Annual report pursuant to Section 13 and 15(d)

SEGMENT INFORMATION (Financial Information by Geographic Area) (Detail)

v2.4.0.8
SEGMENT INFORMATION (Financial Information by Geographic Area) (Detail) (USD $)
In Millions, unless otherwise specified
 3 Months Ended 12 Months Ended
Dec. 31, 2013
Sep. 30, 2013
Jun. 30, 2013
Mar. 31, 2013
Dec. 31, 2012
Sep. 30, 2012
Jun. 30, 2012
Mar. 31, 2012
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Revenues from External Customers and Long-Lived Assets [Line Items]                      
Operating revenue $ 578.5 $ 572.0 $ 586.9 $ 566.5 $ 533.8 $ 520.0 $ 513.3 $ 505.9 $ 2,303.9 $ 2,073.0 $ 1,893.2
Percentage of operating revenues                 100.00% 100.00% 100.00%
Long-lived assets 3,891.5       3,981.4       3,891.5 3,981.4  
Percentage of consolidated long-lived assets                 100.00% 100.00%  
UNITED STATES
                      
Revenues from External Customers and Long-Lived Assets [Line Items]                      
Operating revenue                 1,766.0 1,561.9 1,374.3
Percentage of operating revenues                 77.00% 76.00% 72.00%
Long-lived assets 3,332.8       3,453.6       3,332.8 3,453.6  
Percentage of consolidated long-lived assets                 86.00% 87.00%  
Canada
                      
Revenues from External Customers and Long-Lived Assets [Line Items]                      
Operating revenue                 155.6 153.9 151.3
Percentage of operating revenues                 7.00% 7.00% 8.00%
Long-lived assets 54.7       63.9       54.7 63.9  
Percentage of consolidated long-lived assets                 1.00% 1.00%  
UNITED KINGDOM
                      
Revenues from External Customers and Long-Lived Assets [Line Items]                      
Operating revenue                 144.7 133.5 124.1
Percentage of operating revenues                 6.00% 6.00% 7.00%
Long-lived assets 122.3       122.3       122.3 122.3  
Percentage of consolidated long-lived assets                 3.00% 3.00%  
Other Countries
                      
Revenues from External Customers and Long-Lived Assets [Line Items]                      
Operating revenue                 237.6 223.7 243.5
Percentage of operating revenues                 10.00% 11.00% 13.00%
Long-lived assets $ 381.7       $ 341.6       $ 381.7 $ 341.6  
Percentage of consolidated long-lived assets                 10.00% 9.00%