Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Document Period End Date	Dec. 31, 2020
Operating loss carryforwards	$ 392.5
Unrecognized tax benefits	1,479.2	[1]	$ 1,439.1	[1]	$ 1,342.8
Reasonably possible amount of unrecognized tax benefits decrease within the next 12 months - minimum	1,040.0
Effective tax rate adjustment	940.0
Accrued interest and penalties related to income tax matters	177.4		174.4
Provision for income taxes, interest and penalties expense related to tax matters	$ 32.4		$ 39.9		13.9
Tax Cuts and Jobs Act, Transition Tax for Accumulated Foreign Earnings, Liability, Noncurrent						$ 1,200.0
Adjustments to Provisional Amounts Recorded at December 31, 2017 (Tax Cuts and Jobs Act of 2017)					$ 75.0
Statutory U.S. federal income tax rate	21.00%		21.00%		21.00%
Indefinite [Member]
Income Taxes [Line Items]
Operating loss carryforwards	$ 228.2

[1] Of this amount, $1,137.8 million and $1,285.3 million are included in Long-term income taxes for 2020 and 2019, respectively, and $325.0 million and $138.8 million are included in Prepaid expenses and other current assets for 2020 and 2019, respectively, on the Consolidated Balance Sheet. The remainder is included in Deferred income taxes on the Consolidated Balance Sheet.