Derivative Instruments - Customer-Related Derivative Positions (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Derivative [Line Items]
Notional Value	$ 1,300,000
Asset and Liability Management Positions
Derivative [Line Items]
Notional Value	111,371	$ 91,328
Fair Value, Assets	378	312
Fair Value, Liabilities	208	241
Customer-Related Positions
Derivative [Line Items]
Notional Value	1,182,451	1,119,842
Fair Value, Assets	5,988	6,219
Fair Value, Liabilities	6,396	8,068
Customer-Related Positions | Interest rate contracts | Receive fixed/pay floating swaps
Derivative [Line Items]
Notional Value	406,992	363,375
Fair Value, Assets	1,664	791
Fair Value, Liabilities	2,968	4,395
Customer-Related Positions | Interest rate contracts | Pay fixed/receive floating swaps
Derivative [Line Items]
Notional Value	372,912	330,539
Fair Value, Assets	1,287	1,817
Fair Value, Liabilities	526	280
Customer-Related Positions | Interest rate contracts | Other
Derivative [Line Items]
Notional Value	75,406	82,209
Fair Value, Assets	17	17
Fair Value, Liabilities	51	51
Customer-Related Positions | Interest rate contracts | Options | Buy/ Purchased
Derivative [Line Items]
Notional Value	94,273	102,423
Fair Value, Assets	490	1,026
Fair Value, Liabilities	15	18
Customer-Related Positions | Interest rate contracts | Options | Sell/ Written
Derivative [Line Items]
Notional Value	88,602	97,690
Fair Value, Assets	28	20
Fair Value, Liabilities	579	1,087
Customer-Related Positions | Foreign exchange rate contracts | Forwards, spots and swaps
Derivative [Line Items]
Notional Value	116,108	121,119
Fair Value, Assets	2,006	2,252
Fair Value, Liabilities	1,771	1,942
Customer-Related Positions | Foreign exchange options | Buy/ Purchased
Derivative [Line Items]
Notional Value	608	1,532
Fair Value, Assets	15	28
Fair Value, Liabilities	0	0
Customer-Related Positions | Foreign exchange options | Sell/ Written
Derivative [Line Items]
Notional Value	608	1,532
Fair Value, Assets	0	0
Fair Value, Liabilities	15	28
Customer-Related Positions | Commodity contracts | Swaps
Derivative [Line Items]
Notional Value	6,608	2,498
Fair Value, Assets	236	116
Fair Value, Liabilities	234	110
Customer-Related Positions | Commodity contracts | Futures | Sell/ Written
Derivative [Line Items]
Notional Value	152	0
Fair Value, Assets	25	0
Fair Value, Liabilities	16	0
Customer-Related Positions | Commodity options | Buy/ Purchased
Derivative [Line Items]
Notional Value	3,454	1,936
Fair Value, Assets	218	151
Fair Value, Liabilities	1	0
Customer-Related Positions | Commodity options | Sell/ Written
Derivative [Line Items]
Notional Value	3,453	1,936
Fair Value, Assets	1	0
Fair Value, Liabilities	216	151
Customer-Related Positions | Credit contracts
Derivative [Line Items]
Notional Value	13,258	13,053
Fair Value, Assets	1	1
Fair Value, Liabilities	4	6
Other economic hedges | Interest rate contracts | Receive fixed/pay floating swaps | Asset and Liability Management Positions
Derivative [Line Items]
Notional Value	11,532	7,029
Fair Value, Assets	162	9
Fair Value, Liabilities	1	3
Other economic hedges | Interest rate contracts | Pay fixed/receive floating swaps | Asset and Liability Management Positions
Derivative [Line Items]
Notional Value	2,792	3,801
Fair Value, Assets	0	0
Fair Value, Liabilities	0	0
Other economic hedges | Interest rate contracts | Options | Buy/ Purchased | Asset and Liability Management Positions
Derivative [Line Items]
Notional Value	6,560	6,085
Fair Value, Assets	163	237
Fair Value, Liabilities	0	0
Other economic hedges | Interest rate contracts | Options | Sell/ Written | Asset and Liability Management Positions
Derivative [Line Items]
Notional Value	2,494	3,696
Fair Value, Assets	21	14
Fair Value, Liabilities	40	75
Other economic hedges | Credit contracts | Asset and Liability Management Positions
Derivative [Line Items]
Notional Value	3,558	2,620
Fair Value, Assets	0	1
Fair Value, Liabilities	27	0
Other economic hedges | Equity contracts
Derivative [Line Items]
Notional Value	17	0
Fair Value, Assets	0	0
Fair Value, Liabilities	0	0
Other economic hedges | Equity contracts | Asset and Liability Management Positions
Derivative [Line Items]
Notional Value	282	227
Fair Value, Assets	5	2
Fair Value, Liabilities	$ 0	$ 0