Fair Value Option - Changes in fair value under the fair value option (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	$ (172)	$ (294)	$ (992)
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)	(76)	(38)	(15)
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)	(76)	(38)	(15)
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
Securities borrowed
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	1	(6)	(10)
Securities borrowed | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	1	(6)	(10)
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
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)	119	746	639
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)	120	756	639
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)	(10)	0
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)	504	179	914
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)	461	138	885
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)	43	41	29
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)	763	1,050	1,705
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)	79	232	352
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)	684	818	1,353
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)	13	35	40
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)	13	35	40
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
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)	(7)	4	34
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)	(7)	4	34
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
Other assets
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	82	78	30
Other assets | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	20	79	24
Other assets | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	62	(1)	6
Deposits
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(134)	93	(287)
Deposits | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(134)	93	(287)
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
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)	19	8	(33)
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)	19	8	(33)
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
Other borrowed funds
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(236)	1,996	(891)
Other borrowed funds | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(236)	1,996	(891)
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
Trading liabilities
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	6	(20)	(17)
Trading liabilities | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	6	(20)	(17)
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
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)	23	49	(233)
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)	23	49	(233)
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
Other liabilities
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	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	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
Long-term debt: DVA on fair value option elected liabilities
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	300	101
Long-term debt: DVA on fair value option elected liabilities | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	300	101
Long-term debt: DVA on fair value option elected 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
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)	(773)	1,088	(615)
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)	(773)	1,088	(615)
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