Debt (Tables)

12 Months Ended

Dec. 31, 2011

Debt Disclosure [Abstract]

Commercial Paper and Borrowings Under Bank Credit Facilities

	December 31
	2011			2010
Balance	$	28.6		$	115.6
Weighted average interest rate		1.26	%		0.64	%

Outstanding balances of debt obligations and the applicable interest rates

	Date of Issue		Final Maturity		Interest Rate			2011		2010
Recourse Fixed Rate Debt
Unsecured		04/30/09		05/15/14		8.75	%	$	300.0	$	300.0
Unsecured		09/24/09		10/01/12		4.75	%		300.0		300.0
Unsecured		02/05/10		05/15/15		4.75	%		250.0		250.0
Unsecured		11/19/10		07/15/16		3.50	%		250.0		250.0
Unsecured		05/27/11		06/01/21		4.85	%		250.0		—
Unsecured		02/06/08		02/15/18		6.00	%		200.0		200.0
Unsecured		03/03/06		03/01/16		5.80	%		200.0		200.0
Unsecured		10/11/06		02/15/12		5.50	%		200.0		200.0
Secured		11/06/08		11/15/13		9.00	%		168.3		179.0
Unsecured		12/22/05		12/22/15		5.75	%		115.0		130.0
Unsecured		09/20/11		07/15/16		3.50	%		100.0		—
Unsecured		04/14/05		04/15/15		5.70	%		100.0		100.0
Unsecured		09/20/11		06/01/21		4.85	%		50.0		—
Unsecured		03/29/06		12/11/12		3.49	%		40.5		41.8
Unsecured		12/18/07		11/30/12		4.70	%		27.2		28.1
Unsecured		06/29/07		05/31/12		4.25	%		22.7		23.4
Unsecured		12/27/10		10/31/18		3.84	%		20.7		21.4
Unsecured		11/29/10		11/30/18		3.70	%		20.7		21.4
Unsecured		02/11/02		07/31/12		5.73	%		0.6		1.4
Unsecured		02/11/02		01/31/12		5.83	%		0.2		1.0
Unsecured		06/22/04		06/15/11		6.27	%		—		181.8
Unsecured		09/25/06		08/31/11		3.45	%		—		18.8
Total recourse fixed rate debt								$	2,615.9	$	2,448.1
Recourse Floating Rate Debt(a)
Unsecured		03/18/08		03/18/14		1.46	%	$	150.0	$	150.0
Unsecured		12/12/11		06/12/17		2.19	%		115.0		—
Unsecured		06/30/06		06/28/13		0.93	%		100.0		100.0
Unsecured		05/17/11		05/17/13		1.50	%		100.0		—
Secured		12/19/11		12/19/20		2.41	%		100.0		—
Unsecured		12/15/10		10/31/15		2.97	%		49.9		13.4
Secured		05/14/09		05/14/14		3.00	%		41.4		44.8
Unsecured		12/06/11		08/31/16		2.87	%		29.8		—
Unsecured		09/02/11		11/30/16		2.53	%		15.6		—
Unsecured		03/01/10		02/28/15		3.31	%		13.0		13.4
Unsecured		12/27/10		06/30/12		3.59	%		5.2		5.4
Unsecured		12/31/03		09/30/13		2.57	%		4.3		6.9
Unsecured		11/29/10		12/31/12		3.45	%		1.9		5.4
Unsecured		12/15/03		12/15/12		2.44	%		1.2		2.5
Unsecured		12/31/03		12/31/12		2.37	%		0.3		0.6
Total recourse floating rate debt								$	727.6	$	342.4
Nonrecourse Fixed Rate Debt
Secured		09/30/97		09/20/16		6.69	%	$	45.2	$	56.2
Secured		06/13/06		12/31/13		6.26	%		22.2		22.9
Secured		05/29/07		05/31/12		5.84	%		3.5		3.6
Secured		08/01/07		06/30/17		6.77	%		2.5		2.6
Secured		06/01/07		05/31/12		6.27	%		2.4		2.4
Secured		05/11/07		05/31/12		6.06	%		1.4		1.5
Secured		06/16/06		04/29/16		6.80	%		1.3		1.4
Secured		08/01/07		07/31/17		6.78	%		0.8		0.8
Secured		06/28/07		03/05/11		6.34	%		—		12.4
Secured		10/10/06		09/30/11		5.98	%		—		12.1
Secured		06/16/06		08/31/11		5.37	%		—		11.2
Secured		12/21/06		08/01/11		5.89	%		—		6.1
Secured		12/21/06		03/31/11		5.89	%		—		4.3
Secured		06/29/07		10/05/11		6.54	%		—		5.4
Secured		10/01/07		02/05/11		5.62	%		—		4.4
Total nonrecourse fixed rate debt								$	79.3	$	147.3

Nonrecourse Floating Rate Debt(a)
Secured	Various	05/08/14	1.53	%	$	51.0		$	52.5
Secured	Various	01/15/15	1.53	%		24.4			25.3
Total nonrecourse floating rate debt					$	75.4		$	77.8
Total debt principal					$	3,498.2		$	3,015.6
Debt discount, net						(9.3	)		(14.2	)
Debt adjustment for fair value hedges						15.3			17.6
Total Debt					$	3,504.2		$	3,019.0

(a) Floating rates as of December 31, 2011.

Maturities of GATX's debt obligation

	Debt Principal
2012	$	755.5
2013		461.9
2014		489.7
2015		515.0
2016		589.9
Thereafter		686.2
Total debt principal	$	3,498.2