Derivative Instruments - Impact on Statements of Income, Fair Value Hedges (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Gains/(losses) recorded in income
Derivatives	$ 1,417	$ 7,221	$ 10,434
Hedged items	(337)	(6,237)	(9,188)
Total income statement impact	1,080	984	1,246
Income statement impact due to:
Hedge ineffectiveness	(3)	(10)	173
Excluded components	1,083	994	1,073
Interest rate
Gains/(losses) recorded in income
Derivatives	(482)	38	2,106
Hedged items	1,338	911	(801)
Total income statement impact	856	949	1,305
Income statement impact due to:
Hedge ineffectiveness	6	3	131
Excluded components	850	946	1,174
Foreign exchange
Gains/(losses) recorded in income
Derivatives	2,435	6,030	8,279
Hedged items	(2,261)	(6,006)	(8,532)
Total income statement impact	174	24	(253)
Income statement impact due to:
Hedge ineffectiveness	0	0	0
Excluded components	174	24	(253)
Commodity
Gains/(losses) recorded in income
Derivatives	(536)	1,153	49
Hedged items	586	(1,142)	145
Total income statement impact	50	11	194
Income statement impact due to:
Hedge ineffectiveness	(9)	(13)	42
Excluded components	$ 59	$ 24	$ 152