Revenue Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 714.0	$ 682.4	$ 1,388.8	$ 1,321.0
Freight Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	678.4	653.1	1,321.8	1,264.5
Chemical and Petroleum [Member]
Disaggregation of Revenue [Line Items]
Revenues	188.3	157.8	356.9	297.5
Chemicals [Member]
Disaggregation of Revenue [Line Items]
Revenues	61.6	60.4	122.1	118.1
Petroleum [Member]
Disaggregation of Revenue [Line Items]
Revenues	90.0	57.8	164.3	106.8
Plastics [Member]
Disaggregation of Revenue [Line Items]
Revenues	36.7	39.6	70.5	72.6
Industrial and Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenues	150.3	152.7	300.1	299.0
Forest Products [Member]
Disaggregation of Revenue [Line Items]
Revenues	63.2	69.2	129.6	134.5
Metals and Scrap [Member]
Disaggregation of Revenue [Line Items]
Revenues	59.9	54.0	116.9	107.8
Other Industrial and Consumer Products [Member]
Disaggregation of Revenue [Line Items]
Revenues	27.2	29.5	53.6	56.7
Agriculture and Minerals [Member]
Disaggregation of Revenue [Line Items]
Revenues	122.4	125.1	245.3	238.5
Grain [Member]
Disaggregation of Revenue [Line Items]
Revenues	73.2	75.4	145.9	140.6
Food Products [Member]
Disaggregation of Revenue [Line Items]
Revenues	34.7	36.3	70.4	72.5
Ores and Minerals [Member]
Disaggregation of Revenue [Line Items]
Revenues	5.8	5.8	12.3	10.7
Stone, Clay and Glass [Member]
Disaggregation of Revenue [Line Items]
Revenues	8.7	7.6	16.7	14.7
Energy [Member]
Disaggregation of Revenue [Line Items]
Revenues	53.9	56.5	118.5	117.8
Utility Coal [Member]
Disaggregation of Revenue [Line Items]
Revenues	27.5	23.9	60.0	53.2
Coal and Petroleum Coke [Member]
Disaggregation of Revenue [Line Items]
Revenues	10.1	11.2	20.6	21.4
Frac Sand [Member]
Disaggregation of Revenue [Line Items]
Revenues	6.7	10.5	14.7	21.6
Crude Oil [Member]
Disaggregation of Revenue [Line Items]
Revenues	9.6	10.9	23.2	21.6
Intermodal [Member]
Disaggregation of Revenue [Line Items]
Revenues	92.6	93.7	172.5	184.6
Automotive [Member]
Disaggregation of Revenue [Line Items]
Revenues	70.9	67.3	128.5	127.1
Other Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 35.6	$ 29.3	$ 67.0	$ 56.5