Taxation (Schedule of Deferred Tax Recongnized on Balance Sheet) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred Tax Assets, Gross	$ 304.8	$ 320.4
Deferred Tax Assets, Valuation Allowance	(137.5)	(140.9)
Deferred Tax Assets, Net of Valuation Allowance	167.3	179.5
Deferred Tax Liabilities	(440.3)	(424.8)
Net Deferred Tax Assets/(Liabilities)	(273.0)	(245.3)
Deferred Compensation Arrangements [Member]
Deferred Tax Assets, Gross	69.4	75.7
Accrued Rent Expenses [Member]
Deferred Tax Assets, Gross	23.4	19.9
Tax Loss Carryforwards [Member]
Deferred Tax Assets, Gross	137.5	140.9
Postretirement Medical, Pension and Other Benefits [Member]
Deferred Tax Assets, Gross	41.6	40.4
Investment Basis Differences [Member]
Deferred Tax Assets, Gross	11.3	22.9
Accrued bonus [Member]
Deferred Tax Assets, Gross	6.7	6.5
Other Deferred Tax Assets [Member]
Deferred Tax Assets, Gross	14.9	14.1
Deferred Sales Commissions [Member]
Deferred Tax Assets, Gross	(23.7)	(14.4)
Goodwill and Intangibles [Member]
Deferred Tax Assets, Gross	(397.7)	(381.4)
Undistributed Earnings of Subsidiaries [Member]
Deferred Tax Assets, Gross	(4.3)	(3.5)
Revaluation Reserve [Member]
Deferred Tax Assets, Gross	(5.2)	(5.0)
Other Deferred Tax Liability [Member]
Deferred Tax Assets, Gross	$ (9.4)	$ (20.5)