Retirement Benefits (Details 14) $ in Millions	Dec. 31, 2020 USD ($)
Pension Benefits [Member]
Defined Benefit Plan Expected Future Benefit Payments [Abstract]
2021	$ 167.2
2022	165.0
2023	164.1
2024	161.5
2025	158.8
2026-2030	747.4
Other Postretirement Benefits
Defined Benefit Plan Expected Future Benefit Payments [Abstract]
2021	30.9
2022	29.7
2023	30.1
2024	28.5
2025	26.5
2026-2030	107.2
Medicare Part D Subsidy [Abstract]
2021	0.1
2022	0.1
2023	0.1
2024	0.1
2025	0.1
2026-2030	$ 0.3

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