Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenue from External Customer [Line Items]
Total revenue	$ 5,244.7	$ 5,121.8	$ 4,513.7
LTL revenue
Revenue from External Customer [Line Items]
Total revenue	4,719.3	4,605.9	4,093.3
Other revenue
Revenue from External Customer [Line Items]
Total revenue	$ 525.4	$ 515.9	$ 420.4