Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities:
Net income	$ 364.7	$ 826.0	$ 709.3
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	283.0	266.4	244.6
Stock-based compensation expense	41.3	61.1	53.3
Excess tax benefits from stock-based compensation	(1.0)	(13.3)	(24.4)
Provision (benefit) for deferred income taxes	321.4	116.6	(5.8)
Net gains on railcar lease fleet sales owned more than one year at the time of sale	(13.5)	(166.1)	(92.3)
Gains on disposition of property and other assets	(3.9)	(12.7)	(12.1)
Non-cash interest expense	28.5	30.1	30.7
Other	(3.4)	(2.5)	(4.5)
Changes in assets and liabilities:
(Increase) decrease in receivables	(16.0)	(0.8)	(56.4)
(Increase) decrease in inventories	273.3	128.5	(186.3)
(Increase) decrease in restricted cash	0.0	(9.4)	25.0
(Increase) decrease in other assets	18.6	(40.9)	(8.3)
Increase (decrease) in accounts payable	(60.7)	(78.6)	60.7
Increase (decrease) in accrued liabilities	(104.9)	(169.6)	82.1
Increase (decrease) in other liabilities	(37.2)	4.9	2.6
Net cash provided by operating activities - continuing operations	1,090.2	939.7	818.2
Net cash provided by operating activities - discontinued operations	0.0	0.0	1.0
Net cash provided by operating activities	1,090.2	939.7	819.2
Investing activities:
(Increase) decrease in short-term marketable securities	(149.8)	(9.9)	74.7
Proceeds from railcar lease fleet sales owned more than one year at the time of sale	37.7	514.6	265.8
Proceeds from disposition of property and other assets	16.0	8.2	23.0
Capital expenditures – leasing, net of sold lease fleet railcars owned one year or less with a net cost of $92.0, $295.9, and $350.2	(799.1)	(833.8)	(245.3)
Capital expenditures – manufacturing and other	(134.3)	(196.0)	(219.3)
Acquisitions, net of cash acquired	0.0	(46.2)	(714.4)
Divestitures	0.0	51.3	0.0
Other	6.8	0.5	0.8
Net cash required by investing activities - continuing operations	(1,022.7)	(511.3)	(814.7)
Net cash required by investing activities - discontinued operations	0.0	0.0	0.0
Net cash required by investing activities	(1,022.7)	(511.3)	(814.7)
Financing activities:
Proceeds from issuance of common stock, net	0.0	0.3	0.6
Excess tax benefits from stock-based compensation	1.0	13.3	24.4
Payments to retire debt	(162.5)	(587.2)	(186.6)
Proceeds from issuance of debt	0.0	242.4	727.3
(Increase) decrease in restricted cash	17.6	48.3	1.0
Shares repurchased	(34.7)	(115.0)	(36.5)
Dividends paid to common shareholders	(66.7)	(64.9)	(54.4)
Purchase of shares to satisfy employee tax on vested stock	(16.3)	(27.5)	(38.3)
Contributions from noncontrolling interest	0.0	0.0	49.6
Distributions to noncontrolling interest	(26.4)	(39.2)	(28.2)
Other	(2.1)	(0.8)	(2.5)
Net cash provided (required) by financing activities - continuing	(290.1)	(530.3)	456.4
Net cash required by financing activities - discontinued operations	0.0	0.0	(1.5)
Net cash provided (required) by financing activities	(290.1)	(530.3)	454.9
Net increase (decrease) in cash and cash equivalents	(222.6)	(101.9)	459.4
Cash and cash equivalents at beginning of period	786.0	887.9	428.5
Cash and cash equivalents at end of period	563.4	786.0	887.9
Supplemental Cash Flow Information
Interest paid	151.0	164.3	158.3
Income tax payments made, net	$ (57.9)	$ 326.8	$ 399.0