Defined Benefit Plans (Details) - Pension Plan - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Defined Benefit Plan Disclosure [Line Items] | |||
| Fair value of plan assets | $ 1,500.0 | $ 1,305.0 | $ 1,412.2 |
| Projected benefit obligation | 1,407.5 | 1,217.5 | 1,335.4 |
| Net asset | 92.5 | 87.5 | 76.8 |
| Net periodic pension cost | 8.6 | 7.4 | 4.0 |
| Service cost | 20.9 | 24.4 | $ 22.2 |
| Curtailment gain | 1.4 | $ 1.1 | |
| Contributions by employer | 26.5 | ||
| Contributions expected in next fiscal year | 27.4 | ||
| Quoted prices in active markets for identical assets (Level 1) | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Fair value of plan assets | 1,120.1 | ||
| Significant other observable inputs (Level 2) | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Fair value of plan assets | 113.3 | ||
| Significant unobservable inputs (Level 3) | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Fair value of plan assets | $ 266.6 | ||