Income Tax Expense, Differential Losses Netted Against Uncertain Tax Positions

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Income Tax Reconciliation I R S One Seven Nine D Deduction

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Measurement Period Adjustments On Effective Tax Rate

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to the disposition of a business not qualifying as a discontinued operation.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax credits. Including, but not limited to, research credit, foreign tax credit, investment tax credit, and other tax credits.

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Amount of reasonable estimate for income tax expense for which accounting for tax effect from transition tax on accumulated earnings of controlled foreign corporation deemed repatriated is incomplete pursuant to Tax Cuts and Jobs Act.

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Income Taxes - Narrative (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
Income Taxes - Narrative (Details) - USD ($) $ in Millions	Dec. 22, 2018	Mar. 27, 2020	Mar. 29, 2019	Mar. 27, 2020	Mar. 29, 2019
Income Tax Contingency [Line Items]
Effective income tax rate		34.60%	(7.10%)	9.50%	7.30%
Tax benefit due to divestiture		$ 37.4
Foreign tax credits and research and development		5.8
Benefit from IRC section 179D		$ 4.1
Favorable settlement with the Indian Revenue Service				$ 3.7
Measurement period				1 year
Income tax expense for the measurement period	$ 144.4
Cumulative transition taxes during the measurement period				$ 14.3
CH2M HILL Companies, Ltd.
Income Tax Contingency [Line Items]
Income tax expense for the measurement period	$ 104.2