Other Financial Information, Property and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property and Equipment [Line Items]
Property and equipment, gross	$ 2,157.1	$ 1,976.2
Construction-in-process, gross	26.2	158.2
Accumulated depreciation	(1,093.3)	(955.2)
Property and equipment, net	1,063.8	1,021.0
Depreciation expense	184.5	141.5	$ 141.9
Computers and equipment [Member]
Property and Equipment [Line Items]
Property and equipment, gross	1,070.1	915.1
Software [Member]
Property and Equipment [Line Items]
Property and equipment, gross	285.4	169.1
Leasehold Improvements [Member]
Property and Equipment [Line Items]
Property and equipment, gross	235.6	203.4
Furniture and fixtures [Member]
Property and Equipment [Line Items]
Property and equipment, gross	47.0	43.2
Building and Building Improvements [Member]
Property and Equipment [Line Items]
Property and equipment, gross	251.8	246.1
Land and land improvements [Member]
Property and Equipment [Line Items]
Property and equipment, gross	$ 241.0	$ 241.1

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.

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+ References

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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