Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues:
Total revenues	$ 1,547.0	$ 1,542.2	$ 1,676.8	$ 1,626.7	$ 1,661.4	$ 1,562.8	$ 1,485.3	$ 1,460.5	$ 6,392.7	$ 6,170.0	$ 4,365.3
Cost of revenues:
Total cost of revenues	1,116.1	1,109.4	1,219.6	1,211.1	1,275.3	1,172.2	1,098.3	1,074.0	4,656.2	4,619.8	3,322.3
Selling, engineering, and administrative expenses	137.1	126.6	114.4	98.3	110.6	113.0	96.4	83.6	476.4	403.6	291.3
Gains on disposition of property	64.2	58.7	40.1	15.8	1.0	3.6	11.4	88.4	178.8	104.4	21.2
Operating profit	358.0	364.9	382.9	333.1	276.5	281.2	302.0	391.3	1,438.9	1,251.0	772.9
Net income	204.0	212.2	220.8	189.0	146.3	156.9	173.1	233.0	826.0	709.3	392.4
Net income attributable to Trinity Industries, Inc.	$ 200.0	$ 204.3	$ 212.0	$ 180.2	$ 138.2	$ 149.4	$ 164.2	$ 226.4	$ 796.5	$ 678.2	$ 375.5
Net income attributable to Trinity Industries, Inc. per common share:
Basic (in dollars per share)	$ 1.30	$ 1.32	$ 1.36	$ 1.15	$ 0.89	$ 0.95	$ 1.05	$ 1.46	$ 5.14	$ 4.35	$ 2.38
Diluted (in dollars per share)	$ 1.30	$ 1.31	$ 1.33	$ 1.13	$ 0.86	$ 0.90	$ 1.01	$ 1.42	$ 5.08	$ 4.19	$ 2.38
Manufacturing
Revenues:
Total revenues	$ 1,177.6	$ 1,295.6	$ 1,445.4	$ 1,382.5	$ 1,425.6	$ 1,359.8	$ 1,259.9	$ 1,018.3	$ 5,301.1	$ 5,063.6	$ 3,719.9
Cost of revenues:
Total cost of revenues	881.6	976.0	1,101.8	1,084.5	1,147.6	1,062.6	970.2	794.7	4,043.9	3,975.1	2,990.9
Selling, engineering, and administrative expenses									271.4	235.0	180.4
Leasing
Revenues:
Total revenues	369.4	246.6	231.4	244.2	235.8	203.0	225.4	442.2	1,091.6	1,106.4	645.4
Cost of revenues:
Total cost of revenues	$ 234.5	$ 133.4	$ 117.8	$ 126.6	$ 127.7	$ 109.6	$ 128.1	$ 279.3	612.3	644.7	331.4
Selling, engineering, and administrative expenses									$ 52.4	$ 49.6	$ 37.6