Offsetting Arrangements - Liabilities With Offsetting Arrangements (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	$ 17,397	$ 15,234
Gross Amounts Offset in Statement of Condition	(10,407)	(8,926)
Net Amounts of Liabilities Presented in Statement of Condition	6,990	6,308
Derivative Collateral, Cash Offset	(2,661)	(2,630)
Total Net Derivative Liability	6,990	6,308
Gross Amounts of Recognized Liabilities	48,718	44,562
Gross Amounts Offset in Statement of Condition	(31,407)	(29,157)
Net Amounts of Liabilities Presented in Statement of Condition	17,311	15,405
Gross Amounts of Recognized Liabilities	66,115	59,796
Gross Amounts Offset in Statement of Condition	(41,814)	(38,083)
Total, Net Amount of Liabilities Presented in Statement of Condition	24,301	21,713
Securities sold under repurchase agreements	10,158	8,925
Securities Lending, Fair Value, Amount Not Offset Against Collateral	7,153	6,480
Foreign exchange contracts
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	17,053	14,925
Gross Amounts Offset in Statement of Condition	(7,730)	(6,275)
Net Amounts of Liabilities Presented in Statement of Condition	9,323	8,650
Interest-rate contracts
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	232	239
Gross Amounts Offset in Statement of Condition	(14)	(20)
Net Amounts of Liabilities Presented in Statement of Condition	218	219
Other derivative contracts
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	112	70
Gross Amounts Offset in Statement of Condition	(2)	(1)
Net Amounts of Liabilities Presented in Statement of Condition	$ 110	$ 69