Financial Derivatives (Total Derivatives) (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Derivative [Line Items]
Derivative, notional amount	$ 663,086	$ 656,051
Derivative asset, fair value	3,332	3,429
Derivative liability, fair value	6,365	5,899
Derivative asset, fair value offset amount	1,248	1,406
Derivative liability, fair value offset amount	1,248	1,406
Derivative asset, cash collateral	1,341	1,126
Derivative liability, cash collateral	1,195	955
Derivative Asset, Net	743	897
Derivative liability, net	3,922	3,538
Commodity contracts:
Derivative [Line Items]
Derivative asset, fair value	724	765
Derivative liability, fair value	702	757
Derivative asset, cash collateral	247	283
Derivative liability, cash collateral
Derivative Asset, Net	191	166
Derivative liability, net	343	425
Foreign exchange contracts and other
Derivative [Line Items]
Derivative asset, fair value	316	307
Derivative liability, fair value	329	494
Derivative asset, cash collateral	131	76
Derivative liability, cash collateral		13
Derivative Asset, Net	87	117
Derivative liability, net	226	292
Designated as Hedging Instruments under GAAP
Derivative [Line Items]
Derivative, notional amount	97,531	91,555
Derivative asset, fair value	258	327
Derivative liability, fair value	195	139
Designated as Hedging Instruments under GAAP | Fair value hedges | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	34,824	32,079
Designated as Hedging Instruments under GAAP | Cash flow hedges | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	36,499	33,302
Derivative liability, fair value
Designated as Hedging Instruments under GAAP | Cash flow hedges | Other | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	25,000	25,000
Derivative asset, fair value	250	327
Derivative liability, fair value	195	137
Designated as Hedging Instruments under GAAP | Net investment hedges | Foreign exchange contracts:
Derivative [Line Items]
Derivative, notional amount	1,208	1,174
Derivative asset, fair value	8
Derivative liability, fair value		2
Not Designated as Hedging Instrument under GAAP
Derivative [Line Items]
Derivative, notional amount	565,555	564,496
Derivative asset, fair value	3,074	3,102
Derivative liability, fair value	6,170	5,760
Not Designated as Hedging Instrument under GAAP | Mortgage Banking | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	74,935	72,457
Derivative asset, fair value	81	112
Derivative liability, fair value	65	89
Not Designated as Hedging Instrument under GAAP | Mortgage Banking | Swaps | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	43,746	43,450
Derivative asset, fair value
Derivative liability, fair value
Not Designated as Hedging Instrument under GAAP | Mortgage Banking | Futures | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	9,959	10,370
Not Designated as Hedging Instrument under GAAP | Mortgage Banking | Mortgage-backed commitments | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	4,493	3,093
Derivative asset, fair value	59	66
Derivative liability, fair value	53	67
Not Designated as Hedging Instrument under GAAP | Mortgage Banking | Other | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	16,737	15,544
Derivative asset, fair value	22	46
Derivative liability, fair value	12	22
Not Designated as Hedging Instrument under GAAP | Customer Contracts
Derivative [Line Items]
Derivative, notional amount	475,263	477,157
Derivative asset, fair value	2,939	2,978
Derivative liability, fair value	5,990	5,418
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	431,286	432,761
Derivative asset, fair value	1,961	1,918
Derivative liability, fair value	5,074	4,422
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Commodity contracts:
Derivative [Line Items]
Derivative, notional amount	11,670	11,511
Derivative asset, fair value	724	765
Derivative liability, fair value	702	757
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Foreign exchange contracts and other
Derivative [Line Items]
Derivative, notional amount	32,307	32,885
Derivative asset, fair value	254	295
Derivative liability, fair value	214	239
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Swaps | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	401,246	401,607
Derivative asset, fair value	1,765	1,723
Derivative liability, fair value	4,929	4,228
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Swaps | Commodity contracts:
Derivative [Line Items]
Derivative, notional amount	6,592	6,714
Derivative asset, fair value	565	577
Derivative liability, fair value	544	569
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Futures | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	166	73
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Mortgage-backed commitments | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	4,020	2,592
Derivative asset, fair value	5	9
Derivative liability, fair value	6	25
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Other | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	25,854	28,489
Derivative asset, fair value	191	186
Derivative liability, fair value	139	169
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Other | Commodity contracts:
Derivative [Line Items]
Derivative, notional amount	5,078	4,797
Derivative asset, fair value	159	188
Derivative liability, fair value	158	188
Not Designated as Hedging Instrument under GAAP | Other Risk Management Activity | Foreign exchange contracts and other
Derivative [Line Items]
Derivative, notional amount	15,357	14,882
Derivative asset, fair value	54	12
Derivative liability, fair value	$ 115	$ 253