Fair Value Option - Changes in fair value under the fair value option (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	$ (114)	$ (318)	$ (183)	$ (456)
Debit Valuation Adjustment
Changes in fair value under the fair value option election
Structured note credit adjustments	215	134	323	19
Federal funds sold and securities purchased under resale agreements
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(99)	96	(26)	56
Federal funds sold and securities purchased under resale agreements | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(99)	96	(26)	56
Federal funds sold and securities purchased under resale agreements | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0	0
Securities borrowed
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(2)	(2)	(4)	(5)
Securities borrowed | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(2)	(2)	(4)	(5)
Securities borrowed | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0	0
Debt and equity instruments, excluding loans
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	140	248	520	476
Debt and equity instruments, excluding loans | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	139	245	519	475
Debt and equity instruments, excluding loans | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	1	3	1	1
Loans reported as trading assets: Changes in instrument-specific credit risk
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	69	394	224	766
Loans reported as trading assets: Changes in instrument-specific credit risk | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	59	391	211	754
Loans reported as trading assets: Changes in instrument-specific credit risk | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	10	3	13	12
Loans reported as trading assets: Other changes in fair value
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	85	438	492	794
Loans reported as trading assets: Other changes in fair value | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(15)	38	112	102
Loans reported as trading assets: Other changes in fair value | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	100	400	380	692
Loans: Changes in instrument-specific credit risk
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	20	1	28
Loans: Changes in instrument-specific credit risk | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	20	1	28
Loans: Changes in instrument-specific credit risk | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0	0
Loans: Other changes in fair value
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	24	0	31
Loans: Other changes in fair value | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	24	0	31
Loans: Other changes in fair value | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0	0
Other assets
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	5	6	71	(62)
Other assets | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	2	7	62	12
Other assets | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	3	(1)	9	(74)
Deposits
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	162	(107)	37	(211)
Deposits | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	162	(107)	37	(211)
Deposits | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0	0
Federal funds purchased and securities loaned or sold under repurchase agreements
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	18	(18)	9	(34)
Federal funds purchased and securities loaned or sold under repurchase agreements | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	18	(18)	9	(34)
Federal funds purchased and securities loaned or sold under repurchase agreements | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0	0
Other borrowed funds
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	115	(911)	106	(1,171)
Other borrowed funds | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	115	(911)	106	(1,171)
Other borrowed funds | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0	0
Trading liabilities
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(12)	(3)	(14)	(9)
Trading liabilities | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(12)	(3)	(14)	(9)
Trading liabilities | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0	0
Beneficial interests issued by consolidated VIEs
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	26	(48)	44	(137)
Beneficial interests issued by consolidated VIEs | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	26	(48)	44	(137)
Beneficial interests issued by consolidated VIEs | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0	0
Other liabilities
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	(27)	0	(27)
Other liabilities | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	(27)	0	(27)
Other liabilities | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0	0
Long-term debt: Changes in instrument-specific credit risk
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	209	82	325	5
Long-term debt: Changes in instrument-specific credit risk | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	209	82	325	5
Long-term debt: Changes in instrument-specific credit risk | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0	0
Long-term debt: Other changes in fair value
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	728	(773)	350	(791)
Long-term debt: Other changes in fair value | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	728	(773)	350	(791)
Long-term debt: Other changes in fair value | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	$ 0	$ 0	$ 0	$ 0