municipal Bonds Investment Grade Aplus to A-	Dec. 31, 2012 Nonconsolidated Municipal Bond Vehicles Municipal Bonds Investment Grade Aplus to A-	Mar. 31, 2013 Nonconsolidated Municipal Bond Vehicles Municipal Bonds Investment Grade BBB to BBB-	Dec. 31, 2012 Nonconsolidated Municipal Bond Vehicles Municipal Bonds Investment Grade BBB to BBB-	Mar. 31, 2013 Nonconsolidated Municipal Bond Vehicles Municipal Bonds Noninvestment-grade	Dec. 31, 2012 Nonconsolidated Municipal Bond Vehicles Municipal Bonds Noninvestment-grade
Firm's exposure to nonconsolidated municipal bond VIEs [Abstract]
Fair value of non-consolidated assets held by VIEs	$ 2,389,349,000,000	$ 2,359,141,000,000	$ 2,320,164,000,000			$ 14,300,000,000	$ 14,200,000,000	$ 3,100,000,000	$ 3,100,000,000	$ 11,000,000,000	$ 11,000,000,000	$ 200,000,000	$ 100,000,000	$ 0	$ 0	$ 0	$ 0
Liquidity facilities provided by Firm serving as liquidity provider						8,100,000,000	8,000,000,000
Excess/ (deficit)						6,200,000,000	6,200,000,000
Maximum exposure				$ 8,100,000,000	$ 8,000,000,000
Variable Interest Entity Weighted Average Expected Life Of Assets Unconsolidated V I E						5 years 9 months 18 days	5 years 10 months 24 days