Securities Financing Activities - Summarized Securities Financing Agreements (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Securities Financing Transaction [Line Items]
Reverse repurchase agreements	$ 10	$ 3	$ 5
Securities borrowed			1
Total offsetting of financial assets	10	3	6
Repurchase agreements
Total offsetting of financial liabilities
Gross Amount Presented in Balance Sheet [Member]
Securities Financing Transaction [Line Items]
Reverse repurchase agreements	442	347	311
Securities borrowed	3	12	35
Total offsetting of financial assets	445	359	346
Repurchase agreements	568	517	494
Total offsetting of financial liabilities	568	517	494
Netting Adjustments [Member]
Securities Financing Transaction [Line Items]
Reverse repurchase agreements	(306)	(278)	(195)
Securities borrowed
Total offsetting of financial assets	(306)	(278)	(195)
Repurchase agreements	(306)	(278)	(195)
Total offsetting of financial liabilities	(306)	(278)	(195)
Netting Adjustment [Member]
Securities Financing Transaction [Line Items]
Reverse repurchase agreements	(126)	(66)	(111)
Securities borrowed	(3)	(12)	(34)
Total offsetting of financial assets	(129)	(78)	(145)
Repurchase agreements	(262)	(239)	(299)
Total offsetting of financial liabilities	$ (262)	$ (239)	$ (299)

The carrying value as of the balance sheet date of securities borrowed from broker-dealers or institutions (a) to deliver them in place of securities not available because of short-sales or late or ineffective deliveries; (b) to lend them in connection with finder or conduit transactions; and (c) to be used for other purposes permitted under federal regulations.

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The carrying value as of the balance sheet date of securities that an institution sells and agrees to repurchase (the identical or substantially the same securities) as a seller-borrower at a specified date for a specified price, also known as a repurchase agreement, or repo. Most repos involve obligations of the federal government or its agencies, but other financial instruments, such as commercial paper, banker's acceptances, and negotiable certificates of deposit, are sometimes used in repos.

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