Goodwill and Other Intangible Assets - Summary of Goodwill Assigned to Reportable Segments for Purposes of Testing for Impairment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Goodwill [Line Items]
Goodwill	$ 8,490,089	$ 4,593,112
2022 Transactions	3,896,977
Business Banking [Member]
Goodwill [Line Items]
Goodwill	1,558,271	864,366
2022 Transactions	693,905
Commercial Banking [Member]
Goodwill [Line Items]
Goodwill	4,088,126	1,401,873
2022 Transactions	2,686,253
Commercial Real Estate [Member]
Goodwill [Line Items]
Goodwill	945,606	654,389
2022 Transactions	291,217
Retail Banking [Member]
Goodwill [Line Items]
Goodwill	1,530,387	1,309,191
2022 Transactions	221,196
All Other [Member]
Goodwill [Line Items]
Goodwill	367,699	$ 363,293
2022 Transactions	$ 4,406