Sale of Stock, Proportion of Issuance Price per Share to Initial Public Offering Price per Share

No definition available.

Name:	dnb_SaleOfStockProportionOfIssuancePricePerShareToInitialPublicOfferingPricePerShare
Namespace Prefix:	dnb_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_ClassOfStockLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Face amount or stated value per share of common stock.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

+ References

+ Details

Name:	us-gaap_CommonStockSharesAuthorized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_PreferredStockSharesAuthorized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Cash received on stock transaction after deduction of issuance costs.

+ References

No definition available.

+ Details

Name:	us-gaap_SaleOfStockConsiderationReceivedOnTransaction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

+ References

No definition available.

+ Details

Name:	us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

+ References

No definition available.

+ Details

Name:	us-gaap_SaleOfStockPricePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187143-122770

+ Details

Name:	us-gaap_StockholdersEquityNoteStockSplitConversionRatio1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=us-gaap_IPOMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=us-gaap_PrivatePlacementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=dnb_SubsidiaryOfCannaeHoldingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=dnb_SubsidiaryOfBlackKnightMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=dnb_AffiliateOfCCCapitalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

IPO and Private Placement - Narrative (Details) $ / shares in Units, $ in Millions	Jul. 06, 2020 USD ($) $ / shares shares	Jun. 23, 2020 shares	Feb. 08, 2019 USD ($)	Aug. 08, 2018 USD ($)	Dec. 31, 2020 $ / shares shares	Dec. 31, 2019 $ / shares shares
Class of Stock [Line Items]
Stock issued (shares)	108,506,312
Common stock, par value (USD per share) \| $ / shares					$ 0.0001	$ 0.0001
Gross proceeds from sale of stock \| $	$ 2,381.0		$ 1,028.4	$ 1,028.4
Common stock authorized (shares)		2,000,000,000			2,000,000,000	2,000,000,000
Preferred stock authorized (shares)		25,000,000
Stock split ratio		314,494.968
IPO
Class of Stock [Line Items]
Stock issued (shares)	90,047,612
Common stock, par value (USD per share) \| $ / shares	$ 0.0001
Offering price (USD per share) \| $ / shares	$ 22.00
Private Placement
Class of Stock [Line Items]
Stock issued (shares)	18,458,700
Offering price (USD per share) \| $ / shares	$ 21.67
Issuance price per share relative to IPO price per share (as a percent)	98.50%
Private Placement \| Subsidiary of Cannae Holdings
Class of Stock [Line Items]
Gross proceeds from sale of stock \| $	$ 200.0
Private Placement \| Subsidiary of Black Knight
Class of Stock [Line Items]
Gross proceeds from sale of stock \| $	100.0
Private Placement \| Affiliate of CC Capital
Class of Stock [Line Items]
Gross proceeds from sale of stock \| $	$ 100.0