Commitments, Off-Balance Sheet Arrangements, Legal Proceedings and Regulatory Matters (Tables)

9 Months Ended

Sep. 30, 2021

Commitments and Contingencies Disclosure [Abstract]

Summary of lending-related and other commitments

The following is a summary of lending-related commitments:

($ in Thousands)	Sep 30, 2021		Dec 31, 2020
Commitments to extend credit, excluding commitments to originate residential mortgage loans held for sale(a)(b)	$	10,618,161	$	10,010,492
Commercial letters of credit(a)	6,309		3,642
Standby letters of credit(c)	264,123		278,798

(a) These off-balance sheet financial instruments are exercisable at the market rate prevailing at the date the underlying transaction will be completed and, thus, are deemed to have no
    current fair value, or the fair value is based on fees currently charged to enter into similar agreements and was not material at September 30, 2021 or December 31, 2020.
(b) Interest rate lock commitments to originate residential mortgage loans held for sale are considered derivative instruments and are disclosed in Note 10.
(c) The Corporation has established a liability of $3 million for both September 30, 2021 and December 31, 2020, as an estimate of the fair value of these financial instruments.

Schedule Of Unfunded Commitments [Table Text Block]

The following table presents a summary of the changes in the allowance for unfunded commitments:

($ in Thousands)	Nine months ended Sep 30, 2021		Year Ended Dec 31, 2020
Allowance for Unfunded Commitments
Balance at beginning of period	$	47,776	$	21,907
Cumulative effect of ASU 2016-13 adoption (CECL)	N/A		18,690
Balance at beginning of period, adjusted	47,776		40,597
Provision for unfunded commitments	(6,500)		7,000
Amount recorded at acquisition	N/A		179
Balance at end of period	$	41,276	$	47,776