Debt Financing (Details) (USD $)					0 Months Ended			0 Months Ended					0 Months Ended	9 Months Ended	0 Months Ended		0 Months Ended				0 Months Ended		0 Months Ended							0 Months Ended	9 Months Ended		9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Unsecured	Dec. 31, 2012 Unsecured	Oct. 01, 2013 Senior notes	Sep. 30, 2013 Senior notes	Dec. 31, 2012 Senior notes	Feb. 05, 2013 4.75% senior unsecured notes due 2020	Oct. 01, 2013 3.64% senior unsecured notes due 2016	Oct. 01, 2013 4.49% senior unsecured notes due 2019	Sep. 30, 2013 Revolving credit facilities	Dec. 31, 2012 Revolving credit facilities	May 07, 2013 Syndicated Unsecured Revolving Credit Facility	Sep. 30, 2013 Syndicated Unsecured Revolving Credit Facility	May 07, 2013 Syndicated Unsecured Revolving Credit Facility Amendment and restatement of syndicated unsecured revolving credit agreement	Nov. 04, 2013 Syndicated Unsecured Revolving Credit Facility Amendment and restatement of syndicated unsecured revolving credit agreement	Aug. 26, 2013 Syndicated Unsecured Revolving Credit Facility BBB- Amendment and restatement of syndicated unsecured revolving credit agreement	Sep. 30, 2013 Unsecured term financings	Dec. 31, 2012 Unsecured term financings	Jun. 26, 2013 7.375% senior unsecured notes due January 30, 2019	Jun. 26, 2013 5.625% senior notes due 2017	Jun. 26, 2013 5.625% senior notes due 2017 Maximum	Aug. 26, 2013 5.625% senior notes due 2017 BBB-	Sep. 30, 2013 Convertible senior notes	Dec. 31, 2012 Convertible senior notes	Sep. 30, 2013 Secured item	Dec. 31, 2012 Secured item	Sep. 30, 2013 Warehouse facilities item	Dec. 31, 2012 Warehouse facilities item	Jun. 21, 2013 2010 Warehouse Facility	Sep. 30, 2013 2010 Warehouse Facility	Jun. 21, 2013 Amended 2010 Warehouse Facility	Sep. 30, 2013 Secured term financings item	Dec. 31, 2012 Secured term financings	Sep. 30, 2013 Export credit financing
Debt financing
Secured and unsecured debt financing	$ 5,478,307,000	$ 4,394,355,000	$ 3,874,775,000	$ 2,643,916,000		$ 2,170,620,000	$ 1,775,000,000				$ 1,239,000,000	$ 420,000,000						$ 265,155,000	$ 248,916,000					$ 200,000,000	$ 200,000,000	$ 1,603,532,000	$ 1,750,439,000	$ 839,000,000	$ 1,061,838,000				$ 691,329,000	$ 688,601,000	$ 73,203,000
Less: Debt discount	(12,029,000)	(9,623,000)
Total debt	5,466,278,000	4,384,732,000
Secured Obligations
Nonrecourse																										859,494,000	1,085,941,000
Recourse																										744,038,000	664,498,000
Total																										1,603,532,000	1,750,439,000						168,300,000
Number of aircraft pledged as collateral																										52	55	32	38
Net book value of aircraft pledged as collateral																										2,479,319,000	2,728,636,000	1,200,000,000	1,600,000,000
Increase in borrowings					185,000,000			400,000,000	53,000,000	132,000,000											132,000,000
Interest rate (as a percent)								4.75%	3.64%	4.49%										7.375%	5.625%
Additional interest rate (as a percent)																							0.50%
Aggregate principal amount of debt offered to exchange of existing debt																				125,400,000		151,600,000
Increase in aggregate principal amount of facility															607,000,000	300,000,000
Capacity provided															1,700,000,000	2,000,000,000														1,500,000,000		1,000,000,000
Variable interest rate floor (as a percent)														0.00%	0.00%		0.00%
Term of debt													3 years		4 years															4 years	4 years
Variable interest basis														LIBOR	LIBOR		LIBOR													LIBOR
Interest margin (as a percent)														1.75%	1.45%		1.25%													2.50%		2.25%	0.40%
Interest rate on undrawn balances (as a percent)																														0.75%		0.50%
Commitment fee in respect of unutilized commitments (as a percent)														0.375%	0.30%		0.25%
Amount outstanding											1,200,000,000																	83,900,000	1,100,000,000		664,300,000
Cash collateral and lessee deposits pledged																												75,800,000	104,300,000
Number of term loans amended																																	6
Secured term loans																										1,603,532,000	1,750,439,000						168,300,000
Number of lenders related to term loans amended																																	1
Maturities
2013	46,270,000
2014	217,220,000
2015	267,209,000
2016	894,114,000
2017	2,645,140,000
Thereafter	1,408,354,000
Total	$ 5,478,307,000	$ 4,394,355,000	$ 3,874,775,000	$ 2,643,916,000		$ 2,170,620,000	$ 1,775,000,000				$ 1,239,000,000	$ 420,000,000						$ 265,155,000	$ 248,916,000					$ 200,000,000	$ 200,000,000	$ 1,603,532,000	$ 1,750,439,000	$ 839,000,000	$ 1,061,838,000				$ 691,329,000	$ 688,601,000	$ 73,203,000