Guarantee Arrangements and Pledged Assets and Collateral - Carrying Value and Contractual Amounts of our Sell Protection Credit Derivatives and Major Off-Balance Sheet Guarantee Arrangements (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Credit derivatives [Member]
Guarantor Obligations [Line Items]
Guarantee Arrangement for the benefit of Affiliates	$ 36,188	$ 34,856
Financial standby letters of credit, net of participations [Member]
Guarantor Obligations [Line Items]
Guarantee Arrangement for the benefit of Affiliates	$ 890	$ 865