Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
VIE for Rail	$ 7,390.7	$ 6,855.2
VIE depreciation allowance	2,320.4	2,200.8
VIE nonrecourse debt	72.6	130.6
Common stock, par value	$ 0.625	$ 0.625
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	66,349,906	66,021,444
Common stock, shares outstanding	45,868,698	46,898,924
Treasury stock, shares outstanding	20,118,120	19,122,520
Series A and B $2.50 Cumulative Convertible Preferred Stock [Member]
Preferred stock, par value	$ 1.00	$ 1.00
Preferred stock, shares authorized	(5,000,000)	5,000,000
Preferred stock, shares issued		15,567
Preferred stock, shares outstanding		15,567
Preferred stock, aggregate liquidation preference		0.9
Cumulative annual cash dividend per share on preferred stock	$ 2.50	$ 2.5
Variable Interest Entity, Primary Beneficiary [Member]
VIE for Rail	123.3	123.1
VIE depreciation allowance	30.3	24.7
VIE nonrecourse debt	$ 25.4	$ 35.1