Loans and Related Allowance for Credit Losses (Nonperforming Assets) (Details) - USD ($) $ in Millions		Sep. 30, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[1]	$ 321,381	$ 321,508
Total assets		564,881	561,580
Nonperforming loans, without allowance for credit losses		600	500
Nonperforming Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		2,578	2,180
OREO and foreclosed assets		31	36
Total assets		$ 2,609	$ 2,216
Nonperforming loans to total loans		0.80%	0.68%
Nonperforming assets to total loans, OREO and foreclosed assets		0.81%	0.69%
Nonperforming assets to total assets		0.46%	0.39%
Total commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 220,721	$ 219,558
Total commercial | Nonperforming Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		1,729	1,307
Total consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		100,660	101,950
Total consumer | Nonperforming Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 849	$ 873
Unsecured Consumer Loans | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Threshold period of financing receivable past due, writeoff		120 days
Unsecured Consumer Loans | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Threshold period of financing receivable past due, writeoff		180 days

[1] Our consolidated assets included the following for which we have elected the fair value option: Loans held for sale of $0.7 billion, Loans held for investment of $1.2 billion and Other assets of $0.1 billion at September 30, 2024. Comparable amounts at December 31, 2023 were $0.7 billion, $1.2 billion and $0.1 billion, respectively.