Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Income Tax Contingency [Line Items]
Effective tax rate	23.20%	23.80%	22.90%	22.20%
Provision for tax benefits related to settlement of employee awards			$ 96	$ 59
Provision for income taxes	$ 685	$ 209	1,531	$ 665
Liability for unrecognized tax benefits	626		626		$ 508
Unrecognized tax benefits, accrued interest	95		95		73
Unrecognized tax benefits that would impact effective tax rate	$ 192		$ 192		$ 157

Unrecognized tax benefits including interest accrued net of deferred tax assets.

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- Definition

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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- Definition

Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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

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- Definition

Amount of interest expense accrued for an underpayment of income taxes.

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

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