Acquisitions - Purchase Price Allocation (Details) - USD ($) $ in Millions				9 Months Ended		12 Months Ended
	Nov. 15, 2021	Nov. 05, 2021	Jan. 08, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2022	Dec. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Initial purchase price allocation:
Goodwill				$ 3,493.3	$ 2,857.9	$ 3,431.3	$ 2,857.9
Eyeota
Business Acquisition [Line Items]
Amortization life (years)		2 years
Initial purchase price allocation:
Cash				7.1		7.1
Accounts receivable				9.3		9.3
Other				0.5		0.5
Total current assets				16.9		16.9
Goodwill				138.3		138.5
Total assets acquired				190.2		190.4
Deferred tax liability				5.9		5.9
Other liabilities				12.0		12.1
Total liabilities assumed				17.9		18.0
Total purchase price				172.3		172.4
Measurement period adjustments
Cash						0.0
Accounts receivable						0.0
Other current assets						0.0
Total current assets						0.0
Goodwill						0.2
Total assets acquired						0.2
Deferred tax liability						0.0
Other liabilities						0.1
Total liabilities assumed						0.1
Total purchase price						0.1
NetWise
Initial purchase price allocation:
Cash				2.6		2.6
Accounts receivable				2.6		2.6
Other				0.4		0.4
Total current assets				5.6		5.6
Goodwill				2.2		2.2
Total assets acquired				41.9		45.5
Deferred tax liability				71.0		74.6
Other liabilities				1.2		4.4
Total liabilities assumed				69.8		70.2
Measurement period adjustments
Cash						0.0
Accounts receivable						0.0
Other current assets						0.0
Total current assets						0.0
Goodwill						0.0
Total assets acquired						3.6
Deferred tax liability						3.6
Other liabilities						3.2
Total liabilities assumed						0.4
Bisnode
Initial purchase price allocation:
Cash				29.9				$ 29.9
Accounts receivable				61.0				61.0
Other				13.1				13.1
Total current assets				104.0				104.0
Property, plant & equipment				3.5				3.5
Goodwill				495.4				488.4
Right of use asset				27.4				26.7
Other				2.9				5.2
Total assets acquired				1,186.2				1,185.8
Accounts payable				17.5				17.5
Deferred revenue				80.6				80.6
Accrued payroll				20.7				20.7
Accrued income tax and other tax liabilities				17.1				17.1
Short-term lease liability				8.6				8.4
Other current liabilities				23.7				23.7
Total current liabilities				168.2				168.0
Long-term pension and postretirement obligations				65.4				65.4
Deferred tax liability				127.8				127.6
Long-term lease liability				18.2				18.2
Other liabilities				0.8				0.8
Total liabilities assumed				380.4				380.0
Total purchase price				805.8				805.8
Measurement period adjustments
Cash				0.0
Accounts receivable				0.0
Other current assets				0.0
Total current assets				0.0
Property, plant & equipment				0.0
Goodwill				7.0
Right of use asset				0.7
Other				(2.3)
Total assets acquired				0.4
Long-term lease liability				0.0
Accounts payable				0.0
Deferred revenue				0.0
Accrued payroll				0.0
Accrued income tax and other tax liabilities				0.0
Short-term lease liability				0.2
Other current liabilities				0.0
Total current liabilities				0.2
Long-term pension and postretirement obligations				0.0
Deferred tax liability				0.2
Other liabilities				0.0
Total liabilities assumed				0.4
Total consideration				0.0
Orb Intelligence & coAction.com
Initial purchase price allocation:
Cash					0.5		0.5		$ 0.5
Accounts receivable					0.3		0.3		0.3
Other					0.3		0.3		0.2
Total current assets					1.1		1.1		1.0
Goodwill					10.9		10.9		10.7
Deferred tax asset					0.4		0.4		0.4
Total assets acquired					21.6		21.6		21.3
Total liabilities assumed					0.4		0.4		0.2
Total purchase price					21.2		$ 21.2		21.1
Measurement period adjustments
Cash					0.0
Accounts receivable					0.0
Other current assets					0.1
Total current assets					0.1
Goodwill					0.2
Deferred tax asset					0.0
Total assets acquired					0.3
Total liabilities assumed					0.2
Total purchase price					0.1
Reacquired right | Bisnode
Business Acquisition [Line Items]
Amortization life (years)			15 years
Initial purchase price allocation:
Intangible assets:				270.0				271.0
Measurement period adjustments
Intangible assets:				(1.0)
Database | NetWise
Business Acquisition [Line Items]
Amortization life (years)	3 years
Database | Bisnode
Business Acquisition [Line Items]
Amortization life (years)			12 years
Initial purchase price allocation:
Intangible assets:				111.0				116.0
Measurement period adjustments
Intangible assets:				(5.0)
Customer relationships | Eyeota
Business Acquisition [Line Items]
Amortization life (years)		14 years
Initial purchase price allocation:
Intangible assets:				20.0		20.0
Measurement period adjustments
Intangible assets:						0.0
Customer relationships | NetWise
Business Acquisition [Line Items]
Amortization life (years)	15 years
Initial purchase price allocation:
Intangible assets:				19.8		19.8
Measurement period adjustments
Intangible assets:						0.0
Customer relationships | Bisnode
Business Acquisition [Line Items]
Amortization life (years)			10 years
Initial purchase price allocation:
Intangible assets:				108.0				106.0
Measurement period adjustments
Intangible assets:				2.0
Customer relationships | Orb Intelligence & coAction.com
Business Acquisition [Line Items]
Amortization life (years)							7 years
Initial purchase price allocation:
Intangible assets:					2.4		$ 2.4		2.4
Measurement period adjustments
Intangible assets:					0.0
Technology | Eyeota
Business Acquisition [Line Items]
Amortization life (years)		5 years
Initial purchase price allocation:
Intangible assets:				14.0		14.0
Measurement period adjustments
Intangible assets:						0.0
Technology | NetWise
Business Acquisition [Line Items]
Amortization life (years)	5 years
Initial purchase price allocation:
Intangible assets:				1.3		1.3
Measurement period adjustments
Intangible assets:						0.0
Technology | Bisnode
Business Acquisition [Line Items]
Amortization life (years)			14 years
Initial purchase price allocation:
Intangible assets:				64.0				$ 65.0
Measurement period adjustments
Intangible assets:				(1.0)
Technology | Orb Intelligence & coAction.com
Business Acquisition [Line Items]
Amortization life (years)							11 years
Initial purchase price allocation:
Intangible assets:					6.8		$ 6.8		$ 6.8
Measurement period adjustments
Intangible assets:					$ 0.0
Trademark | Eyeota
Initial purchase price allocation:
Intangible assets:				1.0		1.0
Measurement period adjustments
Intangible assets:						0.0
Trademark | NetWise
Business Acquisition [Line Items]
Amortization life (years)	2 years
Initial purchase price allocation:
Intangible assets:				$ 0.2		0.2
Measurement period adjustments
Intangible assets:						$ 0.0