Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Goodwill, gross carrying value	$ 9,026.6	$ 8,386.7
Goodwill, accumulated amortization	570.3	577.6
Goodwill, net carrying value	8,456.3	7,809.1
Other identifiable intangible assets subject to amortization, gross carrying value	885.3	633.0
Other identifiable intangible assets subject to amortization, accumulated amortization	416.9	354.8
Other identifiable intangible assets subject to amortization, net carrying value	468.4	278.2
Goodwill [Roll Forward]
Goodwill, Balance January 1	7,809.1	7,641.2
Goodwill, Acquisitions	728.3	275.3
Goodwill, Dispositions	(12.1)	(8.9)
Goodwill, Foreign currency translation	(69.0)	(98.5)
Goodwill, Balance December 31	8,456.3	7,809.1
Goodwill, impairment losses	0
Goodwill, accumulated impairment losses	0
Goodwill, acquisitions of noncontrolling interests	140.9	34.5
Purchased and internally developed software [Member]
Other identifiable intangible assets subject to amortization, gross carrying value	270.0	260.5
Other identifiable intangible assets subject to amortization, accumulated amortization	210.3	205.3
Other identifiable intangible assets subject to amortization, net carrying value	59.7	55.2
Customer related and other [Member]
Other identifiable intangible assets subject to amortization, gross carrying value	615.3	372.5
Other identifiable intangible assets subject to amortization, accumulated amortization	206.6	149.5
Other identifiable intangible assets subject to amortization, net carrying value	$ 408.7	$ 223.0