Loans and Related Allowance for Credit Losses, Payment Performance of Commercial Loan Modifications (Details) - Total Commercial [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs	$ 11	$ 27	$ 106	$ 42
Excluding modifications in payment deferral period member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	2,867	755	2,867	755
Current-29 days past due [Member] | Excluding modifications in payment deferral period member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	2,674	724	2,674	724
30-89 days past due [Member] | Excluding modifications in payment deferral period member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	56	29	56	29
90 days or more past due [Member] | Excluding modifications in payment deferral period member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	137	2	137	2
Commercial and industrial loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs	11	27	106	42
Commercial and industrial loans [Member] | Excluding modifications in payment deferral period member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	828	304	828	304
Commercial and industrial loans [Member] | Current-29 days past due [Member] | Excluding modifications in payment deferral period member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	789	275	789	275
Commercial and industrial loans [Member] | 30-89 days past due [Member] | Excluding modifications in payment deferral period member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	29	27	29	27
Commercial and industrial loans [Member] | 90 days or more past due [Member] | Excluding modifications in payment deferral period member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	10	2	10	2
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs	0	0	0	0
Commercial real estate [Member] | Excluding modifications in payment deferral period member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	2,039	451	2,039	451
Commercial real estate [Member] | Current-29 days past due [Member] | Excluding modifications in payment deferral period member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	1,885	449	1,885	449
Commercial real estate [Member] | 30-89 days past due [Member] | Excluding modifications in payment deferral period member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	27	2	27	2
Commercial real estate [Member] | 90 days or more past due [Member] | Excluding modifications in payment deferral period member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	$ 127	$ 0	$ 127	$ 0