Subsequent Events	6 Months Ended
	Jun. 30, 2022
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsFor capital management purposes, in July 2022, the Corporation transferred government sponsored agency and municipal investment securities that had a fair value of $6.38 billion from the AFS to HTM classification. These transferred securities had a total unrealized loss of $889.5 million and included a $665.8 million reduction in AOCI, net of tax. Upon transfer of a debt security from the AFS to HTM classification, the amortized cost is reset to fair value. Any unrealized gain or loss, net of tax, at the date of transfer will remain in AOCI and be amortized into net interest income over the remaining life of the securities using the effective interest method. The amortization of amounts retained in AOCI will offset the effect on interest income of the amortization of the premium or discount resulting from transferring the securities at fair value.