Restructuring and Other Charges - Narrative (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | |||
|---|---|---|---|---|---|
Apr. 26, 2019 |
Jun. 28, 2019 |
Jun. 29, 2018 |
Jun. 28, 2019 |
Jun. 29, 2018 |
|
| ECR Business | |||||
| Restructuring Cost and Reserve [Line Items] | |||||
| Restructuring charges, pre-tax, gross | $ 72.6 | $ 106.1 | |||
| CH2M HILL Companies, Ltd. | |||||
| Restructuring Cost and Reserve [Line Items] | |||||
| Restructuring charges, pre-tax, gross | 6.0 | $ 33.9 | 68.5 | $ 94.6 | |
| Integration related activities | $ 3,400.0 | 17.3 | 12.6 | 30.8 | 40.6 |
| Restructuring pre-tax net charges | $ 23.3 | $ 46.5 | $ 99.3 | $ 135.2 | |