Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Contingency [Line Items]
Provision for tax benefits related to settlement of employee awards		$ 613
Provisional amount related to remeasurement of deferred tax assets and liabilities, recorded as a component of provision for income taxes		67	$ 301
Reduction in provision for income taxes		$ 67
Effective tax rate	21.00%	21.00%	35.00%
Provisional amount reclassified from deferred tax liabilities for the one-time transition tax			$ 127
Reduction to provision for income taxes for tax credits		$ (28)
Provision for tax benefits related to settlement of employee awards	$ 65	124	82
Foreign pretax income	50	86	$ 91
State net operating loss carryforwards	60
Federal net operating loss carryforwards	128
Liability for unrecognized tax benefits	550	435
Unrecognized tax benefits, accrued interest	62	48
Unrecognized tax benefits that would impact effective tax rate	160	137
Deferred tax assets, reductions	$ 34	$ 3
State and Local Jurisdiction [Member] | Minimum [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards, expiration date	2022
State and Local Jurisdiction [Member] | Maximum [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards, expiration date	2038