Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
VIE for Rail	$ 5,868.0	$ 5,692.6
VIE depreciation allowance	2,107.4	2,056.7
VIE nonrecourse debt	136.5	149.4
Common stock, par value	$ 0.625	$ 0.625
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	65,994,298	65,775,568
Common stock, shares outstanding	46,871,778	46,653,048
Treasury stock, shares outstanding	19,122,520	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	16,644
Preferred stock, shares outstanding	15,567	16,644
Preferred stock, aggregate liquidation preference	0.9	1.0
Variable Interest Entity, Primary Beneficiary [Member]
VIE for Rail	123.1	123.5
VIE depreciation allowance	21.9	19.2
VIE nonrecourse debt	$ 40.1	$ 45.2