Derivative Financial Instruments - Notional Amounts and Fair Values for All Derivative Instruments Included in the Condensed Consolidated Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Derivatives, Fair Value
Derivative assets, fair value, gross assets	$ 3,171	$ 2,896
Total derivative assets	3,173	2,908
Derivative liabilities, fair value, gross liabilities	3,951	2,013
Total derivative liabilities	3,952	2,013
Amount of variation margin payment applied to derivative asset contracts	1,000	771
Amount of variation margin payment applied to derivative liability contracts	1,000	570
Designated as Hedging Instrument | Accumulated Net Gain (Loss) from Designated or Qualifying Hedges
Derivatives, Fair Value
Derivative assets, fair value, gross assets	157	522
Derivative liabilities, fair value, gross liabilities	296	3
Designated as Hedging Instrument | Fair Value Hedging | Accumulated Net Gain (Loss) from Designated or Qualifying Hedges
Derivatives, Fair Value
Derivative assets, fair value, gross assets	126	400
Derivative liabilities, fair value, gross liabilities	195	2
Designated as Hedging Instrument | Fair Value Hedging | Interest rate swaps | Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Available-for-sale debt and other securities
Derivatives, Fair Value
Notional     Amount		445
Derivative assets, fair value, gross assets		7
Derivative liabilities, fair value, gross liabilities		0
Designated as Hedging Instrument | Fair Value Hedging | Interest rate swaps | Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Long-term debt
Derivatives, Fair Value
Notional     Amount	5,955	1,955
Derivative assets, fair value, gross assets	126	393
Derivative liabilities, fair value, gross liabilities	195	2
Designated as Hedging Instrument | Cash Flow Hedging | Accumulated Net Gain (Loss) from Designated or Qualifying Hedges
Derivatives, Fair Value
Derivative assets, fair value, gross assets	31	122
Derivative liabilities, fair value, gross liabilities	101	1
Designated as Hedging Instrument | Cash Flow Hedging | Interest rate swaps | Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Commercial and Industrial
Derivatives, Fair Value
Notional     Amount	8,000	8,000
Derivative assets, fair value, gross assets	0	0
Derivative liabilities, fair value, gross liabilities	76	1
Designated as Hedging Instrument | Cash Flow Hedging | Interest rate swaps | Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Commercial Mortgage and Commercial Construction
Derivatives, Fair Value
Notional     Amount	4,000	4,000
Derivative assets, fair value, gross assets	0	0
Derivative liabilities, fair value, gross liabilities	25	0
Designated as Hedging Instrument | Cash Flow Hedging | Interest rate floors | Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Commercial and Industrial
Derivatives, Fair Value
Notional     Amount	3,000	3,000
Derivative assets, fair value, gross assets	4	122
Derivative liabilities, fair value, gross liabilities	0	0
Designated as Hedging Instrument | Cash Flow Hedging | Interest rate swap - forward starting | Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Commercial and Industrial
Derivatives, Fair Value
Notional     Amount	11,000
Derivative assets, fair value, gross assets	22
Derivative liabilities, fair value, gross liabilities	0
Designated as Hedging Instrument | Cash Flow Hedging | Interest rate swap - forward starting | Accumulated Net Gain (Loss) from Designated or Qualifying Hedges | Commercial Mortgage and Commercial Construction
Derivatives, Fair Value
Notional     Amount	4,000
Derivative assets, fair value, gross assets	5
Derivative liabilities, fair value, gross liabilities	0
Not Designated as Hedging Instrument
Derivatives, Fair Value
Total derivative assets	3,016	2,386
Total derivative liabilities	3,656	2,010
Not Designated as Hedging Instrument | Risk Management and Other Business Purposes
Derivatives, Fair Value
Derivative assets, fair value, gross assets	85	147
Derivative liabilities, fair value, gross liabilities	220	221
Not Designated as Hedging Instrument | Risk Management and Other Business Purposes | Interest rate contracts related to MSR portfolio
Derivatives, Fair Value
Notional     Amount	2,975	6,260
Derivative assets, fair value, gross assets	62	140
Derivative liabilities, fair value, gross liabilities	17	0
Not Designated as Hedging Instrument | Risk Management and Other Business Purposes | Forward contracts related to residential mortgage loans held for sale | Loans held for sale
Derivatives, Fair Value
Notional     Amount	1,869	1,952
Derivative assets, fair value, gross assets	9	2
Derivative liabilities, fair value, gross liabilities	7	2
Not Designated as Hedging Instrument | Risk Management and Other Business Purposes | Swap
Derivatives, Fair Value
Notional     Amount	3,358	3,545
Derivative assets, fair value, gross assets	0	0
Derivative liabilities, fair value, gross liabilities	195	214
Not Designated as Hedging Instrument | Risk Management and Other Business Purposes | Foreign exchange contracts
Derivatives, Fair Value
Notional     Amount	156	158
Derivative assets, fair value, gross assets	1	0
Derivative liabilities, fair value, gross liabilities	0	1
Not Designated as Hedging Instrument | Risk Management and Other Business Purposes | Interest-only strips
Derivatives, Fair Value
Notional     Amount	58
Derivative assets, fair value, gross assets	4
Derivative liabilities, fair value, gross liabilities	0
Not Designated as Hedging Instrument | Risk Management and Other Business Purposes | Interest rate contracts for collateral management
Derivatives, Fair Value
Notional     Amount	12,000	12,000
Derivative assets, fair value, gross assets	9	5
Derivative liabilities, fair value, gross liabilities	1	4
Not Designated as Hedging Instrument | Risk Management and Other Business Purposes | Interest rate contracts for LIBOR transition
Derivatives, Fair Value
Notional     Amount	597	2,372
Derivative assets, fair value, gross assets	0	0
Derivative liabilities, fair value, gross liabilities	0	0
Not Designated as Hedging Instrument | Customer Accommodation
Derivatives, Fair Value
Total derivative assets	2,931	2,239
Total derivative liabilities	3,436	1,789
Not Designated as Hedging Instrument | Customer Accommodation | Foreign exchange contracts
Derivatives, Fair Value
Notional     Amount	25,322	23,148
Derivative assets, fair value, gross assets	453	323
Derivative liabilities, fair value, gross liabilities	422	297
Not Designated as Hedging Instrument | Customer Accommodation | Interest rate contracts
Derivatives, Fair Value
Notional     Amount	83,605	76,061
Derivative assets, fair value, gross assets	998	578
Derivative liabilities, fair value, gross liabilities	1,663	232
Amount of variation margin payment applied to derivative asset contracts	694	104
Amount of variation margin payment applied to derivative liability contracts	37	472
Not Designated as Hedging Instrument | Customer Accommodation | Interest rate lock commitments
Derivatives, Fair Value
Notional     Amount	216	673
Derivative assets, not subject to master netting arrangement	2	12
Derivative liabilities, not subject to master netting arrangement	1	0
Not Designated as Hedging Instrument | Customer Accommodation | Commodity contracts
Derivatives, Fair Value
Notional     Amount	16,122	12,376
Derivative assets, fair value, gross assets	1,478	1,326
Derivative liabilities, fair value, gross liabilities	1,350	1,260
Not Designated as Hedging Instrument | Customer Accommodation | TBA securities
Derivatives, Fair Value
Notional     Amount	62	55
Derivative assets, fair value, gross assets	0	0
Derivative liabilities, fair value, gross liabilities	$ 0	$ 0