Investment in Lease Financing (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accumulated allowance for uncollectible minimum lease payments	$ 1,322	[1],[2]	$ 1,582	[1],[3]	$ 1,854	$ 2,255
Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accumulated allowance for uncollectible minimum lease payments	$ 45		$ 53

[1] At December 31, 2014 and 2013, includes $179 and $49 of cash and due from banks, $47 and $48 of commercial mortgage loans, $3,331 and $1,010 of automobile loans, $(22) and $(15) of ALLL, $25 and $13 of other assets, $5 and $1 of other liabilities, $3,434 and $1,048 of long-term debt from consolidated VIEs that are included in their respective captions. For further information, refer to Note 10.

[2] Includes $6 related to leveraged leases.

[3] Includes $9 related to leveraged leases.