Pensions and Postretirement Benefits Other than Pensions (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Company contributions			$ 88.5	$ 82.4
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	$ (5.4)	$ (26.3)	(5.6)	(47.0)
Pension Costs [Member]
Actuarial gain (loss)	(3.9)	(5.8)	(11.9)	(17.5)
Pension Plan, Defined Benefit [Member]
Expected future employer contributions in 2017	97.0		97.0
Postretirement Benefit Costs [Member]
Actuarial gain (loss)	$ 3.3	$ 1.4	$ 9.8	$ 4.2

Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan.

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Amount of contribution expected to be received by defined benefit plan from employer in next fiscal year following current fiscal year.

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Amount, after tax and reclassification adjustment, of (increase) decrease in accumulated other comprehensive income for defined benefit plan.

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Amount of cash outflow for pension benefit. Includes, but is not limited to, employer contribution to fund plan asset and payment to retiree. Excludes other postretirement benefit.

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