Acquisitions - Con-way Inc. - Additional Information (Details) $ / shares in Units, employee in Thousands, customer in Thousands, $ in Millions		12 Months Ended
	Sep. 09, 2015 USD ($) employee Location customer $ / shares shares	Dec. 31, 2015 USD ($) $ / shares	Sep. 08, 2015 $ / shares	Dec. 31, 2014 USD ($) $ / shares	Dec. 31, 2013 USD ($)
Business Acquisition [Line Items]
Common stock, par value (in usd per share) | $ / shares		$ 0.001	$ 0.001	$ 0.001
Goodwill		$ 4,610.6		$ 929.3	$ 363.4
Con-Way, Inc.
Business Acquisition [Line Items]
Number of locations | Location	582
Entity number of employees | employee	30
Number of customers | customer	36
Common stock, par value (in usd per share) | $ / shares	$ 0.625
Common stock, price per share (in usd per share) | $ / shares	$ 47.60
Shares validly tendered, not properly withdrawn | shares	46,150,072
Percentage of voting interests acquired, validly tendered, not properly withdrawn	81.10%
Equity assumed, Shares | shares	1,793,225
Percentage of common stock acquired	3.20%
Consideration	$ 2,317.8
Cash acquired	(437.3)
Cash consideration	2,706.6
Repayment of indebtedness	17.6
Liability for equity award settlement	30.9
Goodwill	1,188.8
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual		896.2
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual		$ 0.5
Con-Way, Inc. | Transportation
Business Acquisition [Line Items]
Goodwill	897.2
Con-Way, Inc. | Logistics
Business Acquisition [Line Items]
Goodwill	$ 291.6