Income Taxes (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012	Dec. 31, 2011
Deferred Tax Assets
State net operating loss carryforwards	$ 25.9	$ 25.9	$ 26.5
Foreign tax credit carryforwards	14.2	14.2	15.1
Deferred compensation	20.5	20.5	17.5
Tax benefit of uncertain tax positions	17.1	17.1	11.6
Accrued expenses	3.7	3.7	11.6
Capital loss carryforwards	1.5	1.5	1.5
Total deferred tax assets	82.9	82.9	83.8
Valuation allowance	(30.4)	(30.4)	(35.6)
Deferred tax assets, net of valuation allowance	52.5	52.5	48.2
Deferred Tax Liabilities
Intangible asset amortization	(245.0)	(245.0)	(247.1)
Convertible securities interest	(180.0)	(180.0)	(171.1)
Non-deductible intangible amortization	(123.2)	(123.2)	(127.2)
Deferred revenue	(4.1)	(4.1)	(5.6)
Other	(3.0)	(3.0)	(3.2)
Total deferred tax liabilities	(555.3)	(555.3)	(554.2)
Net deferred tax liability	(502.8)	(502.8)	(506.0)
State net operating loss carryforwards, expiration period (in years)		15 years
Foreign tax credit carryforwards, expiration period (in years)		10 years
Liability for uncertain tax positions including interest and related charges	27.1	27.1
Accrued income tax interest and related charges	2.1	2.1
Liability for uncertain tax positions for foreign exchange	16.0	16.0
Increase (Decrease) related to foreign exchange rates	$ 5.1