Guarantees, Pledged Assets and Collateral (Details) - USD ($) $ in Millions		Sep. 30, 2019	Dec. 31, 2018
Guarantor Obligations [Line Items]
Carrying Value obligation (asset)		$ (171)	$ (90)
Maximum exposure to loss, expires in one year or less		28,639	32,872
Maximum exposure to loss, expires in one year through three years		18,859	19,053
Maximum exposure to loss, expires in three years through five years		7,032	7,674
Maximum exposure to loss, expires after five years		16,736	15,063
Maximum exposure to loss		71,266	74,662
Total assets (2)	[1]	1,943,950	1,895,883
Securities owned and pledged as collateral related to repurchase agreements not available to be repledged, Fair Value		3,600	4,400
Mortgages held for sale		12,000	7,400
Carrying value of delinquent loans eligible for repurchase		578	1,200
Security Owned and Pledged as Collateral, Fair Value [Abstract]
Equity Securities, Trading		24,436	19,449
Total pledged assets, Trading		118,562	100,316
Total pledged assets		604,754	622,643
Related to non-trading activities [Member]
Security Owned and Pledged as Collateral, Fair Value [Abstract]
Debt securities and other, non-trading activities		55,979	62,438
Mortgages held for sale and loans		425,280	453,894
Total pledged assets		481,259	516,332
Collateral Pledged [Member]
Security Owned and Pledged as Collateral, Fair Value [Abstract]
Debt Securities, Trading		113,861	96,616
Equity Securities, Trading		9,634	9,695
Total pledged assets, Trading		123,495	106,311
Non-investment grade [Member]
Guarantor Obligations [Line Items]
Maximum exposure to loss		34,742	39,591
Written put options [Member]
Guarantor Obligations [Line Items]
Carrying Value obligation (asset)		(259)	(185)
Maximum exposure to loss, expires in one year or less		14,081	17,243
Maximum exposure to loss, expires in one year through three years		10,600	10,502
Maximum exposure to loss, expires in three years through five years		2,008	3,066
Maximum exposure to loss, expires after five years		373	400
Maximum exposure to loss		27,062	31,211
Written put options [Member] | Non-investment grade [Member]
Guarantor Obligations [Line Items]
Maximum exposure to loss		16,953	21,732
Direct pay letters of credit (DPLCs) [Member]
Guarantor Obligations [Line Items]
Maximum exposure to loss		6,500	7,500
Third Party Clearing Indemnifications [Member]
Guarantor Obligations [Line Items]
Third-party Clearing Customer Obligations		81	70
Collateral Provided to Third-party Clearing Agents		678	974
Standby Letters of Credit [Member]
Guarantor Obligations [Line Items]
Carrying Value obligation (asset)		35	40
Maximum exposure to loss, expires in one year or less		13,734	14,636
Maximum exposure to loss, expires in one year through three years		7,631	7,897
Maximum exposure to loss, expires in three years through five years		3,758	3,398
Maximum exposure to loss, expires after five years		471	497
Maximum exposure to loss		25,594	26,428
Standby Letters of Credit [Member] | Non-investment grade [Member]
Guarantor Obligations [Line Items]
Maximum exposure to loss		7,960	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		2	1
Maximum exposure to loss, expires in three years through five years		0	0
Maximum exposure to loss, expires after five years		758	1,044
Maximum exposure to loss		760	1,045
Securities lending and other indemnifications [Member] | Non-investment grade [Member]
Guarantor Obligations [Line Items]
Maximum exposure to loss		2	1
Loans and MHFS sold with recourse [Member]
Guarantor Obligations [Line Items]
Carrying Value obligation (asset)		52	54
Maximum exposure to loss, expires in one year or less		109	104
Maximum exposure to loss, expires in one year through three years		626	653
Maximum exposure to loss, expires in three years through five years		1,263	1,207
Maximum exposure to loss, expires after five years		10,329	10,163
Maximum exposure to loss		12,327	12,127
Loans and MHFS sold with recourse [Member] | Non-investment grade [Member]
Guarantor Obligations [Line Items]
Maximum exposure to loss		9,145	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		715	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		715	889
Factoring guarantee [Member] | Non-investment grade [Member]
Guarantor Obligations [Line Items]
Maximum exposure to loss		681	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		4,805	2,959
Maximum exposure to loss		4,808	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		123,500	106,200
Trading assets and other [Member] | Collateral Pledged [Member]
Security Owned and Pledged as Collateral, Fair Value [Abstract]
Total pledged assets, Trading		51,600	45,500
Other Trading - Off-Balance Sheet [Member] | Collateral Pledged [Member]
Security Owned and Pledged as Collateral, Fair Value [Abstract]
Total pledged assets, Trading		71,900	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		39	68
Securities owned and pledged as collateral related to repurchase agreements not available to be repledged, carrying value		3,600	4,200
Securities owned and pledged as collateral related to repurchase agreements not available to be repledged, Fair Value		3,600	4,100
Consolidated VIEs [Member]
Guarantor Obligations [Line Items]
Total assets (2)		13,637	14,062
Secured Borrowing transactions excluded [Member]
Guarantor Obligations [Line Items]
Total assets (2)		$ 288	$ 617

[1] (2) Our consolidated assets at September 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, $10 million and $139 million; Interest-earning deposits with banks, $118 million and $8 million; Debt securities, $61 million and $45 million; Net loans, $13.1 billion and $13.6 billion; Equity securities, $100 million and $85 million; Other assets, $214 million and $221 million; and Total assets, $13.6 billion and $14.1 billion, respectively.