Trading Assets and Liabilities - Narrative (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Debt and Equity Securities, FV-NI [Line Items]
Derivatives included in trading assets, amount offset	$ 2,344		$ 2,925
Derivatives included in trading liabilities, amount offset	1,178		1,291
Dividend income on equity securities held for trading	42	$ 42
Trading Assets
Debt and Equity Securities, FV-NI [Line Items]
Derivatives included in trading assets, amount offset	2,344		2,813
Trading Liabilities
Debt and Equity Securities, FV-NI [Line Items]
Derivatives included in trading liabilities, amount offset	$ 1,178		$ 1,291

Amount of obligation to return cash collateral under master netting arrangements offset against derivative assets.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 5
-SubTopic 10
-Topic 815
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480463/815-10-45-5

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-SubTopic 20
-Topic 210
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483466/210-20-50-3

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+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-6B

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