Financial Derivatives (Total Gross Derivatives) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Derivative [Line Items]
Derivative, notional amount	$ 656,051	$ 581,268
Derivative asset, fair value	3,429	3,768
Derivative liability, fair value	5,899	7,618
Derivative asset, fair value offset amount	1,406	1,523
Derivative liability, fair value offset amount	1,406	1,523
Derivative asset, cash collateral	1,126	714
Derivative liability, cash collateral	955	1,571
Derivative Asset, Net	897	1,531
Derivative Liability, Net	3,538	4,524
Commodity contracts:
Derivative [Line Items]
Derivative asset, fair value	765	1,208
Derivative liability, fair value	757	1,269
Derivative asset, cash collateral	283	2
Derivative liability, cash collateral		520
Derivative Asset, Net	166	871
Derivative Liability, Net	425	70
Foreign exchange contracts and other
Derivative [Line Items]
Derivative asset, fair value	307	437
Derivative liability, fair value	494	520
Derivative asset, cash collateral	76	82
Derivative liability, cash collateral	13	10
Derivative Asset, Net	117	141
Derivative Liability, Net	292	291
Designated as Hedging Instrument
Derivative [Line Items]
Derivative, notional amount	91,555	65,661
Derivative asset, fair value	327	24
Derivative liability, fair value	139	1
Designated as Hedging Instrument | Fair Value Hedging | Interest rate contracts:
Derivative [Line Items]
Derivative, notional amount	32,079	24,231
Designated as Hedging Instrument | Cash Flow Hedging | Interest Rate Swap
Derivative [Line Items]
Derivative, notional amount	33,302	40,310
Derivative asset, fair value
Derivative liability, fair value		1
Designated as Hedging Instrument | Cash Flow Hedging | Interest Rate Floor And Cap
Derivative [Line Items]
Derivative, notional amount	25,000
Derivative asset, fair value	327
Derivative liability, fair value	137
Designated as Hedging Instrument | Net Investment Hedging | Foreign exchange contracts:
Derivative [Line Items]
Derivative, notional amount	1,174	1,120
Derivative asset, fair value		24
Derivative liability, fair value	2
Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative, notional amount	564,496	515,607
Derivative asset, fair value	3,102	3,744
Derivative liability, fair value	5,760	7,617
Not Designated as Hedging Instrument | Mortgage Banking | Interest rate contracts:
Derivative [Line Items]
Derivative, notional amount	72,457	75,978
Derivative asset, fair value	112	182
Derivative liability, fair value	89	104
Not Designated as Hedging Instrument | Mortgage Banking | Swap | Interest rate contracts:
Derivative [Line Items]
Derivative, notional amount	43,450	47,908
Derivative asset, fair value		7
Derivative liability, fair value		1
Not Designated as Hedging Instrument | Mortgage Banking | Future | Interest rate contracts:
Derivative [Line Items]
Derivative, notional amount	10,370	5,537
Not Designated as Hedging Instrument | Mortgage Banking | Mortgage-backed commitments | Interest rate contracts:
Derivative [Line Items]
Derivative, notional amount	3,093	4,516
Derivative asset, fair value	66	85
Derivative liability, fair value	67	89
Not Designated as Hedging Instrument | Mortgage Banking | Other Contract | Interest rate contracts:
Derivative [Line Items]
Derivative, notional amount	15,544	18,017
Derivative asset, fair value	46	90
Derivative liability, fair value	22	14
Not Designated as Hedging Instrument | Customer-related Contracts
Derivative [Line Items]
Derivative, notional amount	477,157	426,844
Derivative asset, fair value	2,978	3,515
Derivative liability, fair value	5,418	7,286
Not Designated as Hedging Instrument | Customer-related Contracts | Interest rate contracts:
Derivative [Line Items]
Derivative, notional amount	432,761	386,052
Derivative asset, fair value	1,918	1,941
Derivative liability, fair value	4,422	5,724
Not Designated as Hedging Instrument | Customer-related Contracts | Commodity contracts:
Derivative [Line Items]
Derivative, notional amount	11,511	10,280
Derivative asset, fair value	765	1,208
Derivative liability, fair value	757	1,269
Not Designated as Hedging Instrument | Customer-related Contracts | Foreign exchange contracts and other
Derivative [Line Items]
Derivative, notional amount	32,885	30,512
Derivative asset, fair value	295	366
Derivative liability, fair value	239	293
Not Designated as Hedging Instrument | Customer-related Contracts | Swap | Interest rate contracts:
Derivative [Line Items]
Derivative, notional amount	401,607	354,150
Derivative asset, fair value	1,723	1,597
Derivative liability, fair value	4,228	5,397
Not Designated as Hedging Instrument | Customer-related Contracts | Swap | Commodity contracts:
Derivative [Line Items]
Derivative, notional amount	6,714	5,792
Derivative asset, fair value	577	1,003
Derivative liability, fair value	569	1,067
Not Designated as Hedging Instrument | Customer-related Contracts | Future | Interest rate contracts:
Derivative [Line Items]
Derivative, notional amount	73	32
Not Designated as Hedging Instrument | Customer-related Contracts | Mortgage-backed commitments | Interest rate contracts:
Derivative [Line Items]
Derivative, notional amount	2,592	2,799
Derivative asset, fair value	9	10
Derivative liability, fair value	25	6
Not Designated as Hedging Instrument | Customer-related Contracts | Other Contract | Interest rate contracts:
Derivative [Line Items]
Derivative, notional amount	28,489	29,071
Derivative asset, fair value	186	334
Derivative liability, fair value	169	321
Not Designated as Hedging Instrument | Customer-related Contracts | Other Contract | Commodity contracts:
Derivative [Line Items]
Derivative, notional amount	4,797	4,488
Derivative asset, fair value	188	205
Derivative liability, fair value	188	202
Not Designated as Hedging Instrument | Other Risk Management Activity | Foreign exchange contracts and other
Derivative [Line Items]
Derivative, notional amount	14,882	12,785
Derivative asset, fair value	12	47
Derivative liability, fair value	$ 253	$ 227