Take-Private Transaction - 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
Pro forma adjustments - net of tax effect
Pro forma net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor)		$ (77.0)		(113.3)		(343.0)
Dun & Bradstreet
Business Acquisition [Line Items]
Revenue				0.0		178.7
Reported net income (loss) attributable to Dun & Bradstreet Holdings, Inc.(Successor)				0.0		(75.6)
Take Private Acquisition, Dun & Bradstreet
Business Acquisition [Line Items]
Revenue				398.9		573.0
Pro forma revenue				437.5		811.8
Reported net income (loss) attributable to Dun & Bradstreet Holdings, Inc.(Successor)				(94.0)		(321.9)
Pro forma adjustments - net of tax effect
Pro forma net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor)				(73.8)		(196.3)
Take Private Acquisition, Dun & Bradstreet | Deferred revenue fair value adjustment
Business Acquisition [Line Items]
Revenue				38.6		60.1
Pro forma adjustments - net of tax effect
Pro forma net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor)				30.0		46.7
Take Private Acquisition, Dun & Bradstreet | Incremental amortization of intangibles
Pro forma adjustments - net of tax effect
Pro forma net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor)				(6.8)		(37.2)
Take Private Acquisition, Dun & Bradstreet | Amortization of deferred commissions
Pro forma adjustments - net of tax effect
Pro forma net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor)				(3.3)		(4.6)
Take Private Acquisition, Dun & Bradstreet | Transaction costs
Pro forma adjustments - net of tax effect
Pro forma net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor)				0.0		154.9
Take Private Acquisition, Dun & Bradstreet | Pension expense adjustment
Pro forma adjustments - net of tax effect
Pro forma net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor)				0.0		69.5
Take Private Acquisition, Dun & Bradstreet | Equity-based compensation adjustment
Pro forma adjustments - net of tax effect
Pro forma net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor)				0.0		8.1
Take Private Acquisition, Dun & Bradstreet | Preferred dividend adjustment
Pro forma adjustments - net of tax effect
Pro forma net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor)				0.0		(14.6)
Take Private Acquisition, Dun & Bradstreet | Incremental interest expense and facility cost adjustment
Pro forma adjustments - net of tax effect
Pro forma net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor)				$ 0.3		$ (21.6)

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