Fair Value Option - Structured note products by balance sheet classification and risk component (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	$ 53,374	$ 51,928
Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	17,025	15,929
Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	4,154	3,742
Foreign exchange
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	2,797	1,853
Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	26,941	27,733
Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	2,457	2,671
Long-term debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	35,020	32,424
Long-term debt | Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	14,225	12,531
Long-term debt | Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	3,421	3,195
Long-term debt | Foreign exchange
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	2,457	1,765
Long-term debt | Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	14,277	14,293
Long-term debt | Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	640	640
Other borrowed funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	8,721	9,179
Other borrowed funds | Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	118	58
Other borrowed funds | Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	733	547
Other borrowed funds | Foreign exchange
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	329	77
Other borrowed funds | Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	7,503	8,447
Other borrowed funds | Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	38	50
Deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	9,633	10,325
Deposits | Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	2,682	3,340
Deposits | Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	0	0
Deposits | Foreign exchange
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	11	11
Deposits | Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	5,161	4,993
Deposits | Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	$ 1,779	$ 1,981