Taxation (Schedule of Deferred Tax Recongnized on Balance Sheet) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Deferred Tax Assets, Gross	$ 320.4	$ 317.5
Deferred Tax Assets, Valuation Allowance	(140.9)	(129.7)
Deferred Tax Assets, Net of Valuation Allowance	179.5	187.8
Deferred Tax Liabilities	(424.8)	(386.4)
Net Deferred Tax Assets/(Liabilities)	(245.3)	(198.6)
Deferred Compensation Arrangements [Member]
Deferred Tax Assets, Gross	75.7	113.1
Accrued Rent Expenses [Member]
Deferred Tax Assets, Gross	19.9	14.4
Tax Loss Carryforwards [Member]
Deferred Tax Assets, Gross	140.9	130.1
Postretirement Medical, Pension and Other Benefits [Member]
Deferred Tax Assets, Gross	40.4	28.2
Investment Basis Differences [Member]
Deferred Tax Assets, Gross	22.9	17.4
Other Deferred Tax Assets [Member]
Deferred Tax Assets, Gross	20.6	14.3
Deferred Sales Commissions [Member]
Deferred Tax Assets, Gross	(14.4)	(12.5)
Goodwill and Intangibles [Member]
Deferred Tax Assets, Gross	(381.4)	(361.1)
Undistributed Earnings of Subsidiaries [Member]
Deferred Tax Assets, Gross	(3.5)	(3.1)
Revaluation Reserve [Member]
Deferred Tax Assets, Gross	(5.0)	(5.1)
Other Deferred Tax Liability [Member]
Deferred Tax Assets, Gross	$ (20.5)	$ (4.6)

The sum of the tax effects as of the balance sheet date of the amounts of all future tax deductions arising from temporary differences between tax basis and generally accepted accounting principles basis recognition of assets, liabilities, revenues and expenses, which can only be deducted for tax purposes when permitted under enacted tax laws ( before the valuation allowance, if any, to reduce such sum amount to net realizable value). Includes any tax benefit realized in deferred tax assets for significant impacts of tax planning strategies.

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For entities that net deferred tax assets and tax liabilities, represents the unclassified net amount of deferred tax assets and liabilities as of the balance sheet date, which result from applying the applicable enacted tax rate to net temporary differences and carryforwards pertaining to assets or liabilities. A temporary difference is a difference between the tax basis of an asset or liability and its carrying amount in the financial statements prepared in accordance with generally accepted accounting principles that will reverse in ensuing periods.

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- Definition

The sum of the portions of deferred tax assets as of the balance sheet date for which, based on the weight of available evidence, it is more likely than not will not be realized through future reductions of tax-based income.

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- Definition

The cumulative amount of all deferred tax liabilities, which result from applying the applicable tax rate to net taxable temporary differences pertaining to each jurisdiction to which the entity is obligated to pay income tax. A taxable temporary difference is a difference between the tax basis and the carrying amount of an asset or liability in the financial statements prepared in accordance with generally accepted accounting principles that will result in taxable amounts in one or more future periods.

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