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Retirement Benefits (Details 14) $ in Millions | Dec. 31, 2017 USD ($)
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Pension Benefits [Member] |
Defined Benefit Plan Expected Future Benefit Payments [Abstract] |
2018 | $ 201.0
2019 | 194.1
2020 | 192.0
2021 | 188.8
2022 | 186.8
2023-2027 | 891.5
Other Postretirement Benefits [Member] |
Defined Benefit Plan Expected Future Benefit Payments [Abstract] |
2018 | 32.1
2019 | 31.2
2020 | 29.7
2021 | 28.1
2022 | 26.2
2023-2027 | 109.0
Medicare Part D Subsidy [Abstract] |
2018 | 0.8
2019 | 0.8
2020 | 0.8
2021 | 0.7
2022 | 0.7
2023-2027 | $ 2.8

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