Subsequent Events	12 Months Ended
Dec. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsIn January 2024, the Corporation sold certain available-for-sale debt securities with an amortized cost of $2.2 billion that were in an unrealized loss position in conjunction with a repositioning of the portfolio. As a result, the Corporation recognized a $189.4 million loss recorded in Investment Security Gains (Losses), net on the consolidated statements of income in the first quarter of 2024. The $189.4 million realized loss includes $18.4 million of cumulative hedge accounting basis adjustments related to discontinued fair value hedging relationships of certain available-for-sale debt securities sold.

The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 855
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//855/tableOfContent

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 855
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483399/855-10-50-2

Name:	us-gaap_SubsequentEventsTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration