Retirement Benefits Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accrued postretirement benefits	$ 252.4		$ 258.1
Income tax provision	$ 4.9	$ 5.5

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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