Acquisitions - Pro Forma Information (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended		6 Months Ended
		Feb. 07, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Business Acquisition [Line Items]
Revenue	[1]	$ 178.7	$ 420.6	$ 398.9	$ 815.9	$ 573.0
Pro forma revenue		181.6		405.9		584.1
Net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor) / The Dun & Bradstreet Corporation (Predecessor)	[1]	(75.6)	$ (207.1)	(94.0)	$ (165.6)	(321.9)
Pro forma net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor) / The Dun & Bradstreet Corporation (Predecessor)		(77.0)		$ (113.3)		$ (343.0)
Blended statutory tax rate assumed (as a percent)				22.30%		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)		$ (18.4)		$ (19.7)
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)		(0.9)		(1.4)
Lattice
Business Acquisition [Line Items]
Revenue		$ 2.9		$ 7.0		$ 11.1

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