Fair Value Measurements (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Changes in fair value
Distributions			$ (1.6)	$ (1.8)
Purchase of redeemable noncontrolling interests			(0.3)	(0.6)
Change in fair value			1.7	22.1
Level 3 | Fair Value, Measurements, Recurring | Redeemable noncontrolling interests
Changes in fair value
Balance at the beginning of the period	40.3	65.6	42.9	85.4
Distributions	(0.1)	(1.3)	(4.3)	(7.3)
Current earnings	0.7	1.5	2.8	4.9
Purchase of redeemable noncontrolling interests	(33.8)	(2.6)	(33.8)	(5.9)
Vesting of noncontrolling interests			1.2	1.2
Change in fair value		(7.0)	(1.7)	(22.1)
Balance at the end of the period	7.1	56.2	7.1	56.2
Level 3 | Fair Value, Measurements, Recurring | Other investment securities
Changes in fair value
Balance at the beginning of the period				3.2
Sale of investments				$ (3.2)