Accumulated Other Comprehensive Income (Tables)

12 Months Ended

Dec. 31, 2021

Equity [Abstract]

After-tax components of comprehensive income (loss)

The following table sets forth the after-tax components of accumulated other comprehensive income and changes thereto:

	Foreign Currency Translation Adjustment		Prior Service Credit Associated with Postretirement Plans		Total Accumulated Other Comprehensive Income
	(Dollars in millions)
December 31, 2018	$	(4.5)	$	44.6	$	40.1
Reclassification from other comprehensive income to earnings	—		(8.7)		(8.7)
Current period change	0.2		—		0.2
December 31, 2019	(4.3)		35.9		31.6
Reclassification from other comprehensive income to earnings	—		(17.3)		(17.3)
Current period change	6.1		185.4		191.5
December 31, 2020	1.8		204.0		205.8
Reclassification from other comprehensive income to earnings	—		(46.4)		(46.4)
Current period change	(1.0)		139.5		138.5
December 31, 2021	$	0.8	$	297.1	$	297.9