Loans And Allowance For Credit Losses (Summary Of Selected Information On TDRs That Includes Recorded Investment On An Accruing And Nonaccruing Basis By Loan Class And Modification Type) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Modifications [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	$ 269	$ 310
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	1	8
Impaired Financing Receivable, Recorded Investment	229	261
Impaired Financing Receivable, Related Allowance	10	8
Impaired Financing Receivable, Average Recorded Investment	272	238
Impaired Financing Receivable, Interest Income, Accrual Method	5	9
Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	78	112
Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	153	202
Commercial And Industrial [Member]
Financing Receivable, Modifications [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	132	112
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	0	5
Impaired Financing Receivable, Recorded Investment	104	88
Impaired Financing Receivable, Related Allowance	7	4
Impaired Financing Receivable, Average Recorded Investment	103	83
Impaired Financing Receivable, Interest Income, Accrual Method	2	0
Commercial And Industrial [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	16	28
Commercial And Industrial [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	50	45
Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	53	67
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	1	1
Impaired Financing Receivable, Recorded Investment	51	60
Impaired Financing Receivable, Related Allowance	1	2
Impaired Financing Receivable, Average Recorded Investment	61	47
Impaired Financing Receivable, Interest Income, Accrual Method	1	8
Owner Occupied [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	15	21
Owner Occupied [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	10	14
Municipal [Member]
Financing Receivable, Modifications [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	0	1
Impaired Financing Receivable, Recorded Investment	0	1
Impaired Financing Receivable, Related Allowance	0	0
Impaired Financing Receivable, Average Recorded Investment	0	1
Impaired Financing Receivable, Interest Income, Accrual Method	0	0
Municipal [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	1
Commercial Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	185	180
Impaired Financing Receivable, Recorded Investment	155	149
Impaired Financing Receivable, Related Allowance	8	6
Impaired Financing Receivable, Average Recorded Investment	164	131
Impaired Financing Receivable, Interest Income, Accrual Method	3	8
Commercial Portfolio Segment [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	31	49
Commercial Portfolio Segment [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	60	60
Construction And Land Development [Member]
Financing Receivable, Modifications [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	0	1
Impaired Financing Receivable, Recorded Investment	0	0
Impaired Financing Receivable, Related Allowance	0	0
Impaired Financing Receivable, Average Recorded Investment	0	1
Impaired Financing Receivable, Interest Income, Accrual Method	0	0
Construction And Land Development [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Construction And Land Development [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Term [Member]
Financing Receivable, Modifications [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	18	44
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	0	2
Impaired Financing Receivable, Recorded Investment	17	40
Impaired Financing Receivable, Related Allowance	0	0
Impaired Financing Receivable, Average Recorded Investment	34	41
Impaired Financing Receivable, Interest Income, Accrual Method	0	1
Term [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	6	11
Term [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	7	20
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	18	45
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	0	2
Impaired Financing Receivable, Recorded Investment	17	40
Impaired Financing Receivable, Related Allowance	0	0
Impaired Financing Receivable, Average Recorded Investment	34	42
Impaired Financing Receivable, Interest Income, Accrual Method	0	1
Commercial Real Estate Portfolio Segment [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	6	11
Commercial Real Estate Portfolio Segment [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	7	20
Home Equity Line of Credit [Member]
Financing Receivable, Modifications [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	14	15
Impaired Financing Receivable, Recorded Investment	13	14
Impaired Financing Receivable, Related Allowance	0	0
Impaired Financing Receivable, Average Recorded Investment	15	13
Impaired Financing Receivable, Interest Income, Accrual Method	1	0
Home Equity Line of Credit [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	11	12
Home Equity Line of Credit [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2	1
One Through Four Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	52	69
Impaired Financing Receivable, Recorded Investment	44	57
Impaired Financing Receivable, Related Allowance	2	2
Impaired Financing Receivable, Average Recorded Investment	56	51
Impaired Financing Receivable, Interest Income, Accrual Method	1	0
One Through Four Family Residential [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	29	39
One Through Four Family Residential [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	6	9
Construction And Other Consumer Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	0	1
Impaired Financing Receivable, Recorded Investment	0	1
Impaired Financing Receivable, Related Allowance	0	0
Impaired Financing Receivable, Average Recorded Investment	2	1
Impaired Financing Receivable, Interest Income, Accrual Method	0	0
Construction And Other Consumer Real Estate [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1	1
Construction And Other Consumer Real Estate [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Consumer Other Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	0	0
Impaired Financing Receivable, Recorded Investment	0	0
Impaired Financing Receivable, Related Allowance	0	0
Impaired Financing Receivable, Average Recorded Investment	1	0
Impaired Financing Receivable, Interest Income, Accrual Method	0	0
Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	1	6
Consumer Loan [Member]
Financing Receivable, Modifications [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	66	85
Impaired Financing Receivable, Recorded Investment	57	72
Impaired Financing Receivable, Related Allowance	2	2
Impaired Financing Receivable, Average Recorded Investment	74	65
Impaired Financing Receivable, Interest Income, Accrual Method	2	0
Consumer Loan [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	41	52
Consumer Loan [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	8	10
Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	0	0
Accruing [Member] \| Commercial And Industrial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	0	0
Accruing [Member] \| Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	0	0
Accruing [Member] \| Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0
Accruing [Member] \| Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	0	0
Accruing [Member] \| Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	0	0
Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	1	8
Nonaccruing [Member] \| Commercial And Industrial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	0	5
Nonaccruing [Member] \| Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	1	1
Nonaccruing [Member] \| Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		2
Nonaccruing [Member] \| Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	0	2
Nonaccruing [Member] \| Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	1	6
Nonaccruing Trouble Debt Restructuring [Member] \| Nonaccruing Trouble Debt Restructuring [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	75	90
Multiple Modification Types [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	39	59
Multiple Modification Types [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	72	100
Multiple Modification Types [Member] \| Commercial Portfolio Segment [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	12	21
Multiple Modification Types [Member] \| Commercial Portfolio Segment [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	26	33
Multiple Modification Types [Member] \| Commercial Real Estate Portfolio Segment [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	3	6
Multiple Modification Types [Member] \| Commercial Real Estate Portfolio Segment [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	3	1
Multiple Modification Types [Member] \| Nonaccruing Trouble Debt Restructuring [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	33	41
Multiple Modification Types [Member] \| Consumer Loan [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	24	32
Multiple Modification Types [Member] \| Consumer Loan [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	4	7
Multiple Modification Types [Member] \| Accruing [Member] \| Commercial And Industrial [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	5	7
Multiple Modification Types [Member] \| Accruing [Member] \| Owner Occupied [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	7	14
Multiple Modification Types [Member] \| Accruing [Member] \| Construction And Land Development [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Multiple Modification Types [Member] \| Accruing [Member] \| Term [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	3	6
Multiple Modification Types [Member] \| Accruing [Member] \| Home Equity Line of Credit [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2	3
Multiple Modification Types [Member] \| Accruing [Member] \| One Through Four Family Residential [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	22	28
Multiple Modification Types [Member] \| Accruing [Member] \| Construction And Other Consumer Real Estate [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	1
Multiple Modification Types [Member] \| Nonaccruing [Member] \| Commercial And Industrial [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	22	27
Multiple Modification Types [Member] \| Nonaccruing [Member] \| Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		5
Multiple Modification Types [Member] \| Nonaccruing [Member] \| Owner Occupied [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	4
Multiple Modification Types [Member] \| Nonaccruing [Member] \| Municipal [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		1
Multiple Modification Types [Member] \| Nonaccruing [Member] \| Municipal [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0
Multiple Modification Types [Member] \| Nonaccruing [Member] \| Construction And Land Development [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0
Multiple Modification Types [Member] \| Nonaccruing [Member] \| Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		1
Multiple Modification Types [Member] \| Nonaccruing [Member] \| Term [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	3
Multiple Modification Types [Member] \| Nonaccruing [Member] \| Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Multiple Modification Types [Member] \| Nonaccruing [Member] \| Home Equity Line of Credit [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Multiple Modification Types [Member] \| Nonaccruing [Member] \| One Through Four Family Residential [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	4	7
Multiple Modification Types [Member] \| Nonaccruing [Member] \| Construction And Other Consumer Real Estate [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Other Recorded Investment Resulting From Following Modification [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	13	18
Other Recorded Investment Resulting From Following Modification [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	22	45
Other Recorded Investment Resulting From Following Modification [Member] \| Commercial Portfolio Segment [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	12	17
Other Recorded Investment Resulting From Following Modification [Member] \| Commercial Portfolio Segment [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	5	12
Other Recorded Investment Resulting From Following Modification [Member] \| Commercial Real Estate Portfolio Segment [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Other Recorded Investment Resulting From Following Modification [Member] \| Commercial Real Estate Portfolio Segment [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	3	14
Other Recorded Investment Resulting From Following Modification [Member] \| Nonaccruing Trouble Debt Restructuring [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	9	27
Other Recorded Investment Resulting From Following Modification [Member] \| Consumer Loan [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1	1
Other Recorded Investment Resulting From Following Modification [Member] \| Consumer Loan [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1	1
Other Recorded Investment Resulting From Following Modification [Member] \| Accruing [Member] \| Commercial And Industrial [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	8	15
Other Recorded Investment Resulting From Following Modification [Member] \| Accruing [Member] \| Owner Occupied [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	4	2
Other Recorded Investment Resulting From Following Modification [Member] \| Accruing [Member] \| Construction And Land Development [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Other Recorded Investment Resulting From Following Modification [Member] \| Accruing [Member] \| Term [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Other Recorded Investment Resulting From Following Modification [Member] \| Accruing [Member] \| Home Equity Line of Credit [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Other Recorded Investment Resulting From Following Modification [Member] \| Accruing [Member] \| One Through Four Family Residential [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1	1
Other Recorded Investment Resulting From Following Modification [Member] \| Accruing [Member] \| Construction And Other Consumer Real Estate [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Other Recorded Investment Resulting From Following Modification [Member] \| Nonaccruing [Member] \| Commercial And Industrial [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	4	10
Other Recorded Investment Resulting From Following Modification [Member] \| Nonaccruing [Member] \| Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		2
Other Recorded Investment Resulting From Following Modification [Member] \| Nonaccruing [Member] \| Owner Occupied [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1
Other Recorded Investment Resulting From Following Modification [Member] \| Nonaccruing [Member] \| Municipal [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Other Recorded Investment Resulting From Following Modification [Member] \| Nonaccruing [Member] \| Municipal [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0
Other Recorded Investment Resulting From Following Modification [Member] \| Nonaccruing [Member] \| Construction And Land Development [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0
Other Recorded Investment Resulting From Following Modification [Member] \| Nonaccruing [Member] \| Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		14
Other Recorded Investment Resulting From Following Modification [Member] \| Nonaccruing [Member] \| Term [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	3
Other Recorded Investment Resulting From Following Modification [Member] \| Nonaccruing [Member] \| Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Other Recorded Investment Resulting From Following Modification [Member] \| Nonaccruing [Member] \| Home Equity Line of Credit [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Other Recorded Investment Resulting From Following Modification [Member] \| Nonaccruing [Member] \| One Through Four Family Residential [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1	1
Other Recorded Investment Resulting From Following Modification [Member] \| Nonaccruing [Member] \| Construction And Other Consumer Real Estate [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Payment Deferral [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1	2
Payment Deferral [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	21	6
Payment Deferral [Member] \| Commercial Portfolio Segment [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Payment Deferral [Member] \| Commercial Portfolio Segment [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	20	2
Payment Deferral [Member] \| Commercial Real Estate Portfolio Segment [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1	1
Payment Deferral [Member] \| Commercial Real Estate Portfolio Segment [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	2
Payment Deferral [Member] \| Nonaccruing Trouble Debt Restructuring [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	20	4
Payment Deferral [Member] \| Consumer Loan [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	1
Payment Deferral [Member] \| Consumer Loan [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Payment Deferral [Member] \| Accruing [Member] \| Commercial And Industrial [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Payment Deferral [Member] \| Accruing [Member] \| Owner Occupied [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Payment Deferral [Member] \| Accruing [Member] \| Construction And Land Development [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Payment Deferral [Member] \| Accruing [Member] \| Term [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1	1
Payment Deferral [Member] \| Accruing [Member] \| Home Equity Line of Credit [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Payment Deferral [Member] \| Accruing [Member] \| One Through Four Family Residential [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	1
Payment Deferral [Member] \| Accruing [Member] \| Construction And Other Consumer Real Estate [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Payment Deferral [Member] \| Nonaccruing [Member] \| Commercial And Industrial [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	20	1
Payment Deferral [Member] \| Nonaccruing [Member] \| Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		1
Payment Deferral [Member] \| Nonaccruing [Member] \| Owner Occupied [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0
Payment Deferral [Member] \| Nonaccruing [Member] \| Municipal [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Payment Deferral [Member] \| Nonaccruing [Member] \| Municipal [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0
Payment Deferral [Member] \| Nonaccruing [Member] \| Construction And Land Development [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0
Payment Deferral [Member] \| Nonaccruing [Member] \| Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		2
Payment Deferral [Member] \| Nonaccruing [Member] \| Term [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0
Payment Deferral [Member] \| Nonaccruing [Member] \| Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Payment Deferral [Member] \| Nonaccruing [Member] \| Home Equity Line of Credit [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Payment Deferral [Member] \| Nonaccruing [Member] \| One Through Four Family Residential [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Payment Deferral [Member] \| Nonaccruing [Member] \| Construction And Other Consumer Real Estate [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Principal Forgiveness [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	11	14
Principal Forgiveness [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	14	16
Principal Forgiveness [Member] \| Commercial Portfolio Segment [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Principal Forgiveness [Member] \| Commercial Portfolio Segment [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Principal Forgiveness [Member] \| Commercial Real Estate Portfolio Segment [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Principal Forgiveness [Member] \| Commercial Real Estate Portfolio Segment [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Principal Forgiveness [Member] \| Nonaccruing Trouble Debt Restructuring [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	3	2
Principal Forgiveness [Member] \| Consumer Loan [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	11	14
Principal Forgiveness [Member] \| Consumer Loan [Member] \| Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	3	2
Principal Forgiveness [Member] \| Accruing [Member] \| Commercial And Industrial [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Principal Forgiveness [Member] \| Accruing [Member] \| Owner Occupied [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Principal Forgiveness [Member] \| Accruing [Member] \| Construction And Land Development [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Principal Forgiveness [Member] \| Accruing [Member] \| Term [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Principal Forgiveness [Member] \| Accruing [Member] \| Home Equity Line of Credit [Member] \| Accruing [Member]
Financing Receivable, Modifications [Line Items]

Loans And Allowance For Credit Losses (Summary Of Selected Information On TDRs That Includes Recorded Investment On An Accruing And Nonaccruing Basis By Loan Class And Modification Type) (Details) - USD ($)
$ in Millions