Segment Information - (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Summary of Segment Information
Total revenue	$ 943.9	$ 910.7
Segment gross profit	273.2	226.8
Segment selling and administrative expense	203.4	222.1
Segment research, development and engineering expense	34.1	32.5
Operating income (loss) / Segment operating profit	(36.2)	26.0
Restructuring and DN Now transformation expenses	(6.0)	(10.0)
Net non-routine expense	(19.9)
Other income (expense)	(42.0)	(47.4)
Income (loss) from continuing operations before taxes	(5.8)	(73.4)
Eurasia Banking
Summary of Segment Information
Total revenue	327.8	310.5
Americas Banking
Summary of Segment Information
Total revenue	311.7	344.7
Retail
Summary of Segment Information
Total revenue	304.4	255.5
Operating Segments [Member]
Summary of Segment Information
Intersegment revenue	30.7	22.7
Operating income (loss) / Segment operating profit	(92.3)	(80.4)
Operating Segments [Member] | Eurasia Banking
Summary of Segment Information
Total revenue	327.8	310.5
Intersegment revenue	28.5	21.4
Operating income (loss) / Segment operating profit	(25.0)	(22.8)
Operating Segments [Member] | Americas Banking
Summary of Segment Information
Total revenue	311.7	344.7
Intersegment revenue	2.2	1.3
Operating income (loss) / Segment operating profit	(40.2)	(46.5)
Operating Segments [Member] | Retail
Summary of Segment Information
Total revenue	304.4	255.5
Operating income (loss) / Segment operating profit	(27.1)	(11.1)
Corporate and Reconciling Items [Member]
Summary of Segment Information
Reconciliation Of Operating Profit Loss From Segments To Consolidated, Amount	(56.1)	(106.4)
Corporate
Summary of Segment Information
Operating income (loss) / Segment operating profit	(13.3)	(17.4)
Segment Reconciling Items [Member]
Summary of Segment Information
Restructuring and DN Now transformation expenses	(23.1)	(41.6)
Net non-routine expense	$ (19.7)	$ (47.4)