Offsetting Arrangements (Assets With Enforceable Netting Arrangements) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Offsetting [Abstract]
Derivative, Net Amount of Assets Presented in Statement of Condition	$ 4,320		$ 4,556
Derivatives, Counterparty Netting	0	[1]	0	[1]
Derivatives, Collateral Received	(95)	[1]	(105)	[1]
Derivatives, Net Amount	4,225	[2]	4,451	[2]
Resale Agreements and Securities Borrowing, Resale Agreements and Securities Borrowing, Net Amount of Assets Presented in Statement of Condition	15,589	[3]	11,849	[3]
Resale Agreements and Securities Borrowing, Counterparty Netting	(144)	[1]	(126)	[1]
Resale Agreements and Securities Borrowing, Collateral Received	(15,360)	[1]	(11,626)	[1]
Resale Agreements and Securities Borrowing, Net Amount	85	[2]	97	[2]
Total, Net Amounts of Assets Presented in Statement of Condition	19,909		16,405
Total, Counterparty Netting	(144)	[1]	(126)	[1]
Total, Collateral Received	(15,455)	[1]	(11,731)	[1]
Total, Net Amount	$ 4,310	[2]	$ 4,548	[2]

[1] Amounts subject to netting arrangements which have been determined to be legally enforceable

[2] Includes amounts secured by collateral not determined to be subject to enforceable netting arrangements.

[3] Included in the $15,589 million as of September 30, 2013 was $5,827 million of resale agreements and $9,762 million of collateral related to securities borrowing. Included in the $11,849 million as of December 31, 2012 was $5,016 million of resale agreements and $6,833 million of collateral related to securities borrowing. Resale agreements and collateral related to securities borrowing were recorded in securities purchased under resale agreements and other assets, respectively, in our consolidated statement of condition. Refer to note 8 for additional information with respect to principal securities finance transactions.