Income Taxes (Schedule of Tax Effects of Deferred Tax Assets and Deferred Tax Liabilities) (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Gross deferred tax assets:
Book loan loss deduction in excess of tax	$ 136,000,000	$ 205,000,000
Pension and postretirement	1,000,000	1,000,000
Deferred compensation	77,000,000	71,000,000
Security investments and derivative fair value adjustments	26,000,000	0
Lease liabilities	55,000,000	59,000,000
Capitalization of intangible assets	40,000,000	0
Other	44,000,000	35,000,000
Total deferred tax assets before valuation allowance	379,000,000	371,000,000
Valuation allowance	0	0
Total deferred tax assets	379,000,000	371,000,000
Gross deferred tax liabilities:
Premises and equipment, due to differences in depreciation	(88,000,000)	(81,000,000)
Federal Home Loan Bank stock dividends	(2,000,000)	(2,000,000)
Leasing operations	(44,000,000)	(55,000,000)
Prepaid expenses	(8,000,000)	(6,000,000)
Prepaid pension reserves	(6,000,000)	(6,000,000)
Mortgage servicing	(10,000,000)	(8,000,000)
Security investments and derivative fair value adjustments	0	(102,000,000)
Deferred loan costs	(30,000,000)	(32,000,000)
ROU assets	(49,000,000)	(53,000,000)
Qualified opportunity fund deferred gains	(26,000,000)	(11,000,000)
Equity investments	(20,000,000)	(18,000,000)
Total deferred tax liabilities	(283,000,000)	(374,000,000)
Net deferred tax assets (liabilities)	$ 96,000,000
Net deferred tax assets (liabilities)		$ (3,000,000)