Fair Value Option - Structured Note Products by Balance Sheet Classification and Risk Component (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	$ 95,960	$ 93,739
Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	40,977	43,251
Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	8,122	7,431
Foreign exchange
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	4,114	3,705
Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	42,515	38,857
Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	232	495
Long-term debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	74,433	75,344
Long-term debt | Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	35,665	38,129
Long-term debt | Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	6,492	6,409
Long-term debt | Foreign exchange
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	3,357	3,613
Long-term debt | Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	28,719	26,943
Long-term debt | Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	200	250
Short-term borrowings
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	9,697	6,213
Short-term borrowings | Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	115	65
Short-term borrowings | Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	1,630	1,022
Short-term borrowings | Foreign exchange
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	526	92
Short-term borrowings | Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	7,414	5,021
Short-term borrowings | Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	12	13
Deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	11,830	12,182
Deposits | Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	5,197	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	231	0
Deposits | Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	6,382	6,893
Deposits | Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	20	232
Excluded amount of deposits linked to precious metals for which fair value option was not elected	$ 717	$ 739