Comprehensive Income or Loss - Changes in Components (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31, 2014	$ (229.9)
Net unrealized (loss) gain arising during the period	(165.9)
Reclassification of net loss into earnings	0.7
Balance at March 31, 2015	(395.1)
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31, 2014	(190.9)
Net unrealized (loss) gain arising during the period	(166.0)
Reclassification of net loss into earnings	0
Balance at March 31, 2015	(356.9)
Derivative instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31, 2014	(0.3)
Net unrealized (loss) gain arising during the period	0.1
Reclassification of net loss into earnings	0
Balance at March 31, 2015	(0.2)
Defined benefit plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31, 2014	(38.7)
Net unrealized (loss) gain arising during the period	0
Reclassification of net loss into earnings	0.7
Balance at March 31, 2015	$ (38.0)