Derivative Financial Instruments - Classifications and Hedging Relationships (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	$ 441,005	$ 416,320
Derivative Asset, Fair Value, Gross	3,339	2,824
Derivative Liability, Fair Value, Gross	(4,596)	(4,700)
Derivative Asset [Abstract]
Amounts subject to master netting arrangements and exchange traded derivatives	(1,543)	(1,408)
Cash collateral (received) posted for amounts subject to master netting arrangements	(149)	(450)
Net Amount in Consolidated Balance Sheets	1,647	966
Derivative Liability [Abstract]
Amounts subject to master netting arrangements and exchange traded derivatives	1,543	1,408
Cash collateral (received) posted for amounts subject to master netting arrangements	$ 1,241	1,006
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other assets (including $1,977 and $1,271 at fair value, respectively)
Net amount	$ (1,812)	(2,286)
Cash flow hedges | Interest rate contracts | Swap | Commercial loans
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	66,335	66,585
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	0	0
Fair value hedges | Interest rate contracts
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	51,845	47,494
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	0	0
Fair value hedges | Interest rate contracts | Swap | Long-term debt
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	23,258	17,368
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	0	0
Fair value hedges | Interest rate contracts | Swap | AFS securities
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	28,587	30,126
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	0	0
Not designated as hedges
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	322,825	302,241
Derivative Asset, Fair Value, Gross	3,339	2,824
Derivative Liability, Fair Value, Gross	(4,596)	(4,700)
Not designated as hedges | Client-related and other risk management
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	292,233	264,503
Derivative Asset, Fair Value, Gross	3,292	2,705
Derivative Liability, Fair Value, Gross	(4,499)	(4,624)
Not designated as hedges | Client-related and other risk management | Interest rate contracts | Swap
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	165,734	146,194
Derivative Asset, Fair Value, Gross	537	488
Derivative Liability, Fair Value, Gross	(1,104)	(1,706)
Not designated as hedges | Client-related and other risk management | Interest rate contracts | Purchased options
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	9,660	11,321
Derivative Asset, Fair Value, Gross	25	29
Derivative Liability, Fair Value, Gross	(1)	(1)
Not designated as hedges | Client-related and other risk management | Interest rate contracts | Futures and forwards
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	3,685	4,782
Derivative Asset, Fair Value, Gross	3	1
Derivative Liability, Fair Value, Gross	(7)	(2)
Not designated as hedges | Client-related and other risk management | Interest rate contracts | Written Options
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	9,662	9,623
Derivative Asset, Fair Value, Gross	17	16
Derivative Liability, Fair Value, Gross	(31)	(49)
Not designated as hedges | Client-related and other risk management | Foreign exchange contracts | Swap
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	10,126	7,397
Derivative Asset, Fair Value, Gross	468	128
Derivative Liability, Fair Value, Gross	(415)	(114)
Not designated as hedges | Client-related and other risk management | Foreign exchange contracts | Futures and forwards
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	21,766	21,966
Derivative Asset, Fair Value, Gross	339	311
Derivative Liability, Fair Value, Gross	(368)	(270)
Not designated as hedges | Client-related and other risk management | Foreign exchange contracts | Other
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	2,342	760
Derivative Asset, Fair Value, Gross	43	5
Derivative Liability, Fair Value, Gross	(38)	(4)
Not designated as hedges | Client-related and other risk management | Equity contracts | Purchased options
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	15,761	11,956
Derivative Asset, Fair Value, Gross	1,392	1,366
Derivative Liability, Fair Value, Gross	(94)	(23)
Not designated as hedges | Client-related and other risk management | Equity contracts | Other
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	1,220	1,730
Derivative Asset, Fair Value, Gross	38	6
Derivative Liability, Fair Value, Gross	(28)	(41)
Not designated as hedges | Client-related and other risk management | Equity contracts | Written Options
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	30,712	28,228
Derivative Asset, Fair Value, Gross	13	12
Derivative Liability, Fair Value, Gross	(2,025)	(2,102)
Not designated as hedges | Client-related and other risk management | Commodity Contract
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	10,357	10,988
Derivative Asset, Fair Value, Gross	402	318
Derivative Liability, Fair Value, Gross	(379)	(297)
Not designated as hedges | Client-related and other risk management | Credit Contract | Credit default swaps
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	1,529	685
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	(1)	0
Not designated as hedges | Client-related and other risk management | Credit Contract | Total Return Swap
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	2,013	1,485
Derivative Asset, Fair Value, Gross	15	25
Derivative Liability, Fair Value, Gross	(5)	(13)
Not designated as hedges | Client-related and other risk management | Credit Contract | Risk participation agreements
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	7,666	7,388
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	(3)	(2)
Not designated as hedges | MSR and mortgage banking | Interest rate contracts
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	30,592	37,738
Derivative Asset, Fair Value, Gross	47	119
Derivative Liability, Fair Value, Gross	(97)	(76)
Not designated as hedges | MSR and mortgage banking | Interest rate contracts | Swap
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	16,312	20,696
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	0	0
Not designated as hedges | MSR and mortgage banking | Interest rate contracts | Purchased options
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	8,084	8,910
Derivative Asset, Fair Value, Gross	16	60
Derivative Liability, Fair Value, Gross	(80)	(46)
Not designated as hedges | MSR and mortgage banking | Interest rate contracts | Interest rate lock commitments
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	922	939
Derivative Asset, Fair Value, Gross	6	2
Derivative Liability, Fair Value, Gross	(2)	(13)
Not designated as hedges | MSR and mortgage banking | Interest rate contracts | When issued securities, forward rate agreements, forward commitments, and futures
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	4,526	5,261
Derivative Asset, Fair Value, Gross	15	25
Derivative Liability, Fair Value, Gross	(15)	(11)
Not designated as hedges | MSR and mortgage banking | Interest rate contracts | Written Options
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	748	1,932
Derivative Asset, Fair Value, Gross	10	32
Derivative Liability, Fair Value, Gross	$ 0	$ (6)