Illumina (ILMN) 10-Q 30 Oct 20 2020 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares shares in Millions	9 Months Ended
	Sep. 27, 2020	Oct. 23, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 27, 2020
Document Transition Report	false
Entity File Number	001-35406
Entity Registrant Name	Illumina, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	33-0804655
Entity Address, Address Line One	5200 Illumina Way
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92122
City Area Code	858
Local Phone Number	202-4500
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	ILMN
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		146
Entity Central Index Key	0001110803
Current Fiscal Year End Date	--01-03
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 27, 2020	Dec. 29, 2019
Current assets:
Cash and cash equivalents	$ 1,761	$ 2,042
Short-term investments	1,563	1,372
Accounts receivable, net	464	573
Inventory	415	359
Prepaid expenses and other current assets	126	105
Total current assets	4,329	4,451
Property and equipment, net	910	889
Operating lease right-of-use assets	545	555
Goodwill	897	824
Intangible assets, net	149	145
Deferred tax assets, net	19	64
Other assets	555	388
Total assets	7,404	7,316
Current liabilities:
Accounts payable	156	149
Accrued liabilities	452	516
Long-term debt, current portion	507	0
Total current liabilities	1,115	665
Operating lease liabilities	678	695
Long-term debt	666	1,141
Other long-term liabilities	245	202
Stockholders’ equity:
Common stock	2	2
Additional paid-in capital	3,737	3,560
Accumulated other comprehensive income	12	5
Retained earnings	4,466	4,067
Treasury stock, at cost	(3,517)	(3,021)
Total stockholders’ equity	4,700	4,613
Total liabilities and stockholders’ equity	$ 7,404	$ 7,316

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Revenue:
Total revenue	$ 794	$ 907	$ 2,286	$ 2,591
Cost of revenue:
Amortization of acquired intangible assets	7	9	21	28
Total cost of revenue	268	259	713	786
Gross profit	526	648	1,573	1,805
Operating expense:
Research and development	172	151	483	486
Selling, general and administrative	192	189	643	602
Total operating expense	364	340	1,126	1,088
Income from operations	162	308	447	717
Other income (expense):
Interest income	5	16	26	59
Interest expense	(11)	(11)	(33)	(41)
Other income (expense), net	59	(43)	117	114
Total other income (expense), net	53	(38)	110	132
Income before income taxes	215	270	557	849
Provision for income taxes	36	36	158	98
Consolidated net income	179	234	399	751
Add: Net loss attributable to noncontrolling interests	0		0	12
Net income attributable to Illumina stockholders	$ 179	$ 234	$ 399	$ 763
Earnings per share attributable to Illumina stockholders:
Basic (in dollars per share)	$ 1.22	$ 1.59	$ 2.72	$ 5.19
Diluted (in dollars per share)	$ 1.21	$ 1.58	$ 2.70	$ 5.13
Shares used in computing earnings per share:
Basic (in shares)	146	147	147	147
Diluted (in shares)	148	148	148	149
Product revenue
Revenue:
Total revenue	$ 676	$ 746	$ 1,904	$ 2,117
Cost of revenue:
Cost of revenue	209	195	535	573
Service and other revenue
Revenue:
Total revenue	118	161	382	474
Cost of revenue:
Cost of revenue	$ 52	$ 55	$ 157	$ 185

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Statement of Comprehensive Income [Abstract]
Consolidated net income	$ 179	$ 234	$ 399	$ 751
Unrealized (loss) gain on available-for-sale debt securities, net of deferred tax	(2)		7	6
Total consolidated comprehensive income	177	234	406	757
Add: Comprehensive loss attributable to noncontrolling interests	0		0	12
Comprehensive income attributable to Illumina stockholders	$ 177	$ 234	$ 406	$ 769

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders’ Equity - USD ($) shares in Millions, $ in Millions	Total	Cumulative-effect adjustment from adoption of ASU 2016-02, net of deferred tax	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive (Loss) Income	Retained Earnings	Retained EarningsCumulative-effect adjustment from adoption of ASU 2016-02, net of deferred tax	Treasury Stock	Noncontrolling Interests
Beginning balance (in shares) at Dec. 30, 2018			192					45
Beginning balance at Dec. 30, 2018	$ 3,845	$ (18)	$ 2	$ 3,290	$ (1)	$ 3,083	$ (18)	$ (2,616)	$ 87
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	231					233			(2)
Unrealized (loss) gain on available-for-sale debt securities, net of deferred tax	3				3
Issuance of common stock, net of repurchases	(59)			27				$ (86)
Share-based compensation	51			51
Vesting of redeemable equity awards	(1)			(1)
Adjustment to the carrying value of redeemable noncontrolling interests	18			18
Ending balance (in shares) at Mar. 31, 2019			192					45
Ending balance at Mar. 31, 2019	4,070		$ 2	3,385	2	3,298		$ (2,702)	85
Beginning balance (in shares) at Dec. 30, 2018			192					45
Beginning balance at Dec. 30, 2018	3,845	$ (18)	$ 2	3,290	(1)	3,083	$ (18)	$ (2,616)	87
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized (loss) gain on available-for-sale debt securities, net of deferred tax	6
Ending balance (in shares) at Sep. 29, 2019			193					46
Ending balance at Sep. 29, 2019	4,439		$ 2	3,510	5	3,828		$ (2,906)	0
Beginning balance (in shares) at Mar. 31, 2019			192					45
Beginning balance at Mar. 31, 2019	4,070		$ 2	3,385	2	3,298		$ (2,702)	85
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	295					296			(1)
Unrealized (loss) gain on available-for-sale debt securities, net of deferred tax	3				3
Issuance of common stock, net of repurchases (in shares)			1
Issuance of common stock, net of repurchases	0			3				$ (3)
Share-based compensation	48			48
Adjustment to the carrying value of redeemable noncontrolling interests	(2)			(2)
Deconsolidation of Helix	(82)			2					(84)
Ending balance (in shares) at Jun. 30, 2019			193					45
Ending balance at Jun. 30, 2019	4,332		$ 2	3,436	5	3,594		$ (2,705)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	234					234
Issuance of common stock, net of repurchases (in shares)								1
Issuance of common stock, net of repurchases	(172)			29				$ (201)
Share-based compensation	45			45
Ending balance (in shares) at Sep. 29, 2019			193					46
Ending balance at Sep. 29, 2019	4,439		$ 2	3,510	5	3,828		$ (2,906)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	239					239
Issuance of common stock, net of repurchases (in shares)			1					1
Issuance of common stock, net of repurchases	(115)							$ (115)
Share-based compensation	50			50
Ending balance (in shares) at Dec. 29, 2019			194					47
Ending balance at Dec. 29, 2019	4,613		$ 2	3,560	5	4,067		$ (3,021)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	173					173
Unrealized (loss) gain on available-for-sale debt securities, net of deferred tax	1				1
Issuance of common stock, net of repurchases	(191)			32				$ (223)
Share-based compensation	39			39
Ending balance (in shares) at Mar. 29, 2020			194					47
Ending balance at Mar. 29, 2020	4,635		$ 2	3,631	6	4,240		$ (3,244)	0
Beginning balance (in shares) at Dec. 29, 2019			194					47
Beginning balance at Dec. 29, 2019	4,613		$ 2	3,560	5	4,067		$ (3,021)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized (loss) gain on available-for-sale debt securities, net of deferred tax	7
Ending balance (in shares) at Sep. 27, 2020			194					48
Ending balance at Sep. 27, 2020	4,700		$ 2	3,737	12	4,466		$ (3,517)	0
Beginning balance (in shares) at Mar. 29, 2020			194					47
Beginning balance at Mar. 29, 2020	4,635		$ 2	3,631	6	4,240		$ (3,244)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	47					47
Unrealized (loss) gain on available-for-sale debt securities, net of deferred tax	8				8
Issuance of common stock, net of repurchases (in shares)								1
Issuance of common stock, net of repurchases	(143)			2				$ (145)
Share-based compensation	16			16
Ending balance (in shares) at Jun. 28, 2020			194					48
Ending balance at Jun. 28, 2020	4,563		$ 2	3,649	14	4,287		$ (3,389)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	179					179
Unrealized (loss) gain on available-for-sale debt securities, net of deferred tax	(2)				(2)
Issuance of common stock, net of repurchases	(101)			27				$ (128)
Share-based compensation	61			61
Ending balance (in shares) at Sep. 27, 2020			194					48
Ending balance at Sep. 27, 2020	$ 4,700		$ 2	$ 3,737	$ 12	$ 4,466		$ (3,517)	$ 0

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 27, 2020	Sep. 29, 2019
Cash flows from operating activities:
Consolidated net income	$ 399	$ 751
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation expense	114	113
Amortization of intangible assets	23	30
Share-based compensation expense	116	145
Accretion of debt discount	29	36
Deferred income taxes	50	(13)
Unrealized gains on marketable equity securities	(128)	(57)
Payment of accreted debt discount	0	(84)
Gains on deconsolidation		(54)
Loss on derivative assets related to terminated acquisition	116
Other	(14)	(10)
Changes in operating assets and liabilities:
Accounts receivable	108	(29)
Inventory	(56)	(33)
Prepaid expenses and other current assets	(15)	(14)
Operating lease right-of-use assets and liabilities, net	(9)	(3)
Other assets	(25)	(29)
Accounts payable	(2)	(46)
Accrued liabilities	(68)	(81)
Other long-term liabilities	36	(14)
Net cash provided by operating activities	674	608
Cash flows from investing activities:
Maturities of available-for-sale securities	327	1,262
Purchases of available-for-sale securities	(757)	(760)
Sales of available-for-sale securities	379	528
Proceeds from the deconsolidation of GRAIL		15
Cash paid for derivative assets related to terminated acquisition	(132)
Purchases of property and equipment	(127)	(152)
Deconsolidation of Helix cash	0	(29)
Net purchases of strategic investments	(112)	(15)
Net cash paid for acquisitions	(98)	0
Net cash (used in) provided by investing activities	(520)	849
Cash flows from financing activities:
Payments on financing obligations		(550)
Common stock repurchases	(455)	(261)
Taxes paid related to net share settlement of equity awards	(41)	(30)
Proceeds from issuance of common stock	61	59
Net cash used in financing activities	(435)	(782)
Effect of exchange rate changes on cash and cash equivalents		(4)
Net (decrease) increase in cash and cash equivalents	(281)	671
Cash and cash equivalents at beginning of period	2,042	1,144
Cash and cash equivalents at end of period	$ 1,761	$ 1,815

Organization and Significant Ac

Organization and Significant Accounting Policies	9 Months Ended
	Sep. 27, 2020
Accounting Policies [Abstract]
Organization and Significant Accounting Policies	1. ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES Business Overview We are a provider of sequencing- and array-based solutions, serving customers in the research, clinical and applied markets. Our products are used for applications in the life sciences, oncology, reproductive health, agriculture and other emerging segments. Our customers include leading genomic research centers, academic institutions, government laboratories, and hospitals, as well as pharmaceutical, biotechnology, commercial molecular diagnostic laboratories, and consumer genomics companies . Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. Interim financial results are not necessarily indicative of results anticipated for the full year. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and footnotes included in the Annual Report on Form 10-K for the fiscal year ended December 29, 2019, from which the prior year balance sheet information herein was derived. The preparation of financial statements requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenue, and expense, and related disclosure of contingent assets and liabilities. Though the impact of the COVID-19 pandemic to our business and operating results presents additional uncertainty, we continue to use the best information available to inform our critical accounting estimates. Actual results could differ from those estimates. The unaudited condensed consolidated financial statements include our accounts, our wholly-owned subsidiaries, majority-owned or controlled companies, and variable interest entities (VIEs) for which we are the primary beneficiary. All intercompany transactions and balances have been eliminated in consolidation. Certain prior period amounts have been reclassified to conform to the current period presentation. In management’s opinion, the accompanying unaudited condensed consolidated financial statements reflect all adjustments, consisting of normal recurring adjustments, considered necessary for a fair presentation of the results for the interim periods presented. Fiscal Year Our fiscal year is the 52 or 53 weeks ending the Sunday closest to December 31, with quarters of 13 or 14 weeks ending the Sunday closest to March 31, June 30, September 30, and December 31. References to Q3 2020 and Q3 2019 refer to the three months ended September 27, 2020 and September 29, 2019, respectively, which were both 13 weeks, and references to year-to-date (YTD) 2020 and 2019 refer to the nine months ended September 27, 2020 and September 29, 2019, respectively, which were both 39 weeks. Significant Accounting Policies During Q3 2020 and YTD 2020, there were no changes to our significant accounting policies as described in our Annual Report on Form 10-K for the fiscal year ended December 29, 2019, except as described in Recently Adopted Accounting Pronouncements below. Recently Adopted Accounting Pronouncements In May 2020, the SEC issued Final Rule Release No. 33-10786, Amendments to Financial Disclosures about Acquired and Disposed Businesses , which amends the disclosure requirements applicable to acquisitions and dispositions of businesses, including the required pro forma financial information. The amendments are effective for us beginning January 1, 2021, with early compliance permitted. Among other changes, the final amendments revised the investment and income tests used to determine whether a business acquisition is significant, and reduced the filing requirements for financial statements and pro forma financial information of a significant acquired business to cover a maximum of two years. We have elected to adopt the amendments in Q3 2020 in connection with our pending acquisition of GRAIL, which is further described in note “ 3. Investments and Fair Value Measurements ”. In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses: Measurement of Credit Losses on Financial Instruments , which amends the impairment model by requiring entities to use a forward-looking approach based on expected losses to estimate credit losses on certain types of financial instruments, including trade receivables and available-for-sale debt securities. We adopted the standard on its effective date in the first quarter of 2020 using a modified retrospective approach. The cumulative effect of applying the new credit loss standard was not material and, therefore, did not result in an adjustment to retained earnings. There was no material difference to the condensed consolidated financial statements in YTD 2020 due to the adoption of ASU 2016-13. In accordance with ASU 2016-13, we no longer evaluate whether our available-for-sale debt securities in an unrealized loss position are other than temporarily impaired. Instead, we assess whether such unrealized loss positions are credit-related. The credit-related portion of unrealized losses, and any subsequent improvements, are recorded in interest income through an allowance account. Unrealized gains and losses that are not credit-related are included in accumulated other comprehensive income (loss). We estimate our allowance for credit losses on our trade receivables as described in our Accounts Receivable policy, below. Accounts Receivable Trade accounts receivable are considered past due based on the contractual payment terms. We reserve specific receivables when collectibility is no longer probable. We also reserve a percentage of our trade receivable balance based on collection history and current economic trends that we expect will impact the level of credit losses over the life of our receivables. These reserves are re-evaluated on a regular basis and adjusted, as needed. Once a receivable is deemed to be uncollectible, such balance is charged against the reserve. Accounting Pronouncements Pending Adoption In August 2020, the FASB issued ASU 2020-06, Debt - Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging - Contracts in Entity’s Own Equity (Subtopic 815-40). The new standard reduces the number of accounting models for convertible debt instruments, amends the accounting for certain contracts in an entity’s own equity, and modifies how certain convertible instruments and contracts that may be settled in cash or shares impact the calculation of diluted EPS. The standard is effective for us beginning in the first quarter of 2022, with early adoption permitted in Q1 2021. We are currently evaluating the impact of ASU 2020-06 on the consolidated financial statements. Earnings per Share Basic earnings per share attributable to Illumina stockholders is computed based on the weighted average number of common shares outstanding during the period. Diluted earnings per share attributable to Illumina stockholders is computed based on the sum of the weighted average number of common shares and potentially dilutive common shares outstanding during the period. Up to April 25, 2019, the date of Helix Holdings I, LLC’s (Helix) deconsolidation, per-share losses of Helix were included in the consolidated basic and diluted earnings per share computations based on our share of Helix’s securities. Potentially dilutive common shares consist of shares issuable under convertible senior notes and equity awards. Convertible senior notes have a dilutive impact when the average market price of our common stock exceeds the applicable conversion price of the respective notes. Potentially dilutive common shares from equity awards are determined using the average share price for each period under the treasury stock method. In addition, proceeds from exercise of equity awards and the average amount of unrecognized compensation expense for equity awards are assumed to be used to repurchase shares. The following table presents the calculation of weighted average shares used to calculate basic and diluted earnings per share: In millions Q3 2020 Q3 2019 YTD 2020 YTD 2019 Weighted average shares outstanding 146 147 147 147 Effect of potentially dilutive common shares from: Equity awards 1 1 1 1 Convertible senior notes 1 — — 1 Weighted average shares used in calculating diluted earnings per share 148 148 148 149

Revenue

Revenue	9 Months Ended
	Sep. 27, 2020
Revenue from Contract with Customer [Abstract]
Revenue	2. REVENUE Our revenue is generated primarily from the sale of products and services. Product revenue primarily consists of sales of instruments and consumables used in genetic analysis. Service and other revenue primarily consists of revenue generated from genotyping and sequencing services, instrument service contracts, and development and licensing agreements. Revenue by Source Q3 2020 Q3 2019 In millions Sequencing Microarray Total Sequencing Microarray Total Consumables $ 500 $ 62 $ 562 $ 525 $ 75 $ 600 Instruments 109 5 114 142 4 146 Total product revenue 609 67 676 667 79 746 Service and other revenue 99 19 118 138 23 161 Total revenue $ 708 $ 86 $ 794 $ 805 $ 102 $ 907 YTD 2020 YTD 2019 In millions Sequencing Microarray Total Sequencing Microarray Total Consumables $ 1,440 $ 178 $ 1,618 $ 1,503 $ 224 $ 1,727 Instruments 276 10 286 376 14 390 Total product revenue 1,716 188 1,904 1,879 238 2,117 Service and other revenue 317 65 382 353 121 474 Total revenue $ 2,033 $ 253 $ 2,286 $ 2,232 $ 359 $ 2,591 Revenue by Geographic Area Based on region of destination (in millions) Q3 2020 Q3 2019 YTD 2020 YTD 2019 Americas $ 436 $ 514 $ 1,248 $ 1,463 Europe, Middle East, and Africa 213 235 602 653 Greater China (1) 83 95 246 280 Asia-Pacific 62 63 190 195 Total revenue $ 794 $ 907 $ 2,286 $ 2,591 (1) Region includes revenue from China, Taiwan, and Hong Kong. Performance Obligations We regularly enter into contracts with multiple performance obligations. Most performance obligations are generally satisfied within a short time frame, approximately three to six months, after the contract execution date. As of September 27, 2020, the aggregate amount of the transaction price allocated to remaining performance obligations was $735 million, of which approximately 84% is expected to be converted to revenue in the next twelve months, and the remainder thereafter. Contract Liabilities

Investments and Fair Value Meas

Investments and Fair Value Measurements	9 Months Ended
	Sep. 27, 2020
Fair Value Disclosures [Abstract]
Investments and Fair Value Measurements	3. INVESTMENTS AND FAIR VALUE MEASUREMENTS Debt Securities Our short-term investments are primarily available-for-sale debt securities that consisted of the following: September 27, 2020 December 29, 2019 In millions Amortized Gross Estimated Amortized Gross Estimated Debt securities in government-sponsored entities $ 62 $ — $ 62 $ 18 $ — $ 18 Corporate debt securities 610 8 618 627 3 630 U.S. Treasury securities 642 7 649 616 2 618 Total $ 1,314 $ 15 $ 1,329 $ 1,261 $ 5 $ 1,266 Realized gains and losses are determined based on the specific-identification method and are reported in interest income. Contractual maturities of available-for-sale debt securities, as of September 27, 2020, were as follows: In millions Estimated Due within one year $ 627 After one but within five years 702 Total $ 1,329 We have the ability, if necessary, to liquidate any of our cash equivalents and short-term investments to meet our liquidity needs in the next 12 months. Accordingly, those investments with contractual maturities greater than one year from the date of purchase are classified as short-term on the accompanying condensed consolidated balance sheets. Strategic Investments Marketable Equity Securities As of September 27, 2020 and December 29, 2019, the fair value of our marketable equity securities, included in short-term investments, totaled $234 million and $106 million, respectively. Total unrealized gains on our marketable equity securities, included in other income (expense), net, were $59 million and $128 million in Q3 2020 and YTD 2020, respectively, and total unrealized losses and gains were $47 million and $57 million, respectively, in Q3 2019 and YTD 2019. Non-Marketable Equity Securities As of September 27, 2020 and December 29, 2019, the aggregate carrying amounts of our non-marketable equity securities without readily determinable fair values, included in other assets, were $305 million and $220 million, respectively. One of our investments, GRAIL, Inc. (GRAIL), is a VIE for which we have concluded that we are not the primary beneficiary and, therefore, we do not consolidate GRAIL in our consolidated financial statements. On September 20, 2020, we entered into an agreement to acquire GRAIL, as described in Pending Acquisition below. We have determined our maximum exposure to loss, excluding any amounts associated with the pending acquisition of GRAIL, to be the carrying value of our investment, which was $250 million and $190 million as of September 27, 2020 and December 29, 2019, respectively, recorded in other assets. During YTD 2020, we made an additional $60 million investment in GRAIL. Revenue recognized from transactions with our strategic investees was $16 million and $39 million for Q3 2020 and YTD 2020, respectively, and $15 million and $49 million for Q3 2019 and YTD 2019, respectively. Venture Funds We invest in two venture capital investment funds (the Funds) with capital commitments of $100 million, callable through April 2026, and up to $160 million, callable through July 2029, respectively, of which $40 million and up to $143 million, respectively, remained callable as of September 27, 2020. Our investments in the Funds are accounted for as equity-method investments. The aggregate carrying amounts of the Funds, included in other assets, were $90 million and $53 million as of September 27, 2020 and December 29, 2019, respectively. Previously Consolidated Variable Interest Entity Helix Holdings I, LLC (Helix) In July 2015, we obtained a 50% voting equity ownership interest in Helix. At that time, we determined that we had unilateral power over one of the activities that most significantly impacts the economic performance of Helix through its contractual arrangements and, as a result, we were deemed to be the primary beneficiary of Helix and were required to consolidate Helix. The operations of Helix are included in the accompanying condensed consolidated statements of income for YTD 2019, up to the date of the deconsolidation, described below. During this period, we absorbed 50% of Helix’s losses. On April 25, 2019, we entered into an agreement to sell our interest in, and relinquish control over, Helix. As part of the agreement, (i) Helix repurchased all of our outstanding equity interests in exchange for a contingent value right with a 7-year term that entitles us to consideration dependent upon the outcome of Helix’s future financing and/or liquidity events, (ii) we ceased having a controlling financial interest in Helix, including unilateral power over one of the activities that most significantly impacts the economic performance of Helix, (iii) we were relieved of any potential obligation to redeem certain noncontrolling interests, and (iv) we no longer have representation on Helix’s board of directors. As a result, we deconsolidated Helix’s financial statements effective April 25, 2019 and recorded a gain on deconsolidation of $39 million in other income (expense), net. The gain on deconsolidation included (i) the contingent value right received from Helix recorded at a fair value of approximately $30 million, (ii) the derecognition of the carrying amounts of Helix’s assets and liabilities, and (iii) the derecognition of the noncontrolling interests related to Helix. During YTD 2020, changes in the fair value of the contingent value right resulted in unrealized gains of $5 million included in other income (expense), net. There was no change in fair value during Q3 2020. During Q3 2019 and YTD 2019, such changes resulted in an unrealized gain of $2 million and an unrealized loss of $1 million, respectively. Pending Acquisition On September 20, 2020, we entered into an Agreement and Plan of Merger (the “GRAIL Merger Agreement ”) to acquire GRAIL for $8 billion, consisting of $3.5 billion in cash and $4.5 billion in shares of Illumina common stock, subject to a collar. The transaction, which is expected to close in the second half of 2021, is subject to certain customary closing conditions, including GRAIL shareholder approval and the receipt of required regulatory approvals. The cash consideration for the transaction is expected to be funded using balance sheet cash of both Illumina and GRAIL, plus up to $1 billion in capital raised through either a debt or equity issuance. In advance of this anticipated issuance, we have obtained a bridge facility commitment letter from Goldman Sachs Bank USA for a 364-day senior unsecured bridge loan facility, in an aggregate principal amount of $1 billion. The bridge facility commitment letter is subject to certain conditions, including consummation of the acquisition pursuant to the GRAIL Merger Agreement. It is anticipated that we will replace or repay some or all of the bridge facility through one or a combination of the following: issuance of debt securities, preferred stock, common equity, or other securities or borrowings under a credit facility. In connection with the transaction, GRAIL stockholders will receive contingent value rights, which will entitle holders to receive future payments representing a pro rata portion of certain revenues each year for a 12-year period. This will reflect a 2.5% payment right to the first $1 billion of revenue each year for 12 years. Revenue above $1 billion each year will be subject to a 9% contingent payment right during this same period. We will offer GRAIL stockholders the option to receive additional cash and/or stock consideration, in an amount to be determined prior to closing, in lieu of the contingent value rights. If the GRAIL Merger Agreement is not consummated prior to December 20, 2020, we will make monthly cash payments to GRAIL of $35 million (the “Continuation Payments”) until the earlier of the consummation or termination of the GRAIL Merger Agreement, subject to certain exceptions. If the GRAIL Merger Agreement is terminated, we will receive shares of non-voting GRAIL preferred stock in respect of all Continuation Payments in excess of $315 million, subject to certain terms and conditions. The GRAIL Merger Agreement contains certain termination rights if the consummation of the acquisition does not occur on or before September 20, 2021, subject to a three-month extension related to obtaining certain required regulatory clearances. Upon termination of the GRAIL Merger Agreement under specified circumstances, we would be required to pay a termination fee of $300 million and make an additional $300 million investment in GRAIL in exchange for shares of non-voting GRAIL preferred stock, subject to certain terms and conditions. Derivative Assets Related to Terminated Acquisition On November 1, 2018, we entered into an Agreement and Plan of Merger (the “PacBio Merger Agreement ”) to acquire Pacific Biosciences of California, Inc. (PacBio) for an all-cash price of approximately $1.2 billion (or $8.00 per share). On January 2, 2020, we entered into an agreement to terminate the PacBio Merger Agreement (the Termination Agreement ). Pursuant to the Termination Agreement, we made a cash payment to PacBio of $98 million on January 2, 2020, which represented the Reverse Termination Fee (as defined in the PacBio Merger Agreement). The Reverse Termination Fee is repayable, without interest, to us if PacBio enters into a definitive agreement providing for, or consummates, a Change of Control Transaction by September 30, 2020 (as defined in the Termination Agreement), and such transaction is consummated by the two-year anniversary of the execution of the definitive agreement for such Change of Control Transaction. PacBio did not enter into a definitive agreement that provided for, or consummated, a Change of Control Transaction by September 30, 2020 (as defined in the Termination Agreement); therefore, the Reverse Termination Fee is no longer repayable. In addition, we made cash payments to PacBio of $18 million in Q4 2019, pursuant to Amendment No. 1 to the PacBio Merger Agreement , and $34 million in Q1 2020, pursuant to the Termination Agreement, collectively referred to as the Continuation Advances. Up to the $52 million of Continuation Advances is repayable without interest to us if, within two years of March 31, 2020, PacBio enters into a Change of Control Transaction or raises at least $100 million in equity or debt financing in a single transaction (with the amount repayable dependent on the amount raised by PacBio). The potential repayments of the Continuation Advances and Reverse Termination Fee meet the definition of derivative assets and are recorded at fair value. The $92 million difference between the $132 million in cash paid during Q1 2020 for the Continuation Advances and Reverse Termination Fee and the $40 million fair value of these derivative assets on the payment dates was recorded as selling, general and administrative expenses. Changes in the fair value of the derivative assets are included in other income (expense), net, and totaled $10 million and $25 million in unrealized losses in Q3 2020 and YTD 2020, respectively. Fair Value Measurements The following table presents the hierarchy for assets and liabilities measured at fair value on a recurring basis: September 27, 2020 December 29, 2019 In millions Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets: Money market funds (cash equivalents) $ 1,449 $ — $ — $ 1,449 $ 1,732 $ — $ — $ 1,732 Debt securities in government-sponsored entities — 62 — 62 — 18 — 18 Corporate debt securities — 618 — 618 — 630 — 630 U.S. Treasury securities 649 — — 649 618 — — 618 Marketable equity securities 234 — — 234 106 — — 106 Contingent value right — — 33 33 — — 29 29 Derivative assets related to terminated acquisition — — 26 26 — — 10 10 Deferred compensation plan assets — 51 — 51 — 48 — 48 Total assets measured at fair value $ 2,332 $ 731 $ 59 $ 3,122 $ 2,456 $ 696 $ 39 $ 3,191 Liabilities: Deferred compensation plan liability $ — $ 46 $ — $ 46 $ — $ 46 $ — $ 46

Debt

Debt	9 Months Ended
	Sep. 27, 2020
Debt Disclosure [Abstract]
Debt	4. DEBT Summary of debt obligations In millions September 27, December 29, Principal amount of 2023 Notes outstanding $ 750 $ 750 Principal amount of 2021 Notes outstanding 517 517 Unamortized discount of liability component of convertible senior notes (94) (126) Net carrying amount of liability component of convertible senior notes 1,173 1,141 Less: current portion (507) — Long-term debt $ 666 $ 1,141 Carrying value of equity component of convertible senior notes, net of debt issuance costs $ 213 $ 213 Fair value of convertible senior notes outstanding (Level 2) $ 1,447 $ 1,549 Weighted-average remaining amortization period of discount on the liability component of convertible senior notes 2.6 years 3.2 years Bridge Facility In advance of the acquisition of GRAIL, we have obtained a bridge facility commitment letter from Goldman Sachs Bank USA for a 364-day senior unsecured bridge loan facility, in an aggregate principal amount of $1 billion. The bridge facility commitment letter is subject to certain conditions, including consummation of the acquisition pursuant to the GRAIL Merger Agreement. It is anticipated that we will replace or repay some or all of the bridge facility through one or a combination of the following: issuance of debt securities, preferred stock, common equity, or other securities or borrowings under a credit facility. See note “ 3. Investments and Fair Value Measurements ” for further details. 0% Convertible Senior Notes due 2023 (2023 Notes) On August 21, 2018, we issued $750 million aggregate principal amount of convertible senior notes due 2023 (2023 Notes). The 2023 Notes mature on August 15, 2023, and the implied estimated effective rate of the liability component of the Notes was 3.7%, assuming no conversion option. The 2023 Notes will be convertible into cash, shares of our common stock or a combination of cash and shares of our common stock, at our election, based on an initial conversion rate, subject to adjustment, of 2.1845 shares of common stock per $1,000 principal amount of notes (which represents an initial conversion price of approximately $457.77 per share of common stock), only in the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on September 30, 2018 (and only during such calendar quarter), if the last reported sale price of our common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price in effect on each applicable trading day; (2) during the five business day period after any 10 consecutive trading day period (the “measurement period”) in which the trading price per $1,000 principal amount of 2023 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of our common stock and the conversion rate on each such trading day; (3) if we call any or all of the notes for redemption, at any time prior to the close of business on the scheduled trading day immediately preceding the redemption date; or (4) upon the occurrence of specified corporate events described in the indenture. Regardless of the foregoing circumstances, the holders may convert their notes on or after May 15, 2023 until August 11, 2023. We may redeem for cash all or any portion of the 2023 Notes, at our option, on or after August 20, 2021 if the last reported sale price of our common stock has been at least 130% of the conversion price then in effect (currently $595.10) for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending on, and including, the trading day immediately preceding the date on which we provide notice of redemption at a redemption price equal to 100% of the principal amount of the notes to be redeemed, plus any accrued and unpaid special interest to, but excluding, the redemption date. The 2023 Notes were not convertible as of September 27, 2020 and had no dilutive impact during YTD 2020. If the 2023 Notes were converted as of September 27, 2020, the if-converted value would not exceed the principal amount. 0.5% Convertible Senior Notes due 2021 (2021 Notes) In June 2014, we issued $517 million aggregate principal amount of 2021 Notes. The 2021 Notes mature on June 15, 2021, and the implied estimated effective rates of the liability component of the Notes was 3.5%, assuming no conversion option. The 2021 Notes will be convertible into cash, shares of common stock, or a combination of cash and shares of common stock, at our election, based on an initial conversion rate, subject to adjustment, of 3.9318 shares per $1,000 principal amount of the notes (which represents an initial conversion price of approximately $254.34 per share), only in the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending September 30, 2014 (and only during such calendar quarter), if the last reported sale price of our common stock for 20 or more trading days in the period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter exceeds 130% of the applicable conversion price in effect on the last trading day of the immediately preceding calendar quarter; (2) during the 5 business day period after any 10 consecutive trading day period (the “measurement period”) in which the trading price per 2021 Notes for each day of such measurement period was less than 98% of the product of the last reported sale price of our common stock and the conversion rate on each such trading day; or (3) upon the occurrence of specified events described in the indenture for the 2021 Notes. Regardless of the foregoing circumstances, the holders of the 2021 Notes may convert their notes on or after March 15, 2021 until June 11, 2021. The market price of our common stock met the stock trading price conversion requirement of $330.64 and the 2021 Notes became convertible on July 1, 2020, and continued to be convertible through September 30, 2020. The potential dilutive impact of the 2021 Notes has been included in our calculation of diluted earnings per share for Q3 2020 and YTD 2020. If the 2021 Notes were converted as of September 27, 2020, the if-converted value would exceed the principal amount by $97 million. 0% Convertible Senior Notes due 2019 (2019 Notes)

Stockholders_ Equity

Stockholders’ Equity	9 Months Ended
	Sep. 27, 2020
Equity [Abstract]
Stockholders’ Equity	5. STOCKHOLDERS’ EQUITY As of September 27, 2020, approximately 4.1 million shares remained available for future grants under the 2015 Stock Plan. Restricted Stock Restricted stock activity was as follows: Restricted Performance Weighted-Average Grant Date Fair Value per Share Units in thousands RSU PSU Outstanding at December 29, 2019 1,700 271 $ 271.49 $ 258.66 Awarded 234 (82) $ 301.83 $ 343.38 Vested (83) — $ 219.18 — Cancelled (167) (71) $ 267.36 $ 261.19 Outstanding at September 27, 2020 1,684 118 $ 278.68 400.74 ______________________________________ (1) The number of units reflect the estimated number of shares to be issued at the end of the performance period. Awarded units are presented net of performance adjustments. Stock Options Stock option activity was as follows: Options Weighted-Average Outstanding at December 29, 2019 58 $ 56.65 Exercised (48) $ 56.16 Outstanding and exercisable at September 27, 2020 10 $ 59.11 ESPP The price at which common stock is purchased under the Employee Stock Purchase Plan (ESPP) is equal to 85% of the fair market value of the common stock on the first day of the offering period or purchase date, whichever is lower. During YTD 2020, approximately 0.2 million shares were issued under the ESPP. As of September 27, 2020, there were approximately 13.3 million shares available for issuance under the ESPP. Share Repurchases On February 5, 2020, our Board of Directors authorized a new share repurchase program, which supersedes all prior and available repurchase authorizations, to repurchase $750 million of outstanding common stock. The repurchases may be completed under a 10b5-1 plan or at management’s discretion. During YTD 2020, we repurchased 1.4 million shares for approximately $455 million. Authorizations to repurchase approximately $295 million of our common stock remained available as of September 27, 2020. Share-based Compensation Share-based compensation expense reported in our condensed consolidated statements of income was as follows: In millions Q3 2020 Q3 2019 YTD 2020 YTD 2019 Cost of product revenue $ 6 $ 5 $ 13 $ 15 Cost of service and other revenue 1 1 3 3 Research and development 21 15 48 50 Selling, general and administrative 33 24 52 77 Share-based compensation expense before taxes 61 45 116 145 Related income tax benefits (12) (10) (27) (31) Share-based compensation expense, net of taxes $ 49 $ 35 $ 89 $ 114 On August 5, 2020, we modified the performance period for our performance stock units granted in 2018, which vest at the end of the three-year period in Q4 2020. This modification affected 49 employees and is expected to result in total incremental share-based compensation cost of approximately $47 million in FY 2020, of which $17 million was expensed in Q3 2020. The assumptions used for the specified reporting periods and the resulting estimates of weighted-average fair value per share for stock purchased under the ESPP during YTD 2020 were as follows: Employee Stock Purchase Rights Risk-free interest rate 0.11% - 2.04% Expected volatility 30% - 45% Expected term 0.5 - 1.0 year Expected dividends 0 % Weighted-average grant-date fair value per share $ 75.57 As of September 27, 2020, approximately $367 million of total unrecognized compensation cost related to restricted stock and ESPP shares issued to date was expected to be recognized over a weighted-average period of approximately 2.0 years.

Supplemental Balance Sheet Deta

Supplemental Balance Sheet Details	9 Months Ended
	Sep. 27, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Supplemental Balance Sheet Details	6. SUPPLEMENTAL BALANCE SHEET DETAILS Accounts Receivable In millions September 27, December 29, Trade accounts receivable, gross $ 468 $ 575 Allowance for credit losses (4) (2) Total accounts receivable, net $ 464 $ 573 Inventory In millions September 27, December 29, Raw materials $ 142 $ 108 Work in process 246 225 Finished goods 27 26 Total inventory $ 415 $ 359 Intangible Assets and Goodwill We recorded a developed technology intangible asset of $26 million, with a useful life of 10 years, as a result of an acquisition in Q2 2020. Changes to goodwill during YTD 2020 were as follows: In millions Goodwill Balance as of December 29, 2019 $ 824 Acquisitions 73 Balance as of September 27, 2020 $ 897 Goodwill is reviewed for impairment at least annually during the second quarter, or more frequently if an event occurs indicating the potential for impairment. We performed our annual assessment for goodwill impairment in Q2 2020, noting no impairment. Accrued Liabilities In millions September 27, December 29, Contract liabilities, current portion $ 154 $ 167 Accrued compensation expenses 123 154 Accrued taxes payable 46 86 Operating lease liabilities, current portion 54 45 Other, including warranties (a) 75 64 Total accrued liabilities $ 452 $ 516 (a) Changes in the reserve for product warranties were as follows: In millions Q3 2020 Q3 2019 YTD 2020 YTD 2019 Balance at beginning of period $ 10 $ 16 $ 14 $ 19 Additions charged to cost of product revenue 6 3 11 12 Repairs and replacements (6) (5) (15) (17) Balance at end of period $ 10 $ 14 $ 10 $ 14 We generally provide a one-year warranty on instruments. Additionally, we provide a warranty on consumables through the expiration date, which generally ranges from six Derivatives We are exposed to foreign exchange rate risks in the normal course of business. We enter into foreign exchange contracts to manage foreign currency risks related to monetary assets and liabilities that are denominated in currencies other than the U.S. dollar. These foreign exchange contracts are carried at fair value in other current assets or accrued liabilities and are not designated as hedging instruments. Changes in the value of the derivatives are recognized in other income (expense), net, along with the remeasurement gain or loss on the foreign currency denominated assets or liabilities. As of September 27, 2020, we had foreign exchange forward contracts in place to hedge exposures in the euro, Japanese yen, Australian dollar, Canadian dollar, Singapore dollar, Chinese Yuan Renminbi, and British pound. As of September 27, 2020 and December 29, 2019, the total notional amounts of outstanding forward contracts in place for foreign currency purchases were $315 million and $252 million, respectively.

Legal Proceedings

Legal Proceedings	9 Months Ended
	Sep. 27, 2020
Commitments and Contingencies Disclosure [Abstract]
Legal Proceedings	7. LEGAL PROCEEDINGS We are involved in various lawsuits and claims arising in the ordinary course of business, including actions with respect to intellectual property, employment, and contractual matters. In connection with these matters, we assess, on a regular basis, the probability and range of possible loss based on the developments in these matters. A liability is recorded in the consolidated financial statements if it is believed to be probable that a loss has been incurred and the amount of the loss can be reasonably estimated. Because litigation is inherently unpredictable and unfavorable resolutions could occur, assessing contingencies is highly subjective and requires judgments about future events. We regularly review outstanding legal matters to determine the adequacy of the liabilities accrued and related disclosures in consideration of many factors, which include, but are not limited to, past history, scientific and other evidence, and the specifics and status of each matter. We may change our estimates if our assessment of the various factors changes and the amount of ultimate loss may differ from our estimates, resulting in a material effect on our business, financial condition, results of operations, and/or cash flows.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 27, 2020
Income Tax Disclosure [Abstract]
Income Taxes	8. INCOME TAXES

Segment Information

Segment Information	9 Months Ended
	Sep. 27, 2020
Segment Reporting [Abstract]
Segment Information	9. SEGMENT INFORMATION We have one reportable segment, Core Illumina, as of September 27, 2020, which relates to Illumina’s core operations. Prior to the Helix deconsolidation on April 25, 2019, our reportable segments included both Core Illumina and Helix. See note “ 3. Investments and Fair Value Measurements ” for further details. Core Illumina: Core Illumina’s products and services serve customers in the research, clinical and applied markets, and enable the adoption of a variety of genomic solutions. Core Illumina includes all of our operations, excluding the results of our previously consolidated VIE, Helix. Helix: Helix was established to enable individuals to explore their genetic information by providing affordable sequencing and database services for consumers through third-party partners, driving the creation of an ecosystem of consumer applications. Core Illumina sells products and provides services to Helix in accordance with contractual agreements between the entities. In millions Q3 2020 Q3 2019 YTD 2020 YTD 2019 Revenue: Core Illumina $ 794 $ 907 $ 2,286 $ 2,591 Helix — — — 1 Elimination of intersegment revenue — — — (1) Consolidated revenue $ 794 $ 907 $ 2,286 $ 2,591 Income (loss) from operations: Core Illumina $ 162 $ 308 $ 447 $ 740 Helix — — — (24) Elimination of intersegment earnings — — — 1 Consolidated income from operations $ 162 $ 308 $ 447 $ 717

Organization and Significant _2

Organization and Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 27, 2020
Accounting Policies [Abstract]
Basis of Presentation	The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements.
Consolidation	The unaudited condensed consolidated financial statements include our accounts, our wholly-owned subsidiaries, majority-owned or controlled companies, and variable interest entities (VIEs) for which we are the primary beneficiary. All intercompany transactions and balances have been eliminated in consolidation. Certain prior period amounts have been reclassified to conform to the current period presentation. In management’s opinion, the accompanying unaudited condensed consolidated financial statements reflect all adjustments, consisting of normal recurring adjustments, considered necessary for a fair presentation of the results for the interim periods presented.
Fiscal Year	Our fiscal year is the 52 or 53 weeks ending the Sunday closest to December 31, with quarters of 13 or 14 weeks ending the Sunday closest to March 31, June 30, September 30, and December 31.
Recently Adopted Accounting Pronouncements	In May 2020, the SEC issued Final Rule Release No. 33-10786, Amendments to Financial Disclosures about Acquired and Disposed Businesses , which amends the disclosure requirements applicable to acquisitions and dispositions of businesses, including the required pro forma financial information. The amendments are effective for us beginning January 1, 2021, with early compliance permitted. Among other changes, the final amendments revised the investment and income tests used to determine whether a business acquisition is significant, and reduced the filing requirements for financial statements and pro forma financial information of a significant acquired business to cover a maximum of two years. We have elected to adopt the amendments in Q3 2020 in connection with our pending acquisition of GRAIL, which is further described in note “ 3. Investments and Fair Value Measurements ”. In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses: Measurement of Credit Losses on Financial Instruments , which amends the impairment model by requiring entities to use a forward-looking approach based on expected losses to estimate credit losses on certain types of financial instruments, including trade receivables and available-for-sale debt securities. We adopted the standard on its effective date in the first quarter of 2020 using a modified retrospective approach. The cumulative effect of applying the new credit loss standard was not material and, therefore, did not result in an adjustment to retained earnings. There was no material difference to the condensed consolidated financial statements in YTD 2020 due to the adoption of ASU 2016-13. In accordance with ASU 2016-13, we no longer evaluate whether our available-for-sale debt securities in an unrealized loss position are other than temporarily impaired. Instead, we assess whether such unrealized loss positions are credit-related. The credit-related portion of unrealized losses, and any subsequent improvements, are recorded in interest income through an allowance account. Unrealized gains and losses that are not credit-related are included in accumulated other comprehensive income (loss). We estimate our allowance for credit losses on our trade receivables as described in our Accounts Receivable policy, below.
Accounts Receivable	Trade accounts receivable are considered past due based on the contractual payment terms. We reserve specific receivables when collectibility is no longer probable. We also reserve a percentage of our trade receivable balance based on collection history and current economic trends that we expect will impact the level of credit losses over the life of our receivables. These reserves are re-evaluated on a regular basis and adjusted, as needed. Once a receivable is deemed to be uncollectible, such balance is charged against the reserve.
Earnings per Share	Basic earnings per share attributable to Illumina stockholders is computed based on the weighted average number of common shares outstanding during the period. Diluted earnings per share attributable to Illumina stockholders is computed based on the sum of the weighted average number of common shares and potentially dilutive common shares outstanding during the period. Up to April 25, 2019, the date of Helix Holdings I, LLC’s (Helix) deconsolidation, per-share losses of Helix were included in the consolidated basic and diluted earnings per share computations based on our share of Helix’s securities. Potentially dilutive common shares consist of shares issuable under convertible senior notes and equity awards. Convertible senior notes have a dilutive impact when the average market price of our common stock exceeds the applicable conversion price of the respective notes. Potentially dilutive common shares from equity awards are determined using the average share price for each period under the treasury stock method. In addition, proceeds from exercise of equity awards and the average amount of unrecognized compensation expense for equity awards are assumed to be used to repurchase shares.
Warranties	We generally provide a one-year warranty on instruments. Additionally, we provide a warranty on consumables through the expiration date, which generally ranges from six
Derivatives	We are exposed to foreign exchange rate risks in the normal course of business. We enter into foreign exchange contracts to manage foreign currency risks related to monetary assets and liabilities that are denominated in currencies other than the U.S. dollar. These foreign exchange contracts are carried at fair value in other current assets or accrued liabilities and are not designated as hedging instruments. Changes in the value of the derivatives are recognized in other income (expense), net, along with the remeasurement gain or loss on the foreign currency denominated assets or liabilities.

Organization and Significant _3

Organization and Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 27, 2020
Accounting Policies [Abstract]
Summary of Calculation of Weighted Average Shares used to Calculate Basic and Diluted Earnings Per Share, Earnings Per Share	The following table presents the calculation of weighted average shares used to calculate basic and diluted earnings per share: In millions Q3 2020 Q3 2019 YTD 2020 YTD 2019 Weighted average shares outstanding 146 147 147 147 Effect of potentially dilutive common shares from: Equity awards 1 1 1 1 Convertible senior notes 1 — — 1 Weighted average shares used in calculating diluted earnings per share 148 148 148 149

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 27, 2020
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	Revenue by Source Q3 2020 Q3 2019 In millions Sequencing Microarray Total Sequencing Microarray Total Consumables $ 500 $ 62 $ 562 $ 525 $ 75 $ 600 Instruments 109 5 114 142 4 146 Total product revenue 609 67 676 667 79 746 Service and other revenue 99 19 118 138 23 161 Total revenue $ 708 $ 86 $ 794 $ 805 $ 102 $ 907 YTD 2020 YTD 2019 In millions Sequencing Microarray Total Sequencing Microarray Total Consumables $ 1,440 $ 178 $ 1,618 $ 1,503 $ 224 $ 1,727 Instruments 276 10 286 376 14 390 Total product revenue 1,716 188 1,904 1,879 238 2,117 Service and other revenue 317 65 382 353 121 474 Total revenue $ 2,033 $ 253 $ 2,286 $ 2,232 $ 359 $ 2,591 Revenue by Geographic Area Based on region of destination (in millions) Q3 2020 Q3 2019 YTD 2020 YTD 2019 Americas $ 436 $ 514 $ 1,248 $ 1,463 Europe, Middle East, and Africa 213 235 602 653 Greater China (1) 83 95 246 280 Asia-Pacific 62 63 190 195 Total revenue $ 794 $ 907 $ 2,286 $ 2,591 (1) Region includes revenue from China, Taiwan, and Hong Kong.

Investments and Fair Value Me_2

Investments and Fair Value Measurements (Tables)	9 Months Ended
	Sep. 27, 2020
Fair Value Disclosures [Abstract]
Summary of Short-term Investments	Our short-term investments are primarily available-for-sale debt securities that consisted of the following: September 27, 2020 December 29, 2019 In millions Amortized Gross Estimated Amortized Gross Estimated Debt securities in government-sponsored entities $ 62 $ — $ 62 $ 18 $ — $ 18 Corporate debt securities 610 8 618 627 3 630 U.S. Treasury securities 642 7 649 616 2 618 Total $ 1,314 $ 15 $ 1,329 $ 1,261 $ 5 $ 1,266
Summary of Contractual Maturities of Available-for-sale Debt Securities	Contractual maturities of available-for-sale debt securities, as of September 27, 2020, were as follows: In millions Estimated Due within one year $ 627 After one but within five years 702 Total $ 1,329
Summary of Hierarchy for Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following table presents the hierarchy for assets and liabilities measured at fair value on a recurring basis: September 27, 2020 December 29, 2019 In millions Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets: Money market funds (cash equivalents) $ 1,449 $ — $ — $ 1,449 $ 1,732 $ — $ — $ 1,732 Debt securities in government-sponsored entities — 62 — 62 — 18 — 18 Corporate debt securities — 618 — 618 — 630 — 630 U.S. Treasury securities 649 — — 649 618 — — 618 Marketable equity securities 234 — — 234 106 — — 106 Contingent value right — — 33 33 — — 29 29 Derivative assets related to terminated acquisition — — 26 26 — — 10 10 Deferred compensation plan assets — 51 — 51 — 48 — 48 Total assets measured at fair value $ 2,332 $ 731 $ 59 $ 3,122 $ 2,456 $ 696 $ 39 $ 3,191 Liabilities: Deferred compensation plan liability $ — $ 46 $ — $ 46 $ — $ 46 $ — $ 46

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 27, 2020
Debt Disclosure [Abstract]
Summary of Debt Obligations	In millions September 27, December 29, Principal amount of 2023 Notes outstanding $ 750 $ 750 Principal amount of 2021 Notes outstanding 517 517 Unamortized discount of liability component of convertible senior notes (94) (126) Net carrying amount of liability component of convertible senior notes 1,173 1,141 Less: current portion (507) — Long-term debt $ 666 $ 1,141 Carrying value of equity component of convertible senior notes, net of debt issuance costs $ 213 $ 213 Fair value of convertible senior notes outstanding (Level 2) $ 1,447 $ 1,549 Weighted-average remaining amortization period of discount on the liability component of convertible senior notes 2.6 years 3.2 years

Stockholders_ Equity (Tables)

Stockholders’ Equity (Tables)	9 Months Ended
	Sep. 27, 2020
Equity [Abstract]
Summary of Restricted Stock Activity and Related Information, Restricted Stock	Restricted stock activity was as follows: Restricted Performance Weighted-Average Grant Date Fair Value per Share Units in thousands RSU PSU Outstanding at December 29, 2019 1,700 271 $ 271.49 $ 258.66 Awarded 234 (82) $ 301.83 $ 343.38 Vested (83) — $ 219.18 — Cancelled (167) (71) $ 267.36 $ 261.19 Outstanding at September 27, 2020 1,684 118 $ 278.68 400.74 ______________________________________
Summary of Restricted Stock Activity and Related Information, Performance Units	Restricted stock activity was as follows: Restricted Performance Weighted-Average Grant Date Fair Value per Share Units in thousands RSU PSU Outstanding at December 29, 2019 1,700 271 $ 271.49 $ 258.66 Awarded 234 (82) $ 301.83 $ 343.38 Vested (83) — $ 219.18 — Cancelled (167) (71) $ 267.36 $ 261.19 Outstanding at September 27, 2020 1,684 118 $ 278.68 400.74 ______________________________________
Summary of Stock Option Activity Under all Stock Option Plans	Stock option activity was as follows: Options Weighted-Average Outstanding at December 29, 2019 58 $ 56.65 Exercised (48) $ 56.16 Outstanding and exercisable at September 27, 2020 10 $ 59.11
Summary of Share-based Compensation Expense for all Stock Awards	Share-based compensation expense reported in our condensed consolidated statements of income was as follows: In millions Q3 2020 Q3 2019 YTD 2020 YTD 2019 Cost of product revenue $ 6 $ 5 $ 13 $ 15 Cost of service and other revenue 1 1 3 3 Research and development 21 15 48 50 Selling, general and administrative 33 24 52 77 Share-based compensation expense before taxes 61 45 116 145 Related income tax benefits (12) (10) (27) (31) Share-based compensation expense, net of taxes $ 49 $ 35 $ 89 $ 114
Summary of Assumptions used to Estimate the Weighted-Average Fair Value Per Share for Stock Purchase under the Employee Stock Purchase Plan	The assumptions used for the specified reporting periods and the resulting estimates of weighted-average fair value per share for stock purchased under the ESPP during YTD 2020 were as follows: Employee Stock Purchase Rights Risk-free interest rate 0.11% - 2.04% Expected volatility 30% - 45% Expected term 0.5 - 1.0 year Expected dividends 0 % Weighted-average grant-date fair value per share $ 75.57

Supplemental Balance Sheet De_2

Supplemental Balance Sheet Details (Tables)	9 Months Ended
	Sep. 27, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Accounts Receivable	Accounts Receivable In millions September 27, December 29, Trade accounts receivable, gross $ 468 $ 575 Allowance for credit losses (4) (2) Total accounts receivable, net $ 464 $ 573
Summary of Inventory	Inventory In millions September 27, December 29, Raw materials $ 142 $ 108 Work in process 246 225 Finished goods 27 26 Total inventory $ 415 $ 359
Summary of Changes in Goodwill	Changes to goodwill during YTD 2020 were as follows: In millions Goodwill Balance as of December 29, 2019 $ 824 Acquisitions 73 Balance as of September 27, 2020 $ 897
Summary of Accrued Liabilities	Accrued Liabilities In millions September 27, December 29, Contract liabilities, current portion $ 154 $ 167 Accrued compensation expenses 123 154 Accrued taxes payable 46 86 Operating lease liabilities, current portion 54 45 Other, including warranties (a) 75 64 Total accrued liabilities $ 452 $ 516 (a) Changes in the reserve for product warranties were as follows: In millions Q3 2020 Q3 2019 YTD 2020 YTD 2019 Balance at beginning of period $ 10 $ 16 $ 14 $ 19 Additions charged to cost of product revenue 6 3 11 12 Repairs and replacements (6) (5) (15) (17) Balance at end of period $ 10 $ 14 $ 10 $ 14
Summary of Changes in Reserve for Product Warranties	Changes in the reserve for product warranties were as follows: In millions Q3 2020 Q3 2019 YTD 2020 YTD 2019 Balance at beginning of period $ 10 $ 16 $ 14 $ 19 Additions charged to cost of product revenue 6 3 11 12 Repairs and replacements (6) (5) (15) (17) Balance at end of period $ 10 $ 14 $ 10 $ 14

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 27, 2020
Segment Reporting [Abstract]
Summary of Operating Performance and Assets by Segment	Core Illumina sells products and provides services to Helix in accordance with contractual agreements between the entities. In millions Q3 2020 Q3 2019 YTD 2020 YTD 2019 Revenue: Core Illumina $ 794 $ 907 $ 2,286 $ 2,591 Helix — — — 1 Elimination of intersegment revenue — — — (1) Consolidated revenue $ 794 $ 907 $ 2,286 $ 2,591 Income (loss) from operations: Core Illumina $ 162 $ 308 $ 447 $ 740 Helix — — — (24) Elimination of intersegment earnings — — — 1 Consolidated income from operations $ 162 $ 308 $ 447 $ 717

Organization and Significant _4

Organization and Significant Accounting Policies - Summary of Calculation of Weighted Average Shares used to Calculate Basic and Diluted Earnings Per Share (Details) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Weighted average shares used to calculate basic and diluted earnings per share
Weighted average shares outstanding (in shares)	146	147	147	147
Effect of potentially dilutive common shares from:
Equity awards (in shares)	1	1	1	1
Convertible senior notes (in shares)	1		0	1
Weighted average shares used in calculating diluted earnings per share (in shares)	148	148	148	149

Revenue - Disaggregation of Rev

Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 794	$ 907	$ 2,286	$ 2,591
Americas
Disaggregation of Revenue [Line Items]
Total revenue	436	514	1,248	1,463
Europe, Middle East, and Africa
Disaggregation of Revenue [Line Items]
Total revenue	213	235	602	653
Greater China
Disaggregation of Revenue [Line Items]
Total revenue	83	95	246	280
Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenue	62	63	190	195
Consumables
Disaggregation of Revenue [Line Items]
Total revenue	562	600	1,618	1,727
Instruments
Disaggregation of Revenue [Line Items]
Total revenue	114	146	286	390
Total product revenue
Disaggregation of Revenue [Line Items]
Total revenue	676	746	1,904	2,117
Service and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	118	161	382	474
Sequencing
Disaggregation of Revenue [Line Items]
Total revenue	708	805	2,033	2,232
Sequencing | Consumables
Disaggregation of Revenue [Line Items]
Total revenue	500	525	1,440	1,503
Sequencing | Instruments
Disaggregation of Revenue [Line Items]
Total revenue	109	142	276	376
Sequencing | Total product revenue
Disaggregation of Revenue [Line Items]
Total revenue	609	667	1,716	1,879
Sequencing | Service and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	99	138	317	353
Microarray
Disaggregation of Revenue [Line Items]
Total revenue	86	102	253	359
Microarray | Consumables
Disaggregation of Revenue [Line Items]
Total revenue	62	75	178	224
Microarray | Instruments
Disaggregation of Revenue [Line Items]
Total revenue	5	4	10	14
Microarray | Total product revenue
Disaggregation of Revenue [Line Items]
Total revenue	67	79	188	238
Microarray | Service and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 19	$ 23	$ 65	$ 121

Revenue - Remaining Performance

Revenue - Remaining Performance Obligation (Details) $ in Millions	Sep. 27, 2020USD ($)
Accounting Policies [Abstract]
Remaining performance obligation	$ 735
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-09-28
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Percent of remaining performance obligation	84.00%
Expected timing of remaining performance obligation	12 months

Revenue - Narrative (Details)

Revenue - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 27, 2020	Sep. 27, 2020	Dec. 29, 2019
Revenue from Contract with Customer [Abstract]
Contract with customer, liability	$ 196	$ 196	$ 209
Contract liabilities, current portion	154	154	$ 167
Revenue recognized	$ 30	$ 136

Investments and Fair Value Me_3

Investments and Fair Value Measurements - Summary of Short-term Investments (Details) - USD ($) $ in Millions	Sep. 27, 2020	Dec. 29, 2019
Available-for-sale debt securities:
Amortized Cost	$ 1,314	$ 1,261
Gross Unrealized Gains	15	5
Estimated Fair Value	1,329	1,266
Debt securities in government-sponsored entities
Available-for-sale debt securities:
Amortized Cost	62	18
Gross Unrealized Gains	0	0
Estimated Fair Value	62	18
Corporate debt securities
Available-for-sale debt securities:
Amortized Cost	610	627
Gross Unrealized Gains	8	3
Estimated Fair Value	618	630
U.S. Treasury securities
Available-for-sale debt securities:
Amortized Cost	642	616
Gross Unrealized Gains	7	2
Estimated Fair Value	$ 649	$ 618

Investments and Fair Value Me_4

Investments and Fair Value Measurements - Summary of Contractual Maturities of Available-for-sale Debt Securities (Details) - USD ($) $ in Millions	Sep. 27, 2020	Dec. 29, 2019
Estimated Fair Value
Due within one year	$ 627
After one but within five years	702
Total	$ 1,329	$ 1,266

Investments and Fair Value Me_5

Investments and Fair Value Measurements - Narrative (Details)	Sep. 20, 2020USD ($)	Jan. 02, 2020USD ($)	Apr. 25, 2019USD ($)	Nov. 01, 2018USD ($)$ / shares	Mar. 02, 2020USD ($)	Sep. 27, 2020USD ($)	Mar. 29, 2020USD ($)	Dec. 29, 2019USD ($)	Sep. 29, 2019USD ($)	Sep. 27, 2020USD ($)fund	Sep. 29, 2019USD ($)	Jul. 31, 2015
Schedule of Investments [Line Items]
Marketable equity securities						$ 234,000,000		$ 106,000,000		$ 234,000,000
Marketable equity securities unrealized losses and gains						59,000,000			$ 47,000,000	128,000,000	$ 57,000,000
Strategic equity investments, without readily determinable fair values						305,000,000		220,000,000		$ 305,000,000
Number of venture capital investment funds | fund										2
Equity method investments						90,000,000		53,000,000		$ 90,000,000
Gains on deconsolidation											54,000,000
Loss on derivative assets related to terminated acquisition										(116,000,000)
Bridge Loan
Schedule of Investments [Line Items]
Principal amount of notes outstanding	$ 1,000,000,000
Investee
Schedule of Investments [Line Items]
Revenue from transactions with strategic investees						16,000,000			15,000,000	39,000,000	49,000,000
Venture Capital Investment Fund (the Fund)
Schedule of Investments [Line Items]
Commitment in new venture capital investment fund						100,000,000				100,000,000
Remaining capital commitment						40,000,000				40,000,000
Second Venture Capital Investment Fund
Schedule of Investments [Line Items]
Commitment in new venture capital investment fund						160,000,000				160,000,000
Remaining capital commitment						143,000,000				143,000,000
Helix Holdings I, LLC
Schedule of Investments [Line Items]
Contingent value right, terms			7 years
Gains on deconsolidation			$ 39,000,000
Contingent value right			$ 30,000,000
Unrealized gain (loss) from contingent value right									$ 2,000,000	5,000,000	$ (1,000,000)
Helix Holdings I, LLC | Variable Interest Entity, Primary Beneficiary
Schedule of Investments [Line Items]
Absorbed Helix's losses percentage											50.00%
Pacific Biosciences of California, Inc (PacBio)
Schedule of Investments [Line Items]
Cash payments				$ 1,200,000,000	$ 34,000,000		$ 132,000,000	18,000,000
Loss on contract termination		$ 98,000,000
Share price (in dollars per share) | $ / shares				$ 8
Business combination, contingent consideration arrangements, maximum outcome		52,000,000
Equity or debt financing to be raised		$ 100,000,000
Derivative asset						40,000,000				40,000,000
GRAIL Inc
Schedule of Investments [Line Items]
Net Assets						250,000,000		$ 190,000,000		250,000,000
Payments to acquire additional investment in security										60,000,000
Contingent value right, terms	12 years
Merger agreement consideration	$ 8,000,000,000
Cash payments	3,500,000,000
Business combination, equity Interests Issued and Issuable (in shares)	4,500,000,000
Capital raised	1,000,000,000
Business Combination, continuation payments	35,000,000
Business combination, threshold of continuation payments	315,000,000
Termination fee	300,000,000
Investment to be made if merger does not occur	$ 300,000,000
GRAIL Inc | Payment Rights Of One Billion, Each Twelve Years
Schedule of Investments [Line Items]
Contingent payment rights, first percentage	2.50%
Business Acquisition, Contingent Value Rights, Revenue Threshold	$ 1,000,000,000
GRAIL Inc | Payment Rights Of Above One Billion, Each Twelve Years
Schedule of Investments [Line Items]
Contingent payment rights, second percentage	9.00%
Business Acquisition, Contingent Value Rights, Revenue Threshold	$ 1,000,000,000
Helix Holdings I, LLC | Variable Interest Entity, Primary Beneficiary
Schedule of Investments [Line Items]
Equity ownership interest percentage												50.00%
Selling, General and Administrative | Pacific Biosciences of California, Inc (PacBio)
Schedule of Investments [Line Items]
Loss on derivative assets related to terminated acquisition										(92,000,000)
Other Operating Income (Expense) | Pacific Biosciences of California, Inc (PacBio)
Schedule of Investments [Line Items]
Loss on derivative assets related to terminated acquisition						$ (10,000,000)				$ (25,000,000)

Investments and Fair Value Me_6

Investments and Fair Value Measurements - Fair Value Hierarchy of Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 27, 2020	Dec. 29, 2019
Assets:
Available-for-sale securities	$ 1,329	$ 1,266
Marketable equity securities	234	106
Debt securities in government-sponsored entities
Assets:
Available-for-sale securities	62	18
Corporate debt securities
Assets:
Available-for-sale securities	618	630
U.S. Treasury securities
Assets:
Available-for-sale securities	649	618
Fair Value, Measurements, Recurring
Assets:
Marketable equity securities	234	106
Contingent value right	33	29
Derivative assets related to terminated acquisition	26	10
Deferred compensation plan assets	51	48
Total assets measured at fair value	3,122	3,191
Liabilities:
Deferred compensation plan liability	46	46
Fair Value, Measurements, Recurring | Money market funds (cash equivalents)
Assets:
Money market funds (cash equivalents)	1,449	1,732
Fair Value, Measurements, Recurring | Debt securities in government-sponsored entities
Assets:
Available-for-sale securities	62	18
Fair Value, Measurements, Recurring | Corporate debt securities
Assets:
Available-for-sale securities	618	630
Fair Value, Measurements, Recurring | U.S. Treasury securities
Assets:
Available-for-sale securities	649	618
Fair Value, Measurements, Recurring | Level 1
Assets:
Marketable equity securities	234	106
Contingent value right	0	0
Derivative assets related to terminated acquisition	0	0
Deferred compensation plan assets	0	0
Total assets measured at fair value	2,332	2,456
Liabilities:
Deferred compensation plan liability	0	0
Fair Value, Measurements, Recurring | Level 1 | Money market funds (cash equivalents)
Assets:
Money market funds (cash equivalents)	1,449	1,732
Fair Value, Measurements, Recurring | Level 1 | Debt securities in government-sponsored entities
Assets:
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring | Level 1 | Corporate debt securities
Assets:
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury securities
Assets:
Available-for-sale securities	649	618
Fair Value, Measurements, Recurring | Level 2
Assets:
Marketable equity securities	0	0
Contingent value right	0	0
Derivative assets related to terminated acquisition	0	0
Deferred compensation plan assets	51	48
Total assets measured at fair value	731	696
Liabilities:
Deferred compensation plan liability	46	46
Fair Value, Measurements, Recurring | Level 2 | Money market funds (cash equivalents)
Assets:
Money market funds (cash equivalents)	0	0
Fair Value, Measurements, Recurring | Level 2 | Debt securities in government-sponsored entities
Assets:
Available-for-sale securities	62	18
Fair Value, Measurements, Recurring | Level 2 | Corporate debt securities
Assets:
Available-for-sale securities	618	630
Fair Value, Measurements, Recurring | Level 2 | U.S. Treasury securities
Assets:
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring | Level 3
Assets:
Marketable equity securities	0	0
Contingent value right	33	29
Derivative assets related to terminated acquisition	26	10
Deferred compensation plan assets	0	0
Total assets measured at fair value	59	39
Liabilities:
Deferred compensation plan liability	0	0
Fair Value, Measurements, Recurring | Level 3 | Money market funds (cash equivalents)
Assets:
Money market funds (cash equivalents)	0	0
Fair Value, Measurements, Recurring | Level 3 | Debt securities in government-sponsored entities
Assets:
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring | Level 3 | Corporate debt securities
Assets:
Available-for-sale securities	0	0
Fair Value, Measurements, Recurring | Level 3 | U.S. Treasury securities
Assets:
Available-for-sale securities	$ 0	$ 0

Debt - Summary of Debt Obligati

Debt - Summary of Debt Obligations (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 27, 2020	Dec. 29, 2019	Aug. 21, 2018	Jun. 29, 2014
Debt Instrument [Line Items]
Less: current portion	$ (507,000,000)	$ 0
Long-term debt	666,000,000	1,141,000,000
Convertible Senior Notes
Debt Instrument [Line Items]
Unamortized discount of liability component of convertible senior notes	(94,000,000)	(126,000,000)
Net carrying amount of liability component of convertible senior notes	1,173,000,000	1,141,000,000
Carrying value of equity component of convertible senior notes, net of debt issuance costs	$ 213,000,000	$ 213,000,000
Weighted-average remaining amortization period of discount on the liability component of convertible senior notes	2 years 7 months 6 days	3 years 2 months 12 days
Level 2 | Convertible Senior Notes
Debt Instrument [Line Items]
Fair value of convertible senior notes outstanding (Level 2)	$ 1,447,000,000	$ 1,549,000,000
2023 | Convertible Senior Notes
Debt Instrument [Line Items]
Principal amount of notes outstanding	750,000,000	750,000,000	$ 750,000,000
2021 | Convertible Senior Notes
Debt Instrument [Line Items]
Principal amount of notes outstanding	$ 517,000,000	$ 517,000,000		$ 517,000,000

Debt - Narrative (Details)

Debt - Narrative (Details) $ / shares in Units, shares in Millions	Jun. 15, 2019shares	Aug. 21, 2018USD ($)day$ / shares	Jun. 29, 2014USD ($)day$ / shares	Sep. 27, 2020USD ($)$ / shares	Dec. 29, 2019USD ($)
Bridge Facility
Debt Instrument [Line Items]
Principal amount of notes outstanding | $				$ 1,000,000,000
Convertible Senior Notes | 2023
Debt Instrument [Line Items]
Principal amount of notes outstanding | $		$ 750,000,000		750,000,000	$ 750,000,000
Stated rate		0.00%
Effective interest rate used to measure fair value of convertible senior note		3.70%
Conversion rate		0.0021845
Conversion price (in dollars per share) | $ / shares		$ 457.77
Threshold common stock trading days		20
Threshold consecutive common stock trading days		30
Threshold percentage of common stock price trigger		130.00%
Threshold note trading days		5
Threshold consecutive note trading days		10
Threshold percentage of note price trigger		98.00%
Convertible stock price trigger (in dollars per share) | $ / shares		$ 595.10
Redemption price, percentage		100.00%
Convertible Senior Notes | 2021
Debt Instrument [Line Items]
Principal amount of notes outstanding | $			$ 517,000,000	$ 517,000,000	$ 517,000,000
Stated rate			0.50%
Effective interest rate used to measure fair value of convertible senior note			3.50%
Conversion rate			0.0039318
Conversion price (in dollars per share) | $ / shares			$ 254.34
Threshold common stock trading days			20
Threshold consecutive common stock trading days			30
Threshold percentage of common stock price trigger			130.00%
Threshold note trading days			5
Threshold consecutive note trading days			10
Threshold percentage of note price trigger			98.00%
Convertible stock price trigger (in dollars per share) | $ / shares				$ 330.64
Debt instrument, convertible, if-converted value in excess of principal | $				$ 97,000,000
Convertible Senior Notes | 2019
Debt Instrument [Line Items]
Principal amount of notes outstanding | $			$ 633,000,000
Stated rate			0.00%
Effective interest rate used to measure fair value of convertible senior note			2.90%
Number of shares of common stock issued upon conversion (in shares) | shares	0.4

Stockholders_ Equity - Narrativ

Stockholders’ Equity - Narrative (Details) shares in Millions	Sep. 27, 2020shares
2015 Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance (in shares)	4.1

Stockholders_ Equity - Summary

Stockholders’ Equity - Summary of Restricted Stock Activity and Related Information (Details) shares in Thousands	9 Months Ended
	Sep. 27, 2020$ / sharesshares
Restricted Stock Units (RSU)
Stock Units
Outstanding at period start (in shares) | shares	1,700
Awarded (in shares) | shares	234
Vested (in shares) | shares	(83)
Cancelled (in shares) | shares	(167)
Outstanding at period end (in shares) | shares	1,684
Weighted-Average Grant Date Fair Value per Share
Outstanding at period start (in dollars per share) | $ / shares	$ 271.49
Awarded (in dollars per share) | $ / shares	301.83
Vested (in dollars per share) | $ / shares	219.18
Cancelled (in dollars per share) | $ / shares	267.36
Outstanding at period end (in dollars per share) | $ / shares	$ 278.68
Performance Stock Units (PSU)
Stock Units
Outstanding at period start (in shares) | shares	271
Awarded (in shares) | shares	(82)
Cancelled (in shares) | shares	(71)
Outstanding at period end (in shares) | shares	118
Weighted-Average Grant Date Fair Value per Share
Outstanding at period start (in dollars per share) | $ / shares	$ 258.66
Awarded (in dollars per share) | $ / shares	343.38
Cancelled (in dollars per share) | $ / shares	261.19
Outstanding at period end (in dollars per share) | $ / shares	$ 400.74

Stockholders_ Equity - Summar_2

Stockholders’ Equity - Summary of Stock Option Activity Under all Stock Option Plans (Details) shares in Thousands	9 Months Ended
	Sep. 27, 2020$ / sharesshares
Options
Outstanding at period start (in shares) | shares	58
Exercised (in shares) | shares	(48)
Outstanding at period end (in shares) | shares	10
Exercisable at period end (in shares) | shares	10
Weighted-Average Exercise Price
Outstanding at period start (in dollars per share) | $ / shares	$ 56.65
Exercised (in dollars per share) | $ / shares	56.16
Outstanding at period end (in dollars per share) | $ / shares	59.11
Exercisable at period end (in dollars per share) | $ / shares	$ 59.11

Stockholders_ Equity - Narrat_2

Stockholders’ Equity - Narrative - Employee Stock Purchase Plan (Details) - ESPP - Employee Stock shares in Millions	9 Months Ended
	Sep. 27, 2020shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Specified percentage of the fair market value of the common stock on the first or last day of the offering period whichever is lower at which stock is purchased	85.00%
Total shares issued under the ESPP (in shares)	0.2
Shares available for issuance (in shares)	13.3

Stockholders_ Equity - Narrat_3

Stockholders’ Equity - Narrative - Share Repurchases (Details) - USD ($) shares in Millions	9 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Feb. 05, 2020
Class of Stock [Line Items]
Repurchased common stock (in shares)	1.4
Common stock repurchases	$ 455,000,000	$ 261,000,000
Common Stock
Class of Stock [Line Items]
Stock repurchase program, authorized amount			$ 750,000,000
Dollar amount remaining in authorized stock repurchase program	$ 295,000,000

Stockholders_ Equity - Summar_3

Stockholders’ Equity - Summary of Share-based Compensation Expense for all Stock Awards (Details) $ in Millions	Aug. 05, 2020	Sep. 27, 2020USD ($)	Sep. 29, 2019USD ($)	Sep. 27, 2020USD ($)	Sep. 29, 2019USD ($)	Jan. 03, 2021USD ($)numberOfEmployees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense before taxes		$ 61	$ 45	$ 116	$ 145
Related income tax benefits		(12)	(10)	(27)	(31)
Share-based compensation expense, net of taxes		49	35	89	114
Performance Stock Units (PSU)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation vesting performance period	3 years
Incremental share-based compensation cost		17
Scenario, Forecast | Performance Stock Units (PSU)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees effected by modification | numberOfEmployees						49
Incremental share-based compensation cost						$ 47
Cost of product revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense before taxes		6	5	13	15
Cost of service and other revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense before taxes		1	1	3	3
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense before taxes		21	15	48	50
Selling, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense before taxes		$ 33	$ 24	$ 52	$ 77

Stockholders_ Equity- Summary o

Stockholders’ Equity- Summary of Assumptions Used to Estimate the Weighted Average Fair Value Per Share (Details) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 27, 2020USD ($)$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to stock options, restricted stock, and ESPP shares granted to date | $	$ 367
Weighted-average period of unrecognized compensation cost related to stock options, restricted stock, and ESPP shares granted to date	2 years
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, minimum	30.00%
Expected volatility, maximum	45.00%
Expected dividends	0.00%
Weighted-average fair value per share (in dollars per share) | $ / shares	$ 75.57
Minimum | Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	11.00%
Expected term	6 months
Maximum | Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	2.04%
Expected term	1 year

Supplemental Balance Sheet De_3

Supplemental Balance Sheet Details - Schedule of Accounts Receivable (Details) - USD ($) $ in Millions	Sep. 27, 2020	Dec. 29, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Trade accounts receivable, gross	$ 468	$ 575
Allowance for credit losses	(4)	(2)
Total accounts receivable, net	$ 464	$ 573

Supplemental Balance Sheet De_4

Supplemental Balance Sheet Details - Summary of Inventory (Details) - USD ($) $ in Millions	Sep. 27, 2020	Dec. 29, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Raw materials	$ 142	$ 108
Work in process	246	225
Finished goods	27	26
Total inventory	$ 415	$ 359

Supplemental Balance Sheet De_5

Supplemental Balance Sheet Details - Narrative - Intangible Assets and Goodwill (Details) - Developed Technology $ in Millions	3 Months Ended
	Jun. 28, 2020USD ($)
Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired	$ 26
Useful life	10 years

Supplemental Balance Sheet De_6

Supplemental Balance Sheet Details - Summary of Changes in Goodwill (Details) - USD ($)	3 Months Ended	9 Months Ended
	Jun. 28, 2020	Sep. 27, 2020
Goodwill [Roll Forward]
Goodwill, beginning balance		$ 824,000,000
Acquisitions		73,000,000
Goodwill, ending balance		$ 897,000,000
Goodwill, impairment loss	$ 0

Supplemental Balance Sheet De_7

Supplemental Balance Sheet Details - Summary of Accrued Liabilities (Details) - USD ($) $ in Millions	Sep. 27, 2020	Dec. 29, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Contract liabilities, current portion	$ 154	$ 167
Accrued compensation expenses	123	154
Accrued taxes payable	46	86
Operating lease liabilities, current portion	54	45
Other, including warranties	75	64
Total accrued liabilities	$ 452	$ 516

Supplemental Balance Sheet De_8

Supplemental Balance Sheet Details - Summary of Changes in Reserve for Product Warranties (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Reserve for product warranties [Roll Forward]
Balance at beginning of period	$ 10	$ 16	$ 14	$ 19
Additions charged to cost of product revenue	6	3	11	12
Repairs and replacements	(6)	(5)	(15)	(17)
Balance at end of period	$ 10	$ 14	$ 10	$ 14

Supplemental Balance Sheet De_9

Supplemental Balance Sheet Details - Narrative - Warranties (Details)	9 Months Ended
	Sep. 27, 2020
Instruments
Product Warranty Liability [Line Items]
Warranty period	1 year
Consumables | Minimum
Product Warranty Liability [Line Items]
Warranty period	6 months
Consumables | Maximum
Product Warranty Liability [Line Items]
Warranty period	12 months

Supplemental Balance Sheet D_10

Supplemental Balance Sheet Details - Narrative - Derivatives (Details) - USD ($) $ in Millions	Sep. 27, 2020	Dec. 29, 2019
Foreign Exchange Forward | Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative, notional amount	$ 315	$ 252

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 27, 2020	Sep. 27, 2020
Income Tax Disclosure [Abstract]
Effective tax rate	16.80%	28.40%
Valuation allowance of deferred tax asset		$ 62
Tax expense related to the finalization of court case		$ 28

Segment Information (Details)

Segment Information (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 27, 2020USD ($)	Sep. 29, 2019USD ($)	Sep. 27, 2020USD ($)segment	Sep. 29, 2019USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment			1
Segment Reporting Information [Line Items]
Revenue	$ 794	$ 907	$ 2,286	$ 2,591
Income (loss) from operations	162	308	447	717
Operating Segments | Core Illumina
Segment Reporting Information [Line Items]
Revenue	794	907	2,286	2,591
Income (loss) from operations	162	308	447	740
Operating Segments | Helix
Segment Reporting Information [Line Items]
Revenue	0		0	1
Income (loss) from operations	0	0	0	(24)
Elimination of intersegment
Segment Reporting Information [Line Items]
Revenue	0		0	(1)
Income (loss) from operations	$ 0	$ 0	$ 0	$ 1

Uncategorized Items - ilmn-2020

Label	Element	Value
Accounting Standards Update [Extensible List]	us-gaap_AccountingStandardsUpdateExtensibleList	us-gaap:AccountingStandardsUpdate201602Member