Equity Method Investments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended								12 Months Ended
	Dec. 31, 2012	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Feb. 01, 2011 Clemenger Group [Member]	Dec. 31, 2011 Affiliate in India [Member]	Dec. 31, 2011 Affiliate in Turkey [Member]	Dec. 31, 2010 Affiliate in Middle East [Member]	Dec. 31, 2010 Affiliate in South America [Member]	Dec. 31, 2012 Level 3 Income Approach Valuation Technique [Member] Equity Method Investments [Member]
Equity interest in the net income of equity method investments			$ (15.0)	$ 17.2	$ 33.5
Equity interest in the net assets of equity method investments	69.1		69.1	68.4
Impairment charge on equity method investment	29.2		29.2	0	0
Fair Value Inputs, weighted average cost of capital											22.00%
Fair Value Inputs, expected long-term growth rate											5.00%
Acquisition of controlling interests in affiliates, ownership percentage after acquisition						73.70%	100.00%	76.00%	68.60%	100.00%
Acquisition of controlling interests in affiliates, ownership percentage before acquisition						46.70%
Remeasurement gain, equity interest in Clemenger Group		123.4	0	123.4	0
Remeasurement gain, acquisition of controlling interests in affiliates			$ 2.1	$ 15.1	$ 26.0