XML 47 R41.htm IDEA: XBRL DOCUMENT
v3.19.3

Marketable Securities (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Sep. 27, 2019 | Sep. 28, 2018
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Noncurrent, Maximum Contractual Maturity | 2 years |
US Treasury and Government [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale Securities | $ 54.2 |
Corporate Debt Securities [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale Securities | 72.1 |
US States and Political Subdivisions Debt Securities [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale Securities | 104.6 |
Debt Security, Government, Non-US [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale Securities | 0.0 |
Other Noncurrent Assets [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale Securities | 27.6 | $ 22.8
Other Noncurrent Assets [Member] | US Treasury and Government [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale Securities | 20.0 | 0.0
Other Noncurrent Assets [Member] | Corporate Debt Securities [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale Securities | 5.9 | 12.0
Other Noncurrent Assets [Member] | US States and Political Subdivisions Debt Securities [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale Securities | 1.7 | 0.8
Other Noncurrent Assets [Member] | Debt Security, Government, Non-US [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale Securities | 0.0 | 10.0
Other Current Assets [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale Securities | 203.3 | 294.1
Other Current Assets [Member] | US Treasury and Government [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale Securities | 34.3 | 65.0
Other Current Assets [Member] | Corporate Debt Securities [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale Securities | 66.2 | 204.1
Other Current Assets [Member] | US States and Political Subdivisions Debt Securities [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale Securities | 102.9 | 2.0
Other Current Assets [Member] | Debt Security, Government, Non-US [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale Securities | $ 0.0 | $ 23.0

X
- Definition Date of maturity of a debt security categorized as neither trading nor held to maturity, string text + References No definition available. + Details
Name: | swks_DebtSecuritiesAvailableforsaleNoncurrentMaximumContractualMaturity
Namespace Prefix: | swks_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition 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. + References No definition available. + Details
Name: | us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USTreasuryAndGovernmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_ForeignGovernmentDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_OtherNoncurrentAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_OtherCurrentAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |