Take-Private Transaction - Pro Forma Information (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended		9 Months Ended
		Feb. 07, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Business Acquisition [Line Items]
Revenue	[1]	$ 178.7	$ 442.1	$ 408.2	$ 1,258.0	$ 981.2
Pro forma revenue		181.6		409.4		993.5
Pro forma adjustments - net of tax effect
Pro forma net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor)		(77.0)		(87.5)		(430.5)
Deferred revenue fair value adjustment
Business Acquisition [Line Items]
Revenue		$ 0.0		1.2		1.2
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				408.2		981.2
Pro forma revenue				446.8		1,258.6
Reported net income (loss) attributable to Dun & Bradstreet Holdings, Inc.(Successor)				(88.8)		(410.7)
Pro forma adjustments - net of tax effect
Pro forma net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor)				(67.2)		(263.5)
Take Private Acquisition, Dun & Bradstreet | Deferred revenue fair value adjustment
Business Acquisition [Line Items]
Revenue				38.6		98.7
Pro forma adjustments - net of tax effect
Pro forma net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor)				30.0		76.7
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)		(44.0)
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)				(2.7)		(7.3)
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)				$ 1.1		$ (20.5)

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