Quarterly report [Sections 13 or 15(d)]

Outstanding Loans and Leases and Allowance for Credit Losses - Home Equity - Credit Quality Indicators Including Vintage (Details)

Outstanding Loans and Leases and Allowance for Credit Losses - Home Equity - Credit Quality Indicators Including Vintage (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	$ 1,165,900		$ 1,165,900		$ 1,095,835
Total gross charge-offs	1,701	$ 1,800	5,258	$ 5,317
Consumer real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross charge-offs	9	$ 15	29	$ 34
Consumer real estate \| Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	26,482		26,482		25,737
Total gross charge-offs			11		21
Consumer real estate \| Home equity \| Less than 620
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	682		682		645
Consumer real estate \| Home equity \| Greater than or equal to 620 and less than 660
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	588		588		577
Consumer real estate \| Home equity \| Greater than or equal to 660 and less than 740
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	4,983		4,983		4,911
Consumer real estate \| Home equity \| Greater than or equal to 740
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	20,229		20,229		19,604
Consumer real estate \| Home Equity Loans and Reverse Mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	722		722		787
Total gross charge-offs			0		6
Consumer real estate \| Home Equity Loans and Reverse Mortgages \| Less than 620
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	67		67		72
Consumer real estate \| Home Equity Loans and Reverse Mortgages \| Greater than or equal to 620 and less than 660
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	44		44		46
Consumer real estate \| Home Equity Loans and Reverse Mortgages \| Greater than or equal to 660 and less than 740
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	181		181		198
Consumer real estate \| Home Equity Loans and Reverse Mortgages \| Greater than or equal to 740
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	430		430		471
Consumer real estate \| Reverse Mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	471		471		500
Consumer real estate \| Home Equity Loan no Longer Originated
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	251		251		287
Consumer real estate \| Revolving Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans	22,618		22,618		21,526
Gross charge-offs, Revolving Loans			7		9
Consumer real estate \| Revolving Loans \| Less than 620
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans	377		377		320
Consumer real estate \| Revolving Loans \| Greater than or equal to 620 and less than 660
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans	370		370		339
Consumer real estate \| Revolving Loans \| Greater than or equal to 660 and less than 740
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans	3,966		3,966		3,779
Consumer real estate \| Revolving Loans \| Greater than or equal to 740
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans	17,905		17,905		17,088
Consumer real estate \| Revolving Loans Converted to Term Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans Converted to Term Loans	3,142		3,142		3,424
Gross charge-offs, Revolving Loans Converted to Term Loans			4		6
Consumer real estate \| Revolving Loans Converted to Term Loans \| Less than 620
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans Converted to Term Loans	238		238		253
Consumer real estate \| Revolving Loans Converted to Term Loans \| Greater than or equal to 620 and less than 660
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans Converted to Term Loans	174		174		192
Consumer real estate \| Revolving Loans Converted to Term Loans \| Greater than or equal to 660 and less than 740
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans Converted to Term Loans	836		836		934
Consumer real estate \| Revolving Loans Converted to Term Loans \| Greater than or equal to 740
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans Converted to Term Loans	1,894		1,894		2,045
Less than or equal to 90 percent \| Consumer real estate \| Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	26,360		26,360		25,638
Less than or equal to 90 percent \| Consumer real estate \| Home Equity Loans and Reverse Mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	713		713		780
Less than or equal to 90 percent \| Consumer real estate \| Revolving Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans	22,519		22,519		21,450
Less than or equal to 90 percent \| Consumer real estate \| Revolving Loans Converted to Term Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans Converted to Term Loans	3,128		3,128		3,408
Greater than 90 percent but less than or equal to 100 percent \| Consumer real estate \| Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	62		62		51
Greater than 90 percent but less than or equal to 100 percent \| Consumer real estate \| Home Equity Loans and Reverse Mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	5		5		4
Greater than 90 percent but less than or equal to 100 percent \| Consumer real estate \| Revolving Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans	52		52		42
Greater than 90 percent but less than or equal to 100 percent \| Consumer real estate \| Revolving Loans Converted to Term Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans Converted to Term Loans	5		5		5
Greater than 100 percent \| Consumer real estate \| Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	60		60		48
Greater than 100 percent \| Consumer real estate \| Home Equity Loans and Reverse Mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and leases	4		4		3
Greater than 100 percent \| Consumer real estate \| Revolving Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans	47		47		34
Greater than 100 percent \| Consumer real estate \| Revolving Loans Converted to Term Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans Converted to Term Loans	$ 9		$ 9		$ 11