Acquisition and Divestiture - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
	Apr. 01, 2022	Jun. 30, 2023	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Carrying Value			$ 2,010,600		$ 2,010,600
Goodwill			8,490,089		8,490,089
ACL for non-PCD loan and leases	$ 242,000
Initial estimate of expected credit losses	99,000
Assets			202,956,407		200,729,841
Shareholders' equity			25,377,171	$ 17,876,020	25,317,990	$ 17,903,405
Net income (loss)			701,624	362,174
Fiduciary And Trust [Member]
Business Acquisition [Line Items]
Revenue from contract with customer			193,802	169,213
Collective Investment Trust [Member] | Fiduciary And Trust [Member]
Business Acquisition [Line Items]
Revenue from contract with customer			45,000	42,000
Common Stock [Member]
Business Acquisition [Line Items]
Shareholders' equity			$ 89,718	79,871	$ 89,718	$ 79,871
Subsequent Event [Member] | Collective Investment Trust [Member] | Fiduciary And Trust [Member]
Business Acquisition [Line Items]
Gain (loss) on sale of subsidiary, pre-tax		$ 225,000
Peoples United Financial Inc [Member]
Business Acquisition [Line Items]
Business combination, market value	$ 8,400,000
Common stock, price per share	$ 164.66
Assets	$ 60,244,818
Goodwill	3,908,245
Core deposits and other intangible assets	$ 261,000
Peoples United Financial Inc [Member] | Investment Banking, Legal and Other Services [Member]
Business Acquisition [Line Items]
Merger-related expenses				$ 17,000
Peoples United Financial Inc [Member] | Core Deposit and Other Intangible Assets [Member] | Minimum [Member]
Business Acquisition [Line Items]
Amortization period	3 years
Peoples United Financial Inc [Member] | Core Deposit and Other Intangible Assets [Member] | Maximum [Member]
Business Acquisition [Line Items]
Amortization period	7 years
Peoples United Financial Inc [Member] | Common Stock [Member]
Business Acquisition [Line Items]
Common stock issued in transaction	50,325,004
MT [Member]
Business Acquisition [Line Items]
Common stock, price per share	$ 0.118