Condensed Financial Information of Registrant (Details 1) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Gross Income
Lease income									$ 917.8	$ 873.5	$ 905.1
Other income									93.3	76.6	61.6
Total Gross Income	357.1	339.7	329.6	282.1	313.8	314.4	294.8	281.9	1,308.5	1,204.9	1,153.9
Ownership Costs
Depreciation									226.5	217.0	217.7
Interest expense, net									168.9	167.1	167.5
Operating lease expense									132.0	140.2	136.6
Total Ownership Costs									(527.4)	(524.3)	(521.8)
Other Costs and Expenses
Maintenance expense									276.7	267.0	269.0
Selling, general and administrative									155.3	134.8	127.8
Other									49.2	52.3	40.2
Total Other Costs and Expenses									(632.9)	(583.2)	(524.2)
Income Taxes									37.4	16.6	26.5
Equity in Net Income of Subsidiaries									40.6	38.1	29.0
Net Income	31.6	32.9	26.4	19.9	19.5	21.1	21.5	18.7	110.8	80.8	81.4
Other comprehensive income, net of taxes:
Foreign currency translation gain (loss)									(39.6)	(28.4)	18.3
Unrealized (loss) gain on securities									(0.2)	1.3	(0.1)
Unrealized loss on derivative instruments									(0.5)	(3.5)	(4.8)
Post retirement benefit plans									(18.8)	5.1	(12.7)
Other comprehensive (loss) income									(59.1)	(25.5)	0.7
Comprehensive Income									51.7	55.3	82.1
Parent Company [Member]
Gross Income
Lease income									477.7	458.9	490.7
Other income									106.5	83.9	82.5
Total Gross Income									584.2	542.8	573.2
Ownership Costs
Depreciation									117.0	110.2	118.7
Interest expense, net									72.8	74.0	82.4
Operating lease expense									95.2	101.3	97.6
Total Ownership Costs									285.0	285.5	298.7
Other Costs and Expenses
Maintenance expense									163.0	167.8	176.4
Selling, general and administrative									113.3	97.2	88.6
Other									21.8	25.2	24.7
Total Other Costs and Expenses									298.1	290.2	289.7
(Loss) Income before Income Taxes and Equity in Net Income of Subsidiaries									1.1	(32.9)	(15.2)
Income Taxes									(0.6)	(17.8)	5.2
(Loss) Income before Equity in Net Income of Subsidiaries									1.7	(15.1)	(20.4)
Equity in Net Income of Subsidiaries									109.1	95.9	101.8
Net Income									110.8	80.8	81.4
Other comprehensive income, net of taxes:
Foreign currency translation gain (loss)									(39.6)	(28.4)	18.3
Unrealized (loss) gain on securities									(0.2)	1.3	(0.1)
Unrealized loss on derivative instruments									(0.5)	(3.5)	(4.8)
Post retirement benefit plans									(18.8)	5.1	(12.7)
Other comprehensive (loss) income									(59.1)	(25.5)	0.7
Comprehensive Income									$ 51.7	$ 55.3	$ 82.1