Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Restricted cash	$ 234.8	[1]	$ 240.3
Property, plant, and equipment, at cost	5,636.5	[1]	5,407.9
Less accumulated depreciation	(1,352.8)	[1]	(1,228.4)
Unamortized discount on recourse debt	90.7	[1]	99.8
Preferred stock, shares authorized	1.5	[1]	1.5
Preferred stock, shares unissued	1.5	[1]	1.5
Common stock, shares authorized	200.0	[1]	200.0
TRIP Holdings
Restricted cash	59.0	[1]	74.6
Property, plant, and equipment, at cost	1,272.3	[1]	1,257.7
Less accumulated depreciation	$ (145.2)	[1]	$ (122.7)

[1] (unaudited)