Acquisitions - Pro Forma Information (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended								12 Months Ended
	Feb. 07, 2019		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
Business Acquisition [Line Items]
Revenue	$ 178.7	[1]	$ 480.1	$ 442.1	$ 420.6	$ 395.3	$ 432.7	$ 408.2	$ 398.9	$ 174.1	$ 1,738.1	$ 1,413.9	[1]	$ 1,716.4
Pro forma revenue	181.6											1,427.4		1,736.7
Net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor) / The Dun & Bradstreet Corporation (Predecessor)	(75.6)	[1]	$ 7.0	$ (17.0)	$ (207.1)	$ 41.5	$ (263.3)	$ (88.8)	$ (94.0)	$ (227.9)	$ (175.6)	(674.0)	[1]	288.1
Pro forma net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor) / The Dun & Bradstreet Corporation (Predecessor)	(77.0)											$ (692.9)		267.4
Blended statutory tax rate (as a percent)												22.30%
Pre-acquisition net loss
Business Acquisition [Line Items]
Net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor) / The Dun & Bradstreet Corporation (Predecessor)	(1.0)											$ (19.7)		(13.1)
Intangible amortization - net of tax benefits
Business Acquisition [Line Items]
Net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor) / The Dun & Bradstreet Corporation (Predecessor)	(0.4)											(1.4)		(3.6)
Deferred revenue fair value adjustment
Business Acquisition [Line Items]
Revenue	0.0											2.4		(4.8)
Net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor) / The Dun & Bradstreet Corporation (Predecessor)	0.0											1.8		(3.6)
Transaction costs
Business Acquisition [Line Items]
Net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor) / The Dun & Bradstreet Corporation (Predecessor)	0.0											0.4		(0.4)
Lattice
Business Acquisition [Line Items]
Revenue	$ 2.9											$ 11.1		$ 25.1

[1] See Note 1 "Basis of Presentation" for further discussion.