Schedule II - Condensed Statements of Cash Flows Parent Company (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
CASH FLOWS FROM OPERATING ACTIVITIES:
Cash provided by operating activities	$ 897.5	$ 354.3	$ 777.6
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions/dispositions, net of cash acquired/divested	(16.4)	(24.7)	(277.5)
Purchases of equity securities	(44.7)	(170.7)	(157.1)
Proceeds from insurance settlement	4.0	2.2	3.0
Cash (used for) provided by investing activities	(458.7)	599.5	(393.0)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net proceeds from issuance of unsecured senior notes	444.0	0.0	0.0
Repayment of senior unsecured notes	(300.0)	(250.0)	0.0
Net activity related to noncontrolling interests	2.5	(7.1)	(2.2)
Net proceeds in connection with share-based compensation	6.9	0.4	2.5
Repurchases of Company shares	(68.5)	(72.7)	(440.7)
Payments of cash dividends	(220.7)	(216.6)	(217.5)
Cash (used for) provided by financing activities	(2,309.4)	1,423.1	(376.4)
Net increase (decrease) in cash and cash equivalents	(1,887.2)	2,381.8	(4.5)
Cash and cash equivalents—Beginning of year	3,605.3	1,223.5	1,228.0
Cash and cash equivalents—End of year	1,718.1	3,605.3	1,223.5
Parent Company
CASH FLOWS FROM OPERATING ACTIVITIES:
Cash provided by operating activities	221.8	309.0	778.7
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions/dispositions, net of cash acquired/divested	0.0	(2.5)	(296.0)
Net payments to subsidiaries	(70.8)	(160.8)	(154.6)
Purchases of equity securities	0.0	(25.0)	0.0
Cash (used for) provided by investing activities	(66.8)	(188.3)	(450.6)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net proceeds from issuance of unsecured senior notes	444.0	0.0	0.0
Repayment of senior unsecured notes	(300.0)	(250.0)	0.0
Net activity related to noncontrolling interests	0.2	0.3	0.0
Net proceeds in connection with share-based compensation	6.9	0.4	2.5
Repurchases of Company shares	(68.5)	(72.7)	(440.7)
Payments of cash dividends	(220.7)	(216.6)	(217.5)
Cash (used for) provided by financing activities	(138.1)	(538.6)	(655.7)
Net increase (decrease) in cash and cash equivalents	16.9	(417.9)	(327.6)
Cash and cash equivalents—Beginning of year	179.3	597.2	924.8
Cash and cash equivalents—End of year	$ 196.2	$ 179.3	$ 597.2

The cash outflow to acquire equity securities.

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