Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (Unaudited) - USD ($) shares in Millions, $ 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
Income Statement [Abstract]
Revenue	[1]	$ 178.7	$ 442.1	$ 408.2	$ 1,258.0	$ 981.2
Operating expenses	[1]	56.7	126.0	125.0	404.1	317.2
Selling and administrative expenses	[1]	122.4	131.9	152.7	401.2	492.3
Depreciation and amortization	[1]	11.1	134.1	123.3	401.0	340.6
Restructuring charge	[1]	0.1	4.9	8.2	16.2	44.1
Operating costs	[1]	190.3	396.9	409.2	1,222.5	1,194.2
Operating income (loss)	[1]	(11.6)	45.2	(1.0)	35.5	(213.0)
Interest income	[1]	0.3	0.2	0.5	0.7	2.1
Interest expense	[1]	(5.5)	(60.8)	(85.6)	(221.8)	(220.6)
Other income (expense) - net	[1]	(86.0)	(9.5)	6.3	(42.2)	18.6
Non-operating income (expense) - net	[1]	(91.2)	(70.1)	(78.8)	(263.3)	(199.9)
Income (loss) before provision (benefit) for income taxes and equity in net income of affiliates	[1]	(102.8)	(24.9)	(79.8)	(227.8)	(412.9)
Less: provision (benefit) for income taxes	[1]	(27.5)	(9.3)	(24.0)	(111.1)	(84.1)
Equity in net income of affiliates	[1]	0.5	0.7	0.5	1.9	3.4
Net income (loss)	[1]	(74.8)	(14.9)	(55.3)	(114.8)	(325.4)
Less: net (income) loss attributable to the non-controlling interest	[1]	(0.8)	(2.1)	(1.4)	(3.7)	(3.3)
Less: Dividends allocated to preferred stockholders	[1]	0.0	0.0	(32.1)	(64.1)	(82.0)
Net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor) / The Dun & Bradstreet Corporation (Predecessor)	[1]	$ (75.6)	$ (17.0)	$ (88.8)	$ (182.6)	$ (410.7)
Basic earnings (loss) per share of common stock:
Net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor) / The Dun & Bradstreet Corporation (Predecessor)	[1]	$ (2.04)	$ (0.04)	$ (0.28)	$ (0.52)	$ (1.31)
Diluted earnings (loss) per share of common stock:
Net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor) / The Dun & Bradstreet Corporation (Predecessor)	[1]	$ (2.04)	$ (0.04)	$ (0.28)	$ (0.52)	$ (1.31)
Weighted average number of shares outstanding - basic (shares)	[1]	37.2	415.7	314.5	348.5	314.5
Weighted average number of shares outstanding - diluted (shares)	[1]	37.2	415.7	314.5	348.5	314.5
Other comprehensive income (loss), net of income taxes:
Net income (loss)	[1]	$ (74.8)	$ (14.9)	$ (55.3)	$ (114.8)	$ (325.4)
Foreign currency translation adjustments, net of tax	[1],[2]	5.9	36.7	(24.0)	21.8	(40.9)
Defined benefit pension plans:
Prior service credit (cost), net of tax expense (benefit)	[1],[3]	(0.1)	(0.8)	0.0	(0.9)	0.0
Net actuarial gain (loss), net of tax expense (benefit)	[1],[4]	65.5	0.0	0.0	0.0	0.0
Derivative financial instrument, net of tax expense (benefit)	[1],[5]	(0.1)	0.6	0.0	0.1	(1.6)
Total other comprehensive income (loss), net of tax	[1]	71.2	36.5	(24.0)	21.0	(42.5)
Comprehensive income (loss), net of tax	[1]	(3.6)	21.6	(79.3)	(93.8)	(367.9)
Less: comprehensive (income) loss attributable to the non-controlling interest	[1]	(1.0)	(4.4)	4.8	(4.8)	3.0
Comprehensive income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor) / The Dun & Bradstreet Corporation (Predecessor)	[1]	(4.6)	17.2	(74.5)	(98.6)	(364.9)
Income Statement - Parenthetical [Abstract]
Foreign currency translation adjustments, tax expense (benefit)		0.1	2.4	$ 0.6	1.5	(0.2)
Prior service credit (cost), tax benefit			(0.2)		(0.3)
Net actuarial gain (loss), tax expense (benefit)		22.2
Derivative financial instrument, tax expense (benefit)		$ (0.1)	$ 0.3		$ 0.1	$ (0.5)

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

[2] Tax Expense (Benefit) of $2.4 million, $0.6 million, $1.5 million, $(0.2) million, and less than $0.1 million for the Successor three months ended September 30, 2020 and 2019, for the Successor nine months ended September 30, 2020, for the Successor period from January 1 to September 30, 2019, and for the Predecessor period from January 1 to February 7, 2019, respectively.

[3] Tax Expense (Benefit) of $(0.2) million and $(0.3) million for the Successor three months and nine months ended September 30, 2020, respectively.

[4] Tax Expense (Benefit) of $22.2 million for the Predecessor period from January 1 to February 7, 2019.

[5] Tax Expense (Benefit) of $0.3 million, less than $0.1 million, $(0.5) million, and $(0.1) million for the Successor three months ended September 30, 2020, for the Successor nine months ended September 30, 2020, for the Successor period from January 1 to September 30, 2019, and for the Predecessor period from January 1 to February 7, 2019, respectively.