Accumulated Other Comprehensive Loss Statement (Parenthetical) - USD ($) $ in Millions |
Mar. 31, 2020 |
Dec. 31, 2019 |
|---|---|---|
| Statement of Other Comprehensive Income [Abstract] | ||
| Unrecognized actuarial losses and prior service cost related to pension and other postretirement benefit plans, accumulated tax | $ 86.6 | $ 88.4 |
| Cash flow hedging transactions, accumulated tax | $ 0.7 | $ 0.7 |