Derivative Financial Instruments - Classifications and Hedging Relationships (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	$ 336,070	$ 300,572
Derivative Asset, Fair Value, Gross	3,404	4,027
Derivative Liability, Fair Value, Gross	(5,745)	(3,536)
Derivative Asset [Abstract]
Amounts subject to master netting arrangements	(1,621)	(1,312)
Cash collateral (received) posted for amounts subject to master netting arrangements	(643)	(345)
Net Amount in Consolidated Balance Sheets	1,140	2,370
Derivative Liability [Abstract]
Amounts subject to master netting arrangements	1,621	1,312
Cash collateral (received) posted for amounts subject to master netting arrangements	717	1,638
Net amount	(3,407)	(586)
Cash flow hedges | Interest rate contracts | Swap | Commercial loans
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	7,250	0
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	21,990	25,401
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	(80)	(8)
Fair value hedges | Interest rate contracts | Swap | Long-term debt
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	14,893	12,690
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	(80)	(6)
Fair value hedges | Interest rate contracts | Swap | AFS securities
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	7,097	12,711
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	0	(2)
Not designated as hedges
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	306,830	275,171
Derivative Asset, Fair Value, Gross	3,404	4,027
Derivative Liability, Fair Value, Gross	(5,665)	(3,528)
Not designated as hedges | Client-related and other risk management
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	260,906	244,348
Derivative Asset, Fair Value, Gross	3,065	3,981
Derivative Liability, Fair Value, Gross	(5,506)	(3,506)
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	154,257	150,223
Derivative Asset, Fair Value, Gross	540	1,716
Derivative Liability, Fair Value, Gross	(2,830)	(733)
Not designated as hedges | Client-related and other risk management | Interest rate contracts | Options
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	28,266	23,659
Derivative Asset, Fair Value, Gross	160	43
Derivative Liability, Fair Value, Gross	(166)	(30)
Not designated as hedges | Client-related and other risk management | Interest rate contracts | Forward commitments
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	2,435	2,404
Derivative Asset, Fair Value, Gross	27	2
Derivative Liability, Fair Value, Gross	(5)	(5)
Not designated as hedges | Client-related and other risk management | Interest rate contracts | Other
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	4,925	2,927
Derivative Asset, Fair Value, Gross	1	0
Derivative Liability, Fair Value, Gross	(1)	0
Not designated as hedges | Client-related and other risk management | Equity contracts
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	37,582	34,232
Derivative Asset, Fair Value, Gross	653	1,582
Derivative Liability, Fair Value, Gross	(938)	(2,089)
Not designated as hedges | Client-related and other risk management | Credit Contract | Trading assets
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	120	0
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	0	0
Not designated as hedges | Client-related and other risk management | Credit Contract | Loans and leases
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	519	570
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	0	(2)
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	6,342	8,145
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	(1)	(4)
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	1,525	1,445
Derivative Asset, Fair Value, Gross	87	3
Derivative Liability, Fair Value, Gross	0	(19)
Not designated as hedges | Client-related and other risk management | Foreign exchange contracts
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	18,793	16,102
Derivative Asset, Fair Value, Gross	763	160
Derivative Liability, Fair Value, Gross	(725)	(156)
Not designated as hedges | Client-related and other risk management | Commodity Contract
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	6,142	4,641
Derivative Asset, Fair Value, Gross	834	475
Derivative Liability, Fair Value, Gross	(840)	(468)
Not designated as hedges | Mortgage banking | Interest rate contracts
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	6,263	11,941
Derivative Asset, Fair Value, Gross	165	38
Derivative Liability, Fair Value, Gross	(61)	(22)
Not designated as hedges | Mortgage banking | Interest rate contracts | Swap
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	572	441
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	0	0
Not designated as hedges | Mortgage banking | Interest rate contracts | Other
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	106	424
Derivative Asset, Fair Value, Gross	1	1
Derivative Liability, Fair Value, Gross	0	0
Not designated as hedges | Mortgage banking | Interest rate contracts | Interest rate lock commitments
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	1,869	4,163
Derivative Asset, Fair Value, Gross	6	30
Derivative Liability, Fair Value, Gross	(61)	(7)
Not designated as hedges | Mortgage banking | Interest rate contracts | When issued securities, forward rate agreements and forward commitments
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	3,716	6,913
Derivative Asset, Fair Value, Gross	158	7
Derivative Liability, Fair Value, Gross	0	(15)
Not designated as hedges | Loan Servicing Rights | Interest rate contracts
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	39,661	18,882
Derivative Asset, Fair Value, Gross	174	8
Derivative Liability, Fair Value, Gross	(98)	0
Not designated as hedges | Loan Servicing Rights | Interest rate contracts | Swap
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	22,327	12,837
Derivative Asset, Fair Value, Gross	10	0
Derivative Liability, Fair Value, Gross	0	0
Not designated as hedges | Loan Servicing Rights | Interest rate contracts | Options
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	13,599	101
Derivative Asset, Fair Value, Gross	160	1
Derivative Liability, Fair Value, Gross	(47)	0
Not designated as hedges | Loan Servicing Rights | Interest rate contracts | Other
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	1,265	2,017
Derivative Asset, Fair Value, Gross	1	0
Derivative Liability, Fair Value, Gross	(3)	0
Not designated as hedges | Loan Servicing Rights | Interest rate contracts | When issued securities, forward rate agreements and forward commitments
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	2,470	3,927
Derivative Asset, Fair Value, Gross	3	7
Derivative Liability, Fair Value, Gross	$ (48)	$ 0