v3.5.0.1

Basis of Presentation and Summary of Significant Accounting Policies (Schedule of Subscriber System Assets Depreciation) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
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Mar. 31, 2016 | Mar. 27, 2015 | Mar. 31, 2016 | Mar. 27, 2015
Subscriber System Assets Depreciation Expense [Line Items] |  |  |  |
Depreciation | $ 120 | $ 107 | $ 237 | $ 211

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- Definition [Line Items] for Subscriber System Assets Depreciation Expense [Table] + References No definition available. + Details
Name: | adt_SubscriberSystemAssetsDepreciationExpenseLineItems
Namespace Prefix: | adt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229 + Details
Name: | us-gaap_Depreciation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration