Consolidated Statements of Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues
Lease revenue	$ 271.9	$ 276.6	$ 816.1	$ 823.4
Revenue Recognition, Cargo and Freight, Policy [Policy Text Block]	60.8	62.9	130.8	135.0
Other revenue	17.0	20.1	57.6	65.7
Total Revenues	349.7	359.6	1,004.5	1,024.1
Expenses
Maintenance expense	77.5	84.9	240.7	247.7
Marine operating expense	39.4	38.9	89.5	89.8
Depreciation	81.6	78.6	240.1	227.9
Operating lease expense	11.8	15.8	37.5	46.8
Other operating expense	8.5	8.5	26.2	25.9
Selling, general and administrative	46.5	42.5	137.6	127.8
Total Expenses	265.3	269.2	771.6	765.9
Other Income (Expense)
Net gain on asset dispositions	10.3	9.4	72.5	56.3
Interest expense, net	(42.6)	(40.2)	(124.7)	(119.4)
Other (expense) income	(3.8)	(2.4)	(14.9)	(5.5)
Income before Income Taxes and Share of Affiliates’ Earnings	48.3	57.2	165.8	189.6
Income Taxes	(13.1)	(20.4)	(42.8)	(60.3)
Share of Affiliates’ Earnings (net of tax)	11.8	12.2	39.1	30.6
Net Income	47.0	49.0	162.1	159.9
Other Comprehensive Income, net of taxes
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	(4.7)	15.4	(40.2)	74.0
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	1.6	0.7	2.3	3.6
Post-retirement benefit plans	5.3	1.4	9.1	4.1
Other comprehensive income (loss)	2.2	17.5	(28.8)	81.7
Comprehensive Income	$ 49.2	$ 66.5	$ 133.3	$ 241.6
Share Data
Basic earnings per share (in dollars per share)	$ 1.25	$ 1.27	$ 4.29	$ 4.10
Average number of common shares (in shares)	37.7	38.6	37.8	39.0
Diluted earnings per share (in dollars per share)	$ 1.22	$ 1.25	$ 4.21	$ 4.04
Average number of common shares and common share equivalents (in shares)	38.5	39.2	38.5	39.6
Dividends declared per common share (in dollars per share)	$ 0.44	$ 0.42	$ 1.32	$ 1.26