Acquisition - Summary of Identifiable Assets Acquired, Liabilities Assumed and Preferred Stock Exchanged as of Acquisition (Details) - USD ($) $ in Thousands	Apr. 01, 2022	Jun. 30, 2022	Dec. 31, 2021
Liabilities and preferred stock:
Total liabilities and shareholders’ equity		$ 204,032,889	$ 155,107,160
Goodwill		8,501,357	4,593,112
Peoples United Financial Inc [Member]
Consideration:
Common stock issued (50,325,004 shares)	$ 8,286,515
Common stock awards converted	104,810
Cash	1,824
Total consideration	8,393,149
Identifiable assets:
Cash and due from banks	395,747
Interest-bearing deposits at banks and other short-term investments	9,193,346
Investment securities	11,574,689
Loans and leases	35,840,648
Core deposit and other intangible assets	261,000
Other assets	2,979,388
Total identifiable assets acquired	60,244,818
Liabilities and preferred stock:
Deposits	52,967,915
Borrowings	1,389,012
Other liabilities	1,142,387
Total liabilities assumed	55,499,314
Preferred stock	260,600
Total liabilities and shareholders’ equity	55,759,914
Net assets acquired	4,484,904
Goodwill	$ 3,908,245	$ 8,501,357	$ 4,593,112