Income Taxes - Pre-tax Income and the Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pre-tax income:
Ireland	$ (109.0)	$ (454.0)	$ (3,624.1)
United States	(428.6)	(144.9)	(90.0)
Other foreign	828.2	879.0	(1,134.2)
Income (loss) before income taxes	290.6	280.1	(4,848.3)
Current:
Ireland	22.7	(8.1)	0.3
United States	66.4	100.4	93.7
Other foreign	75.1	46.1	26.7
Subtotal	164.2	138.4	120.7
Deferred (credit):
Ireland	(13.9)	13.1	(549.4)
United States	7.3	7.8	(12.7)
Other foreign	2.0	1.2	(394.1)
Subtotal	(4.6)	22.1	(956.2)
Total (benefit) provision for income taxes	$ 159.6	$ 160.5	$ (835.5)