Fair Value Option - Structured note products by balance sheet classification and risk component (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	$ 51,928	$ 52,829
Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	15,929	13,437
Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	3,742	4,473
Foreign exchange
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	1,853	2,378
Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	27,733	29,175
Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	2,671	3,366
Long-term debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	32,424	30,089
Long-term debt | Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	12,531	10,858
Long-term debt | Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	3,195	4,023
Long-term debt | Foreign exchange
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	1,765	2,150
Long-term debt | Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	14,293	12,348
Long-term debt | Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	640	710
Other borrowed funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	9,179	14,177
Other borrowed funds | Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	58	460
Other borrowed funds | Credit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	547	450
Other borrowed funds | Foreign exchange
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	77	211
Other borrowed funds | Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	8,447	12,412
Other borrowed funds | Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	50	644
Deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	10,325	8,563
Deposits | Interest rate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	3,340	2,119
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	17
Deposits | Equity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	4,993	4,415
Deposits | Commodity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Structured notes balance	$ 1,981	$ 2,012