Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
Provisional transition tax obligation for repatriation of foreign earnings	$ 0	$ 144	$ 0
Reduction in current income tax payable attributable to stock-based compensation	34	100	76
Valuation allowance	80	$ 76
Increase (decrease) in NOL valuation allowance	4
Undistributed earnings of foreign subsidiaries	$ 104
Effective interest rate of federal statutory income tax rate	21.00%	35.00%
Unrecognized tax benefits	$ 293	$ 261	220	$ 171
Unrecognized tax benefits that would impact effective tax rate	180	155	181
Uncertain tax positions, interest and penalties	30	22
Interest and penalties	8	7	$ 5
Federal
Income Taxes [Line Items]
Net operating loss carryforwards	84
Unrecognized deferred tax liability related to the U.S. federal income tax consequences of undistributed earnings of foreign subsidiaries	22
State
Income Taxes [Line Items]
Net operating loss carryforwards	91
Foreign
Income Taxes [Line Items]
Net operating loss carryforwards	404
Indefinite foreign net operating loss carryforwards	250
Foreign net operating loss carryforwards subject to expiration	$ 154
IRS
Income Taxes [Line Items]
Increase in prior years taxable revenue due to tax examination		105
Additional federal tax expense due to tax examination		$ 37