Other Operating Credits and Charges, Net Non-Operating Income and Expense (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest Expense		$ 15.0	$ 17.0	$ 18.0
Amortization of financing costs and discounts		2.0	2.0	2.0
Interest Costs Capitalized Adjustment		3.0	0.0	1.0
Interest expense, net of capitalized interest		(14.0)	(19.0)	(19.0)
Investment Income, Interest and Dividend		1.0	2.0	9.0
Realized Investment Gains (Losses)		0.0	3.0	0.0
Interest Income, Other		0.0	(1.0)	1.0
Investment income		1.0	4.0	10.0
Net Periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component		1.0	1.0	3.0
Foreign Currency Transaction Gain (Loss), Realized		(3.0)	1.0	(5.0)
Loss on early debt extinguishment		(11.0)	0.0	0.0
Loss due to settlement		(2.0)	0.0	0.0
Gain on Acquisition		0.0	0.0	14.0
Other nonoperating items		(16.0)	$ 0.0	$ 6.0
Redemption Premium		9.0
Write off of deferred debt issuance cost		$ 2.0
Entekra [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Gain on Acquisition	$ 0.0