Accounting Policies - Reclassifications Out of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Additional interest expense	$ 169.0	$ 142.7	$ 118.1
Tax effect	234.8	153.2	168.2
Earnings from Continuing Operations	9.5
Pension and Postretirement Benefit Plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings from Continuing Operations	9.5	9.2	13.4
Reclassification out of Accumulated Other Comprehensive Income | Pension and Postretirement Benefit Plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Settlement charge	4.6		3.7
Prior service cost (credit)	4.0		(0.1)
Actuarial loss	3.7	12.1	14.3
Tax effect	(2.8)	(2.9)	(4.5)
Earnings from Continuing Operations		9.2	13.4
Reclassification out of Accumulated Other Comprehensive Income | Pension and Postretirement Benefit Plans | Other Nonoperating Income, Net
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications out of accumulated other comprehensive loss before taxes	$ 12.3	$ 12.1	$ 17.9