Redeemable Noncontrolling Interests (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Changes in redeemable noncontrolling interests
Balance at beginning of period	$ 291.2		$ 277.8		$ 288.4
Change in related noncontrolling interest balance	(7.7)		1.5		2.5
Changes in redemption value of redeemable noncontrolling interests:
Additions	17.9		31.9		0.5
Redemptions and reclassifications	(70.7)		(30.1)		(5.3)
Redemption value adjustments	12.7	[1]	10.1	[1]	(8.3)	[1]
Balance at end of period	$ 243.4		$ 291.2		$ 277.8

[1] Redeemable noncontrolling interests are reported at their estimated redemption value in each reporting period, but not less than their initial fair value. Any adjustment to the redemption value impacts retained earnings or additional paid-in capital, except adjustments as a result of currency translation.