CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Class A ordinary shares/ Common stock [Member]	Additional paid-in capital [Member]	Retained earnings [Member]	Treasury shares [Member]	Accumulated other comprehensive income (loss) [Member]
Beginning Balance at Dec. 31, 2015	$ 4,772.5	$ 15.7	$ 1,458.5	$ 3,509.8	$ (12.2)	$ (199.3)
Beginning Balance (in shares) at Dec. 31, 2015		124.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net shares issued (acquired) under share-based compensation plans	(4.4)	$ 0.0	(9.5)		5.1
Net shares issued (acquired) under share-based compensation plans (in shares)		0.6
Share-based compensation	16.3		16.3
Excess tax benefit from share-based awards	2.6		2.6
Retirement benefit adjustments, net of taxes	25.2					25.2
Net income (loss)	345.0			345.0
Ending Balance at Sep. 30, 2016	5,157.2	$ 15.7	1,467.9	3,854.8	(7.1)	(174.1)
Ending Balance (in shares) at Sep. 30, 2016		125.4
Beginning Balance at Dec. 31, 2016	5,113.9	$ 16.0	1,471.7	3,830.4	(7.2)	(197.0)
Beginning Balance (in shares) at Dec. 31, 2016		125.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net shares issued (acquired) under share-based compensation plans	(4.4)	$ 0.0	(2.3)		(2.1)
Net shares issued (acquired) under share-based compensation plans (in shares)		0.7
Share-based compensation	15.2		15.2
Retirement benefit adjustments, net of taxes	2.7					2.7
Net income (loss)	(39.3)			(39.3)
Ending Balance at Sep. 30, 2017	5,294.7	$ 16.0	$ 1,484.6	3,997.7	$ (9.3)	$ (194.3)
Ending Balance (in shares) at Sep. 30, 2017		126.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of new accounting standard	$ 206.6			$ 206.6