Derivative Instruments - Impact on Statements of Income, Fair Value Hedges (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Gains/(losses) recorded in income
Derivatives	$ 222	$ 7,403
Hedged items	45	(7,015)
Total income statement impact	267	388
Income statement impact due to:
Hedge ineffectiveness	26	11
Excluded components	241	377
Interest rate
Gains/(losses) recorded in income
Derivatives	1,378	606
Hedged items	(1,199)	(248)
Total income statement impact	179	358
Income statement impact due to:
Hedge ineffectiveness	28	17
Excluded components	151	341
Foreign exchange
Gains/(losses) recorded in income
Derivatives	(1,298)	6,475
Hedged items	1,382	(6,459)
Total income statement impact	84	16
Income statement impact due to:
Hedge ineffectiveness	0	0
Excluded components	84	16
Commodity
Gains/(losses) recorded in income
Derivatives	142	322
Hedged items	(138)	(308)
Total income statement impact	4	14
Income statement impact due to:
Hedge ineffectiveness	(2)	(6)
Excluded components	$ 6	$ 20