Segment Information (Revenue By Geographic Segment) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2012	Mar. 31, 2011
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues, total	$ 928.4	$ 911.2
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	383.0	361.0
United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	96.2	99.8
Other Foreign [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 449.2	$ 450.4

Revenues from external customers attributed to all foreign countries in total from which the entity derives revenues.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 131

-Paragraph 38

-Subparagraph a(2)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 41

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9038-108599

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration