Noninterest Revenue and Noninterest Expense - Investment Banking Fees (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Schedule of Noninterest revenue [Line Items]
Underwriting	$ 1,384	$ 951	$ 4,265	$ 2,877
Advisory	847	771	2,224	2,007
Total investment banking fees	2,231	1,722	6,489	4,884
Equity
Schedule of Noninterest revenue [Line Items]
Underwriting	344	274	1,192	824
Debt
Schedule of Noninterest revenue [Line Items]
Underwriting	$ 1,040	$ 677	$ 3,073	$ 2,053

Includes (1) underwriting revenue (the spread between the resale price received and the cost of the securities and related expenses) generated through the purchasing, distributing and reselling of new issues of securities (alternatively, could be a secondary offering of a large block of previously issued securities); and (2) fees earned for mergers, acquisitions, divestitures, restructurings, and other types of financial advisory services.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(13)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(13)(d))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration