Financial Derivatives (Total Derivatives) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Derivative [Line Items]
Derivative, notional amount	$ 687,330	$ 656,051
Derivative asset, fair value	3,120	3,429
Derivative liability, fair value	6,216	5,899
Derivative asset, fair value offset amount	1,321	1,406
Derivative liability, fair value offset amount	1,321	1,406
Derivative asset, cash collateral	1,139	1,126
Derivative liability, cash collateral	1,189	955
Derivative Asset, Net	660	897
Derivative liability, net	3,706	3,538
Commodity contracts:
Derivative [Line Items]
Derivative asset, fair value	610	765
Derivative liability, fair value	586	757
Derivative asset, cash collateral	156	283
Derivative liability, cash collateral
Derivative Asset, Net	130	166
Derivative liability, net	168	425
Foreign exchange contracts and other
Derivative [Line Items]
Derivative asset, fair value	300	307
Derivative liability, fair value	389	494
Derivative asset, cash collateral	113	76
Derivative liability, cash collateral	1	13
Derivative Asset, Net	104	117
Derivative liability, net	287	292
Designated as Hedging Instruments under GAAP
Derivative [Line Items]
Derivative, notional amount	124,659	91,555
Derivative asset, fair value	218	327
Derivative liability, fair value	217	139
Designated as Hedging Instruments under GAAP | Fair value hedges | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	45,627	32,079
Designated as Hedging Instruments under GAAP | Cash flow hedges | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	52,797	33,302
Derivative asset, fair value	2
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	209	327
Derivative liability, fair value	217	137
Designated as Hedging Instruments under GAAP | Net investment hedges | Foreign exchange contracts:
Derivative [Line Items]
Derivative, notional amount	1,235	1,174
Derivative asset, fair value	7
Derivative liability, fair value		2
Not Designated as Hedging Instrument under GAAP
Derivative [Line Items]
Derivative, notional amount	562,671	564,496
Derivative asset, fair value	2,902	3,102
Derivative liability, fair value	5,999	5,760
Not Designated as Hedging Instrument under GAAP | Mortgage Banking | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	75,435	72,457
Derivative asset, fair value	76	112
Derivative liability, fair value	62	89
Not Designated as Hedging Instrument under GAAP | Mortgage Banking | Swaps | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	46,247	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	8,920	10,370
Not Designated as Hedging Instrument under GAAP | Mortgage Banking | Mortgage-backed commitments | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	4,573	3,093
Derivative asset, fair value	58	66
Derivative liability, fair value	51	67
Not Designated as Hedging Instrument under GAAP | Mortgage Banking | Other | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	15,695	15,544
Derivative asset, fair value	18	46
Derivative liability, fair value	11	22
Not Designated as Hedging Instrument under GAAP | Customer Contracts
Derivative [Line Items]
Derivative, notional amount	474,864	477,157
Derivative asset, fair value	2,781	2,978
Derivative liability, fair value	5,744	5,418
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	427,956	432,761
Derivative asset, fair value	1,923	1,918
Derivative liability, fair value	4,962	4,422
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Commodity contracts:
Derivative [Line Items]
Derivative, notional amount	15,628	11,511
Derivative asset, fair value	610	765
Derivative liability, fair value	586	757
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Foreign exchange contracts and other
Derivative [Line Items]
Derivative, notional amount	31,280	32,885
Derivative asset, fair value	248	295
Derivative liability, fair value	196	239
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Swaps | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	395,502	401,607
Derivative asset, fair value	1,733	1,723
Derivative liability, fair value	4,815	4,228
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Swaps | Commodity contracts:
Derivative [Line Items]
Derivative, notional amount	6,498	6,714
Derivative asset, fair value	380	577
Derivative liability, fair value	356	569
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Futures | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	110	73
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Mortgage-backed commitments | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	4,595	2,592
Derivative asset, fair value	5	9
Derivative liability, fair value	9	25
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Other | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	27,749	28,489
Derivative asset, fair value	185	186
Derivative liability, fair value	138	169
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Other | Commodity contracts:
Derivative [Line Items]
Derivative, notional amount	9,130	4,797
Derivative asset, fair value	230	188
Derivative liability, fair value	230	188
Not Designated as Hedging Instrument under GAAP | Other Risk Management Activity | Foreign exchange contracts and other
Derivative [Line Items]
Derivative, notional amount	12,372	14,882
Derivative asset, fair value	45	12
Derivative liability, fair value	$ 193	$ 253