Condensed Consolidated Statements of Stockholder Equity (Deficit) (Unaudited) - USD ($) $ in Millions		Total		Dun & Bradstreet Corp	Total Stockholder Equity (Deficit)	Total Stockholder Equity (Deficit) Dun & Bradstreet Corp	Common Stock	Common Stock  Dun & Bradstreet Corp	Capital Surplus	Capital Surplus Dun & Bradstreet Corp	(Accumulated Deficit) Retained Earnings	(Accumulated Deficit) Retained Earnings Dun & Bradstreet Corp	Treasury Stock	Treasury Stock Dun & Bradstreet Corp	Cumulative Translation Adjustment	Cumulative Translation Adjustment Dun & Bradstreet Corp	Defined Benefit Postretirement Plans	Defined Benefit Postretirement Plans Dun & Bradstreet Corp	Cash Flow Hedging Derivative	Cash Flow Hedging Derivative Dun & Bradstreet Corp	Non-Controlling Interest	Non-Controlling Interest Dun & Bradstreet Corp
Pension adjustments, tax expense (benefit)		$ 22.2
Change in cumulative translation adjustment, tax expense (benefit)		0.1
Derivative financial instruments, tax expense (benefit)		(0.1)
Balance at beginning of period at Dec. 31, 2018		(13.5)		$ (689.9)	$ (13.5)	$ (705.8)	$ 0.0	$ 0.8	$ 0.0	$ 332.8	$ (13.5)	$ 3,325.0	$ 0.0	$ (3,310.3)	$ 0.0	$ (235.5)	$ 0.0	$ (818.3)	$ 0.0	$ (0.3)	$ 0.0	$ 15.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(74.8)	[1]		(75.6)						(75.6)										0.8
Equity-based compensation plans		11.7			11.7				11.7
Payment to non-controlling interest		(0.1)																			(0.1)
Pension adjustments, net of tax expense (benefit)		65.4			65.4												65.4
Change in cumulative translation adjustment, net of tax expense (benefit)		5.9	[1],[2]		5.7										5.7						0.2
Derivative financial instruments, net of tax expense (benefit)		(0.1)	[1],[3]		(0.1)														(0.1)
Balance at end of period at Feb. 07, 2019		(681.9)			(698.7)		0.8		344.5		3,249.4		(3,310.3)		(229.8)		(752.9)		(0.4)		16.8
Change in cumulative translation adjustment, tax expense (benefit)		(0.2)
Derivative financial instruments, tax expense (benefit)		(0.5)
Balance at beginning of period at Dec. 31, 2018		(13.5)		$ (689.9)	(13.5)	$ (705.8)	0.0	$ 0.8	0.0	$ 332.8	(13.5)	$ 3,325.0	0.0	$ (3,310.3)	0.0	$ (235.5)	0.0	$ (818.3)	0.0	$ (0.3)	0.0	$ 15.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(325.4)	[1]		(328.7)						(328.7)										3.3
Take-Private Transaction		2,163.2			2,048.4				2,048.4												114.8
Capital / equity contribution		100.0			100.0				100.0
Equity-based compensation plans		63.1			63.1				63.1
Preferred dividend	[4]	(64.1)			(64.1)				(64.1)
Payment to non-controlling interest		(5.5)																			(5.5)
Change in cumulative translation adjustment, net of tax expense (benefit)		(40.9)	[1],[2]		(34.6)										(34.6)						(6.3)
Derivative financial instruments, net of tax expense (benefit)		(1.6)	[1],[3]		(1.6)														(1.6)
Balance at end of period at Sep. 30, 2019		1,875.3			1,769.0		0.0		2,147.4		(342.2)		0.0		(34.6)		0.0		(1.6)		106.3
Change in cumulative translation adjustment, tax expense (benefit)		0.6
Balance at beginning of period at Jun. 30, 2019		1,812.0			1,796.6		0.0		2,100.5		(285.5)		0.0		(16.8)		0.0		(1.6)		15.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(55.3)	[1]		(56.7)						(56.7)										1.4
Take-Private Transaction		98.0																			98.0
Capital / equity contribution		75.4			75.4				75.4
Equity-based compensation plans		3.6			3.6				3.6
Preferred dividend	[4]	(32.1)			(32.1)				(32.1)
Payment to non-controlling interest		(2.3)																			(2.3)
Change in cumulative translation adjustment, net of tax expense (benefit)		(24.0)	[1],[2]		(17.8)										(17.8)						(6.2)
Derivative financial instruments, net of tax expense (benefit)	[1],[3]	0.0
Balance at end of period at Sep. 30, 2019		1,875.3			1,769.0		0.0		2,147.4		(342.2)		0.0		(34.6)		0.0		(1.6)		106.3
Pension adjustments, tax expense (benefit)		(0.3)
Change in cumulative translation adjustment, tax expense (benefit)		1.5
Derivative financial instruments, tax expense (benefit)		0.1
Conversion of pre-IPO liability classified as equity-based awards to restricted stock units		1.7
Balance at beginning of period at Dec. 31, 2019		1,577.7			1,519.9		0.0		2,116.9		(573.5)		0.0		(6.6)		(15.8)		(1.1)		57.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(114.8)	[1]		(118.5)						(118.5)										3.7
Accretion - Series A Preferred Stock		(36.1)			(36.1)				(36.1)
Issuance of Class A Common Stock in IPO, net of issuance costs	[5]	2,248.2			2,248.2				2,248.2
Equity-based compensation plans	[6]	38.6			38.6				38.6
Preferred dividend	[4]	(64.1)			(64.1)				(64.1)
Payment to non-controlling interest		(6.8)																			(6.8)
Pension adjustments, net of tax expense (benefit)		(0.9)			(0.9)												(0.9)
Change in cumulative translation adjustment, net of tax expense (benefit)		21.8	[1],[2]		20.7										20.7						1.1
Derivative financial instruments, net of tax expense (benefit)		0.1	[1],[3]		0.1														0.1
Balance at end of period at Sep. 30, 2020		3,663.7			3,607.9		0.0		4,303.5		(692.0)		0.0		14.1		(16.7)		(1.0)		55.8
Pension adjustments, tax expense (benefit)		(0.2)
Change in cumulative translation adjustment, tax expense (benefit)		2.4
Derivative financial instruments, tax expense (benefit)		0.3
Balance at beginning of period at Jun. 30, 2020		1,389.0			1,331.1		0.0		2,043.9		(675.0)		0.0		(20.3)		(15.9)		(1.6)		57.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(14.9)	[1]		(17.0)						(17.0)										2.1
Issuance of Class A Common Stock in IPO, net of issuance costs	[5]	2,248.2			2,248.2				2,248.2
Equity-based compensation plans	[6]	11.4			11.4				11.4
Payment to non-controlling interest		(6.5)																			(6.5)
Pension adjustments, net of tax expense (benefit)		(0.8)			(0.8)												(0.8)
Change in cumulative translation adjustment, net of tax expense (benefit)		36.7	[1],[2]		34.4										34.4						2.3
Derivative financial instruments, net of tax expense (benefit)		0.6	[1],[3]		0.6														0.6
Balance at end of period at Sep. 30, 2020		$ 3,663.7			$ 3,607.9		$ 0.0		$ 4,303.5		$ (692.0)		$ 0.0		$ 14.1		$ (16.7)		$ (1.0)		$ 55.8

[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 $0.3 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.

[4] Related to the preferred stock dividends declared by the Board of Directors of Dun & Bradstreet Holdings, Inc. (formerly Star Intermediate I, Inc.) on May 31, 2019, July 30, 2019, March 4, 2020 and May 14, 2020, respectively, associated with its cumulative Series A Preferred Stock. The dividend payments of $21.3 million, $10.7 million, $32.1 million, $32.0 million and $32.1 million were made on June 19, 2019, June 28, 2019, September 27, 2019, March 27, 2020 and June 26, 2020, respectively. See further discussion in Note 20.

[5] Net of IPO costs of $131.9 million paid by proceeds raised from the offering (see Note 2) and $0.9 million paid prior to the IPO.

[6] Includes $1.7 million related to the conversion of pre-IPO liability classified equity-based awards into restricted stock units.