Derivative Financial Instruments - Classifications and Hedging Relationships (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	$ 331,671	$ 300,572
Derivative Asset, Fair Value, Gross	3,144	4,027
Derivative Liability, Fair Value, Gross	(4,362)	(3,536)
Derivative Asset [Abstract]
Amounts subject to master netting arrangements	(1,395)	(1,312)
Cash collateral (received) posted for amounts subject to master netting arrangements	(363)	(345)
Net Amount in Consolidated Balance Sheets	1,386	2,370
Derivative Liability [Abstract]
Amounts subject to master netting arrangements	1,395	1,312
Cash collateral (received) posted for amounts subject to master netting arrangements	1,053	1,638
Net amount	(1,914)	(586)
Cash flow hedges | Interest rate contracts | Swap | Commercial loans
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	10,500	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	19,990	25,401
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	(41)	(8)
Fair value hedges | Interest rate contracts | Swap | Long-term debt
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	12,893	12,690
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	(41)	(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	301,181	275,171
Derivative Asset, Fair Value, Gross	3,144	4,027
Derivative Liability, Fair Value, Gross	(4,321)	(3,528)
Not designated as hedges | Client-related and other risk management
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	260,430	244,348
Derivative Asset, Fair Value, Gross	3,000	3,981
Derivative Liability, Fair Value, Gross	(4,220)	(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	154,805	150,223
Derivative Asset, Fair Value, Gross	525	1,716
Derivative Liability, Fair Value, Gross	(1,759)	(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	29,619	23,659
Derivative Asset, Fair Value, Gross	140	43
Derivative Liability, Fair Value, Gross	(130)	(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	2,039	2,404
Derivative Asset, Fair Value, Gross	11	2
Derivative Liability, Fair Value, Gross	(11)	(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	2,836	2,927
Derivative Asset, Fair Value, Gross	2	0
Derivative Liability, Fair Value, Gross	(3)	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	36,531	34,232
Derivative Asset, Fair Value, Gross	717	1,582
Derivative Liability, Fair Value, Gross	(811)	(2,089)
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	484	570
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	(1)	(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	6,429	8,145
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	(2)	(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	1,542	1,445
Derivative Asset, Fair Value, Gross	89	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	19,446	16,102
Derivative Asset, Fair Value, Gross	449	160
Derivative Liability, Fair Value, Gross	(427)	(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	6,699	4,641
Derivative Asset, Fair Value, Gross	1,067	475
Derivative Liability, Fair Value, Gross	(1,076)	(468)
Not designated as hedges | Mortgage banking | Interest rate contracts
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	9,295	11,941
Derivative Asset, Fair Value, Gross	40	38
Derivative Liability, Fair Value, Gross	(31)	(22)
Not designated as hedges | Mortgage banking | Interest rate contracts | Swap
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	573	441
Derivative Asset, Fair Value, Gross	0	0
Derivative Liability, Fair Value, Gross	0	0
Not designated as hedges | Mortgage banking | Interest rate contracts | Options
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	216	0
Derivative Asset, Fair Value, Gross	3	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	317	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	2,597	4,163
Derivative Asset, Fair Value, Gross	12	30
Derivative Liability, Fair Value, Gross	(19)	(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	5,592	6,913
Derivative Asset, Fair Value, Gross	24	7
Derivative Liability, Fair Value, Gross	(12)	(15)
Not designated as hedges | Loan Servicing Rights | Interest rate contracts
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	31,456	18,882
Derivative Asset, Fair Value, Gross	104	8
Derivative Liability, Fair Value, Gross	(70)	0
Not designated as hedges | Loan Servicing Rights | Interest rate contracts | Swap
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	14,727	12,837
Derivative Asset, Fair Value, Gross	0	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	13,241	101
Derivative Asset, Fair Value, Gross	77	1
Derivative Liability, Fair Value, Gross	(23)	0
Not designated as hedges | Loan Servicing Rights | Interest rate contracts | Other
Derivative Instruments, Notional, Fair Value Assets and Liabilities[Line Items]
Notional Amount	1,320	2,017
Derivative Asset, Fair Value, Gross	2	0
Derivative Liability, Fair Value, Gross	0	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	2,168	3,927
Derivative Asset, Fair Value, Gross	25	7
Derivative Liability, Fair Value, Gross	$ (47)	$ 0