Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (Unaudited) - USD ($) shares in Millions, $ in Millions		1 Months Ended		12 Months Ended
		Feb. 07, 2019	[1]	Dec. 31, 2020	Dec. 31, 2019	[1]	Dec. 31, 2018
Income Statement [Abstract]
Revenue		$ 178.7		$ 1,738.1	$ 1,413.9		$ 1,716.4
Operating expenses		56.7		545.6	448.5		563.4
Selling and administrative expenses		122.4		557.8	651.2		610.0
Depreciation and amortization		11.1		536.9	482.4		88.7
Restructuring charges		0.1		34.8	51.8		25.4
Operating costs		190.3		1,675.1	1,633.9		1,287.5
Operating income (loss)		(11.6)		63.0	(220.0)		428.9
Interest income		0.3		0.8	2.4		1.9
Interest expense		(5.5)		(271.1)	(303.5)		(54.4)
Other income (expense) - net		(86.0)		(12.0)	(154.8)		(3.3)
Non-operating income (expense) - net		(91.2)		(282.3)	(455.9)		(55.8)
Income (loss) before provision (benefit) for income taxes and equity in net income of affiliates		(102.8)		(219.3)	(675.9)		373.1
Less: provision (benefit) for income taxes		(27.5)		(110.5)	(118.2)		81.6
Equity in net income of affiliates		0.5		2.3	4.2		2.8
Net income (loss)		(74.8)		(106.5)	(553.5)		294.3
Less: net (income) loss attributable to the non-controlling interest		(0.8)		(5.0)	(6.5)		(6.2)
Less: Dividends allocated to preferred stockholders		0.0		(64.1)	(114.0)		0.0
Net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor) / The Dun & Bradstreet Corporation (Predecessor)		$ (75.6)		$ (175.6)	$ (674.0)		$ 288.1
Basic earnings (loss) per share of common stock:
Net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor) / The Dun & Bradstreet Corporation (Predecessor)		$ (2.04)		$ (0.48)	$ (2.14)		$ 7.76
Diluted earnings (loss) per share of common stock:
Net income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor) / The Dun & Bradstreet Corporation (Predecessor)		$ (2.04)		$ (0.48)	$ (2.14)		$ 7.72
Weighted average number of shares outstanding - basic (shares)		37.2		367.1	314.5		37.1
Weighted average number of shares outstanding - diluted (shares)		37.2		367.1	314.5		37.3
Other comprehensive income (loss), net of income taxes:
Net income (loss)		$ (74.8)		$ (106.5)	$ (553.5)		$ 294.3
Foreign currency translation adjustments, net of tax	[2]	5.9		26.4	(9.9)		(18.2)
Defined benefit pension plans:
Prior service credit (cost), net of tax expense (benefit)	[3]	(0.1)		(0.8)	2.2		4.5
Net actuarial gain (loss), net of tax expense (benefit)	[4]	65.5		(105.7)	(18.0)		(24.1)
Derivative financial instrument, net of tax expense (benefit)	[5]	(0.1)		0.7	(1.1)		(0.3)
Total other comprehensive income (loss), net of tax		71.2		(79.4)	(26.8)		(38.1)
Comprehensive income (loss), net of tax		(3.6)		(185.9)	(580.3)		256.2
Less: comprehensive (income) loss attributable to the non-controlling interest		(1.0)		(8.1)	(3.2)		(5.4)
Comprehensive income (loss) attributable to Dun & Bradstreet Holdings, Inc. (Successor) / The Dun & Bradstreet Corporation (Predecessor)		$ (4.6)		$ (194.0)	$ (583.5)		$ 250.8

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

[2] Tax Expense (Benefit) of $3.0 million, $(1.8) million, less than $0.1 million, and $(2.6) million for the Successor year ended December 31, 2020, for the Successor period from January 1 to December 31, 2019, for the Predecessor period from January 1 to February 7, 2019, and for Predecessor year ended December 31, 2018, respectively.

[3] Tax Expense (Benefit) of $(0.2) million, $0.9 million, and $1.2 million for the Successor year ended December 31, 2020, for the Successor period from January 1 to December 31, 2019, and for Predecessor year ended December 31, 2018, respectively.

[4] Tax Expense (Benefit) of $(34.6) million, $(6.1) million, $22.2 million, and $(6.7) million for the Successor year ended December 31, 2020, for the Successor period from January 1 to December 31, 2019, for the Predecessor period from January 1 to February 7, 2019, and for Predecessor year ended December 31, 2018, respectively.

[5] Tax Expense (Benefit) of $0.2 million, $(0.4) million, $(0.1) million, and $(0.1) million for the Successor year ended December 31, 2020, for the Successor period from January 1 to December 31, 2019, for the Predecessor period from January 1 to February 7, 2019, and for Predecessor year ended December 31, 2018, respectively.