GATX (GATX) 10-Q 28 Apr 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015
Document and Entity Information [Abstract]
Entity Registrant Name	GATX Corporation
Entity Central Index Key	40211
Document Type	10-Q
Document Period End Date	31-Mar-15
Amendment Flag	FALSE
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding	43.9

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Assets
Cash and Cash Equivalents	$351.40	$209.90
Restricted Cash	15.6	14.5
Receivables
Rent and other receivables	64.1	86
Loans	13.4	97.3
Finance leases	175.4	174.7
Less: allowance for losses	-5.6	-5.7
Receivables, net	247.3	352.3
Operating Assets and Facilities
Operating Assets and Facilities ($123.1 and $123.1 related to a consolidated VIE)	8,194.20	8,143.50
Less: allowance for depreciation ($36.2 and $35.0 related to a consolidated VIE)	-2,434.90	-2,455.50
Operating assets and facilities, net	5,759.30	5,688
Investments in Affiliated Companies	359.7	357.7
Goodwill	79.1	86.1
Other Assets	244	229
Total Assets	7,056.40	6,937.50
Liabilities and Shareholders’ Equity
Accounts Payable and Accrued Expenses	163.8	165.9
Debt
Commercial paper and borrowings under bank credit facilities	2.8	72.1
Recourse	4,443.80	4,179.90
Nonrecourse ($13.7 and $15.9 related to a consolidated VIE)	-13.7	-15.9
Capital lease obligations	5	6.3
Total Debt	4,465.30	4,274.20
Deferred Income Taxes	952.1	937.3
Other Liabilities	192.7	246.1
Total Liabilities	5,773.90	5,623.50
Shareholders’ Equity
Common stock, $0.625 par value: Authorized shares — 120,000,000 Issued shares — 66,724,418 and 66,600,984 Outstanding shares — 43,900,464 and 44,198,850	-41.5	-41.4
Additional paid in capital	-671.2	-672.8
Retained earnings	1,547.20	1,501.70
Accumulated other comprehensive loss	196.9	148.4
Treasury stock at cost (22,823,954 and 22,402,134 shares)	-780.5	-753.5
Total Shareholders’ Equity	1,282.50	1,314
Total Liabilities and Shareholders’ Equity	$7,056.40	$6,937.50

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, except Share data, unless otherwise specified
Operating Assets and Facilities ($123.2 and $123.3 related to a consolidated VIE)	$8,194.20	$8,143.50
Less: allowance for depreciation ($36.2 and $35.0 related to a consolidated VIE)	-2,434.90	-2,455.50
Nonrecourse ($13.7 and $15.9 related to a consolidated VIE)	-13.7	-15.9
Common stock, par value	$0.63	$0.63
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	66,724,418	66,600,984
Common stock, shares outstanding	43,900,464	44,198,850
Treasury stock, shares outstanding	22,823,954	22,402,134
Variable Interest Entity, Primary Beneficiary [Member]
Operating Assets and Facilities ($123.2 and $123.3 related to a consolidated VIE)	123.1	123.1
Less: allowance for depreciation ($36.2 and $35.0 related to a consolidated VIE)	-36.2	-35
Nonrecourse ($13.7 and $15.9 related to a consolidated VIE)	($13.70)	($15.90)

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Revenues
Lease revenue	$278.30	$250.60
Marine operating revenue	24.2	17.7
Other revenue	17.2	18.3
Total Revenues	319.7	286.6
Expenses
Maintenance expense	78.3	73.1
Marine operating expense	18.9	15
Depreciation expense	68.5	58.7
Operating lease expense	20.7	26.9
Other operating expense	7.3	6.6
Selling, general and administrative	45.7	42.7
Total Expenses	239.4	223
Other Income (Expense)
Net gain on asset dispositions	45.3	28.1
Interest expense, net	-40.9	-42
Other (expense) income	-4	-3.4
Income before Income Taxes and Share of Affiliates’ Earnings	80.7	46.3
Income Taxes	-27	-14.1
Share of Affiliates’ Earnings (net of tax)	8.5	9.9
Net Income	62.2	42.1
Other Comprehensive Income, net of taxes
Foreign currency translation adjustments	48	-0.7
Unrealized gain (loss) on securities	0	0.2
Unrealized gain (loss) on derivative instruments	2.6	-0.7
Post-retirement benefit plans	2.1	1.4
Other comprehensive income (loss)	-48.5	2.6
Comprehensive Income	$13.70	$44.70
Share Data
Basic earnings per share (in dollars per share)	$1.41	$0.92
Average number of common shares (in shares)	44.1	46
Diluted earnings per share (in dollars per share)	$1.39	$0.90
Average number of common shares and common share equivalents (in shares)	44.8	46.8
Dividends declared per common share (in dollars per share)	$0.38	$0.33

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
		railcar
Operating Activities
Net income	$62.20	$42.10
Adjustments to reconcile income to net cash provided by operating activities:
Depreciation expense	71.7	62.1
Gains on sales of assets	-43.7	-26.9
Deferred income taxes	-24	-11
Share of affiliates’ earnings, net of dividends	-8.5	1.9
Change in accrued operating lease expense	-47.4	-39.8
Other	-2.5	1
Net cash provided by operating activities	55.8	51.4
Investing Activities
Purchases of leased-in assets	-99.5	-150.5
Portfolio proceeds	-176.8	-66.6
Proceeds from sales of other assets	-8.6	-7
Net decrease (increase) in restricted cash	-1.1	5.5
Other	9.7	0
Net cash used in investing activities	-86.4	-516.9
Financing Activities
Net proceeds from issuances of debt (original maturities longer than 90 days)	667.7	842.5
Repayments of debt (original maturities longer than 90 days)	-381.1	-307.1
Net increase (decrease) in debt with original maturities of 90 days or less	69.1	-14.5
Stock repurchases	-25.3	0
Dividends	-18	-16.9
Other	2.9	-1.2
Net cash (used in) provided by financing activities	-177.1	-531.8
Effect of Exchange Rate Changes on Cash and Cash Equivalents	-5	1
Net increase in Cash and Cash Equivalents	141.5	67.3
Cash and Cash Equivalents at beginning of period	209.9	379.7
Cash and Cash Equivalents at end of period	351.4	447
Noncash Investing Transactions
Distributions from affiliates	0	1.1	[1]
Portfolio proceeds	176.8	66.6
Number of railcars received		62
Portfolio Investments and Capital Additions	($180.90)	($445.50)
[1]	(1) In 2014, we received distributions of 62 railcars from our Southern Capital affiliate.

Description_of_Business

Description of Business	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business
	As used herein, "GATX," "we," "us," "our," and similar terms refer to GATX Corporation and its subsidiaries, unless indicated otherwise.
	We lease, operate, manage, and remarket long-lived, widely-used assets, primarily in the rail and marine markets. We also invest in joint ventures that complement our existing business activities. We report our financial results through four primary business segments: Rail North America, Rail International, American Steamship Company (“ASC”), and Portfolio Management.

Basis_of_Presentation_Basis_of

Basis of Presentation Basis of Presentation (Notes)	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation
	We prepared the accompanying unaudited consolidated financial statements in accordance with US Generally Accepted Accounting Principles ("GAAP") for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, our unaudited consolidated financial statements do not include all of the information and footnotes required for complete financial statements. We have included all of the normal recurring adjustments that we deemed necessary for a fair presentation.
	Operating results for the three months ended March 31, 2015, are not necessarily indicative of the results we may achieve for the entire year ending December 31, 2015. In particular, ASC's fleet is inactive for a significant portion of the first quarter of each year due to winter conditions on the Great Lakes. In addition, asset remarketing income does not occur evenly throughout the year. For more information, refer to the consolidated financial statements and footnotes in our Annual Report on Form 10-K for the year ended December 31, 2014.
	Accounting Changes
	Discontinued Operations
	In April 2014, the Financial Accounting Standards Board ("FASB") issued amendments to authoritative guidance for reporting discontinued operations and disposals of components of an entity. The amendments require that disposals representing strategic shifts that have (or will have) a major effect on an entity’s operations or financial results should be reported as discontinued operations. The amendments also expand the disclosure requirements for both discontinued operations and significant dispositions that do not qualify as discontinued operations.
	The amendments were effective for us beginning in the first quarter of 2015. Adoption of the new guidance did not impact the amount or timing of net income or the presentation and disclosures of our financial statements.
	New Accounting Pronouncements
	Debt Issue Costs
	In April 2015, the FASB issued authoritative guidance that requires presentation of debt issue costs as a deduction from the carrying amount of the related debt liability on the balance sheet, rather than as a deferred charge. The new guidance is effective for us beginning in the first quarter of 2016, with early adoption permitted. Adoption of the new guidance is not expected to impact the amount or timing of net income but may result in changes to the presentation and disclosures of our financial statements.
	Consolidation
	In February 2015, the FASB issued authoritative guidance amending the analysis required to determine whether to consolidate certain types of legal entities such as limited partnerships, limited liability corporations, and certain securitization structures. The new guidance is effective for us beginning in the first quarter of 2016, with early adoption permitted. We are currently evaluating the effect, if any, the new guidance will have on our financial statements and related disclosures.
	Revenue from Contracts with Customers
	In May 2014, the FASB issued authoritative accounting guidance that supersedes most current revenue recognition guidance, including industry-specific guidance. The new guidance requires companies to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration it expects to be entitled to in exchange for those goods or services.
	The guidance is effective for us beginning in the first quarter of 2017, and early adoption is not permitted. We can adopt the new guidance using either the retrospective method or the cumulative effect transition method. We are still evaluating the effect that the new guidance will have on our consolidated financial statements and related disclosures, including which transition method we will use.

Variable_Interest_Entities

Variable Interest Entities	3 Months Ended
	Mar. 31, 2015
Variable Interest Entity, Not Primary Beneficiary, Disclosures [Abstract]
Variable Interest Entities	Variable Interest Entities
	We are the primary beneficiary of one of our variable interest entities, a structured lease financing of a portfolio of railcars, because we have the power to direct its significant activities. As a result, we consolidate this variable interest entity. The risks associated with it are similar to those of our wholly owned railcar leasing activities.
	The following table shows the carrying amounts of assets and liabilities of the consolidated variable interest entity (in millions):
		31-Mar		31-Dec
		2015		2014
	Operating assets, net of accumulated depreciation (1)	$	86.9	$	88.1
	Nonrecourse debt	13.7		15.9
	_________
	-1	All operating assets are pledged as collateral on the nonrecourse debt.
	We determined that we are not the primary beneficiary of our other variable interest entities, which are primarily investments in equipment leasing affiliates that were financed through a variety of equity investments and third party lending arrangements. We are not the primary beneficiary of these variable interest entities because we do not have the power to direct the activities that most significantly impact the entities’ economic performance. For investments in affiliates we determined were variable interest entities, we concluded that power was shared by the affiliate partners based on the terms of the relevant joint venture agreements, which require approval of all partners for significant decisions regarding the variable interest entity.
	The following table shows the carrying amounts and maximum exposure to loss for our unconsolidated variable interest entities (in millions):
		March 31, 2015				31-Dec-14
		Net Carrying Amount		Maximum Exposure to Loss		Net Carrying Amount		Maximum Exposure to Loss
	Investments in affiliates	$	148.5	$	148.5	$	143.9	$	143.9
	Other investment	0.4		0.4		0.4		0.4
	Total	$	148.9	$	148.9	$	144.3	$	144.3

Fair_Value_Disclosure

Fair Value Disclosure	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Disclosures [Text Block]	Fair Value Disclosure
	The following tables show our assets and liabilities that are measured at fair value on a recurring basis (in millions):
	Assets	March 31,			Quoted Prices in Active Markets for Identical Assets			Significant Observable Inputs		Significant Unobservable Inputs
		2015			(Level 1)			(Level 2)		(Level 3)
	Interest rate derivatives (1)	$	2.9		$	—		$	2.9	$	—
	Foreign exchange rate derivatives	18.4			—			18.4		—
	Available-for-sale equity securities	4.4			4.4			—		—
	Liabilities
	Foreign exchange rate derivatives (2)	5.4			—			5.4		—
	Assets	December 31,			Quoted Prices in Active Markets for Identical Assets			Significant Observable Inputs		Significant Unobservable Inputs
		2014			(Level 1)			(Level 2)		(Level 3)
	Interest rate derivatives (1)	$	1.8		$	—		$	1.8	$	—
	Foreign exchange date derivatives (2)	9.7			—			9.7		—
	Available-for-sale equity securities	4.4			4.4			—		—
	Liabilities
	Interest rate derivatives (1)	5.9			—			5.9		—
	Foreign exchange rate derivatives (2)	1.6			—			1.6		—
	_________
	(1) Designated as hedges.
	(2) Not designated as hedges.
	We base our valuations of available-for-sale equity securities on their quoted prices on an active exchange. We value derivatives using a pricing model with inputs (such as yield curves and foreign currency rates) that are observable in the market or that can be derived principally from observable market data.
	Derivative instruments
	Fair Value Hedges
	We use interest rate swaps to manage the fixed-to-floating rate mix of our debt obligations by converting the fixed rate debt to floating rate debt. For fair value hedges, we recognize changes in fair value of both the derivative and the hedged item as interest expense. We had eight instruments outstanding with an aggregate notional amount of $600.0 million as of March 31, 2015 and December 31, 2014. These derivatives have maturities ranging from 2015 to 2020.
	Cash Flow Hedges
	We use interest rate swaps to convert floating rate debt to fixed rate debt. We use Treasury rate locks to hedge our exposure to interest rate risk on anticipated transactions. We also use currency swaps to hedge our exposure to fluctuations in the exchange rates of the foreign currencies in which we conduct business. We had six instruments outstanding with an aggregate notional amount of $312.6 million as of March 31, 2015, and seven instruments outstanding with an aggregate notional amount of $281.5 million as of December 31, 2014. These derivatives had maturities ranging from 2015 to 2022. Within the next 12 months, we expect to reclassify $5.9 million ($3.7 million after-tax) of net losses on previously terminated derivatives from accumulated other comprehensive loss. We reclassify these amounts when interest and operating lease expense on the related hedged transactions affect earnings.
	Non-designated Derivatives
	We do not hold derivative financial instruments for purposes other than hedging, although certain of our derivatives are not designated as accounting hedges. We recognize changes in the fair value of these derivatives in other (income) expense immediately.
	Some of our derivative instruments contain credit risk provisions that could require us to make immediate payment on net liability positions in the event that we default on certain outstanding debt obligations. The aggregate fair value of our derivative instruments with credit risk related contingent features that are in a liability position as of March 31, 2015, was zero. We are not required to post any collateral on our derivative instruments and do not expect the credit risk provisions to be triggered.
	In the event that a counterparty fails to meet the terms of an interest rate swap agreement or a foreign exchange contract, our exposure is limited to the fair value of the swap, if in our favor. We manage the credit risk of counterparties by transacting with institutions that we consider financially sound and by avoiding concentrations of risk with a single counterparty. We believe that the risk of non-performance by any of our counterparties is remote.
	The following table shows the impacts of our derivative instruments on our statements of comprehensive income (in millions):
				Three Months Ended
				31-Mar
	Derivative Designation		Location of Loss (Gain) Recognized	2015			2014
	Fair value hedges (1)		Interest expense	$	(2.3	)	$	2.1
	Cash flow hedges		Other comprehensive (income) loss (effective portion)	(8.4		)	1.8
	Cash flow hedges		Interest expense (effective portion reclassified from accumulated other comprehensive loss)	1.3			1.2
	Cash flow hedges		Operating lease expense (effective portion reclassified from accumulated other comprehensive loss)	0.1			0.2
	Cash flow hedges (2)		Other (income) expense (effective portion reclassified from accumulated other comprehensive loss)	(8.4		)	2.2
	Non-designated (3)		Other (income) expense	(4.2		)	0.1
	_________
	(1) The fair value adjustments related to the underlying debt equally offset the amounts recognized in interest expense.
	(2) For 2015, includes $9.9 million of gains on foreign currency derivatives which are substantially offset by losses from foreign currency remeasurement adjustments, also recognized in Other (income) expense.
	(3) For 2015, includes $5.1 million of gains on foreign currency derivatives which are substantially offset by losses from foreign currency remeasurement adjustments on the AAE loan, also recognized in Other (income) expense.
	Other Financial Instruments
	The carrying amounts of cash and cash equivalents, restricted cash, rent and other receivables, accounts payable, and commercial paper and bank credit facilities approximate fair value due to the short maturity of those instruments. We base the fair values of investment funds, which are accounted for under the cost method, on the best information available, which may include quoted investment fund values. We estimate the fair values of loans and fixed and floating rate debt using discounted cash flow analyses based on interest rates currently offered for loans with similar terms to borrowers of similar credit quality. The estimated fair values for these investments are classified in Level 2 of the fair value hierarchy because they are based on directly or indirectly observable inputs.
	The following table shows the carrying amounts and fair values of our other financial instruments as of (in millions):
		March 31, 2015						31-Dec-14
		Carrying			Fair			Carrying		Fair
		Amount			Value			Amount		Value
	Assets
	Investment funds	$	1.3		$	2.1		$	1.5	$	2.4
	Loans	13.4			13.4			97.3		97.4
	Liabilities
	Recourse fixed rate debt	$	4,068.80		$	4,219.10		$	3,639.90	$	3,775.00
	Recourse floating rate debt	375.1			376			540		540
	Nonrecourse debt	13.7			14.3			15.9		16.6
Fair Value Disclosure	The following table shows the carrying amounts and fair values of our other financial instruments as of (in millions):
		March 31, 2015						31-Dec-14
		Carrying			Fair			Carrying		Fair
		Amount			Value			Amount		Value
	Assets
	Investment funds	$	1.3		$	2.1		$	1.5	$	2.4
	Loans	13.4			13.4			97.3		97.4
	Liabilities
	Recourse fixed rate debt	$	4,068.80		$	4,219.10		$	3,639.90	$	3,775.00
	Recourse floating rate debt	375.1			376			540		540
	Nonrecourse debt	13.7			14.3			15.9		16.6

Pension_and_Other_PostRetireme

Pension and Other Post-Retirement Benefits	3 Months Ended
	Mar. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Pension and Other Post-Retirement Benefits	Pension and Other Post-Retirement Benefits
	The following table shows components of our pension and other post-retirement benefits expense for the three months ended March 31, 2015 and 2014 (in millions):
		2015 Pension			2014 Pension			2015 Retiree		2014 Retiree
		Benefits			Benefits			Health		Health
								and Life		and Life
	Service cost	$	1.7		$	1.4		$	—	$	—
	Interest cost	4.9			5.1			0.4		0.4
	Expected return on plan assets	(6.5		)	(7.2		)	—		—
	Amortization of (1):
	Unrecognized prior service credit	(0.2		)	(0.2		)	—		—
	Unrecognized net actuarial loss	3.5			2.6			—		—
	Net expense	$	3.4		$	1.7		$	0.4	$	0.4
	_________
	(1) Amounts reclassified from accumulated other comprehensive loss.

ShareBased_Compensation

Share-Based Compensation	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-Based Compensation
	During the first three months of 2015, we granted 341,100 stock appreciation rights (“SARs”), 65,640 restricted stock units, 61,740 performance shares, and 5,091 phantom stock units. For the three months ended March 31, 2015, total share-based compensation expense was $2.9 million and the related tax benefit was $1.1 million. For the three months ended March 31, 2014, total share-based compensation expense was $3.1 million and the related tax benefit was $1.2 million.
	The estimated fair value of our 2015 SARs awards and related underlying assumptions are shown in the table below.
		2015
	Estimated fair value	$	18.16
	Quarterly dividend rate	$	0.38
	Expected term of stock appreciation rights, in years	4.7
	Risk-free interest rate	1.2		%
	Dividend yield	2.6		%
	Expected stock price volatility	29.2		%
	Present value of dividends	$	6.9

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes
	Our effective tax rate was 33% for the three months ended March 31, 2015, compared to 30% for the three months ended March 31, 2014. The difference in the effective rates for each period, compared to the statutory rate of 35%, is primarily attributable to the mix of pretax income in each year among domestic and foreign jurisdictions which are taxed at different rates. The current year reflects a higher contribution from domestic source income, which is taxed at a higher rate.
	As of March 31, 2015, our gross liability for unrecognized tax benefits was $5.6 million. If fully recognized, these tax benefits would decrease our income tax expense by $5.6 million ($3.6 million, net of federal tax). We do not anticipate the recognition of any tax benefits that were previously unrecognized within the next 12 months.

Commercial_Commitments

Commercial Commitments	3 Months Ended
	Mar. 31, 2015
Guarantees [Abstract]
Commercial Commitments	Commercial Commitments
	We have entered into various commercial commitments, such as guarantees and standby letters of credit, related to certain transactions. These commercial commitments require us to fulfill specific obligations in the event of third party demands. Similar to our balance sheet investments, these commitments expose us to credit, market, and equipment risk. Accordingly, we evaluate these commitments and other contingent obligations using techniques similar to those we use to evaluate funded transactions.
	The following table shows our commercial commitments (in millions):
		31-Mar		31-Dec
		2015		2014
	Lease payment guarantees	$	26.8	$	28.5
	Standby letters of credit	8.6		8.7
	Performance bonds	0.4		0.4
	Total commercial commitments (1)	$	35.8	$	37.6
	_________
	(1) The carrying value of liabilities on the balance sheet for commercial commitments was $4.9 million at March 31, 2015 and $5.1 million at December 31, 2014. The expirations of these commitments range from 2017 to 2023. We are not aware of any event that would require us to satisfy any of our commitments.
	Lease payment guarantees are commitments to financial institutions to make lease payments for a third party in the event they default. We reduce any liability that may result from these guarantees by the value of the underlying asset or group of assets.
	We are also parties to standby letters of credit and performance bonds, which primarily relate to contractual obligations and general liability insurance coverages. No material claims have been made against these obligations, and no material losses are anticipated.

Earnings_Per_Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Earnings Per Share	Earnings per Share
	We compute basic earnings per share by dividing net income available to our common shareholders by the weighted average number of shares of our common stock outstanding. We appropriately weighted shares issued or reacquired during the period that they were outstanding. Our diluted earnings per share reflect the impacts of our potentially dilutive securities and our equity compensation awards.
	In the first quarter of 2014, our board of directors authorized a $250 million share repurchase program. During the first quarter of 2015, 0.5 million shares were acquired for $27.0 million. As of March 31, 2015, 2.4 million shares had been repurchased for $151.6 million and $98.4 million was available under the repurchase authorization.
	The following table shows the computation of our basic and diluted net income per common share (in millions, except per share amounts):
		Three Months Ended
		31-Mar
		2015		2014
	Numerator:
	Net income	$	62.2	$	42.1
	Denominator:
	Weighted average shares outstanding - basic	44.1		46
	Effect of dilutive securities:
	Equity compensation plans	0.7		0.8
	Weighted average shares outstanding - diluted	44.8		46.8
	Basic earnings per share	$	1.41	$	0.92
	Diluted earnings per share	$	1.39	$	0.9

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Loss
	The following table shows the change in components for accumulated other comprehensive loss (in millions):
		Foreign Currency Translation Gain (Loss)			Unrealized Gain (Loss) on Securities		Unrealized Gain (Loss) on Derivative Instruments			Post-Retirement Benefit Plans			Total
	Balance at December 31, 2014	$	(21.9	)	$	0.3	$	(19.1	)	$	(107.7	)	$	(148.4	)
	Change in component	(48.0		)	—		6			—			(42.0		)
	Reclassification adjustments into earnings	—			—		(7.0		)	3.3			(3.7		)
	Income tax effect	—			—		(1.6		)	(1.2		)	(2.8		)
	Balance at March 31, 2015	$	(69.9	)	$	0.3	$	(21.7	)	$	(105.6	)	$	(196.9	)
	________
	See "Note 4. Fair Value Disclosure" and "Note 5. Pension and Other Post-Retirement Benefits" for impacts of the reclassification adjustments on the statement of comprehensive income.

Legal_Proceedings_and_Other_Co

Legal Proceedings and Other Contingencies	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Legal Proceedings and Other Contingencies	Legal Proceedings and Other Contingencies
	Various legal actions, claims, assessments and other contingencies arising in the ordinary course of business are pending against GATX and certain of our subsidiaries. These matters are subject to many uncertainties, and it is possible that some of these matters could ultimately be decided, resolved or settled adversely. For a full discussion of our pending legal matters, please refer to "Note 23. Legal Proceedings and Other Contingencies" of our consolidated financial statements in our Annual Report on Form 10-K for the year ended December 31, 2014.
	Viareggio Derailment
	In June 2009, a train consisting of fourteen liquefied petroleum gas (“LPG”) tank cars owned by GATX Rail Austria GmbH (an indirect subsidiary of the Company, "GATX Rail Austria") and its subsidiaries derailed while passing through the City of Viareggio, in the province of Lucca, Italy. Five tank cars overturned and one of the overturned cars was punctured by a peg or obstacle along the side of the track, resulting in a release of LPG, which subsequently ignited. Thirty-two people died and others were injured in the fire, which also resulted in property damage. The LPG tank cars were leased to FS Logistica S.p.A., a subsidiary of the Italian state-owned railway, Ferrovie dello Stato S.p.A (the “Italian Railway”).
	On December 14, 2012, the Public Prosecutors of Lucca ("Public Prosecutors") formally charged GATX Rail Austria and two of its subsidiaries (collectively, "GRA"), as well as ten maintenance and supervisory employees (the "Employees"), with various negligence-based crimes related to the accident, all of which are punishable under Italian law by incarceration, damages and fines. Similar charges were brought against four Italian Railway companies and eighteen of their employees, among others. The Public Prosecutors assert that the axle on a tank car broke, causing the derailment and resulting in a tank rupture and release of LPG, after the car hit an obstacle placed on the side of the track by the Italian Railway. The Public Prosecutors further allege that a crack in the axle was detectable at the time of final inspection but was overlooked by the Employees at the Jungenthal Waggon GmbH workshop (a subsidiary of GATX Rail Austria). The trial in the Court of Lucca (the “Lucca Trial”) commenced on November 13, 2013.
	With respect to civil claims, GRA’s insurers continue to work cooperatively with the insurer for the Italian Railway to adjust and settle personal injury and property damage claims. These joint settlement efforts have so far settled most of the significant civil claims related to the accident; however, approximately 90 civil claimants did not settle and are currently parties to the Lucca Trial. The Court of Lucca will determine both the civil and criminal liability of the defendants in the one proceeding. GRA expects that its insurers will cover any civil damages if awarded to the claimants in the Lucca trial.
	Since May 2012, one of the excess insurers providing coverage, Liberty Mutual Insurance Europe Limited (“Liberty”), has settled civil claims but has refused to reimburse GRA for its ongoing legal defense fees and costs, taking a position contrary to our other insurers in the prior underlying layers who had provided coverage for such expenses. As of March 31, 2015, GRA had incurred approximately $7.8 million in unreimbursed defense fees and costs, and GRA continues to incur costs in connection with the Lucca Trial. Consequently, in October 2013, GRA filed an arbitration proceeding against Liberty seeking to recoup its unreimbursed defense fees and costs (the “Liberty Arbitration”), which is set for hearing in November 2015. GRA is also negotiating issues of reimbursement for outstanding defense costs with the three other insurers in the current coverage layer, which includes a 25% share held by Liberty. GRA cannot predict the outcome of the Liberty Arbitration or the amount of defense fees and costs that ultimately may not be reimbursed by Liberty or the other excess insurers in the current coverage layer.
	GRA believes that it and its Employees acted diligently and properly, but we cannot predict the outcome of the Lucca Trial or what other legal proceedings or claims, if any, may be initiated against GRA or its personnel, and, therefore, cannot reasonably estimate the possible amount or range of loss that may ultimately be incurred in connection with this accident. Accordingly, we have not established any accruals with respect to this matter.

Financial_Data_of_Business_Seg

Financial Data of Business Segments	3 Months Ended
	Mar. 31, 2015																			Mar. 31, 2014
Segment Reporting Information [Line Items]
Segment Reporting Disclosure [Text Block]	Financial Data of Business Segments
	The financial data presented below depicts the profitability, financial position, and capital expenditures of each of our business segments.
	We lease, operate, manage, and remarket long-lived, widely-used assets, primarily in the rail and marine markets. We also invest in joint ventures that complement our existing business activities. We report our financial results through four primary business segments: Rail North America, Rail International, ASC, and Portfolio Management.
	Rail North America comprises our wholly owned operations in the United States, Canada, and Mexico, as well as an affiliate investment. Rail North America primarily provides railcars pursuant to full-service leases under which it maintains the railcars, pays ad valorem taxes and insurance, and provides other ancillary services.
	Rail International comprises our wholly owned European operations ("GATX Rail Europe" or "GRE"), a railcar leasing business in India ("GATX India Pte. Ltd." or "GIPL"), and a recently established railcar leasing business in Russia ("GATX Rail Vostok LLC" or "GRV"), as well as one development stage affiliate in China. GRE leases railcars to customers throughout Europe pursuant to full-service leases under which it maintains the railcars and provides insurance and other ancillary services.
	ASC operates the largest fleet of US-flagged vessels on the Great Lakes, providing waterborne transportation of dry bulk commodities such as iron ore, coal, limestone aggregates, and metallurgical limestone.
	Portfolio Management generates leasing, marine operating, asset remarketing and management fee income through a collection of diversified wholly owned assets and joint venture investments.
	Segment profit is an internal performance measure used by the Chief Executive Officer to assess the performance of each segment in a given period. Segment profit includes all revenues, pretax earnings from affiliates, and net gains on asset dispositions that are attributable to the segments, as well as expenses that management believes are directly associated with the financing, maintenance, and operation of the revenue earning assets. Segment profit excludes selling, general and administrative expenses, income taxes, and certain other amounts not allocated to the segments. These amounts are included in Other.
	We allocate debt balances and related interest expense to each segment based upon a predetermined fixed recourse leverage level expressed as a ratio of recourse debt (including off-balance-sheet debt) to equity. The leverage levels are 5:1 for Rail North America, 2:1 for Rail International, 1.5:1 for ASC, and 3:1 for Portfolio Management. We believe that by using this leverage and interest expense allocation methodology, each operating segment’s financial performance reflects appropriate risk-adjusted borrowing costs.
	The following tables show certain segment data for each of our business segments (in millions):
		Rail North America			Rail International			ASC			Portfolio Management			Other			GATX Consolidated
	Three Months Ended March 31, 2015
	Profitability
	Revenues
	Lease revenue	$	228.5		$	42.1		$	1		$	6.7		$	—		$	278.3
	Marine operating revenue	—			—			7			17.2			—			24.2
	Other revenue	14.7			1.9			—			0.6			—			17.2
	Total Revenues	243.2			44			8			24.5			—			319.7
	Expenses
	Maintenance expense	69.2			8.9			0.2			—			—			78.3
	Marine operating expense	—			—			6.9			12			—			18.9
	Depreciation expense	52.3			10.7			—			5.5			—			68.5
	Operating lease expense	20.7			—			—			—			—			20.7
	Other operating expense	5.5			0.9			—			0.9			—			7.3
	Total Expenses	147.7			20.5			7.1			18.4			—			193.7
	Other Income (Expense)
	Net gain on asset dispositions	36.8			4.9			—			3.6			—			45.3
	Interest expense, net	(24.5		)	(6.5		)	(1.3		)	(5.2		)	(3.4		)	(40.9		)
	Other expense	(2.2		)	—			—			—			(1.8		)	(4.0		)
	Share of affiliates' earnings (pretax)	0.2			(0.1		)	—			11.4			—			11.5
	Segment Profit (Loss)	$	105.8		$	21.8		$	(0.4	)	$	15.9		$	(5.2	)	137.9
	Selling, general and administrative expense																45.7
	Income taxes (including $3.0 related to affiliates' earnings)																30
	Net Income																$	62.2
	Net Gain on Asset Dispositions
	Asset Remarketing Income:
	Disposition gains on owned assets	$	35.9		$	—		$	—		$	2		$	—		$	37.9
	Residual sharing income	0.2			—			—			1.6			—			1.8
	Non-remarketing disposition gains (1)	0.7			5			—			—			—			5.7
	Asset impairment	—			(0.1		)	—			—			—			(0.1		)
		$	36.8		$	4.9		$	—		$	3.6		$	—		$	45.3
	Capital Expenditures
	Portfolio investments and capital additions	$	129.8		$	41.4		$	9.3		$	—		$	0.4		$	180.9
	Selected Balance Sheet Data at March 31, 2015
	Investments in affiliated companies	$	13.9		$	1.6		$	—		$	344.2		$	—		$	359.7
	Identifiable assets	$	4,518.90		$	1,161.00		$	273.5		$	794.4		$	308.6		$	7,056.40
	_____
	(1) Includes scrapping gains.
		Rail North America			Rail International			ASC			Portfolio Management			Other			GATX Consolidated
	Three Months Ended March 31, 2014
	Profitability
	Revenues
	Lease revenue	$	194.9		$	47.2		$	1.1		$	7.4		$	—		$	250.6
	Marine operating revenue	—			—			3.1			14.6			—			17.7
	Other revenue	14.6			2			—			1.7			—			18.3
	Total Revenues	209.5			49.2			4.2			23.7			—			286.6
	Expenses
	Maintenance expense	61.4			11.5			0.2			—			—			73.1
	Marine operating expense	—			—			3.4			11.6			—			15
	Depreciation expense	41.5			11.7			—			5.5			—			58.7
	Operating lease expense	26.9			—			—			—			—			26.9
	Other operating expense	4.8			1.4			—			0.4			—			6.6
	Total Expenses	134.6			24.6			3.6			17.5			—			180.3
	Other Income (Expense)
Net gain on asset dispositions	24.8			2.4			(0.4		)	1.3			—			28.1
Interest expense, net	(24.6		)	(6.2		)	(1.4		)	(6.8		)	(3.0		)	(42.0		)
Other (expense) income	(3.4		)	—			—			0.3			(0.3		)	(3.4		)
Share of affiliates' earnings (pretax)	3.3			(0.1		)	—			10.9			—			14.1
Segment Profit (Loss)	$	75		$	20.7		$	(1.2	)	$	11.9		$	(3.3	)	103.1
Selling, general and administrative expense																42.7
Income taxes (including $4.2 related to affiliates' earnings)																18.3
Net Income																$	42.1
Net Gain on Asset Dispositions
Asset Remarketing Income:
Disposition gains on owned assets	$	21.6		$	—		$	—		$	—		$	—		$	21.6
Residual sharing income	0.6			—			—			1.2			—			1.8
Non-remarketing disposition gains (1)	2.6			2.4			—			—			—			5
Asset impairment	—			—			(0.4		)	0.1			—			(0.3		)
	$	24.8		$	2.4		$	(0.4	)	$	1.3		$	—		$	28.1
Capital Expenditures
Portfolio investments and capital additions	$	396		$	39.3		$	8.3		$	—		$	1.9		$	445.5
Selected Balance Sheet Data at December 31, 2014
Investments in affiliated companies	$	17.2		$	1.8		$	—		$	338.7		$	—		$	357.7
Identifiable assets	$	4,358.30		$	1,229.40		$	286.7		$	813.3		$	249.8		$	6,937.50
_____
(1) Includes scrapping gains.
Financial Data of Business Segments																				The following tables show certain segment data for each of our business segments (in millions):
																					Rail North America			Rail International			ASC			Portfolio Management			Other			GATX Consolidated
																				Three Months Ended March 31, 2015
																				Profitability
																				Revenues
																				Lease revenue	$	228.5		$	42.1		$	1		$	6.7		$	—		$	278.3
																				Marine operating revenue	—			—			7			17.2			—			24.2
																				Other revenue	14.7			1.9			—			0.6			—			17.2
																				Total Revenues	243.2			44			8			24.5			—			319.7
																				Expenses
																				Maintenance expense	69.2			8.9			0.2			—			—			78.3
																				Marine operating expense	—			—			6.9			12			—			18.9
																				Depreciation expense	52.3			10.7			—			5.5			—			68.5
																				Operating lease expense	20.7			—			—			—			—			20.7
																				Other operating expense	5.5			0.9			—			0.9			—			7.3
																				Total Expenses	147.7			20.5			7.1			18.4			—			193.7
																				Other Income (Expense)
																				Net gain on asset dispositions	36.8			4.9			—			3.6			—			45.3
																				Interest expense, net	(24.5		)	(6.5		)	(1.3		)	(5.2		)	(3.4		)	(40.9		)
																				Other expense	(2.2		)	—			—			—			(1.8		)	(4.0		)
																				Share of affiliates' earnings (pretax)	0.2			(0.1		)	—			11.4			—			11.5
																				Segment Profit (Loss)	$	105.8		$	21.8		$	(0.4	)	$	15.9		$	(5.2	)	137.9
																				Selling, general and administrative expense																45.7
																				Income taxes (including $3.0 related to affiliates' earnings)																30
																				Net Income																$	62.2
																				Net Gain on Asset Dispositions
																				Asset Remarketing Income:
																				Disposition gains on owned assets	$	35.9		$	—		$	—		$	2		$	—		$	37.9
																				Residual sharing income	0.2			—			—			1.6			—			1.8
																				Non-remarketing disposition gains (1)	0.7			5			—			—			—			5.7
																				Asset impairment	—			(0.1		)	—			—			—			(0.1		)
																					$	36.8		$	4.9		$	—		$	3.6		$	—		$	45.3
																				Capital Expenditures
																				Portfolio investments and capital additions	$	129.8		$	41.4		$	9.3		$	—		$	0.4		$	180.9
																				Selected Balance Sheet Data at March 31, 2015
																				Investments in affiliated companies	$	13.9		$	1.6		$	—		$	344.2		$	—		$	359.7
																				Identifiable assets	$	4,518.90		$	1,161.00		$	273.5		$	794.4		$	308.6		$	7,056.40
																				_____
																				(1) Includes scrapping gains.
																					Rail North America			Rail International			ASC			Portfolio Management			Other			GATX Consolidated
																				Three Months Ended March 31, 2014
																				Profitability
																				Revenues
																				Lease revenue	$	194.9		$	47.2		$	1.1		$	7.4		$	—		$	250.6
																				Marine operating revenue	—			—			3.1			14.6			—			17.7
																				Other revenue	14.6			2			—			1.7			—			18.3
																				Total Revenues	209.5			49.2			4.2			23.7			—			286.6
																				Expenses
																				Maintenance expense	61.4			11.5			0.2			—			—			73.1
																				Marine operating expense	—			—			3.4			11.6			—			15
																				Depreciation expense	41.5			11.7			—			5.5			—			58.7
																				Operating lease expense	26.9			—			—			—			—			26.9
																				Other operating expense	4.8			1.4			—			0.4			—			6.6
																				Total Expenses	134.6			24.6			3.6			17.5			—			180.3
																				Other Income (Expense)
																				Net gain on asset dispositions	24.8			2.4			(0.4		)	1.3			—			28.1
																				Interest expense, net	(24.6		)	(6.2		)	(1.4		)	(6.8		)	(3.0		)	(42.0		)
																				Other (expense) income	(3.4		)	—			—			0.3			(0.3		)	(3.4		)
																				Share of affiliates' earnings (pretax)	3.3			(0.1		)	—			10.9			—			14.1
																				Segment Profit (Loss)	$	75		$	20.7		$	(1.2	)	$	11.9		$	(3.3	)	103.1
																				Selling, general and administrative expense																42.7
																				Income taxes (including $4.2 related to affiliates' earnings)																18.3
																				Net Income																$	42.1
																				Net Gain on Asset Dispositions
Asset Remarketing Income:
Disposition gains on owned assets	$	21.6		$	—		$	—		$	—		$	—		$	21.6
Residual sharing income	0.6			—			—			1.2			—			1.8
Non-remarketing disposition gains (1)	2.6			2.4			—			—			—			5
Asset impairment	—			—			(0.4		)	0.1			—			(0.3		)
	$	24.8		$	2.4		$	(0.4	)	$	1.3		$	—		$	28.1
Capital Expenditures
Portfolio investments and capital additions	$	396		$	39.3		$	8.3		$	—		$	1.9		$	445.5
Selected Balance Sheet Data at December 31, 2014
Investments in affiliated companies	$	17.2		$	1.8		$	—		$	338.7		$	—		$	357.7
Identifiable assets	$	4,358.30		$	1,229.40		$	286.7		$	813.3		$	249.8		$	6,937.50
_____
(1) Includes scrapping gains.

Variable_Interest_Entities_Tab

Variable Interest Entities (Tables)	3 Months Ended
	Mar. 31, 2015
Variable Interest Entity, Not Primary Beneficiary, Disclosures [Abstract]
Carrying amounts of assets and liabilities of consolidated VIE	Variable Interest Entities
	We are the primary beneficiary of one of our variable interest entities, a structured lease financing of a portfolio of railcars, because we have the power to direct its significant activities. As a result, we consolidate this variable interest entity. The risks associated with it are similar to those of our wholly owned railcar leasing activities.
	The following table shows the carrying amounts of assets and liabilities of the consolidated variable interest entity (in millions):
		31-Mar		31-Dec
		2015		2014
	Operating assets, net of accumulated depreciation (1)	$	86.9	$	88.1
	Nonrecourse debt	13.7		15.9
	_________
	-1	All operating assets are pledged as collateral on the nonrecourse debt.
	We determined that we are not the primary beneficiary of our other variable interest entities, which are primarily investments in equipment leasing affiliates that were financed through a variety of equity investments and third party lending arrangements. We are not the primary beneficiary of these variable interest entities because we do not have the power to direct the activities that most significantly impact the entities’ economic performance. For investments in affiliates we determined were variable interest entities, we concluded that power was shared by the affiliate partners based on the terms of the relevant joint venture agreements, which require approval of all partners for significant decisions regarding the variable interest entity.
Carrying amounts and maximum exposure to loss for non consolidated VIEs	The following table shows the carrying amounts and maximum exposure to loss for our unconsolidated variable interest entities (in millions):
		March 31, 2015				31-Dec-14
		Net Carrying Amount		Maximum Exposure to Loss		Net Carrying Amount		Maximum Exposure to Loss
	Investments in affiliates	$	148.5	$	148.5	$	143.9	$	143.9
	Other investment	0.4		0.4		0.4		0.4
	Total	$	148.9	$	148.9	$	144.3	$	144.3

Fair_Value_Disclosure_Tables

Fair Value Disclosure (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements, Recurring and Nonrecurring	The following tables show our assets and liabilities that are measured at fair value on a recurring basis (in millions):
	Assets	March 31,			Quoted Prices in Active Markets for Identical Assets			Significant Observable Inputs		Significant Unobservable Inputs
		2015			(Level 1)			(Level 2)		(Level 3)
	Interest rate derivatives (1)	$	2.9		$	—		$	2.9	$	—
	Foreign exchange rate derivatives	18.4			—			18.4		—
	Available-for-sale equity securities	4.4			4.4			—		—
	Liabilities
	Foreign exchange rate derivatives (2)	5.4			—			5.4		—
	Assets	December 31,			Quoted Prices in Active Markets for Identical Assets			Significant Observable Inputs		Significant Unobservable Inputs
		2014			(Level 1)			(Level 2)		(Level 3)
	Interest rate derivatives (1)	$	1.8		$	—		$	1.8	$	—
	Foreign exchange date derivatives (2)	9.7			—			9.7		—
	Available-for-sale equity securities	4.4			4.4			—		—
	Liabilities
	Interest rate derivatives (1)	5.9			—			5.9		—
	Foreign exchange rate derivatives (2)	1.6			—			1.6		—
	_________
	(1) Designated as hedges.
	(2) Not designated as hedges.
	We base our valuations of available-for-sale equity securities on their quoted prices on an active exchange. We value derivatives using a pricing model with inputs (such as yield curves and foreign currency rates) that are observable in the market or that can be derived principally from observable market data.
Derivative Instruments, Gain (Loss) [Table Text Block]	Derivative instruments
	Fair Value Hedges
	We use interest rate swaps to manage the fixed-to-floating rate mix of our debt obligations by converting the fixed rate debt to floating rate debt. For fair value hedges, we recognize changes in fair value of both the derivative and the hedged item as interest expense. We had eight instruments outstanding with an aggregate notional amount of $600.0 million as of March 31, 2015 and December 31, 2014. These derivatives have maturities ranging from 2015 to 2020.
	Cash Flow Hedges
	We use interest rate swaps to convert floating rate debt to fixed rate debt. We use Treasury rate locks to hedge our exposure to interest rate risk on anticipated transactions. We also use currency swaps to hedge our exposure to fluctuations in the exchange rates of the foreign currencies in which we conduct business. We had six instruments outstanding with an aggregate notional amount of $312.6 million as of March 31, 2015, and seven instruments outstanding with an aggregate notional amount of $281.5 million as of December 31, 2014. These derivatives had maturities ranging from 2015 to 2022. Within the next 12 months, we expect to reclassify $5.9 million ($3.7 million after-tax) of net losses on previously terminated derivatives from accumulated other comprehensive loss. We reclassify these amounts when interest and operating lease expense on the related hedged transactions affect earnings.
	Non-designated Derivatives
	We do not hold derivative financial instruments for purposes other than hedging, although certain of our derivatives are not designated as accounting hedges. We recognize changes in the fair value of these derivatives in other (income) expense immediately.
	Some of our derivative instruments contain credit risk provisions that could require us to make immediate payment on net liability positions in the event that we default on certain outstanding debt obligations. The aggregate fair value of our derivative instruments with credit risk related contingent features that are in a liability position as of March 31, 2015, was zero. We are not required to post any collateral on our derivative instruments and do not expect the credit risk provisions to be triggered.
	In the event that a counterparty fails to meet the terms of an interest rate swap agreement or a foreign exchange contract, our exposure is limited to the fair value of the swap, if in our favor. We manage the credit risk of counterparties by transacting with institutions that we consider financially sound and by avoiding concentrations of risk with a single counterparty. We believe that the risk of non-performance by any of our counterparties is remote.
	The following table shows the impacts of our derivative instruments on our statements of comprehensive income (in millions):
				Three Months Ended
				31-Mar
	Derivative Designation		Location of Loss (Gain) Recognized	2015			2014
	Fair value hedges (1)		Interest expense	$	(2.3	)	$	2.1
	Cash flow hedges		Other comprehensive (income) loss (effective portion)	(8.4		)	1.8
	Cash flow hedges		Interest expense (effective portion reclassified from accumulated other comprehensive loss)	1.3			1.2
	Cash flow hedges		Operating lease expense (effective portion reclassified from accumulated other comprehensive loss)	0.1			0.2
	Cash flow hedges (2)		Other (income) expense (effective portion reclassified from accumulated other comprehensive loss)	(8.4		)	2.2
	Non-designated (3)		Other (income) expense	(4.2		)	0.1
	_________
	(1) The fair value adjustments related to the underlying debt equally offset the amounts recognized in interest expense.

Pension_and_Other_PostRetireme1

Pension and Other Post-Retirement Benefits (Tables)	3 Months Ended
	Mar. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Pension obligations and plan assets and other post-retirement obligations	The following table shows components of our pension and other post-retirement benefits expense for the three months ended March 31, 2015 and 2014 (in millions):
		2015 Pension			2014 Pension			2015 Retiree		2014 Retiree
		Benefits			Benefits			Health		Health
								and Life		and Life
	Service cost	$	1.7		$	1.4		$	—	$	—
	Interest cost	4.9			5.1			0.4		0.4
	Expected return on plan assets	(6.5		)	(7.2		)	—		—
	Amortization of (1):
	Unrecognized prior service credit	(0.2		)	(0.2		)	—		—
	Unrecognized net actuarial loss	3.5			2.6			—		—
	Net expense	$	3.4		$	1.7		$	0.4	$	0.4
	_________
	(1) Amounts reclassified from accumulated other comprehensive loss.

Share_Based_Compensation_Table

Share Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Weighted Average Fair Value and Assumptions	The estimated fair value of our 2015 SARs awards and related underlying assumptions are shown in the table below.
		2015
	Estimated fair value	$	18.16
	Quarterly dividend rate	$	0.38
	Expected term of stock appreciation rights, in years	4.7
	Risk-free interest rate	1.2		%
	Dividend yield	2.6		%
	Expected stock price volatility	29.2		%
	Present value of dividends	$	6.9

Commercial_Commitments_Tables

Commercial Commitments (Tables)	3 Months Ended
	Mar. 31, 2015
Guarantees [Abstract]
Commercial Commitments	The following table shows our commercial commitments (in millions):
		31-Mar		31-Dec
		2015		2014
	Lease payment guarantees	$	26.8	$	28.5
	Standby letters of credit	8.6		8.7
	Performance bonds	0.4		0.4
	Total commercial commitments (1)	$	35.8	$	37.6
	_________
	(1) The carrying value of liabilities on the balance sheet for commercial commitments was $4.9 million at March 31, 2015 and $5.1 million at December 31, 2014. The expirations of these commitments range from 2017 to 2023. We are not aware of any event that would require us to satisfy any of our commitments.

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Computation of basic and diluted net income per common share	he following table shows the computation of our basic and diluted net income per common share (in millions, except per share amounts):
		Three Months Ended
		31-Mar
		2015		2014
	Numerator:
	Net income	$	62.2	$	42.1
	Denominator:
	Weighted average shares outstanding - basic	44.1		46
	Effect of dilutive securities:
	Equity compensation plans	0.7		0.8
	Weighted average shares outstanding - diluted	44.8		46.8
	Basic earnings per share	$	1.41	$	0.92
	Diluted earnings per share	$	1.39	$	0.9

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Accumulated other comprehensive income (loss)	The following table shows the change in components for accumulated other comprehensive loss (in millions):
		Foreign Currency Translation Gain (Loss)			Unrealized Gain (Loss) on Securities		Unrealized Gain (Loss) on Derivative Instruments			Post-Retirement Benefit Plans			Total
	Balance at December 31, 2014	$	(21.9	)	$	0.3	$	(19.1	)	$	(107.7	)	$	(148.4	)
	Change in component	(48.0		)	—		6			—			(42.0		)
	Reclassification adjustments into earnings	—			—		(7.0		)	3.3			(3.7		)
	Income tax effect	—			—		(1.6		)	(1.2		)	(2.8		)
	Balance at March 31, 2015	$	(69.9	)	$	0.3	$	(21.7	)	$	(105.6	)	$	(196.9	)

Financial_Data_of_Business_Seg1

Financial Data of Business Segments (Tables)	3 Months Ended
	Mar. 31, 2015																			Mar. 31, 2014
Segment Reporting Information [Line Items]
Segment Reporting Disclosure [Text Block]	Financial Data of Business Segments
	The financial data presented below depicts the profitability, financial position, and capital expenditures of each of our business segments.
	We lease, operate, manage, and remarket long-lived, widely-used assets, primarily in the rail and marine markets. We also invest in joint ventures that complement our existing business activities. We report our financial results through four primary business segments: Rail North America, Rail International, ASC, and Portfolio Management.
	Rail North America comprises our wholly owned operations in the United States, Canada, and Mexico, as well as an affiliate investment. Rail North America primarily provides railcars pursuant to full-service leases under which it maintains the railcars, pays ad valorem taxes and insurance, and provides other ancillary services.
	Rail International comprises our wholly owned European operations ("GATX Rail Europe" or "GRE"), a railcar leasing business in India ("GATX India Pte. Ltd." or "GIPL"), and a recently established railcar leasing business in Russia ("GATX Rail Vostok LLC" or "GRV"), as well as one development stage affiliate in China. GRE leases railcars to customers throughout Europe pursuant to full-service leases under which it maintains the railcars and provides insurance and other ancillary services.
	ASC operates the largest fleet of US-flagged vessels on the Great Lakes, providing waterborne transportation of dry bulk commodities such as iron ore, coal, limestone aggregates, and metallurgical limestone.
	Portfolio Management generates leasing, marine operating, asset remarketing and management fee income through a collection of diversified wholly owned assets and joint venture investments.
	Segment profit is an internal performance measure used by the Chief Executive Officer to assess the performance of each segment in a given period. Segment profit includes all revenues, pretax earnings from affiliates, and net gains on asset dispositions that are attributable to the segments, as well as expenses that management believes are directly associated with the financing, maintenance, and operation of the revenue earning assets. Segment profit excludes selling, general and administrative expenses, income taxes, and certain other amounts not allocated to the segments. These amounts are included in Other.
	We allocate debt balances and related interest expense to each segment based upon a predetermined fixed recourse leverage level expressed as a ratio of recourse debt (including off-balance-sheet debt) to equity. The leverage levels are 5:1 for Rail North America, 2:1 for Rail International, 1.5:1 for ASC, and 3:1 for Portfolio Management. We believe that by using this leverage and interest expense allocation methodology, each operating segment’s financial performance reflects appropriate risk-adjusted borrowing costs.
	The following tables show certain segment data for each of our business segments (in millions):
		Rail North America			Rail International			ASC			Portfolio Management			Other			GATX Consolidated
	Three Months Ended March 31, 2015
	Profitability
	Revenues
	Lease revenue	$	228.5		$	42.1		$	1		$	6.7		$	—		$	278.3
	Marine operating revenue	—			—			7			17.2			—			24.2
	Other revenue	14.7			1.9			—			0.6			—			17.2
	Total Revenues	243.2			44			8			24.5			—			319.7
	Expenses
	Maintenance expense	69.2			8.9			0.2			—			—			78.3
	Marine operating expense	—			—			6.9			12			—			18.9
	Depreciation expense	52.3			10.7			—			5.5			—			68.5
	Operating lease expense	20.7			—			—			—			—			20.7
	Other operating expense	5.5			0.9			—			0.9			—			7.3
	Total Expenses	147.7			20.5			7.1			18.4			—			193.7
	Other Income (Expense)
	Net gain on asset dispositions	36.8			4.9			—			3.6			—			45.3
	Interest expense, net	(24.5		)	(6.5		)	(1.3		)	(5.2		)	(3.4		)	(40.9		)
	Other expense	(2.2		)	—			—			—			(1.8		)	(4.0		)
	Share of affiliates' earnings (pretax)	0.2			(0.1		)	—			11.4			—			11.5
	Segment Profit (Loss)	$	105.8		$	21.8		$	(0.4	)	$	15.9		$	(5.2	)	137.9
	Selling, general and administrative expense																45.7
	Income taxes (including $3.0 related to affiliates' earnings)																30
	Net Income																$	62.2
	Net Gain on Asset Dispositions
	Asset Remarketing Income:
	Disposition gains on owned assets	$	35.9		$	—		$	—		$	2		$	—		$	37.9
	Residual sharing income	0.2			—			—			1.6			—			1.8
	Non-remarketing disposition gains (1)	0.7			5			—			—			—			5.7
	Asset impairment	—			(0.1		)	—			—			—			(0.1		)
		$	36.8		$	4.9		$	—		$	3.6		$	—		$	45.3
	Capital Expenditures
	Portfolio investments and capital additions	$	129.8		$	41.4		$	9.3		$	—		$	0.4		$	180.9
	Selected Balance Sheet Data at March 31, 2015
	Investments in affiliated companies	$	13.9		$	1.6		$	—		$	344.2		$	—		$	359.7
	Identifiable assets	$	4,518.90		$	1,161.00		$	273.5		$	794.4		$	308.6		$	7,056.40
	_____
	(1) Includes scrapping gains.
		Rail North America			Rail International			ASC			Portfolio Management			Other			GATX Consolidated
	Three Months Ended March 31, 2014
	Profitability
	Revenues
	Lease revenue	$	194.9		$	47.2		$	1.1		$	7.4		$	—		$	250.6
	Marine operating revenue	—			—			3.1			14.6			—			17.7
	Other revenue	14.6			2			—			1.7			—			18.3
	Total Revenues	209.5			49.2			4.2			23.7			—			286.6
	Expenses
	Maintenance expense	61.4			11.5			0.2			—			—			73.1
	Marine operating expense	—			—			3.4			11.6			—			15
	Depreciation expense	41.5			11.7			—			5.5			—			58.7
	Operating lease expense	26.9			—			—			—			—			26.9
	Other operating expense	4.8			1.4			—			0.4			—			6.6
	Total Expenses	134.6			24.6			3.6			17.5			—			180.3
	Other Income (Expense)
Net gain on asset dispositions	24.8			2.4			(0.4		)	1.3			—			28.1
Interest expense, net	(24.6		)	(6.2		)	(1.4		)	(6.8		)	(3.0		)	(42.0		)
Other (expense) income	(3.4		)	—			—			0.3			(0.3		)	(3.4		)
Share of affiliates' earnings (pretax)	3.3			(0.1		)	—			10.9			—			14.1
Segment Profit (Loss)	$	75		$	20.7		$	(1.2	)	$	11.9		$	(3.3	)	103.1
Selling, general and administrative expense																42.7
Income taxes (including $4.2 related to affiliates' earnings)																18.3
Net Income																$	42.1
Net Gain on Asset Dispositions
Asset Remarketing Income:
Disposition gains on owned assets	$	21.6		$	—		$	—		$	—		$	—		$	21.6
Residual sharing income	0.6			—			—			1.2			—			1.8
Non-remarketing disposition gains (1)	2.6			2.4			—			—			—			5
Asset impairment	—			—			(0.4		)	0.1			—			(0.3		)
	$	24.8		$	2.4		$	(0.4	)	$	1.3		$	—		$	28.1
Capital Expenditures
Portfolio investments and capital additions	$	396		$	39.3		$	8.3		$	—		$	1.9		$	445.5
Selected Balance Sheet Data at December 31, 2014
Investments in affiliated companies	$	17.2		$	1.8		$	—		$	338.7		$	—		$	357.7
Identifiable assets	$	4,358.30		$	1,229.40		$	286.7		$	813.3		$	249.8		$	6,937.50
_____
(1) Includes scrapping gains.
Segment data																				The following tables show certain segment data for each of our business segments (in millions):
																					Rail North America			Rail International			ASC			Portfolio Management			Other			GATX Consolidated
																				Three Months Ended March 31, 2015
																				Profitability
																				Revenues
																				Lease revenue	$	228.5		$	42.1		$	1		$	6.7		$	—		$	278.3
																				Marine operating revenue	—			—			7			17.2			—			24.2
																				Other revenue	14.7			1.9			—			0.6			—			17.2
																				Total Revenues	243.2			44			8			24.5			—			319.7
																				Expenses
																				Maintenance expense	69.2			8.9			0.2			—			—			78.3
																				Marine operating expense	—			—			6.9			12			—			18.9
																				Depreciation expense	52.3			10.7			—			5.5			—			68.5
																				Operating lease expense	20.7			—			—			—			—			20.7
																				Other operating expense	5.5			0.9			—			0.9			—			7.3
																				Total Expenses	147.7			20.5			7.1			18.4			—			193.7
																				Other Income (Expense)
																				Net gain on asset dispositions	36.8			4.9			—			3.6			—			45.3
																				Interest expense, net	(24.5		)	(6.5		)	(1.3		)	(5.2		)	(3.4		)	(40.9		)
																				Other expense	(2.2		)	—			—			—			(1.8		)	(4.0		)
																				Share of affiliates' earnings (pretax)	0.2			(0.1		)	—			11.4			—			11.5
																				Segment Profit (Loss)	$	105.8		$	21.8		$	(0.4	)	$	15.9		$	(5.2	)	137.9
																				Selling, general and administrative expense																45.7
																				Income taxes (including $3.0 related to affiliates' earnings)																30
																				Net Income																$	62.2
																				Net Gain on Asset Dispositions
																				Asset Remarketing Income:
																				Disposition gains on owned assets	$	35.9		$	—		$	—		$	2		$	—		$	37.9
																				Residual sharing income	0.2			—			—			1.6			—			1.8
																				Non-remarketing disposition gains (1)	0.7			5			—			—			—			5.7
																				Asset impairment	—			(0.1		)	—			—			—			(0.1		)
																					$	36.8		$	4.9		$	—		$	3.6		$	—		$	45.3
																				Capital Expenditures
																				Portfolio investments and capital additions	$	129.8		$	41.4		$	9.3		$	—		$	0.4		$	180.9
																				Selected Balance Sheet Data at March 31, 2015
																				Investments in affiliated companies	$	13.9		$	1.6		$	—		$	344.2		$	—		$	359.7
																				Identifiable assets	$	4,518.90		$	1,161.00		$	273.5		$	794.4		$	308.6		$	7,056.40
																				_____
																				(1) Includes scrapping gains.
																					Rail North America			Rail International			ASC			Portfolio Management			Other			GATX Consolidated
																				Three Months Ended March 31, 2014
																				Profitability
																				Revenues
																				Lease revenue	$	194.9		$	47.2		$	1.1		$	7.4		$	—		$	250.6
																				Marine operating revenue	—			—			3.1			14.6			—			17.7
																				Other revenue	14.6			2			—			1.7			—			18.3
																				Total Revenues	209.5			49.2			4.2			23.7			—			286.6
																				Expenses
																				Maintenance expense	61.4			11.5			0.2			—			—			73.1
																				Marine operating expense	—			—			3.4			11.6			—			15
																				Depreciation expense	41.5			11.7			—			5.5			—			58.7
																				Operating lease expense	26.9			—			—			—			—			26.9
																				Other operating expense	4.8			1.4			—			0.4			—			6.6
																				Total Expenses	134.6			24.6			3.6			17.5			—			180.3
																				Other Income (Expense)
																				Net gain on asset dispositions	24.8			2.4			(0.4		)	1.3			—			28.1
																				Interest expense, net	(24.6		)	(6.2		)	(1.4		)	(6.8		)	(3.0		)	(42.0		)
																				Other (expense) income	(3.4		)	—			—			0.3			(0.3		)	(3.4		)
																				Share of affiliates' earnings (pretax)	3.3			(0.1		)	—			10.9			—			14.1
																				Segment Profit (Loss)	$	75		$	20.7		$	(1.2	)	$	11.9		$	(3.3	)	103.1
																				Selling, general and administrative expense																42.7
																				Income taxes (including $4.2 related to affiliates' earnings)																18.3
																				Net Income																$	42.1
																				Net Gain on Asset Dispositions
Asset Remarketing Income:
Disposition gains on owned assets	$	21.6		$	—		$	—		$	—		$	—		$	21.6
Residual sharing income	0.6			—			—			1.2			—			1.8
Non-remarketing disposition gains (1)	2.6			2.4			—			—			—			5
Asset impairment	—			—			(0.4		)	0.1			—			(0.3		)
	$	24.8		$	2.4		$	(0.4	)	$	1.3		$	—		$	28.1
Capital Expenditures
Portfolio investments and capital additions	$	396		$	39.3		$	8.3		$	—		$	1.9		$	445.5
Selected Balance Sheet Data at December 31, 2014
Investments in affiliated companies	$	17.2		$	1.8		$	—		$	338.7		$	—		$	357.7
Identifiable assets	$	4,358.30		$	1,229.40		$	286.7		$	813.3		$	249.8		$	6,937.50
_____
(1) Includes scrapping gains.

Description_of_Business_Detail

Description of Business (Details)	3 Months Ended
	Mar. 31, 2015
	Segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of business segments	4

Variable_Interest_Entities_Det

Variable Interest Entities (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Variable Interest Entity [Line Items]
Variable Interest Entity, Qualitative or Quantitative Information, Type of Entity	one
Variable Interest, Held by Entity [Member]
Carrying amounts of assets and liabilities of the VIE
Operating assets, net of accumulated depreciation	86.9	[1]	$88.10	[1]
Nonrecourse debt	13.7		$15.90
[1]	(1) All operating assets are pledged as collateral on the nonrecourse debt.

Variable_Interest_Entities_Det1

Variable Interest Entities (Details 1) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Carrying amounts and maximum exposure to loss with respect to VIEs
Net Carrying Amount	$148.90	$144.30
Maximum Exposure to Loss	148.9	144.3
Investments in Affiliates [Member]
Carrying amounts and maximum exposure to loss with respect to VIEs
Net Carrying Amount	148.5	143.9
Maximum Exposure to Loss	148.5	143.9
Other investment [Member]
Carrying amounts and maximum exposure to loss with respect to VIEs
Net Carrying Amount	0.4	0.4
Maximum Exposure to Loss	$0.40	$0.40

Fair_Value_Disclosure_Details

Fair Value Disclosure (Details) (Fair Value, Measurements, Recurring [Member], USD $)	Mar. 31, 2015		Dec. 31, 2014
In Millions, unless otherwise specified
Assets
Available for sale equity securities	$4.40		$4.40
Designated as Hedging Instrument [Member]
Assets
Interest rate derivatives	2.9	[1]	1.8	[1]
Liabilities
Interest rate derivatives			5.9	[1]
Not Designated as Hedging Instrument [Member]
Assets
Foreign exchange rate derivatives	18.4	[2]	9.7	[2]
Liabilities
Foreign exchange rate derivatives	5.4	[2]	1.6	[2]
Fair Value, Inputs, Level 1 [Member]
Assets
Available for sale equity securities	4.4		4.4
Fair Value, Inputs, Level 1 [Member] | Designated as Hedging Instrument [Member]
Assets
Interest rate derivatives	0	[1]	0	[1]
Liabilities
Interest rate derivatives			0	[1]
Fair Value, Inputs, Level 1 [Member] | Not Designated as Hedging Instrument [Member]
Assets
Foreign exchange rate derivatives	0	[2]	0	[2]
Liabilities
Foreign exchange rate derivatives	0	[2]	0	[2]
Fair Value, Inputs, Level 2 [Member]
Assets
Available for sale equity securities	0		0
Fair Value, Inputs, Level 2 [Member] | Designated as Hedging Instrument [Member]
Assets
Interest rate derivatives	2.9	[1]	1.8	[1]
Liabilities
Interest rate derivatives			5.9	[1]
Fair Value, Inputs, Level 2 [Member] | Not Designated as Hedging Instrument [Member]
Assets
Foreign exchange rate derivatives	18.4	[2]	9.7	[2]
Liabilities
Foreign exchange rate derivatives	5.4	[2]	1.6	[2]
Fair Value, Inputs, Level 3 [Member]
Assets
Available for sale equity securities	0		0
Fair Value, Inputs, Level 3 [Member] | Designated as Hedging Instrument [Member]
Assets
Interest rate derivatives	0	[1]	0	[1]
Liabilities
Interest rate derivatives			0	[1]
Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member]
Assets
Foreign exchange rate derivatives	0	[2]	0	[2]
Liabilities
Foreign exchange rate derivatives	$0	[2]	$0	[2]
[1]	(1) Designated as hedges
[2]	(2) Not designated as hedges

Fair_Value_Disclosure_Details_

Fair Value Disclosure (Details 2) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Interest Expense [Member] | Fair Value Hedging [Member]
Impact of GATX's Derivative Instrument on Income Statement and Other comprehensive income (loss)
Interest expense	($2.30)	[1]	$2.10	[1]
Interest Expense [Member] | Cash Flow Hedges [Member]
Impact of GATX's Derivative Instrument on Income Statement and Other comprehensive income (loss)
Effective portion reclassified from accumulated other comprehensive loss	1.3		1.2
Other Comprehensive Income (Loss) [Member] | Cash Flow Hedges [Member]
Impact of GATX's Derivative Instrument on Income Statement and Other comprehensive income (loss)
Other comprehensive loss (effective portion)	-8.4		1.8
Operating Expense [Member] | Cash Flow Hedges [Member]
Impact of GATX's Derivative Instrument on Income Statement and Other comprehensive income (loss)
Effective portion reclassified from accumulated other comprehensive loss	0.1		0.2
Other Expense [Member] | Cash Flow Hedges [Member]
Impact of GATX's Derivative Instrument on Income Statement and Other comprehensive income (loss)
Other expense	-8.4		2.2
Not Designated as Hedging Instrument [Member] | Other Expense [Member]
Impact of GATX's Derivative Instrument on Income Statement and Other comprehensive income (loss)
Other expense	-4.2		0.1
Not Designated as Hedging Instrument [Member] | Other Expense [Member] | Aae Cargo Ag [Member]
Impact of GATX's Derivative Instrument on Income Statement and Other comprehensive income (loss)
Other expense	5.1
Foreign Currency Gain (Loss) [Member] | Other Expense [Member] | Cash Flow Hedges [Member]
Impact of GATX's Derivative Instrument on Income Statement and Other comprehensive income (loss)
Other expense	$9.90
[1]	(1) The fair value adjustments related to the underlying debt equally offset the amounts recognized in interest expense.

Fair_Value_Disclosure_Details_1

Fair Value Disclosure (Details 3) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Assets
Loans	$13.40	$97.30
Carrying Amount [Member]
Assets
Investment Funds	1.3	1.5
Loans	13.4	97.3
Liabilities
Recourse fixed rate debt	4,068.80	3,639.90
Recourse floating rate debt	375.1	540
Nonrecourse debt	13.7	15.9
Fair Value [Member]
Assets
Investment Funds	2.1	2.4
Loans	13.4	97.4
Liabilities
Recourse fixed rate debt	4,219.10	3,775
Recourse floating rate debt	376	540
Nonrecourse debt	$14.30	$16.60

Fair_Value_Disclosure_Details_2

Fair Value Disclosure (Details Textual) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Sep. 30, 2014	Dec. 31, 2014
Fair Value Disclosure (Textual) [Abstract]
Derivative Asset, Notional Amount	$600
Derivative, Notional Amount	312.6		281.5
Cash Flow Hedge Pre Tax Gain Loss to be Reclassified within Twelve Months	-5.9
Expected After tax reclassification of net losses from accumulated other comprehensive income to earnings in Next Twelve Months	3.7
Aggregate fair value of all derivative instruments with Net liability position	$0
Fair Value Hedging [Member]
Fair Value Disclosure (Textual) [Abstract]
Number of instruments, outstanding	8
Maturity Date Range of Derivative Instruments		2015 to 2020
Cash Flow Hedges [Member]
Fair Value Disclosure (Textual) [Abstract]
Number of instruments, outstanding	6		7
Maturity Date Range of Derivative Instruments	2015 to 2022

Pension_and_Other_PostRetireme2

Pension and Other Post-Retirement Benefits (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Defined Benefit Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$1.70	$1.40
Interest cost	4.9	5.1
Expected return on plan assets	-6.5	-7.2
Unrecognized prior service credit	-0.2	-0.2
Unrecognized net actuarial loss	3.5	2.6
Net expense	3.4	1.7
Retiree Health and Life [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0
Interest cost	0.4	0.4
Expected return on plan assets	0	0
Unrecognized prior service credit	0	0
Unrecognized net actuarial loss	0	0
Net expense	$0.40	$0.40

Share_Based_Compensation_Detai

Share Based Compensation (Details Textual) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$2.90	$3.10
Tax benefit from share-based compensation expense	$1.10	$1.20
Stock Option SAR Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units granted during period	341,100
Restricted Stock and Performance Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units granted during period	65,640
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units granted during period	61,740
Phantom Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units granted during period	5,091

Share_Based_Compensation_Weigh

Share Based Compensation - Weighted Average and Assumptions (Details) (USD $)	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Estimated fair value	$18.16
Quarterly dividend rate	$0.38
Risk-free interest rate	1.20%
Dividend yield	2.60%
Expected stock price volatility	29.20%
Present value of dividends	$6.90

Income_Taxes_Details_Textual

Income Taxes (Details Textual) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Sep. 30, 2014
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits	$5.60
Effective Income Tax Rate Reconciliation, Percent	33.00%	30.00%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	35.00%
Unrecognized Tax Benefits that Would Impact Effective Tax Rate			5.6
Decrease in Income Tax Expenses Unrecognized Tax Benefits if Recognized Net of Federal Tax	$3.60

Income_Taxes_Effective_tax_rat

Income Taxes Effective tax rate (Details)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, Percent	33.00%	30.00%

Income_Taxes_Effective_Income_

Income Taxes Effective Income Tax Reconciliation, Percent (Details)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, Percent	33.00%	30.00%

Income_Taxes_Statutory_Tax_Rat

Income Taxes Statutory Tax Rate Reconciliation, Percent (Details)	3 Months Ended
	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	35.00%

Commercial_Commitments_Details

Commercial Commitments (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Millions, unless otherwise specified
Guarantor Obligations [Line Items]
Total commercial commitments	$35.80	[1]	$37.60	[1]
Lease payment guarantees [Member]
Guarantor Obligations [Line Items]
Total commercial commitments	26.8		28.5
Standby letters of credit [Member]
Guarantor Obligations [Line Items]
Total commercial commitments	8.6		8.7
Performance bonds [Member]
Guarantor Obligations [Line Items]
Total commercial commitments	$0.40		$0.40
[1]	(1) The carrying value of liabilities on the balance sheet for commercial commitments was $4.9 million at March 31, 2015 and $5.1 million at December 31, 2014. The expirations of these commitments range from 2017 to 2023. We are not aware of any event that would require us to satisfy any of our commitments.

Commercial_Commitments_Details1

Commercial Commitments (Details Textual) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Guarantees [Abstract]
Amount of liability included in recorded value of the company's commitment	$4.90	$5.10
Expiration of commitment range	2017 to 2023

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended		15 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015
Earnings Per Share [Abstract]
Stock Repurchase Program, Authorized Amount		$250,000,000
Stock Repurchased During Period, Shares	500,000		2,400,000
Treasury Stock, Value, Acquired, Cost Method	27,000,000		151,600,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	98,400,000		98,400,000
Numerator:
Net income	$62,200,000	$42,100,000
Denominator:
Denominator for basic earnings per share — weighted average shares	44,100,000	46,000,000
Effect of dilutive securities:
Equity compensation plans	700,000	800,000
Denominator for diluted earnings per share — adjusted weighted average and assumed conversion	44,800,000	46,800,000
Basic earnings per share (in dollars per share)	$1.41	$0.92
Diluted earnings per share (in dollars per share)	$1.39	$0.90

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Loss) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Equity [Abstract]
Beginning Balance, Foreign Currency Translation Gain (Loss)	($21.90)
Change in Foreign Currency Translation Gain (Loss)	-48
Foreign currency translation gain loss before reclassification adjustment into earnings	0
Foreign Currency Translation Gain (Loss), Income tax effect	0
Ending Balance, Foreign Currency Translation Gain (Loss)	-69.9
Beginning Balance, Unrealized Gain (Loss) on Securities	0.3
Change in Unrealized Gain (Loss) on Securities	0
Unrealized Gain (Loss) on Securities, Reclassification adjustments into earnings	0
Unrealized Gain (Loss) on Securities, Income tax effect	0
Ending Balance, Unrealized Gain (Loss) on Securities	0.3
Beginning Balance, Unrealized Loss on Derivative Instruments	-19.1
Change in Unrealized Loss on Derivative Instruments	6
Unrealized Loss on Derivative Instruments, Reclassification adjustments into earnings	-7
Unrealized Loss on Derivative Instruments, Income tax effect	-1.6
Ending Balance, Unrealized Loss on Derivative Instruments	-21.7
Beginning Balance, Post-Retirement Benefit Plans	-107.7
Change in Post-Retirement Benefit Plans	0
Post-Retirement Benefit Plans, Reclassification adjustments into earnings	3.3
Post-Retirement Benefit Plans, Income tax effect	-1.2
Ending Balance, Post-Retirement Benefit Plans	-105.6
Other Comprehensive Income Change in Component	-42
Reclassification adjustments into earnings, Total	-3.7
Income tax effect, Total	-2.8
Accumulated other comprehensive income (loss), net of tax	($196.90)	($148.40)

Legal_Proceedings_and_Other_Co1

Legal Proceedings and Other Contingencies (Details) (Viareggio [Member], USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Oct. 02, 2013	Dec. 14, 2012	Jun. 29, 2009
	case	Insurance_Provider	Corporations
			Employee
Loss Contingencies [Line Items]
Number of casualties				32
Number of subsidiaries			2
Number of Maintenance and Supervisory employees			10
Number of Italian railway companies			4
Number of employees			18
Loss Contingency, Pending Claims, Number	90
Number of insurers		3
Court Proceedings	1
Legal Fees	$7.80
Percentage of coverage held by Liberty Mutual Insurance Europe Limited		25.00%
Derailed [Member]
Loss Contingencies [Line Items]
number of railcars				14
Overturned [Member]
Loss Contingencies [Line Items]
number of railcars				5
Punctured and Ignited [Member]
Loss Contingencies [Line Items]
number of railcars				1

Financial_Data_of_Business_Seg2

Financial Data of Business Segments (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
	Segment
Segment Reporting Information [Line Items]
Lease Income	$278.30	$250.60
Cargo and Freight Revenue	24.2	17.7
Provision for Income Taxes, Equity Method Investment	3	4.2
Number of business segments	4
Profitability
Other revenue	17.2	18.3
Maintenance expense	78.3	73.1
Depreciation expense	68.5	58.7
Marine operating expense	18.9	15
Operating lease expense	20.7	26.9
Other operating expense	7.3	6.6
Total Expenses	193.7	180.3
Disposition gains on owned assets	37.9	21.6
Residual sharing income	1.8	1.8
Nonremarketing disposition gains	5.7	5
Asset impairment	-0.1	-0.3
Net gain on asset dispositions	45.3	28.1
Interest expense, net	-40.9	-42
Other (expense) income	-4	-3.4
Share of affiliates' earnings (pre-tax)	11.5	14.1
Segment profit (loss)	137.9	103.1
SG&A	45.7	42.7
Income tax benefit	27	14.1
Net Income	62.2	42.1
Revenues	319.7	286.6
Selected Balance Sheet Data
Portfolio Investments and Capital Additions	180.9	445.5
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	359.7		357.7
Identifiable assets	7,056.40		6,937.50
Rail North America [Member]
Segment Reporting Information [Line Items]
Lease Income	228.5	194.9
Cargo and Freight Revenue	0	0
Leverage level expressed as a ratio of recourse debt to equity	5
Profitability
Other revenue	14.7	14.6
Maintenance expense	69.2	61.4
Depreciation expense	52.3	41.5
Marine operating expense	0	0
Operating lease expense	20.7	26.9
Other operating expense	5.5	4.8
Total Expenses	147.7	134.6
Disposition gains on owned assets	35.9	21.6
Residual sharing income	0.2	0.6
Nonremarketing disposition gains	0.7	2.6
Asset impairment	0	0
Net gain on asset dispositions	36.8	24.8
Interest expense, net	-24.5	-24.6
Other (expense) income	-2.2	-3.4
Share of affiliates' earnings (pre-tax)	0.2	3.3
Segment profit (loss)	105.8	75
Revenues	243.2	209.5
Selected Balance Sheet Data
Portfolio Investments and Capital Additions	129.8	396
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	13.9		17.2
Identifiable assets	4,518.90		4,358.30
Rail International [Member]
Segment Reporting Information [Line Items]
Lease Income	42.1	47.2
Cargo and Freight Revenue	0	0
Leverage level expressed as a ratio of recourse debt to equity	2
Profitability
Other revenue	1.9	2
Maintenance expense	8.9	11.5
Depreciation expense	10.7	11.7
Marine operating expense	0	0
Operating lease expense	0	0
Other operating expense	0.9	1.4
Total Expenses	20.5	24.6
Disposition gains on owned assets	0	0
Residual sharing income	0	0
Nonremarketing disposition gains	5	2.4
Asset impairment	-0.1	0
Net gain on asset dispositions	4.9	2.4
Interest expense, net	-6.5	-6.2
Other (expense) income	0	0
Share of affiliates' earnings (pre-tax)	-0.1	-0.1
Segment profit (loss)	21.8	20.7
Revenues	44	49.2
Selected Balance Sheet Data
Portfolio Investments and Capital Additions	41.4	39.3
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	1.6		1.8
Identifiable assets	1,161		1,229.40
ASC [Member]
Segment Reporting Information [Line Items]
Lease Income	1	1.1
Cargo and Freight Revenue	7	3.1
Leverage level expressed as a ratio of recourse debt to equity	1.5
Profitability
Other revenue	0	0
Maintenance expense	0.2	0.2
Depreciation expense	0	0
Marine operating expense	6.9	3.4
Operating lease expense	0	0
Other operating expense	0	0
Total Expenses	7.1	3.6
Disposition gains on owned assets	0	0
Residual sharing income	0	0
Nonremarketing disposition gains	0	0
Asset impairment	0	-0.4
Net gain on asset dispositions	0	-0.4
Interest expense, net	-1.3	-1.4
Other (expense) income	0	0
Share of affiliates' earnings (pre-tax)	0	0
Segment profit (loss)	-0.4	-1.2
Revenues	8	4.2
Selected Balance Sheet Data
Portfolio Investments and Capital Additions	9.3	8.3
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0		0
Identifiable assets	273.5		286.7
Portfolio Management [Member]
Segment Reporting Information [Line Items]
Lease Income	6.7	7.4
Cargo and Freight Revenue	17.2	14.6
Leverage level expressed as a ratio of recourse debt to equity	3
Profitability
Other revenue	0.6	1.7
Maintenance expense	0	0
Depreciation expense	5.5	5.5
Marine operating expense	12	11.6
Operating lease expense	0	0
Other operating expense	0.9	0.4
Total Expenses	18.4	17.5
Disposition gains on owned assets	2	0
Residual sharing income	1.6	1.2
Nonremarketing disposition gains	0	0
Asset impairment	0	0.1
Net gain on asset dispositions	3.6	1.3
Interest expense, net	-5.2	-6.8
Other (expense) income	0	0.3
Share of affiliates' earnings (pre-tax)	11.4	10.9
Segment profit (loss)	15.9	11.9
Revenues	24.5	23.7
Selected Balance Sheet Data
Portfolio Investments and Capital Additions	0	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	344.2		338.7
Identifiable assets	794.4		813.3
Other [Member]
Segment Reporting Information [Line Items]
Lease Income	0	0
Cargo and Freight Revenue	0	0
Profitability
Other revenue	0	0
Maintenance expense	0	0
Depreciation expense	0	0
Marine operating expense	0	0
Operating lease expense	0	0
Other operating expense	0	0
Total Expenses	0	0
Disposition gains on owned assets	0	0
Residual sharing income	0	0
Nonremarketing disposition gains	0	0
Asset impairment	0	0
Net gain on asset dispositions	0	0
Interest expense, net	-3.4	-3
Other (expense) income	-1.8	-0.3
Share of affiliates' earnings (pre-tax)	0	0
Segment profit (loss)	-5.2	-3.3
Revenues	0	0
Selected Balance Sheet Data
Portfolio Investments and Capital Additions	0.4	1.9
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0		0
Identifiable assets	308.6		249.8
Parent [Member]
Profitability
Income tax benefit	$30	$18.30