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, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Financing Receivable, Modifications
Total	$ 382	$ 183	$ 748	$ 511
Commercial
Financing Receivable, Modifications
Year One			1	1
Year Two			9	2
Year Three			24	15
Year Four			7	1
Year Five			6	1
Prior			14	0
Revolving Loans			378	183
Total	$ 282	$ 80	439	203
Commercial | Commercial and industrial loans
Financing Receivable, Modifications
Year One			1	1
Year Two			9	2
Year Three			23	15
Year Four			6	1
Year Five			3	1
Prior			1	0
Revolving Loans			376	183
Total			419	203
Commercial | Commercial mortgage owner-occupied loans
Financing Receivable, Modifications
Year One			0	0
Year Two			0	0
Year Three			0	0
Year Four			0	0
Year Five			3	0
Prior			11	0
Revolving Loans			2	0
Total			16	0
Commercial | Commercial leases
Financing Receivable, Modifications
Year One			0	0
Year Two			0	0
Year Three			1	0
Year Four			1	0
Year Five			0	0
Prior			2	0
Revolving Loans			0	0
Total			$ 4	$ 0