Activity in the Allowance for Credit Losses (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013		Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
Components:
Balance at beginning of period	$ 2,046		$ 2,172		$ 2,094		$ 2,219
Provision for loan losses	93		92		275		448
Provision(Benefit) for unfunded commitments	0		3		(7)		5
Allowance for Loan and Lease Losses, Write-offs	(164)		(189)		(473)		(695)
Loan recoveries	36		43		122		144
Balance at end of period	2,011		2,121		2,011		2,121
Loans and Leases Receivable, Allowance	1,968		2,071		1,968		2,071		2,003	2,044	2,125	2,174
Unfunded commitments reserve	43	[1]	50	[1]	43	[1]	50	[1]
Allowance for credit losses	$ 2,011		$ 2,121		$ 2,011		$ 2,121

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