Commitments and Contingencies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Financial Guarantee [Member]
Loss Contingencies [Line Items]
Letter of credit outstanding, amount	$ 5.3		$ 5.3
Percent guarantee of unconsolidated affiliate debt	50.00%		50.00%
KCSM [Member]
Loss Contingencies [Line Items]
Total period of time for payments due under railroad Concession to Mexican government			50 years
Percentage of gross revenue payable under railroad Concession to Mexican government			1.25%
KCSM [Member] | Materials and Other Expense [Member]
Loss Contingencies [Line Items]
Concession duty expense	4.2	3.7	11.8	10.5
NAFTA [Member]
Loss Contingencies [Line Items]
Value added tax receivable, noncurrent	$ 14.0		$ 14.0
Panama Canal Railway Company [Member] | Financial Guarantee [Member] | 7.0% Senior Secured Notes due November 1, 2026 [Member]
Loss Contingencies [Line Items]
Debt instrument, stated interest rate	7.00%		7.00%
Debt instrument, maturity date			Nov. 01, 2026