Income Taxes Effective Tax Rate Reconciliation (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Tax provision at statutory rate	35.00%	35.00%	35.00%
Effect of acquisitions/divestitures	0.00%	24.80%	(3.10%)
Effect of foreign operations	(2.10%)	(7.70%)	(2.90%)
State income taxes, net of federal income tax benefit	2.20%	3.80%	2.30%
Benefit of track maintenance credit	(21.00%)	0.00%	(6.50%)
Other, net	0.40%	(0.30%)	(0.40%)
Effective income tax rate	14.50%	55.60%	24.40%
Tax credits percentage of qualified maintenance expenditures to reduce federal income tax	50.00%
Tax credits limitation per mile on maintenance expenditures to reduce federal income tax	$ 3,500