Goodwill and Other Intangible Assets - Summary of Goodwill Assigned to Reportable Segments for Purposes of Testing for Impairment (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Goodwill [Line Items]
Goodwill	$ 8,465	$ 8,490
2023 Transactions	(25)
Commercial Banking [Member]
Goodwill [Line Items]
Goodwill	5,076	5,076
Retail Banking [Member]
Goodwill [Line Items]
Goodwill	3,089	3,089
Institutional Services & Wealth Management [Member]
Goodwill [Line Items]
Goodwill	300	$ 325
2023 Transactions	$ (25)