Debt and Other Commitments - Summary of Debt Obligations (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Jan. 01, 2017	Jun. 29, 2014
Debt Instrument [Line Items]
Obligations under financing leases	$ 113	$ 9
Other	4	4
Less: current portion	(10)	(2)
Long-term debt	1,182	1,056
Convertible Debt [Member]
Debt Instrument [Line Items]
Unamortized discount of liability component	75	105
Net carrying amount of liability component	1,075	1,045
Carrying value of equity component, net of issuance costs	$ 161	$ 161
Weighted average remaining amortization period of discount on the liability component	2 years 9 months	3 years 7 months
Convertible Debt [Member] \| 2019 Notes [Member]
Debt Instrument [Line Items]
Principal amount of notes outstanding	$ 633	$ 633	$ 633
Convertible Debt [Member] \| 2021 Notes [Member]
Debt Instrument [Line Items]
Principal amount of notes outstanding	517	517	$ 517
Level 2 [Member] \| Convertible Debt [Member]
Debt Instrument [Line Items]
Fair value of outstanding notes (Level 2)	$ 1,305	$ 1,108

The carrying amount of the equity component of convertible debt which may be settled in cash upon conversion.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
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Remaining amortization period for discount on the liability component of convertible debt which may be settled in cash upon conversion, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Face (par) amount of debt instrument at time of issuance.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount, after accumulated amortization, of debt discount.

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Represents the aggregate of total long-term debt, including current maturities and short-term debt.

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Present value of lessee's discounted obligation for lease payments from finance lease.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount of long-term debt classified as other.

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