Concentrations - Portfolio Carrying Values of Customers (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Entity Wide Portfolio Carrying Amount, Major Customer [Line Items]
Carrying Value	$ 2,456	$ 2,559
% of Total Portfolio	60.60%	59.30%
Air Tran /Southwest [Member]
Entity Wide Portfolio Carrying Amount, Major Customer [Line Items]
Carrying Value	1,221	1,261
% of Total Portfolio	30.10%	29.20%
Hawaiian [Member]
Entity Wide Portfolio Carrying Amount, Major Customer [Line Items]
Carrying Value	393	374
% of Total Portfolio	9.70%	8.70%
Continental [Member]
Entity Wide Portfolio Carrying Amount, Major Customer [Line Items]
Carrying Value	392	415
% of Total Portfolio	9.70%	9.60%
American [Member]
Entity Wide Portfolio Carrying Amount, Major Customer [Line Items]
Carrying Value	278	350
% of Total Portfolio	6.90%	8.10%
Volotea [Member]
Entity Wide Portfolio Carrying Amount, Major Customer [Line Items]
Carrying Value	172
% of Total Portfolio	4.20%
Korean [Member]
Entity Wide Portfolio Carrying Amount, Major Customer [Line Items]
Carrying Value		$ 159
% of Total Portfolio		3.70%