Derivative Instruments - Impact on Statements of Income, Cash Flow Hedges (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Gains/(losses) recorded in income and other comprehensive income/(loss)
Planned reduction of non-operating deposits by the end of 2015 announced in February, 2015	$ 100,000,000,000
Net losses reclassified from AOCI to other income	150,000,000
Recognition of gain (loss) related to cash flow hedges in Income	(4,000,000)
Maximum length of time hedged in forecasted transactions	9 years
Cash Flow Hedging
Gains/(losses) recorded in income and other comprehensive income/(loss)
Derivatives - effective portion reclassified from AOCI to income	(175,000,000)	(27,000,000)
Hedge ineffectiveness recorded directly in income	0	0
Total income statement impact	(175,000,000)	(27,000,000)
Effective portion recorded in OCI	(49,000,000)	72,000,000
Total change in OCI for period	126,000,000	99,000,000
Cash Flow Hedging | Interest rate contracts
Gains/(losses) recorded in income and other comprehensive income/(loss)
Derivatives - effective portion reclassified from AOCI to income	(149,000,000)	(26,000,000)
Hedge ineffectiveness recorded directly in income	0	0
Total income statement impact	(149,000,000)	(26,000,000)
Effective portion recorded in OCI	3,000,000	63,000,000
Total change in OCI for period	152,000,000	89,000,000
Cash Flow Hedging | Foreign exchange contracts
Gains/(losses) recorded in income and other comprehensive income/(loss)
Derivatives - effective portion reclassified from AOCI to income	(26,000,000)	(1,000,000)
Hedge ineffectiveness recorded directly in income	0	0
Total income statement impact	(26,000,000)	(1,000,000)
Effective portion recorded in OCI	(52,000,000)	9,000,000
Total change in OCI for period	$ (26,000,000)	$ 10,000,000