Segment Information Segment Information by Major Geographic Area (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues and Long-Lived Assets
Long-Lived Assets	$ 840.1				$ 796.5				$ 840.1	$ 796.5
Revenue	2,063.3	1,670.4	1,715.7	1,506.8	2,072.6	1,726.5	1,740.7	1,474.8	6,956.2	7,014.6	6,507.3
Domestic
Revenues and Long-Lived Assets
Long-Lived Assets	502.5				477.2				502.5	477.2
Revenue									3,803.6	3,887.7	3,709.9
Total international
Revenues and Long-Lived Assets
Long-Lived Assets	337.6				319.3				337.6	319.3
Revenue									3,152.6	3,126.9	2,797.4
United Kingdom
Revenues and Long-Lived Assets
Long-Lived Assets	64.3				65.2				64.3	65.2
Revenue									572.0	539.4	469.6
Continental Europe
Revenues and Long-Lived Assets
Long-Lived Assets	76.0				72.1				76.0	72.1
Revenue									823.1	908.9	863.2
Asia Pacific
Revenues and Long-Lived Assets
Long-Lived Assets	88.0				78.4				88.0	78.4
Revenue									838.1	741.7	639.8
Latin America
Revenues and Long-Lived Assets
Long-Lived Assets	70.5				69.1				70.5	69.1
Revenue									450.1	444.4	363.3
Other
Revenues and Long-Lived Assets
Long-Lived Assets	38.8				34.5				38.8	34.5
Revenue									$ 469.3	$ 492.5	$ 461.5