Other Financial Information, Property, Plants and Equipments (Details) (USD $)	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 1,260,400,000	$ 1,065,400,000
Construction in Progress, Gross	99,700,000	41,900,000
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(661,800,000)	(571,500,000)
Property, Plant and Equipment, Net	598,581,000	493,881,000
Depreciation	142,160,000	146,757,000	132,946,000
Asset Impairment Charges	13,462,000	0	0
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	604,600,000	514,300,000
Software [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	110,200,000	101,600,000
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	204,100,000	179,000,000
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	27,400,000	24,900,000
Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	6,200,000	0
Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 208,200,000	$ 203,700,000

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

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The charge against earnings resulting from the aggregate write down of all assets from their carrying value to their fair value.

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- Definition

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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- Definition

Gross amount, at the balance sheet date, of long-lived physical assets used in the normal conduct of business and not intended for resale. This can include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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- Definition

Tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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