Allowance For Credit Losses (TDRs on Financing Receivables) (Details) $ in Millions	12 Months Ended
Dec. 31, 2021 USD ($) obligor	Dec. 31, 2020 USD ($) obligor
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	755	689
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 301	$ 440
Increase in Allowance at Modification	$ 8	$ 11
Commercial And Industrial [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	65	151
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 116	$ 250
Increase in Allowance at Modification	$ 0	$ 0
Commercial Real Estate Mortgage - Owner-Occupied [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	28	21
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 11	$ 16
Increase in Allowance at Modification	$ 0	$ 0
Commercial Real Estate Construction - Owner-Occupied [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	2	1
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 2	$ 1
Increase in Allowance at Modification	$ 0	$ 0
Commercial investor real estate mortgage [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	8	11
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 77	$ 78
Increase in Allowance at Modification	$ 0	$ 0
Commercial Investor Real Estate Construction [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	0	4
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 0	$ 5
Increase in Allowance at Modification	$ 0	$ 0
Residential First Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	492	378
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 85	$ 85
Increase in Allowance at Modification	$ 8	$ 11
Home Equity Lines of Credit[Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	7	0
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 1	$ 0
Increase in Allowance at Modification	$ 0	$ 0
Home Equity Loan [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	72	43
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 6	$ 4
Increase in Allowance at Modification	$ 0	$ 0
Consumer Credit Card Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	1	14
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 0	$ 0
Increase in Allowance at Modification	$ 0	$ 0
Other consumer- exit portfolios
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	0	17
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 0	$ 0
Increase in Allowance at Modification	$ 0	$ 0
Indirect-vehicles and other consumer [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	80	49
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 3	$ 1
Increase in Allowance at Modification	$ 0	$ 0
Commercial Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	95	173
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 129	$ 267
Increase in Allowance at Modification	$ 0	$ 0
Total Investor Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	8	15
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 77	$ 83
Increase in Allowance at Modification	$ 0	$ 0
Consumer Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Obligors \| obligor	652	501
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 95	$ 90
Increase in Allowance at Modification	$ 8	$ 11

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 http://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
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-Topic 310
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-Paragraph 33
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