Leasing Activities (Net Investment In Leases By Published Credit Ratings) (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Leases [Line Items]
Rated Entities	$ 869	[1]	$ 1,237	[1]
AA/Aa And Above [Member]
Leases [Line Items]
Rated Entities	537	[1]	766	[1]
A [Member]
Leases [Line Items]
Rated Entities	$ 332	[1]	$ 471	[1]

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