Pension and Postretirement Benefit Plans - Pension Asset Fair Value Level 3 (Details) - Qualified and Non-qualified Pension Benefits - International - Funded - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
|
| Benefit Plan Information | ||
| Foreign currency exchange | $ (376.0) | $ (80.0) |
| Level 3 | ||
| Benefit Plan Information | ||
| Defined benefit plan increase/decrease related to currency exchange rates | 43.5 | (7.0) |
| Defined benefit plan increase/decrease related to aggregate of net purchases and net unrealized gains and losses | (0.5) | 24.0 |
| Defined benefit plan increase/decrease related to Level 3 assets | $ 43.0 | $ 17.0 |