Fair Value Option - Structured Note Products by Balance Sheet Classification and Risk Component (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	$ 103,918	$ 80,724
Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	52,784	36,571
Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	5,487	5,004
Foreign exchange
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	3,702	3,364
Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	40,152	34,172
Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	1,793	1,613
Long-term debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	65,903	53,069
Long-term debt | Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	31,670	24,137
Long-term debt | Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	4,848	4,009
Long-term debt | Foreign exchange
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	3,580	3,169
Long-term debt | Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	25,338	21,382
Long-term debt | Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	467	372
Short-term borrowings
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	7,332	6,670
Short-term borrowings | Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	66	62
Short-term borrowings | Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	639	995
Short-term borrowings | Foreign exchange
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	85	157
Short-term borrowings | Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	6,536	5,422
Short-term borrowings | Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	6	34
Deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	30,683	20,985
Deposits | Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	21,048	12,372
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	37	38
Deposits | Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	8,278	7,368
Deposits | Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total structured notes	$ 1,320	$ 1,207