Financial Derivatives (Total Derivatives) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Derivative [Line Items]
Derivative, notional amount	$ 677,174	$ 581,268
Derivative asset, fair value	3,838	3,768
Derivative liability, fair value	8,220	7,618
Derivative asset, fair value offset amount	1,396	1,523
Derivative liability, fair value offset amount	1,396	1,523
Derivative asset, cash collateral	1,593	714
Derivative liability, cash collateral	1,599	1,571
Derivative Asset, Net	849	1,531
Derivative liability, net	5,225	4,524
Commodity contracts:
Derivative [Line Items]
Derivative asset, fair value	548	1,208
Derivative liability, fair value	577	1,269
Derivative asset, cash collateral	71	2
Derivative liability, cash collateral	31	520
Derivative Asset, Net	227	871
Derivative liability, net	87	70
Foreign exchange contracts and other
Derivative [Line Items]
Derivative asset, fair value	451	437
Derivative liability, fair value	387	520
Derivative asset, cash collateral	204	82
Derivative liability, cash collateral	1	10
Derivative Asset, Net	115	141
Derivative liability, net	260	291
Mortgage Banking | Overlay Swap | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	400
Customer Contracts | Overlay Swap | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	22,600
Designated as Hedging Instruments under GAAP
Derivative [Line Items]
Derivative, notional amount	90,932	65,661
Derivative asset, fair value	244	24
Derivative liability, fair value	283	1
Designated as Hedging Instruments under GAAP | Fair value hedges | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	29,523	24,231
Designated as Hedging Instruments under GAAP | Cash flow hedges | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	35,241	40,310
Derivative liability, fair value	2	1
Designated as Hedging Instruments under GAAP | Cash flow hedges | Other | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	25,000
Derivative asset, fair value	222
Derivative liability, fair value	281
Designated as Hedging Instruments under GAAP | Net investment hedges | Foreign exchange contracts:
Derivative [Line Items]
Derivative, notional amount	1,168	1,120
Derivative asset, fair value	22	24
Derivative liability, fair value
Not Designated as Hedging Instrument under GAAP
Derivative [Line Items]
Derivative, notional amount	586,242	515,607
Derivative asset, fair value	3,594	3,744
Derivative liability, fair value	7,937	7,617
Not Designated as Hedging Instrument under GAAP | Mortgage Banking | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	75,254	75,978
Derivative asset, fair value	128	182
Derivative liability, fair value	98	104
Not Designated as Hedging Instrument under GAAP | Mortgage Banking | Swaps | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	45,056	47,908
Derivative asset, fair value		7
Derivative liability, fair value	4	1
Not Designated as Hedging Instrument under GAAP | Mortgage Banking | Futures | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	8,860	5,537
Not Designated as Hedging Instrument under GAAP | Mortgage Banking | Mortgage-backed commitments | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	4,750	4,516
Derivative asset, fair value	77	85
Derivative liability, fair value	73	89
Not Designated as Hedging Instrument under GAAP | Mortgage Banking | Other | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	16,588	18,017
Derivative asset, fair value	51	90
Derivative liability, fair value	21	14
Not Designated as Hedging Instrument under GAAP | Customer Contracts
Derivative [Line Items]
Derivative, notional amount	493,561	426,844
Derivative asset, fair value	3,349	3,515
Derivative liability, fair value	7,729	7,286
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	452,751	386,052
Derivative asset, fair value	2,489	1,941
Derivative liability, fair value	6,875	5,724
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Commodity contracts:
Derivative [Line Items]
Derivative, notional amount	9,452	10,280
Derivative asset, fair value	548	1,208
Derivative liability, fair value	577	1,269
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Foreign exchange contracts and other
Derivative [Line Items]
Derivative, notional amount	31,358	30,512
Derivative asset, fair value	312	366
Derivative liability, fair value	277	293
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Swaps | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	420,301	354,150
Derivative asset, fair value	2,170	1,597
Derivative liability, fair value	6,579	5,397
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Swaps | Commodity contracts:
Derivative [Line Items]
Derivative, notional amount	6,558	5,792
Derivative asset, fair value	477	1,003
Derivative liability, fair value	504	1,067
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Futures | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	41	32
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Mortgage-backed commitments | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	3,675	2,799
Derivative asset, fair value	27	10
Derivative liability, fair value	11	6
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Other | Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	28,734	29,071
Derivative asset, fair value	292	334
Derivative liability, fair value	285	321
Not Designated as Hedging Instrument under GAAP | Customer Contracts | Other | Commodity contracts:
Derivative [Line Items]
Derivative, notional amount	2,894	4,488
Derivative asset, fair value	71	205
Derivative liability, fair value	73	202
Not Designated as Hedging Instrument under GAAP | Other Risk Management Activity | Foreign exchange contracts and other
Derivative [Line Items]
Derivative, notional amount	17,427	12,785
Derivative asset, fair value	117	47
Derivative liability, fair value	$ 110	$ 227