Guarantees, Pledged Assets and Collateral (Details) - USD ($) $ in Millions		Jun. 30, 2019	Dec. 31, 2018
Guarantor Obligations [Line Items]
Carrying Value obligation (asset)		$ (279)	$ (90)
Maximum exposure to loss, expires in one year or less		27,402	32,872
Maximum exposure to loss, expires in one year through three years		19,502	19,053
Maximum exposure to loss, expires in three years through five years		7,912	7,674
Maximum exposure to loss, expires after five years		16,442	15,063
Maximum exposure to loss		71,258	74,662
Total assets	[1]	1,923,388	1,895,883
Securities owned and pledged as collateral related to repurchase agreements not available to be repledged, Fair Value		3,500	4,400
Mortgages held for sale		2,000	7,400
Carrying value of delinquent loans eligible for repurchase		551	1,200
Security Owned and Pledged as Collateral, Fair Value [Abstract]
Equity Securities, Trading		23,327	19,449
Total pledged assets, Trading		106,509	100,316
Total pledged assets		588,562	622,643
Related to non-trading activities [Member]
Security Owned and Pledged as Collateral, Fair Value [Abstract]
Debt securities and other, non-trading activities		56,413	62,438
Mortgages held for sale and loans		413,882	453,894
Total pledged assets		470,295	516,332
Collateral Pledged [Member]
Security Owned and Pledged as Collateral, Fair Value [Abstract]
Debt Securities, Trading		107,673	96,616
Equity Securities, Trading		10,594	9,695
Total pledged assets, Trading		118,267	106,311
Non-investment grade [Member]
Guarantor Obligations [Line Items]
Maximum exposure to loss		33,698	39,591
Written put options [Member]
Guarantor Obligations [Line Items]
Carrying Value obligation (asset)		(371)	(185)
Maximum exposure to loss, expires in one year or less		12,574	17,243
Maximum exposure to loss, expires in one year through three years		11,682	10,502
Maximum exposure to loss, expires in three years through five years		2,803	3,066
Maximum exposure to loss, expires after five years		386	400
Maximum exposure to loss		27,445	31,211
Written put options [Member] | Non-investment grade [Member]
Guarantor Obligations [Line Items]
Maximum exposure to loss		15,882	21,732
Direct pay letters of credit (DPLCs) [Member]
Guarantor Obligations [Line Items]
Maximum exposure to loss		6,400	7,500
Third Party Clearing Indemnifications [Member]
Guarantor Obligations [Line Items]
Third-party Clearing Customer Obligations		90	70
Collateral Provided to Third-party Clearing Agents		759	974
Standby Letters of Credit [Member]
Guarantor Obligations [Line Items]
Carrying Value obligation (asset)		38	40
Maximum exposure to loss, expires in one year or less		14,078	14,636
Maximum exposure to loss, expires in one year through three years		7,185	7,897
Maximum exposure to loss, expires in three years through five years		3,901	3,398
Maximum exposure to loss, expires after five years		464	497
Maximum exposure to loss		25,628	26,428
Standby Letters of Credit [Member] | Non-investment grade [Member]
Guarantor Obligations [Line Items]
Maximum exposure to loss		7,938	8,027
Securities lending and other indemnifications [Member]
Guarantor Obligations [Line Items]
Carrying Value obligation (asset)		0	0
Maximum exposure to loss, expires in one year or less		0	0
Maximum exposure to loss, expires in one year through three years		1	1
Maximum exposure to loss, expires in three years through five years		0	0
Maximum exposure to loss, expires after five years		849	1,044
Maximum exposure to loss		850	1,045
Securities lending and other indemnifications [Member] | Non-investment grade [Member]
Guarantor Obligations [Line Items]
Maximum exposure to loss		1	1
Loans and MHFS sold with recourse [Member]
Guarantor Obligations [Line Items]
Carrying Value obligation (asset)		53	54
Maximum exposure to loss, expires in one year or less		111	104
Maximum exposure to loss, expires in one year through three years		634	653
Maximum exposure to loss, expires in three years through five years		1,205	1,207
Maximum exposure to loss, expires after five years		10,597	10,163
Maximum exposure to loss		12,547	12,127
Loans and MHFS sold with recourse [Member] | Non-investment grade [Member]
Guarantor Obligations [Line Items]
Maximum exposure to loss		9,318	9,079
Factoring guarantee [Member]
Guarantor Obligations [Line Items]
Carrying Value obligation (asset)		0	0
Maximum exposure to loss, expires in one year or less		639	889
Maximum exposure to loss, expires in one year through three years		0	0
Maximum exposure to loss, expires in three years through five years		0	0
Maximum exposure to loss, expires after five years		0	0
Maximum exposure to loss		639	889
Factoring guarantee [Member] | Non-investment grade [Member]
Guarantor Obligations [Line Items]
Maximum exposure to loss		558	751
Other guarantees [Member]
Guarantor Obligations [Line Items]
Carrying Value obligation (asset)		1	1
Maximum exposure to loss, expires in one year or less		0	0
Maximum exposure to loss, expires in one year through three years		0	0
Maximum exposure to loss, expires in three years through five years		3	3
Maximum exposure to loss, expires after five years		4,146	2,959
Maximum exposure to loss		4,149	2,962
Other guarantees [Member] | Non-investment grade [Member]
Guarantor Obligations [Line Items]
Maximum exposure to loss		1	1
Trading assets and other [Member]
Guarantor Obligations [Line Items]
Securities owned and pledged as collateral available to be repledged, Fair Value		118,200	106,200
Trading assets and other [Member] | Collateral Pledged [Member]
Security Owned and Pledged as Collateral, Fair Value [Abstract]
Total pledged assets, Trading		45,900	45,500
Other Trading - Off-Balance Sheet [Member] | Collateral Pledged [Member]
Security Owned and Pledged as Collateral, Fair Value [Abstract]
Total pledged assets, Trading		72,300	60,800
Debt securities and other [Member] | Related to non-trading activities [Member]
Guarantor Obligations [Line Items]
Securities owned and pledged as collateral available to be repledged, Fair Value		33	68
Securities owned and pledged as collateral related to repurchase agreements not available to be repledged, carrying value		3,500	4,200
Securities owned and pledged as collateral related to repurchase agreements not available to be repledged, Fair Value		3,500	4,100
Consolidated VIEs [Member]
Guarantor Obligations [Line Items]
Total assets		14,010	14,062
Secured Borrowing transactions excluded [Member]
Guarantor Obligations [Line Items]
Total assets		$ 357	$ 617

[1] (2) Our consolidated assets at June 30, 2019, and December 31, 2018, include the following assets of certain variable interest entities (VIEs) that can only be used to settle the liabilities of those VIEs: Cash and due from banks, $11 million and $139 million; Interest-earning deposits with banks, $8 million and $8 million; Debt securities, $60 million and $45 million; Net loans, $13.6 billion and $13.6 billion; Equity securities, $121 million and $85 million; Other assets, $208 million and $221 million; and Total assets, $14.0 billion and $14.1 billion, respectively.