Pension and Postretirement Health and Life Benefits (Schedule of Changes in Projected Benefit Obligations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan, Actuarial (Gain) Loss From Remeasurement	$ 50.5	$ (7.2)
Defined Benefit Plan, Plan Assets, Amount	681.8	633.0
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Benefit Obligation	696.2	757.9	$ 763.5
Defined Benefit Plan, Actuarial (Gain) Loss From Remeasurement	(28.7)	56.7
Defined Benefit Plan, Service Cost	2.7	3.5
Defined Benefit Plan, Interest Cost	18.1	24.3
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement	0.0	(30.4)
Defined Benefit Plan, Benefit Obligation, Administrative Expenses Paid	(2.1)	(2.9)
Defined Benefit Plan, Plan Assets, Amount	672.7	633.1	621.2
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	57.8	85.4
Defined Benefit Plan, Plan Assets, Contributions by Employer	35.7	16.6
Defined Benefit Plan, Plan Assets, Benefits Paid	51.7	56.8
Defined Benefit Plan, Plan Assets, Payment for Settlement	0.0	(30.4)
Defined Benefit Plan, Plan Assets, Administration Expense	(2.2)	(2.9)
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(23.5)	(124.8)
Amounts Recognized In Current Liabilities	(0.4)	(0.4)
Amounts Recognized In Noncurrent Liabilities	(23.1)	(124.4)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(23.5)	(124.8)
Recognized In Accumulated Other Comprehensive Income Pre Tax Prior Service Cost Credit	(0.9)	(1.1)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	(0.9)	(1.1)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Benefit Obligation	131.1	142.4	152.8
Defined Benefit Plan, Actuarial (Gain) Loss From Remeasurement	(2.3)	(1.6)
Defined Benefit Plan, Service Cost	0.0	0.0
Defined Benefit Plan, Interest Cost	3.4	4.8
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement	0.0	0.0
Defined Benefit Plan, Benefit Obligation, Administrative Expenses Paid	0.0	0.0
Defined Benefit Plan, Plan Assets, Amount	9.2	0.0	$ 0.0
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	0.0	0.0
Defined Benefit Plan, Plan Assets, Contributions by Employer	21.5	13.6
Defined Benefit Plan, Plan Assets, Benefits Paid	12.3	13.6
Defined Benefit Plan, Plan Assets, Payment for Settlement	0.0	0.0
Defined Benefit Plan, Plan Assets, Administration Expense	0.0	0.0
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(121.9)	(142.4)
Amounts Recognized In Current Liabilities	(7.0)	(11.6)
Amounts Recognized In Noncurrent Liabilities	(114.9)	(130.8)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(121.9)	(142.4)
Recognized In Accumulated Other Comprehensive Income Pre Tax Prior Service Cost Credit	(2.0)	(2.1)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	(2.0)	(2.1)
Plan paid [Member] | Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(51.3)	(56.3)
Plan paid [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(12.4)	(13.6)
Company paid [Member] | Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(0.4)	(0.5)
Company paid [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Benefit Obligation, Benefits Paid	$ 0.0	$ 0.0