Derivative Instruments - Impact on Statements of Income, Fair Value Hedges (Details 2a) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Fair value hedge gains (losses) recorded in income
Derivatives	$ 4,005,000,000	$ (5,692,000,000)
Hedged items	(3,602,000,000)	5,284,000,000
Total income statement impact	403,000,000	(408,000,000)
Hedge ineffectiveness	(58,000,000)	55,000,000
Excluded components	461,000,000	(463,000,000)
Interest rate contract
Fair value hedge gains (losses) recorded in income
Derivatives	(499,000,000)	(556,000,000)
Hedged items	875,000,000	640,000,000
Total income statement impact	376,000,000	84,000,000
Hedge ineffectiveness	(40,000,000)	28,000,000
Excluded components	416,000,000	56,000,000
Foreign exchange
Fair value hedge gains (losses) recorded in income
Derivatives	3,753,000,000	(2,960,000,000)
Hedged items	(3,752,000,000)	2,950,000,000
Total income statement impact	1,000,000	(10,000,000)
Hedge ineffectiveness	0	0
Excluded components	1,000,000	(10,000,000)
Included revenue related to certain foreign exchange trading derivatives	4,000,000,000	(2,800,000,000)
Commodity
Fair value hedge gains (losses) recorded in income
Derivatives	751,000,000	(2,176,000,000)
Hedged items	(725,000,000)	1,694,000,000
Total income statement impact	26,000,000	(482,000,000)
Hedge ineffectiveness	(18,000,000)	27,000,000
Excluded components	$ 44,000,000	$ (509,000,000)