Operating Loss Carryforwards, Percentage Subject to Expiration

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- Definition

Amount of decrease reasonably possible in the next twelve months for the unrecognized tax benefit.

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- Definition

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

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Amount of deferred tax liability attributable to taxable temporary differences from undistributed earnings of subsidiary and other recognized entity not within country of domicile. Includes, but is not limited to, other basis differences.

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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- Definition

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 increase (decrease) in the valuation allowance for deferred tax assets.

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- Definition

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.

+ References

No definition available.

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- Definition

Amount of undistributed earnings of foreign subsidiaries intended to be permanently reinvested outside the country of domicile.

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Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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- Definition

The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset.

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Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
Income Taxes (Narrative) (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 01, 2021	Nov. 30, 2021
Tax Credit Carryforward [Line Items]
Undistributed earnings of foreign subsidiaries	$ 830,000,000
Differences related to non-U.S. operations	543,000,000	$ 624,000,000
Net increases in valuation allowances	1,000,000	36,000,000	$ 72,000,000
Increase (decrease) in income tax expense due to adjustments to valuation allowance	$ 5,000,000	2,000,000	14,000,000
Net operating loss carryforwards (as a percent)	14.00%
Unrecognized tax benefits	$ 94,000,000	87,000,000	90,000,000
Accrued interest and penalties, before any applicable federal benefit	48,000,000	$ 45,000,000	$ 40,000,000
Maximum
Tax Credit Carryforward [Line Items]
Reasonably possible decrease in unrecognized tax benefits	$ 42,000,000
Marsh India
Tax Credit Carryforward [Line Items]
Percentage of interest acquired	92.00%	49.00%		92.00%	49.00%
Marsh India \| Minimum
Tax Credit Carryforward [Line Items]
Percentage of interest acquired		49.00%
Marsh India \| Maximum
Tax Credit Carryforward [Line Items]
Percentage of interest acquired		92.00%
State and Local
Tax Credit Carryforward [Line Items]
Differences related to non-U.S. operations	$ 80,000,000
Operating loss carryforwards tax benefits	13,000,000
Federal
Tax Credit Carryforward [Line Items]
Operating loss carryforwards tax benefits	5,000,000
Non-U.S.
Tax Credit Carryforward [Line Items]
Operating loss carryforwards tax benefits	$ 342,000,000