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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Section 50
-Paragraph 3
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-Topic 210
-Publisher FASB
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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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Trading Assets and Liabilities - Narrative (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Debt and Equity Securities, FV-NI [Line Items]
Derivatives included in trading assets, amount offset	$ 1,170		$ 1,170		$ 1,760
Derivatives included in trading liabilities, amount offset	1,511		1,511		1,321
Dividend income on equity securities held for trading	46	$ 41	133	$ 111
Trading Assets
Debt and Equity Securities, FV-NI [Line Items]
Derivatives included in trading assets, amount offset	889		889		1,416
Trading Liabilities
Debt and Equity Securities, FV-NI [Line Items]
Derivatives included in trading liabilities, amount offset	$ 1,511		$ 1,511		$ 1,321