Noninterest Revenue and Noninterest Expense - Investment Banking Fees (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Schedule of Noninterest revenue [Line Items]
Underwriting	$ 1,583	$ 1,490
Advisory	1,275	688
Total investment banking fees	2,858	2,178
Equity
Schedule of Noninterest revenue [Line Items]
Underwriting	476	321
Debt
Schedule of Noninterest revenue [Line Items]
Underwriting	$ 1,107	$ 1,169

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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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration