Leasing Activities (Net Investment In Leases By Published Credit Ratings) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Leases [Line Items]
Rated Entities	$ 1,237	[1]	$ 1,349	[1]
Non Rated Entities		[1]		[1]
Investment in finance leases held in trust	1,237	[1]	1,349	[1]
AA/Aa And Above [Member]
Leases [Line Items]
Rated Entities	766	[1]	737	[1]
A [Member]
Leases [Line Items]
Rated Entities	$ 471	[1]	$ 612	[1]

[1] Excludes the credit ratings of collateral posted by the lessees in these transactions.