Concentrations - Portfolio Carrying Values of Customers (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Entity Wide Portfolio Carrying Amount, Major Customer [Line Items]
Carrying Value	$ 2,490	$ 2,559
% of Total Portfolio	61.20%	59.30%
Air Tran /Southwest [Member]
Entity Wide Portfolio Carrying Amount, Major Customer [Line Items]
Carrying Value	1,204	1,261
% of Total Portfolio	29.60%	29.20%
Hawaiian [Member]
Entity Wide Portfolio Carrying Amount, Major Customer [Line Items]
Carrying Value	384	374
% of Total Portfolio	9.40%	8.70%
Continental [Member]
Entity Wide Portfolio Carrying Amount, Major Customer [Line Items]
Carrying Value	384	415
% of Total Portfolio	9.40%	9.60%
Air India (Member)
Entity Wide Portfolio Carrying Amount, Major Customer [Line Items]
Carrying Value	265
% of Total Portfolio	6.50%
American [Member]
Entity Wide Portfolio Carrying Amount, Major Customer [Line Items]
Carrying Value	253	350
% of Total Portfolio	6.30%	8.10%
Korean [Member]
Entity Wide Portfolio Carrying Amount, Major Customer [Line Items]
Carrying Value		$ 159
% of Total Portfolio		3.70%