Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net Income
Income from continuing operations	$ 74.3	$ 74.9
Less: net income attributable to the noncontrolling interests	(4.1)	(2.4)
Income from continuing operations attributable to TransUnion	70.2	72.5
Discontinued operations, net of tax	0.0	(1.6)
Net income attributable to TransUnion	$ 70.2	$ 70.9
Basic earnings per common share from:
Income from continuing operations attributable to TransUnion	$ 0.37	$ 0.39
Discontinued operations, net of tax	0	(0.01)
Net Income attributable to TransUnion common stockholders, Basic	0.37	0.38
Diluted earnings per common share from:
Income from continuing operations attributable to TransUnion	0.37	0.38
Discontinued operations, net of tax	0	(0.01)
Net Income attributable to TransUnion common stockholders, Diluted	$ 0.37	$ 0.37
Weighted Average Number of Shares Outstanding, Basic	189.2	186.6
Weighted Average Number Diluted Shares Outstanding Adjustment	3.0	4.4
Weighted Average Number of Shares Outstanding, Diluted	192.2	191.0
Performance Shares Contingency Not Met [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1.3	1.3
Performance Shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0.2	0.2