Fair Value Option - Structured Note Products by Balance Sheet Classification and Risk Component (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	$ 94,324	$ 93,739
Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	41,284	43,251
Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	8,281	7,431
Foreign exchange
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	4,113	3,705
Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	40,319	38,857
Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	327	495
Long-term debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	74,879	75,344
Long-term debt | Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	35,571	38,129
Long-term debt | Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	6,843	6,409
Long-term debt | Foreign exchange
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	3,648	3,613
Long-term debt | Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	28,496	26,943
Long-term debt | Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	321	250
Short-term borrowings
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	7,953	6,213
Short-term borrowings | Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	13	65
Short-term borrowings | Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	1,438	1,022
Short-term borrowings | Foreign exchange
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	244	92
Short-term borrowings | Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	6,258	5,021
Short-term borrowings | Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	0	13
Deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	11,492	12,182
Deposits | Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	5,700	5,057
Deposits | Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	0	0
Deposits | Foreign exchange
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	221	0
Deposits | Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	5,565	6,893
Deposits | Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	6	232
Excluded amount of deposits linked to precious metals for which fair value option was not elected	$ 676	$ 739