Allowance For Credit Losses (Loans by Class Modified byTDRs) (Details) $ in Millions	3 Months Ended
Mar. 31, 2022 USD ($) obligor
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	439
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 104
Increase in Allowance at Modification	$ 4
Commercial Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	13
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 39
Increase in Allowance at Modification	$ 0
Total Investor Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	1
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 8
Increase in Allowance at Modification	$ 0
Consumer Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	425
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 57
Increase in Allowance at Modification	$ 4
Commercial And Industrial [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	10
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 37
Increase in Allowance at Modification	$ 0
Commercial Real Estate Mortgage - Owner-Occupied [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	3
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 2
Increase in Allowance at Modification	$ 0
Commercial Real Estate Construction - Owner-Occupied [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	0
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 0
Increase in Allowance at Modification	$ 0
Commercial investor real estate mortgage [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	1
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 8
Increase in Allowance at Modification	$ 0
Commercial Investor Real Estate Construction [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	0
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 0
Increase in Allowance at Modification	$ 0
Residential First Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	357
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 52
Increase in Allowance at Modification	$ 3
Home Equity Lines of Credit[Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	22
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 2
Increase in Allowance at Modification	$ 1
Home Equity Loan [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	42
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 3
Increase in Allowance at Modification	$ 0
Consumer Credit Card Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	2
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 0
Increase in Allowance at Modification	$ 0
Other consumer- exit portfolios
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	0
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 0
Increase in Allowance at Modification	$ 0
Other Consumer [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	2
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 0
Increase in Allowance at Modification	$ 0

Amount of other addition (reduction) in allowance reserve for credit loss.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953676-111524

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