Income Taxes (Schedule Of Tax Effects Of Deferred Tax Assets And Deferred Tax Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Abstract]
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	$ 0	$ 0	$ 0
Gross deferred tax assets, Book loan loss deduction in excess of tax	137	137
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Postretirement Benefits	5	7
Gross deferred tax assets, Deferred compensation	72	70
Gross deferred tax assets, Security investments and derivative fair value adjustments	0	78
Gross deferred tax assets, Net operating losses, capital losses and tax credits	0	2
FDIC Supported Transactions	61	0
Gross deferred tax assets, Other	35	31
Gross deferred tax assets	310	325
Gross deferred tax assets, Valuation allowance	0	0
Total deferred tax assets	310	325
Gross deferred tax liabilities, Premises and equipment, due to differences in depreciation	(66)	(61)
Gross deferred tax liabilities, FHLB stock dividends	(2)	(2)
Gross deferred tax liabilities, Leasing operations	(52)	(54)
Gross deferred tax liabilities, Prepaid expenses	(6)	(6)
Gross deferred tax liabilities, Prepaid pension reserves	(12)	(12)
Deferred Tax Liabilities, Mortgage Servicing Rights	(7)	(8)
Gross deferred tax liabilities, Subordinated debt modification	(17)	0
Deferred Tax Liabilities, Financing Arrangements	(30)	(27)
Deferred loan fees	55	0
Deferred Tax Liabilities, Investments	(26)	(25)
Total deferred tax liabilities	(273)	(195)
Net deferred tax assets	$ 37	$ 130