Herbalife Ltd. Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt - Additional Information (Detail)

Long-Term Debt - Additional Information (Detail)							1 Months Ended				3 Months Ended				9 Months Ended		12 Months Ended
Long-Term Debt - Additional Information (Detail)	Mar. 19, 2020 USD ($)	Dec. 12, 2019 USD ($)	Aug. 15, 2019 USD ($)	Aug. 16, 2018 USD ($)	Aug. 16, 2018 USD ($)	Feb. 15, 2017 USD ($)	May 31, 2020 USD ($)	Aug. 31, 2018 USD ($)	Mar. 31, 2018 USD ($) $ / shares	Feb. 28, 2014 USD ($) $ / shares	Sep. 30, 2020 USD ($) $ / shares	Sep. 30, 2019 USD ($)	Mar. 31, 2018 USD ($) $ / shares	Mar. 31, 2014 USD ($)	Sep. 30, 2020 USD ($) Day $ / shares	Sep. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)	May 29, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2018 USD ($)
Debt Instrument [Line Items]
Outstanding principal amount											$ 2,544,300,000				$ 2,544,300,000
Borrowings under the senior secured credit facility											981,200,000				981,200,000				$ 965,300,000
Interest expense											37,000,000.0	$ 36,700,000			96,400,000	$ 121,500,000
Paid-in-capital in excess of par value											335,800,000				335,800,000				366,600,000
Long-term debt											2,428,600,000				2,428,600,000				1,803,000,000.0
Convertible notes paid																675,000,000.0
Letters of credit issued but undrawn											35,600,000				35,600,000
Capped call transactions [Member]
Debt Instrument [Line Items]
Capped call transactions with financial institutions										$ 123,800,000
Prepaid forward share repurchase transactions [Member]
Debt Instrument [Line Items]
Forward share repurchase transactions amount										685,800,000				$ 685,800,000
Convertible Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Outstanding principal amount										1,150,000,000
Deferred financing costs														26,600,000
Aggregate principal amount of convertible senior notes issued										1,000,000,000
Interest expense											5,400,000				27,000,000.0
Non-cash interest expense											3,500,000				17,000,000.0
Amortization of deferred financing costs											400,000				1,700,000
Additional principal amount of convertible notes										$ 150,000,000
Convertible notes, interest rate										2.00%
Convertible notes maturity										Aug. 15, 2019
Principal amount of convertible notes										$ 1,000
Convertible notes conversion rate										23.1816
Convertible notes conversion price \| $ / shares										$ 43.14
Paid-in-capital in excess of par value										$ 219,100,000				5,100,000
Long-term debt										$ 930,900,000
Effective interest rate on convertible notes										6.20%
Convertible notes paid			$ 675,000,000.0						$ 583,500,000
Accrued interest			$ 6,700,000						1,000,000.0				$ 1,000,000.0
Convertible Senior Notes Due 2019 [Member] \| Repurchase of 2019 Convertible Notes [Member]
Debt Instrument [Line Items]
Loss on extinguishment of debt									13,100,000
Repurchase of convertible notes									475,000,000.0
Fair value of liability to convertible notes									459,400,000				459,400,000
Fair value of equity component to convertible notes									123,000,000.0				123,000,000.0
Reduction to long-term debt representing liability component of convertible notes									446,400,000
Reduction to additional paid-in capital representing equity component									123,000,000.0
Convertible Senior Notes Due 2019 [Member] \| Debt Issuance Costs [Member]
Debt Instrument [Line Items]
Deferred financing costs														$ 21,500,000
Convertible Senior Notes Due 2024 [Member]
Debt Instrument [Line Items]
Outstanding principal amount											550,000,000.0				550,000,000.0				550,000,000.0
Deferred financing costs									12,900,000				12,900,000
Aggregate principal amount of convertible senior notes issued									$ 550,000,000				$ 550,000,000
Interest expense											9,500,000	9,000,000.0			28,100,000	26,700,000
Non-cash interest expense											5,500,000	5,100,000			16,200,000	14,900,000
Amortization of deferred financing costs											$ 400,000	300,000			$ 1,100,000	1,000,000.0
Convertible notes, interest rate									2.625%		2.625%		2.625%		2.625%
Convertible notes maturity													Mar. 15, 2024		Mar. 15, 2024
Principal amount of convertible notes									$ 1,000						$ 1,000
Convertible notes conversion rate									16.0056						16.0352
Convertible notes conversion price \| $ / shares									$ 62.48		$ 62.36		$ 62.48		$ 62.36
Paid-in-capital in excess of par value									$ 139,900,000				$ 139,900,000
Long-term debt									$ 410,100,000				$ 410,100,000
Effective interest rate on convertible notes									8.40%				8.40%
Fair value of liability to convertible notes											$ 503,100,000				$ 503,100,000				508,600,000
Convertible notes, conversion feature															Holders of the 2024 Convertible Notes may convert their notes at their option under the following circumstances: (i) during any calendar quarter commencing after the calendar quarter ending June 30, 2018, if the last reported sale price of the Company’s common shares for at least 20 trading days (whether or not consecutive) in a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter exceeds 130% of the conversion price for the 2024 Convertible Notes on each applicable trading day; (ii) during the five business-day period immediately after any five consecutive trading day period, or the measurement period, in which the trading price per $1,000 principal amount of 2024 Convertible Notes for each trading day of that measurement period was less than 98% of the product of the last reported sale price of the Company’s common shares and the conversion rate for the 2024 Convertible Notes for each such day; (iii) if the Company calls the 2024 Convertible Notes for redemption; or (iv) upon the occurrence of specified corporate events. On and after December 15, 2023, holders may convert their 2024 Convertible Notes at any time, regardless of the foregoing circumstances.
Convertible notes, number of trading days of threshold limit (whether or not consecutive) \| Day															20
Convertible notes, number of trading days of threshold limit in consecutive days \| Day															30
Minimum percentage of common share price over conversion price for conversion									130.00%
Minimum percentage of the product of common share price and conversion rate for convertible notes									98.00%
Deferred financing costs recorded as additional paid-in-capital in excess of par value									$ 3,300,000				$ 3,300,000
Unamortized debt discount and debt issuance costs											95,400,000				$ 95,400,000				112,600,000
Convertible senior notes, carrying value of liability component											454,600,000				454,600,000				437,400,000
Convertible Senior Notes Due 2024 [Member] \| Debt Issuance Costs [Member]
Debt Instrument [Line Items]
Deferred financing costs									$ 9,600,000				$ 9,600,000
7.875% Senior Notes Due 2025 [Member]
Debt Instrument [Line Items]
Outstanding principal amount											600,000,000.0				600,000,000.0
Deferred financing costs											7,400,000				7,400,000			$ 7,900,000
Aggregate principal amount of convertible senior notes issued							$ 600,000,000
Interest expense											12,100,000				16,400,000
Amortization of deferred financing costs											$ 300,000				$ 400,000
Convertible notes, interest rate							7.875%				7.875%				7.875%
Convertible notes maturity							Sep. 01, 2025								Sep. 01, 2025
Senior notes, redemption price, percentage							100.00%
Senior notes, redemption price percentage with equity offerings							107.875%
Carrying amount											$ 592,600,000				$ 592,600,000
Fair value of notes											646,100,000				646,100,000
7.875% Senior Notes Due 2025 [Member] \| Debt Issuance Costs [Member]
Debt Instrument [Line Items]
Deferred financing costs																		$ 7,900,000
7.875% Senior Notes Due 2025 [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Percentage of aggregate principal amount of senior notes being redeemed							40.00%
7.250% Senior Notes Due 2026 [Member]
Debt Instrument [Line Items]
Outstanding principal amount											400,000,000.0				400,000,000.0				400,000,000.0
Deferred financing costs											4,300,000				4,300,000				4,700,000	$ 5,400,000
Aggregate principal amount of convertible senior notes issued								$ 400,000,000
Interest expense											7,400,000	7,300,000			22,200,000	22,100,000
Amortization of deferred financing costs											$ 100,000	100,000			$ 400,000	400,000
Convertible notes, interest rate								7.25%			7.25%				7.25%
Convertible notes maturity								Aug. 15, 2026							Aug. 15, 2026
Senior notes, redemption price, percentage								100.00%
Senior notes, redemption price percentage with equity offerings								107.25%
Carrying amount											$ 395,700,000				$ 395,700,000				395,300,000
Fair value of notes											$ 410,900,000				$ 410,900,000				$ 424,100,000
7.250% Senior Notes Due 2026 [Member] \| Debt Issuance Costs [Member]
Debt Instrument [Line Items]
Deferred financing costs																				$ 5,400,000
7.250% Senior Notes Due 2026 [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Percentage of aggregate principal amount of senior notes being redeemed								40.00%
Eurodollar [Member]
Debt Instrument [Line Items]
Base rate interest rate floor					0.00%
2017 Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum amount						$ 1,450,000,000.0
Credit Facility amended, effective date															Mar. 16, 2018
Deferred financing costs						$ 22,600,000
Credit facility, amount repaid					$ 1,178,100,000
2017 Credit Facility [Member] \| Other Expense (Income), Net [Member]
Debt Instrument [Line Items]
Loss on extinguishment of debt																	$ 35,400,000
2017 Credit Facility [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Base rate interest rate floor						1.75%
2017 Credit Facility [Member] \| Federal Funds Rate [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate						0.50%
2017 Credit Facility [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate						1.00%
2017 Credit Facility [Member] \| 2017 Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum amount						$ 150,000,000.0
Credit facility, maturity date															Feb. 15, 2022
Repayment of prior senior secured credit facility					1,178,100,000
Credit facility LIBOR minimum floor rate interest						0.75%
2017 Credit Facility [Member] \| 2017 Revolving Credit Facility [Member] \| Eurodollar [Member] \| Scenario Leverage Ratio One [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate						4.50%
2017 Credit Facility [Member] \| 2017 Revolving Credit Facility [Member] \| Eurodollar [Member] \| Scenario Leverage Ratio Two [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate						4.75%
2017 Credit Facility [Member] \| 2017 Revolving Credit Facility [Member] \| Base Rate [Member] \| Scenario Leverage Ratio One [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate						3.50%
2017 Credit Facility [Member] \| 2017 Revolving Credit Facility [Member] \| Base Rate [Member] \| Scenario Leverage Ratio Two [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate						3.75%
2017 Credit Facility [Member] \| 2017 Term Loan B [Member]
Debt Instrument [Line Items]
Outstanding principal amount						$ 1,300,000,000.0
Credit facility, maturity date															Feb. 15, 2023
Senior secured credit facility, discount percentage						2.00%
Senior secured credit facility, discount amount						$ 26,000,000.0
2017 Credit Facility [Member] \| 2017 Term Loan B [Member] \| Eurodollar [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate						5.50%
2017 Credit Facility [Member] \| 2017 Term Loan B [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate						4.50%
2017 Credit Facility [Member] \| 2017 Term Loan B [Member] \| 2017 Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Revolving credit facility termination date															Aug. 16, 2018
2018 Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum amount				$ 1,250,000,000	1,250,000,000
Deferred financing costs		$ 1,200,000		11,700,000	11,700,000
Credit facility, amount repaid															$ 15,600,000	15,000,000.0
Credit facility amendment date															Dec. 12, 2019
Line of credit facility, frequency of interest payments															quarterly
Long-term debt, weighted average interest rate											3.55%				3.55%				5.52%
Borrowings under the senior secured credit facility											$ 989,900,000				$ 989,900,000				$ 975,000,000.0
Foreign currency borrowings, outstanding											0				0				0
Interest expense											8,000,000.0	14,600,000			29,200,000	44,500,000
Non-cash interest expense											100,000	100,000			200,000	200,000
Amortization of deferred financing costs											500,000	$ 500,000			$ 1,400,000	$ 1,300,000
2018 Credit Facility [Member] \| 2024 Convertible Notes Exceeds 350 Million [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Outstanding principal amount	$ 350,000,000.0			350,000,000.0	$ 350,000,000.0
2018 Credit Facility [Member] \| Second Amendment [Member]
Debt Instrument [Line Items]
Deferred financing costs	$ 1,600,000
Credit facility amendment date															Mar. 19, 2020
Extended maturity date	Mar. 19, 2025
Amortization	$ 1,100,000
Recognized in interest expense, net	$ 500,000
2018 Credit Facility [Member] \| Eurodollar [Member] \| Second Amendment [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate	2.50%				3.00%
2018 Credit Facility [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Base rate interest rate floor					1.00%
2018 Credit Facility [Member] \| Base Rate [Member] \| Second Amendment [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate	1.50%				2.00%
2018 Credit Facility [Member] \| Federal Funds Rate [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate					0.50%
2018 Credit Facility [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate					1.00%
2018 Credit Facility [Member] \| 2018 Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum amount				250,000,000.0	$ 250,000,000.0
Credit facility, maturity date					Aug. 16, 2023
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage					0.35%
Borrowings under the senior secured credit facility											0				$ 0				0
2018 Credit Facility [Member] \| 2018 Revolving Credit Facility [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Credit facility, maximum amount	$ 250,000,000.0
2018 Credit Facility [Member] \| 2018 Revolving Credit Facility [Member] \| Second Amendment [Member]
Debt Instrument [Line Items]
Extended maturity date	Mar. 19, 2025
2018 Credit Facility [Member] \| 2018 Revolving Credit Facility [Member] \| Second Amendment [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Credit facility, maximum amount	$ 282,500,000
2018 Credit Facility [Member] \| 2018 Revolving Credit Facility [Member] \| Eurodollar [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate					1.50%
2018 Credit Facility [Member] \| 2018 Revolving Credit Facility [Member] \| Eurodollar [Member] \| Second Amendment [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate	2.50%				3.00%
2018 Credit Facility [Member] \| 2018 Revolving Credit Facility [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate					1.50%
2018 Credit Facility [Member] \| 2018 Revolving Credit Facility [Member] \| Base Rate [Member] \| Second Amendment [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate	1.50%				2.00%
2018 Credit Facility [Member] \| 2018 Term Loan A [Member]
Debt Instrument [Line Items]
Outstanding principal amount				250,000,000.0	$ 250,000,000.0
Credit facility, maturity date					Aug. 16, 2023
Borrowings under the senior secured credit facility											254,900,000				254,900,000				234,400,000
2018 Credit Facility [Member] \| 2018 Term Loan A [Member] \| Level 2 [Member]
Debt Instrument [Line Items]
Outstanding principal amount											253,700,000				253,700,000				233,200,000
Debt instrument, fair value											251,600,000				251,600,000				235,700,000
2018 Credit Facility [Member] \| 2018 Term Loan A [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Credit facility, maximum amount	$ 234,400,000
2018 Credit Facility [Member] \| 2018 Term Loan A [Member] \| 2024 Convertible Notes Exceeds 350 Million [Member]
Debt Instrument [Line Items]
Credit facility, maturity date	Sep. 15, 2023
2018 Credit Facility [Member] \| 2018 Term Loan A [Member] \| Second Amendment [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Credit facility, maximum amount	$ 264,800,000
2018 Credit Facility [Member] \| 2018 Term Loan A [Member] \| Eurodollar [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate					2.50%
2018 Credit Facility [Member] \| 2018 Term Loan A [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate					2.50%
2018 Credit Facility [Member] \| 2018 Term Loan B [Member]
Debt Instrument [Line Items]
Outstanding principal amount				750,000,000.0	$ 750,000,000.0
Credit facility, maturity date					Aug. 18, 2025
Senior secured credit facility, discount percentage					0.25%
Senior secured credit facility, discount amount				$ 1,900,000	$ 1,900,000
Borrowings under the senior secured credit facility											735,000,000.0				735,000,000.0				740,600,000
2018 Credit Facility [Member] \| 2018 Term Loan B [Member] \| Level 2 [Member]
Debt Instrument [Line Items]
Outstanding principal amount											727,500,000				727,500,000				732,100,000
Debt instrument, fair value											$ 725,400,000				$ 725,400,000				$ 744,800,000
2018 Credit Facility [Member] \| 2018 Term Loan B [Member] \| 2024 Convertible Notes Exceeds 350 Million [Member]
Debt Instrument [Line Items]
Credit facility, maturity date					Dec. 15, 2023
2018 Credit Facility [Member] \| 2018 Term Loan B [Member] \| Eurodollar [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate		2.75%		3.25%	2.75%
2018 Credit Facility [Member] \| 2018 Term Loan B [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate		1.75%		2.25%	1.75%
Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Aggregate principal amount of convertible senior notes issued				$ 400,000,000	$ 400,000,000