Occupancy Expense and Information Systems and Communications Expense - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Expenses [Line Items]
Depreciation and amortization	$ 824	$ 829	$ 842
Finance lease right-of-use asset	67	119
Finance lease liability	79	130
Accumulated amortization for finance lease right-of-use assets	135
Interest on lease liabilities	3	5
Right-of-use assets	$ 818	$ 805
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Other assets	Other assets
Lease liabilities	$ 839
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Accrued expenses and other liabilities
Operating leases not yet commenced	$ 207
Minimum
Expenses [Line Items]
Operating leases not yet commenced, lease terms	3 years
Maximum
Expenses [Line Items]
Operating leases not yet commenced, lease terms	11 years