Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Net sales	[1]	$ 4,731.7	$ 4,946.2	$ 5,280.6
Cost of sales		2,900.2	2,966.7	3,228.8
Gross profit		1,831.5	1,979.5	2,051.8
Operating expenses
Distribution		94.2	87.0	88.3
Research and development		218.6	167.7	184.0
Selling		595.7	598.4	665.0
Administration		435.9	461.1	452.2
Impairment charges		224.4	47.5	2,631.0
Restructuring		21.0	61.0	31.0
Other operating expense (income)		5.2	(41.4)	0.0
Total operating expenses		1,595.0	1,381.3	4,051.5
Operating income (loss)		236.5	598.2	(1,999.7)
Change in financial assets		(188.7)	24.9	2,608.2
Interest expense, net		128.0	168.1	216.6
Other (income) expense, net		6.1	(10.1)	22.7
Loss on extinguishment of debt		0.5	135.2	1.1
Income (loss) before income taxes		290.6	280.1	(4,848.3)
Income tax expense (benefit)		159.6	160.5	(835.5)
Net income (loss)		$ 131.0	$ 119.6	$ (4,012.8)
Earnings (loss) per share
Basic (in dollars per share)		$ 0.95	$ 0.84	$ (28.01)
Diluted (in dollars per share)		$ 0.95	$ 0.84	$ (28.01)
Weighted-average shares outstanding
Basic (in dollars per share)		137.8	142.3	143.3
Diluted (in dollars per shares)		138.3	142.6	143.3

[1] (1)    The net sales by geography is derived from the location of the entity that sells to a third party.