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Asset Quality - Additional Information (Details) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2023 USD ($) loan	Dec. 31, 2022 USD ($) loan	Dec. 31, 2021 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of carrying amount of our commercial nonperforming loans outstanding	72.00%	72.00%
Percentage of nonperforming loans outstanding face value	77.00%	77.00%
Percentage of loans held for sale and other nonperforming assets	80.00%	80.00%
Net reduction to interest income		$ 37	$ 17	$ 17
Contractually current percentage of nonperforming loans	51.00%	51.00%	41.00%
Financial receivable, modifications, subsequent default, recorded investment			$ 12
Number   of Loans   | loan			4,205
Loan restructuring trial modifications amount		$ 295
Commitments outstanding to lend additional funds	$ 61	$ 61
Commitments outstanding to lend additional funds to borrowers			$ 10
Trial Modification Plans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number   of Loans   | loan		121
Loan restructuring trial modifications amount		$ 15
Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan restructuring trial modifications amount		$ 269
TDRs, period for default (in days)		90 days
Total consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivable, modifications, subsequent default, recorded investment		$ 89	$ 156
Loan restructuring trial modifications amount		$ 26
TDRs, period for default (in days)		60 days
Continuing Operations | Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase (decrease) in ALLL		$ 196
Percentage of increase (decrease) in ALLL		22.70%
Continuing Operations | Total consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase (decrease) in ALLL		$ (25)
Percentage of increase (decrease) in ALLL		(5.30%)
Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans | loan			12
Total consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans | loan			191
Commercial and Industrial | Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivable, modifications, subsequent default, recorded investment		$ 11
Loan restructuring trial modifications amount		263
Commercial mortgage | Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivable, modifications, subsequent default, recorded investment	1
Loan restructuring trial modifications amount		6
Non-performing Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonperforming loans on nonaccrual status with no allowance	$ 301	$ 301
Number   of Loans   | loan			1,240
Non-performing Loans | Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number   of Loans   | loan			31
Non-performing Loans | Total consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number   of Loans   | loan			1,209
Non-performing Loans | Commercial and Industrial | Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number   of Loans   | loan			27
Non-performing Loans | Commercial mortgage | Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number   of Loans   | loan			4

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