Fair Value Measurements, Recurring and Nonrecurring Basis (Details) - USD ($) $ in Millions		Sep. 30, 2015	Dec. 31, 2014
Fair Value, Measurements, Recurring | Level 1
Fair Value Assets and Liabilities
Cash equivalents		$ 133.2	$ 901.4
Short-term marketable securities		6.9	6.6
Long-term investments		0.5	0.5
Fair Value of Total Assets, Recurring		$ 140.6	$ 908.5
Fair value of assets measured on a recurring basis, percentage of total assets		1.20%	7.10%
Mandatorily redeemable noncontrolling interests	[1]	$ 0.0	$ 0.0
Fair Value, Measurements, Recurring | Level 2
Fair Value Assets and Liabilities
Cash equivalents		0.0	0.0
Short-term marketable securities		0.0	0.0
Long-term investments		0.0	0.0
Fair Value of Total Assets, Recurring		$ 0.0	$ 0.0
Fair value of assets measured on a recurring basis, percentage of total assets		0.00%	0.00%
Mandatorily redeemable noncontrolling interests	[1]	$ 0.0	$ 0.0
Fair Value, Measurements, Recurring | Level 3
Fair Value Assets and Liabilities
Cash equivalents		0.0	0.0
Short-term marketable securities		0.0	0.0
Long-term investments		0.0	0.0
Fair Value of Total Assets, Recurring		$ 0.0	$ 0.0
Fair value of assets measured on a recurring basis, percentage of total assets		0.00%	0.00%
Mandatorily redeemable noncontrolling interests	[1]	$ 44.1	$ 32.8
Fair Value, Measurements, Recurring | Fair Value, Total
Fair Value Assets and Liabilities
Cash equivalents		133.2	901.4
Short-term marketable securities		6.9	6.6
Long-term investments		0.5	0.5
Fair Value of Total Assets, Recurring		$ 140.6	$ 908.5
Fair value of assets measured on a recurring basis, percentage of total assets		1.20%	7.10%
Mandatorily redeemable noncontrolling interests	[1]	$ 44.1	$ 32.8
Fair Value, Measurements, Nonrecurring | Level 1
Fair Value Assets and Liabilities
Long-term Debt, Fair Value		0.0	0.0
Fair Value, Measurements, Nonrecurring | Level 2
Fair Value Assets and Liabilities
Long-term Debt, Fair Value		1,546.3	1,566.0
Fair Value, Measurements, Nonrecurring | Level 3
Fair Value Assets and Liabilities
Long-term Debt, Fair Value		77.5	80.4
Fair Value, Measurements, Nonrecurring | Fair Value, Total
Fair Value Assets and Liabilities
Long-term Debt, Fair Value		$ 1,623.8	$ 1,646.4

[1] Relates to unconditional obligations to purchase additional noncontrolling equity shares of consolidated subsidiaries. Fair value measurement of the obligations was based upon the amounts payable as if the forward contracts were settled. The amounts redeemable within the next twelve months are classified in accrued liabilities; any interests redeemable thereafter are classified in other non-current liabilities.