Income Taxes (Details) (USD $)	3 Months Ended		12 Months Ended			24 Months Ended
	Dec. 31, 2012	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2010 Convertible Debt [Member]
Reduction of income tax expense	$ 53,000,000
Increase in income tax expense	16,000,000
Income Before Income Taxes [Abstract]
Income before income taxes, Domestic			683,500,000	581,000,000	573,200,000
Income before income taxes, International			976,100,000	968,000,000	777,200,000
Income Before Income Taxes and Income (Loss) From Equity Method Investments			1,659,600,000	1,549,000,000	1,350,400,000
Income Tax Expense [Abstract]
Income tax expense, current, Federal			163,300,000	158,600,000	107,200,000
Income tax expense, current, State and local			40,100,000	14,400,000	11,700,000
Income tax expense, current, International			298,300,000	239,500,000	233,100,000
Income tax expense, current			501,700,000	412,500,000	352,000,000
Income tax expense, deferred, Federal			41,700,000	83,600,000	98,900,000
Income tax expense, deferred, State and local			4,700,000	4,900,000	3,600,000
Income tax expense, deferred, International			(21,000,000)	4,800,000	5,700,000
Income tax expense, deferred			25,400,000	93,300,000	108,200,000
Income tax expense			527,100,000	505,800,000	460,200,000
Reconciliation from the Statutory U.S. Federal Income Tax Rate to Effective Tax Rate [Abstract]
Statutory U.S. federal income tax rate			35.00%	35.00%	35.00%
State and local income taxes, net of federal income tax benefit			1.70%	0.80%	0.70%
Reduction of tax on unremitted foreign earnings due to legal reorganization			(1.30%)	0.00%	0.00%
Remeasurement gain Clemenger Group, tax rate differential			0.00%	(2.60%)	0.00%
International tax rate differentials			(3.30%)	(1.40%)	(2.10%)
Other			(0.30%)	0.90%	0.50%
Effective tax rate			31.80%	32.70%	34.10%
Tax benefit related to charges incurred in connection with repositioning actions		(39,500,000)
Tax provision related to remeasurement gain		(2,800,000)
Tax accrual for agreed upon adjustments to income tax returns currently under examination		9,000,000
Unrecognized Tax Benefits, Penalties and Interest [Abstract]
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense			2,500,000	2,800,000	3,900,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	18,800,000		18,800,000	10,700,000
Deferred tax assets:
Compensation and severance	283,000,000		283,000,000	291,500,000
Tax loss and credit carryforwards	176,100,000		176,100,000	156,300,000
Basis differences from acquisitions	20,700,000		20,700,000	37,200,000
Basis differences from short-term assets and liabilities	31,800,000		31,800,000	33,600,000
Other	44,200,000		44,200,000	19,800,000
Deferred tax assets	555,800,000		555,800,000	538,400,000
Valuation allowance	(47,800,000)		(47,800,000)	(24,900,000)
Net deferred tax assets	508,000,000		508,000,000	513,500,000
Deferred tax liabilities:
Goodwill and intangible assets	635,200,000		635,200,000	577,400,000
Financial instruments	508,700,000		508,700,000	480,300,000
Unremitted foreign earnings	124,700,000		124,700,000	143,200,000
Basis differences from investments	12,200,000		12,200,000	11,100,000
Deferred tax liabilities	1,280,800,000		1,280,800,000	1,212,000,000
Net deferred tax assets (liabilities)	(772,800,000)		(772,800,000)	(698,500,000)
Net deferred tax assets and (liabilities), classified [Abstract]
Other current assets - Deferred taxes	160,200,000		160,200,000	169,100,000
Long-term deferred tax liabilities	(933,000,000)		(933,000,000)	(867,600,000)
Convertible debt, repayments of convertible debt						1,382,000,000
Convertible debt, repayments of convertible debt, deferred tax liability	340,000,000		340,000,000
Tax loss and credit carryforwards, expiration dates			5 to 20 years
Cumulative undistributed earnings of certain foreign subsidiaries indefinitely reinvested	1,400,000,000		1,400,000,000
Cumulative undistributed earnings of certain foreign subsidiaries not deemed to be indefinitely reinvested	1,800,000,000		1,800,000,000
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Balance January 1		165,100,000	157,800,000	165,100,000
Current year tax positions			17,100,000	12,200,000
Prior year tax positions			27,300,000	12,500,000
Reduction of prior year tax positions			(7,900,000)	(14,800,000)
Settlements			(200,000)	(16,700,000)
Lapse of statute of limitations			(6,000,000)	0
Foreign currency translation			500,000
Foreign currency translation				(500,000)
Balance December 31	188,600,000		188,600,000	157,800,000	165,100,000
Unrecognized tax benefits that would impact effective tax rate	$ 69,700,000		$ 69,700,000	$ 62,400,000