Summary of Significant Accounting Policies (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Prior Period Adjustment [Abstract]
Impairment of assets									$ 7.5	$ 30.2	$ 180.2
Net loss attributable to Diebold Nixdorf, Incorporated	$ 51.2	$ 101.4	$ 23.7	$ 92.8	$ 122.6	$ 35.7	$ 50.3	$ 132.7	$ 269.1	$ 341.3	$ 531.4
Basic and diluted loss per share	$ (0.66)	$ (1.31)	$ (0.31)	$ (1.20)	$ (1.60)	$ (0.46)	$ (0.66)	$ (1.74)	$ (3.47)	$ (4.45)	$ (6.99)
Other current assets	$ 227.0				$ 230.7				$ 227.0	$ 230.7
Goodwill	800.4				764.0				800.4	764.0	$ 798.2
Deferred income taxes	97.5				120.8				97.5	120.8
Current assets held for sale	64.7				233.3				64.7	233.3
Current liabilities held for sale	15.4				113.4				15.4	113.4
Trade receivables, net	646.9				619.3				646.9	619.3	737.2
Deferred revenue	346.8				320.5				346.8	320.5	378.2
Deferred Revenue, Revenue Recognized									266.2
Revenue, Remaining Performance Obligation, Amount	1,500.0								1,500.0
Advertising expense									7.2	7.5	10.1
Research, development and engineering expense									$ 133.4	147.1	157.4
Cash equivalents, maturity period									3
Restricted Cash and Cash Equivalents	0.0				3.6				$ 0.0	3.6
Expected rate of return period									20
Amortization of unrecognized net gain (loss)									5.00%
Accounts Receivable, Related Parties	4.8								$ 4.8
Accounts Payable, Related Parties	35.9								35.9
Equity in earnings (loss) of unconsolidated subsidiaries, net									0.7	1.0	(13.2)
CloudComputingArrangementsAdditions	27.1								27.1
Balance at January 1				$ 42.2				$ 58.2	42.2	58.2	71.7
Charged to costs and expenses									10.1	5.2	22.8
Charged to other accounts (1)									(1.2)	(0.9)	(4.1)
Deductions (2)									(13.6)	(20.3)	(32.2)
Balance at December 31	$ 37.5				$ 42.2				$ 37.5	42.2	58.2
Aisino JV [Domain]
Prior Period Adjustment [Abstract]
Equity in earnings (loss) of unconsolidated subsidiaries, net											$ 19.2
Kony, Inc. [Member]
Prior Period Adjustment [Abstract]
Proceeds from Noncontrolling Interests										21.3
Cost Method Investments						$ 14.0
Gain on Sale of Investments										$ 7.3
Inspur (Suzhou) Financial Technology Service Co Ltd [Member]
Prior Period Adjustment [Abstract]
Equity Method Investment, Ownership Percentage	48.10%				40.00%				48.10%	40.00%
Aisino-Wincor Retail And Banking Systems (Shanghai) Co.,Ltd [Member]
Prior Period Adjustment [Abstract]
Equity Method Investment, Ownership Percentage	43.60%								43.60%