Changes In Equity And Accumulated Other Comprehensive Loss (Classification Of Accumulated Other Comprehensive Income Reflected On Consolidated Balance Sheets) (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Changes In Equity And Comprehensive Income [Line Items]
Accumulated other comprehensive loss, beginning balance	$ (466.4)
Other comprehensive income (loss) before reclassifications	(28.0)
Amounts reclassified from accumulated other comprehensive income	10.1
Net current-period othre comprehensive income (loss)	(17.9)
Accumulated other comprehensive loss, ending balance	(484.3)
Deferred tax assets, other comprehensive loss	150.6	$ 148.2
Accumulated Defined Benefit Plans Adjustment
Changes In Equity And Comprehensive Income [Line Items]
Accumulated other comprehensive loss, beginning balance	(397.9)
Net current-period othre comprehensive income (loss)	10.1
Accumulated other comprehensive loss, ending balance	(387.8)
Accumulated Translation Adjustment
Changes In Equity And Comprehensive Income [Line Items]
Accumulated other comprehensive loss, beginning balance	(68.5)
Other comprehensive income (loss) before reclassifications	(28.0)
Net current-period othre comprehensive income (loss)	(28.0)
Accumulated other comprehensive loss, ending balance	$ (96.5)