Asset Quality - Schedule of Breakdown of Nonperforming TDRs by Loans Category (Details) $ in Millions	6 Months Ended
Jun. 30, 2022 USD ($) loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	4,344
Pre-modification Outstanding Recorded Investment	$ 301
Post-modification Outstanding Recorded Investment	$ 216
Prior-Year Accruing
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	3,054
Pre-modification Outstanding Recorded Investment	$ 161
Post-modification Outstanding Recorded Investment	$ 122
Prior-Year Accruing \| Total commercial loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	12
Pre-modification Outstanding Recorded Investment	$ 0
Post-modification Outstanding Recorded Investment	$ 0
Prior-Year Accruing \| Total consumer loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	3,042
Pre-modification Outstanding Recorded Investment	$ 161
Post-modification Outstanding Recorded Investment	$ 122
Non-performing Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	1,290
Pre-modification Outstanding Recorded Investment	$ 140
Post-modification Outstanding Recorded Investment	$ 94
Non-performing Loans \| Total commercial loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	43
Pre-modification Outstanding Recorded Investment	$ 75
Post-modification Outstanding Recorded Investment	$ 35
Non-performing Loans \| Total consumer loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	1,247
Pre-modification Outstanding Recorded Investment	$ 65
Post-modification Outstanding Recorded Investment	$ 59
Total commercial real estate loans \| Prior-Year Accruing \| Total commercial real estate loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	1
Pre-modification Outstanding Recorded Investment	$ 0
Post-modification Outstanding Recorded Investment	$ 0
Total commercial real estate loans \| Non-performing Loans \| Total commercial real estate loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	3
Pre-modification Outstanding Recorded Investment	$ 50
Post-modification Outstanding Recorded Investment	$ 23
Commercial and industrial \| Prior-Year Accruing \| Total commercial loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	11
Pre-modification Outstanding Recorded Investment	$ 0
Post-modification Outstanding Recorded Investment	$ 0
Commercial and industrial \| Non-performing Loans \| Total commercial loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	40
Pre-modification Outstanding Recorded Investment	$ 25
Post-modification Outstanding Recorded Investment	$ 12
Commercial mortgage \| Prior-Year Accruing \| Total commercial real estate loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	1
Pre-modification Outstanding Recorded Investment	$ 0
Post-modification Outstanding Recorded Investment	$ 0
Commercial mortgage \| Non-performing Loans \| Total commercial real estate loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	3
Pre-modification Outstanding Recorded Investment	$ 50
Post-modification Outstanding Recorded Investment	$ 23
Real estate — residential mortgage \| Prior-Year Accruing \| Total consumer loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	457
Pre-modification Outstanding Recorded Investment	$ 42
Post-modification Outstanding Recorded Investment	$ 35
Real estate — residential mortgage \| Non-performing Loans \| Total consumer loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	224
Pre-modification Outstanding Recorded Investment	$ 27
Post-modification Outstanding Recorded Investment	$ 25
Home equity loans \| Prior-Year Accruing \| Total consumer loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	1,612
Pre-modification Outstanding Recorded Investment	$ 99
Post-modification Outstanding Recorded Investment	$ 76
Home equity loans \| Non-performing Loans \| Total consumer loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	486
Pre-modification Outstanding Recorded Investment	$ 32
Post-modification Outstanding Recorded Investment	$ 29
Consumer direct loans \| Prior-Year Accruing \| Total consumer loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	253
Pre-modification Outstanding Recorded Investment	$ 4
Post-modification Outstanding Recorded Investment	$ 3
Consumer direct loans \| Non-performing Loans \| Total consumer loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	172
Pre-modification Outstanding Recorded Investment	$ 2
Post-modification Outstanding Recorded Investment	$ 2
Credit cards \| Prior-Year Accruing \| Total consumer loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	607
Pre-modification Outstanding Recorded Investment	$ 4
Post-modification Outstanding Recorded Investment	$ 2
Credit cards \| Non-performing Loans \| Total consumer loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	345
Pre-modification Outstanding Recorded Investment	$ 2
Post-modification Outstanding Recorded Investment	$ 2
Consumer indirect loans \| Prior-Year Accruing \| Total consumer loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	113
Pre-modification Outstanding Recorded Investment	$ 12
Post-modification Outstanding Recorded Investment	$ 6
Consumer indirect loans \| Non-performing Loans \| Total consumer loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	20
Pre-modification Outstanding Recorded Investment	$ 2
Post-modification Outstanding Recorded Investment	$ 1

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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