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Trading Assets and Liabilities - Narrative (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Debt and Equity Securities, FV-NI [Line Items]
Derivatives included in trading assets, amount offset	$ 4,919		$ 4,919		$ 2,797
Derivatives included in trading liabilities, amount offset	2,674		2,674		1,296
Dividend income on equity securities held for trading	40	$ 44	130	$ 108
Trading Assets
Debt and Equity Securities, FV-NI [Line Items]
Derivatives included in trading assets, amount offset	4,920		4,920		1,419
Trading Liabilities
Debt and Equity Securities, FV-NI [Line Items]
Derivatives included in trading liabilities, amount offset	$ 2,042		$ 2,042		$ 1,296