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Credit Quality and the Allowance for Loan and Lease Losses - Summary of Gross Charge-Offs Within the Commercial Portfolio Segments, by Class and Vintage (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Financing Receivable, Modifications
Total	$ 158	$ 104	$ 389	$ 259
Commercial
Financing Receivable, Modifications
Year One			24
Year Two			6
Year Three			12
Year Four			1
Year Five			0
Prior			5
Revolving Loans			92
Revolving Loans Converted to Term Loans			0
Total	$ 70	$ 47	140	$ 95
Commercial \| Commercial and industrial loans
Financing Receivable, Modifications
Year One			24
Year Two			6
Year Three			12
Year Four			1
Year Five			0
Prior			5
Revolving Loans			90
Revolving Loans Converted to Term Loans			0
Total			138
Commercial \| Commercial mortgage owner-occupied loans
Financing Receivable, Modifications
Year One			0
Year Two			0
Year Three			0
Year Four			0
Year Five			0
Prior			0
Revolving Loans			1
Revolving Loans Converted to Term Loans			0
Total			1
Commercial \| Commercial construction loans
Financing Receivable, Modifications
Year One			0
Year Two			0
Year Three			0
Year Four			0
Year Five			0
Prior			0
Revolving Loans			1
Revolving Loans Converted to Term Loans			0
Total			$ 1