Goodwill (Carrying Amount of Goodwill by Reportable Segment) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 1,798.2	$ 1,587.6
Acquisitions	7.5	217.3
Transfers		0.0
Dispositions	(0.9)
Foreign currency translation	2.7	(6.7)
Goodwill, Ending Balance	1,807.5	1,798.2
Title Insurance and Services
Goodwill [Line Items]
Goodwill, Beginning Balance	1,757.3	1,575.0
Acquisitions	7.5	217.3
Transfers		(28.3)
Dispositions	(0.9)
Foreign currency translation	2.7	(6.7)
Goodwill, Ending Balance	1,766.6	1,757.3
Home Warranty
Goodwill [Line Items]
Goodwill, Beginning Balance	40.9	12.6
Acquisitions	0.0	0.0
Transfers		28.3
Dispositions	0.0
Foreign currency translation	0.0	0.0
Goodwill, Ending Balance	$ 40.9	$ 40.9