Basis of Presentation (Policies)	9 Months Ended
Basis of Presentation (Policies)	Sep. 29, 2018
Accounting Policies [Abstract]
Business and Basis of Presentation, Policy	We prepared the condensed consolidated financial statements as of and for the three and nine months ended September 29, 2018 of Sleep Number Corporation and 100%-owned subsidiaries (Sleep Number or the Company), without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (SEC) and they reflect, in the opinion of management, all normal recurring adjustments necessary to present fairly our financial position as of September 29, 2018 and December 30, 2017, and the consolidated results of operations and cash flows for the periods presented. Our historical and quarterly consolidated results of operations may not be indicative of the results that may be achieved for the full year or any future period. Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles (GAAP) have been condensed or omitted pursuant to such rules and regulations. These condensed consolidated financial statements should be read in conjunction with our most recent audited consolidated financial statements and related notes included in our Annual Report on Form 10-K for the fiscal year ended December 30, 2017 and other recent filings with the SEC.
Use of Estimates, Policy	The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires us to make estimates and assumptions. These estimates and assumptions affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, and the reported amounts of sales, expenses and income taxes during the reporting period. Predicting future events is inherently an imprecise activity and, as such, requires the use of judgment. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Changes in these estimates will be reflected in the consolidated financial statements in future periods. Our critical accounting policies consist of stock-based compensation, goodwill and indefinite-lived intangible assets, warranty liabilities and revenue recognition.
Consolidation, Policy	The condensed consolidated financial statements include the accounts of Sleep Number Corporation and our 100%-owned subsidiaries. All significant intra-entity balances and transactions have been eliminated in consolidation.
New Accounting Pronouncements, Policy	New Accounting Pronouncements Recently Adopted Accounting Guidance Adoption of ASC Topic 230, Restricted Cash Effective December 31, 2017, we adopted ASC Topic 230, Restricted Cash, which requires amounts generally described as restricted cash and restricted cash equivalents be included with cash and cash equivalents when reconciling the total beginning and ending amounts for the periods shown on the statement of cash flows. Amounts for prior periods have been retrospectively adjusted to conform to the current period presentation. Adoption of ASC Topic 606, Revenue from Contracts with Customers On December 31, 2017, we adopted ASC Topic 606, Revenue from Contracts with Customers, using the modified retrospective method applied to those contracts which were not completed as of December 30, 2017. Results for reporting periods beginning after December 30, 2017 are presented under the new guidance, while prior period amounts are not restated. The cumulative effect of the changes made to our consolidated balance sheet as of December 31, 2017 resulting from the adoption of the new revenue guidance was not material and did not impact opening retained earnings. The impact on the timing of net sales for the three and nine months ended September 29, 2018, as a result of applying the new guidance, was not material. Practical expedients and exemptions permissible under ASC Topic 606 that we elected are as follows: we do not disclose the value of unsatisfied performance obligations for (i) contracts with an original expected length of one year or less; and (ii) contracts for which we recognize revenue at the amount to which we have the right to invoice for services performed. See Note 2, Revenue Recognition, for further details regarding our revenue recognition policy. Accounting Guidance Issued but Not Yet Adopted as of September 29, 2018 We are the lessee under various agreements for facilities, equipment and vehicles that are currently accounted for as operating leases. In February 2016, the FASB issued ASC Topic 842, Leases, that requires most leases to be recognized on the balance sheet and expands disclosure requirements. Leases will be classified as finance or operating, with classification affecting the pattern and classification of expense recognition in the income statement. This new guidance is effective for us beginning December 30, 2018 (fiscal 2019). The provisions of this new guidance require a modified-retrospective approach, with elective reliefs. The new guidance will apply to all leases existing at the date of initial application. We have the option to choose either (1) the effective date, or (2) the beginning of the earliest comparative period presented in the financial statements as the date of initial application. We expect to adopt the new standard using the effective date option. The new guidance establishes a right-of-use model (ROU) that requires a lessee to recognize a ROU asset and lease liability on the balance sheet for all leases with a term longer than 12 months. On adoption, we expect to recognize additional lease liabilities and corresponding ROU assets of approximately $300 million based on the present value of the remaining minimum rental payments for existing operating leases. This amount will vary based on the interest rates in effect upon adoption and any new leases we enter into or exit from prior to adoption. The new guidance provides a number of optional practical expedients in transition. We expect to elect the package of practical expedients, which permits us to not reassess under the new standard our prior conclusions about lease identification, lease classification and initial direct costs. We do not expect to elect the use of hindsight. The new guidance also provides practical expedients for an entity’s ongoing accounting. We expect to elect the short-term lease recognition exemption for all leases that qualify, primarily small equipment leases. This means, for those leases that qualify, we will not recognize ROU assets or lease liabilities, and this includes not recognizing ROU assets or lease liabilities for existing short-term leases of those assets in transition. We also expect to elect the practical expedient option to not separate lease and non-lease components for all of our leases. We will be providing significant new disclosures about our leasing activities and are in the process of implementing a new lease accounting system in connection with the adoption. We also expect that adoption of the new guidance will require changes to our internal controls over financial reporting. We continue to evaluate the effect of the new standard on our consolidated financial statements and related disclosures.
Revenue Recognition, Policy [Policy Text Block]	We accept sales returns during a 100-night trial period. Accrued sales returns represents a refund liability for the amount of consideration that we do not expect to be entitled to because it will be refunded to customers. The refund liability estimate is based on historical return rates and is adjusted for any current trends as appropriate. Each reporting period we remeasure the liability to reflect changes in the estimate, with a corresponding adjustment to net sales. We recognize revenue when control of the promised goods or services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services. Revenue recognized excludes sales taxes. Amounts billed to customers for delivery and setup are included in net sales. For most products, we receive payment before, or promptly after, the products or services are delivered to the customer. Our beds sold with SleepIQ^® technology contain multiple performance obligations including the bed and SleepIQ hardware and software. We analyze our multiple performance obligation(s) to determine whether they are distinct and can be separated or whether they must be accounted for as a single performance obligation. We determined that the beds sold with the SleepIQ technology have two performance obligations consisting of: (i) the bed; and (ii) SleepIQ hardware and software. SleepIQ hardware and software are not separable as the hardware and related software are not sold separately and the software is integral to the hardware’s functionality. We determine the transaction price for multiple performance obligations based on their relative standalone selling prices. The performance obligation related to the bed is satisfied at a point in time. The performance obligation related to SleepIQ technology is satisfied over time based on the ongoing access and usage by the customer of software essential to the functionality of SleepIQ technology. The deferred revenue and costs related to SleepIQ technology are recognized on a straight-line basis over the product’s estimated life of four years because our inputs are generally expended evenly throughout the performance period.
Stockholders' Equity, Policy	There is no expiration date governing the period over which we can repurchase shares. Any repurchased shares are constructively retired and returned to an unissued status. The cost of stock repurchases is first charged to additional paid-in capital. Once additional paid-in capital is reduced to zero, any additional amounts are charged to (accumulated deficit) retained earnings.
Profit Sharing and 401(k) Plan Policy	Under our profit sharing and 401(k) plan, eligible employees may defer up to 50% of their compensation on a pre-tax basis, subject to Internal Revenue Service limitations. Each pay period, we may make a discretionary contribution equal to a percentage of the employee’s contribution.