Derivatives, Notional or Contractual Amounts and Fair Values of Derivatives (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Notional Or Contractual Amounts And Fair Values For Derivatives [Abstract]
Fair value derivative assets, gross	$ 73,154	$ 73,371
Fair value derivative assets, netting	(55,433)	(55,148)
Derivative assets	17,721	18,223
Fair value of derivative liabilities, gross	76,005	80,639
Fair value derivative liabilities, netting	(64,615)	(62,144)
Derivative liabilities	11,390	18,495
Designated as hedging instrument [Member]
Notional Or Contractual Amounts And Fair Values For Derivatives [Abstract]
Fair value derivative assets, gross	729	723
Fair value of derivative liabilities, gross	937	977
Designated as hedging instrument [Member] | Interest rate contracts [Member]
Notional Or Contractual Amounts And Fair Values For Derivatives [Abstract]
Notional or contractual amount	342,859	357,096
Fair value derivative assets, gross	699	639
Fair value of derivative liabilities, gross	640	570
Designated as hedging instrument [Member] | Commodity contracts [Member]
Notional Or Contractual Amounts And Fair Values For Derivatives [Abstract]
Notional or contractual amount	3,722	2,600
Fair value derivative assets, gross	9	24
Fair value of derivative liabilities, gross	12	12
Designated as hedging instrument [Member] | Foreign exchange contracts [Member]
Notional Or Contractual Amounts And Fair Values For Derivatives [Abstract]
Notional or contractual amount	3,455	4,193
Fair value derivative assets, gross	21	60
Fair value of derivative liabilities, gross	285	395
Not designated as hedging instrument [Member]
Notional Or Contractual Amounts And Fair Values For Derivatives [Abstract]
Fair value derivative assets, gross	72,425	72,648
Fair value of derivative liabilities, gross	75,068	79,662
Not designated as hedging instrument [Member] | Interest rate contracts [Member]
Notional Or Contractual Amounts And Fair Values For Derivatives [Abstract]
Notional or contractual amount	10,075,086	10,409,720
Fair value derivative assets, gross	25,722	31,806
Fair value of derivative liabilities, gross	27,040	36,312
Not designated as hedging instrument [Member] | Commodity contracts [Member]
Notional Or Contractual Amounts And Fair Values For Derivatives [Abstract]
Notional or contractual amount	91,151	88,491
Fair value derivative assets, gross	2,439	2,717
Fair value of derivative liabilities, gross	2,311	2,734
Not designated as hedging instrument [Member] | Equity contracts [Member]
Notional Or Contractual Amounts And Fair Values For Derivatives [Abstract]
Notional or contractual amount	462,077	438,458
Fair value derivative assets, gross	16,535	13,305
Fair value of derivative liabilities, gross	16,476	13,810
Not designated as hedging instrument [Member] | Foreign exchange contracts [Member]
Notional Or Contractual Amounts And Fair Values For Derivatives [Abstract]
Notional or contractual amount	3,504,791	2,273,383
Fair value derivative assets, gross	27,636	24,707
Fair value of derivative liabilities, gross	29,195	26,762
Not designated as hedging instrument [Member] | Credit contracts [Member]
Notional Or Contractual Amounts And Fair Values For Derivatives [Abstract]
Notional or contractual amount	47,613	60,439
Fair value derivative assets, gross	93	113
Fair value of derivative liabilities, gross	$ 46	$ 44