Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Goodwill, gross carrying value	$ 9,304.0		$ 9,026.6
Goodwill, accumulated amortization	575.4		570.3
Goodwill, net carrying value	8,728.6	8,397.5
Other identifiable intangible assets subject to amortization, gross carrying value	924.2		885.3
Other identifiable intangible assets subject to amortization, accumulated amortization	477.4		416.9
Other identifiable intangible assets subject to amortization, net carrying value	446.8		468.4
Goodwill [Roll Forward]
Goodwill, Balance January 1	8,456.3	7,809.1
Goodwill, Acquisitions	225.6	640.8
Goodwill, Dispositions	(2.5)	(10.0)
Goodwill, Foreign currency translation	49.2	(42.4)
Goodwill, Balance June 30	8,728.6	8,397.5
Goodwill, impairment losses	0
Goodwill, accumulated impairment losses	0
Goodwill, acquisitions of noncontrolling interests	16.2	129.7
Purchased and internally developed software [Member]
Other identifiable intangible assets subject to amortization, gross carrying value	280.3		270.0
Other identifiable intangible assets subject to amortization, accumulated amortization	217.5		210.3
Other identifiable intangible assets subject to amortization, net carrying value	62.8		59.7
Customer related and other [Member]
Other identifiable intangible assets subject to amortization, gross carrying value	643.9		615.3
Other identifiable intangible assets subject to amortization, accumulated amortization	259.9		206.6
Other identifiable intangible assets subject to amortization, net carrying value	$ 384.0		$ 408.7