Activity in the Allowance for Credit Losses (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2013	Dec. 31, 2012
Components:
Balance at beginning of period	$ 2,094		$ 2,219
Provision for loan losses	106		204
Provision(Benefit) for unfunded commitments	(4)		8
Loan charge-offs	(151)		(273)
Loan recoveries	41		47
Balance at end of period	2,086		2,205
Loans and Leases Receivable, Allowance	2,040		2,152		2,044	2,174
Unfunded commitments reserve	46	[1]	53	[1]
Allowance for credit losses	$ 2,086		$ 2,205

[1] The unfunded commitments reserve is recorded in other liabilities in the Consolidated Balance Sheets.