Basis of Presentation and Summary of Significant Accounting Policies (Policies)	6 Months Ended
Jun. 30, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
amortization policy for Deferred SAC and SAS [Policy Text Block]	Subscriber system assets and any related deferred subscriber acquisition costs resulting from customer acquisitions are accounted for on a pooled basis based on the month and year of acquisition. The Company depreciates and amortizes its pooled subscriber system assets and related deferred subscriber acquisition costs using an accelerated method over the estimated life of the customer relationship, which is 15 years.
Deferred Subscriber Acquisition Costs [Policy Text Block]	Deferred subscriber acquisition costs represent selling expenses (primarily commissions) that are incremental to acquiring customers. Amortization expense relating to deferred subscriber acquisition costs, which is included in selling, general, and administrative expenses in the Condensed Consolidated Statements of Operations was $30 million and $23 million for the three months ended June 30, 2021 and 2020, respectively, and $59 million and $45 million for the six months ended June 30, 2021 and 2020, respectively.
Basis of Presentation	The condensed consolidated financial statements included herein are unaudited, but in the opinion of management, such financial statements include all adjustments, consisting of normal recurring adjustments, necessary to summarize fairly the Company’s financial position, results of operations, and cash flows for the interim periods presented. The interim results reported in these condensed consolidated financial statements should not be taken as indicative of results that may be expected for future interim periods or the full year. For a more comprehensive understanding of the Company and its interim results, these condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements included in its Annual Report on Form 10-K for the year ended December 31, 2020 (the “2020 Annual Report”), which was filed with the U.S. Securities and Exchange Commission (the “SEC”) on February 25, 2021. The Company’s accounting policies used in the preparation of these condensed consolidated financial statements do not differ from those used in the annual consolidated financial statements, unless otherwise noted. The Condensed Consolidated Balance Sheet as of December 31, 2020 included herein was derived from the audited consolidated financial statements as of that date but does not include all the footnote disclosures from the annual consolidated financial statements. The condensed consolidated financial statements include the accounts of ADT Inc. and its wholly-owned subsidiaries and have been prepared in U.S. dollars in accordance with GAAP. All intercompany transactions have been eliminated. Certain prior period amounts have been reclassified to conform with the current period presentation. Segment Change Effective in the first quarter of 2021, the manner in which the Company’s Chief Executive Officer, who is the chief operating decision maker (the “CODM”), evaluates performance and makes decisions about how to allocate resources changed. Therefore, the Company now reports results in two operating and reportable segments, Consumer and Small Business (“CSB”) and Commercial, rather than a single operating and reportable segment. Where applicable, prior periods have been retrospectively adjusted to reflect the new operating and reportable segment structure. The accounting policies of the Company’s reportable segments are the same as those of the Company. The Company organizes its segments based on customer type as follows: •Consumer and Small Business (CSB) - Customers in the CSB segment are comprised of residential homeowners, small business operators, and other individual consumers. The CSB segment primarily includes (i) revenue and operating costs from the sale, installation, servicing, and monitoring of integrated security and automation systems, as well as other offerings such as mobile security and home health solutions; (ii) other operating costs associated with support functions related to these operations; and (iii) general corporate costs and other income and expense items not included in the Commercial segment. Where applicable, results for the Company’s Canadian operations prior to its sale in the fourth quarter of 2019 are included in the CSB segment based on the primary customer market served in Canada. •Commercial - Customers in the Commercial segment are comprised of larger businesses with more expansive facilities (typically larger than 10,000 square feet) and/or multi-site operations, which often require more sophisticated integrated solutions. The Commercial segment primarily includes (i) revenue and operating costs from the sale, installation, servicing, and monitoring of integrated security and automation systems, fire detection and suppression systems, and other related offerings; (ii) other operating costs associated with support functions related to these operations; and (iii) dedicated corporate and other costs. Refer to Note 13 “Segment Information” for additional information on the Company’s segments. COVID-19 Pandemic During March 2020, the World Health Organization declared the outbreak of a novel coronavirus as a pandemic (the “COVID-19 Pandemic”). While responses have varied by individuals, businesses, and state and local municipalities, the COVID-19 Pandemic has had certain notable adverse impacts on general economic conditions, including the temporary closures of many businesses, increased governmental regulations, supply chain disruptions, and changes in consumer spending due to significant unemployment and other effects attributable to the COVID-19 Pandemic. In order to continue to both protect its employees and serve its customers, the Company has adjusted and is continuously evolving certain aspects of its operations, such as (i) detailed protocols for infectious disease safety for employees, (ii) employee daily wellness checks, and (iii) certain work from home actions, including for the majority of the Company’s call center professionals. The Company considered the on-going and pervasive economic impact of the COVID-19 Pandemic in its assessment of its financial position, results of operations, cash flows, and certain accounting estimates as of and for the three and six months ended June 30, 2021. Due to the evolving and uncertain nature of the COVID-19 Pandemic, it is possible that the effects of the COVID-19 Pandemic could materially impact the Company’s estimates and condensed consolidated financial statements in future reporting periods.
Subscriber System Assets, Net	Subscriber System Assets, net and Deferred Subscriber Acquisition Costs, net The Company capitalizes certain costs including equipment, installation, and other incremental costs associated with transactions in which the Company retains ownership of the security system, as well as selling expenses that are incremental to acquiring customers. These costs are recorded in subscriber system assets, net, and deferred subscriber acquisition costs, net, in the Condensed Consolidated Balance Sheets as these assets embody a probable future economic benefit as they contribute to the generation of future monitoring and related services revenue for the Company. Upon customer termination, the Company may retrieve such assets. Subscriber system assets represent capitalized equipment and installation costs incurred in connection with transactions in which the Company retains ownership of the security system. Depreciation expense relating to subscriber system assets, which is included in depreciation and intangible asset amortization in the Condensed Consolidated Statements of Operations, was $124 million and $126 million for the three months ended June 30, 2021 and 2020, respectively, and $247 million and $259 million for the six months ended June 30, 2021 and 2020, respectively.
Financial Instruments	Fair Value of Financial InstrumentsThe Company’s financial instruments primarily consist of cash and cash equivalents, restricted cash and restricted cash equivalents, accounts receivable, retail installment contract receivables, accounts payable, debt, and derivative financial instruments. Due to their short-term and/or liquid nature, the fair values of cash, restricted cash, accounts receivable, and accounts payable approximate their respective carrying amounts
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents	Cash and Cash Equivalents and Restricted Cash and Restricted Cash Equivalents All highly liquid investments with original maturities of three months or less from the time of purchase are considered to be cash equivalents. Restricted cash and restricted cash equivalents are cash and cash equivalents that are restricted for a specific purpose and cannot be included in the general cash and cash equivalents account. Restricted cash and restricted cash equivalents are reflected in prepaid expenses and other current assets in the Condensed Consolidated Balance Sheets.
Retail Installment Contract Receivables	Retail Installment Contract Receivables, net - The fair value of the Company’s retail installment contract receivables was determined using a discounted cash flow model. The resulting fair value is classified as a Level 3 fair value measurement.
Derivative Financial Instruments	The Company's derivative financial instruments primarily consist of LIBOR-based interest rate swap contracts, which were entered into with the objective of managing exposure to variability in interest rates on the Company's debt. All interest rate swap contracts are reported in the Condensed Consolidated Balance Sheets at fair value. For interest rate swap contracts not designated as cash flow hedges, unrealized gains and losses are recognized in interest expense, net, in the Condensed Consolidated Statements of Operations. For interest rate swap contracts designated as cash flow hedges, unrealized gains and losses are recognized as a component of accumulated other comprehensive income (“AOCI”) in the Condensed Consolidated Balance Sheets and are reclassified into interest expense, net, in the same period in which the related interest on debt affects earnings. For interest rate swap contracts that have been de-designated as cash flow hedges and for which the forecasted cash flows are probable or reasonably possible of occurring, unrealized gains and losses previously recognized as a component of AOCI are reclassified into interest expense, net, in the same period in which the related interest on variable-rate debt affects earnings through the original maturity date of the related interest rate swap contracts. For interest rate swap contracts that have been de-designated as cash flow hedges and for which the forecasted cash flows are probable of not occurring, unrealized gains and losses previously recognized as a component of AOCI are immediately reclassified into interest expense, net. The cash flows associated with interest rate swap contracts that included an other-than-significant financing element at inception are reflected as cash flows from financing activities in the Condensed Consolidated Statements of Cash Flows.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements Financial Accounting Standards Board Accounting Standards Update (“ASU”) 2020-06, Debt with Conversion and Other Options and Derivatives and Hedging - Contracts in Entity’s Own Equity, provides guidance to ease the potential burden of accounting for convertible instruments, derivatives related to an entity’s own equity, and the related earnings per share considerations. The Company early adopted the guidance as of January 1, 2021. The impact from adoption was not material. ASU 2021-01, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting amends ASU 2020-04, which was disclosed in the Company’s 2020 Annual Report. ASU 2021-01 clarifies the scope and guidance of Topic 848 and allows derivatives impacted by the reference rate reform to qualify for certain optional expedients and exceptions for contract modifications and hedge accounting. The guidance is optional and is effective for a limited period of time through December 31, 2022. As of June 30, 2021, this guidance had no impact on the Condensed Consolidated Financial Statements. However, the Company will continue to evaluate this guidance.
Radio conversion costs	Radio conversion costs and radio conversion revenue are included in selling, general, and administrative expenses and monitoring and related services revenue, respectively, in the Condensed Consolidated Statements of Operations.
Segment Reporting, Policy	Segment Change Effective in the first quarter of 2021, the manner in which the Company’s Chief Executive Officer, who is the chief operating decision maker (the “CODM”), evaluates performance and makes decisions about how to allocate resources changed. Therefore, the Company now reports results in two operating and reportable segments, Consumer and Small Business (“CSB”) and Commercial, rather than a single operating and reportable segment. Where applicable, prior periods have been retrospectively adjusted to reflect the new operating and reportable segment structure. The accounting policies of the Company’s reportable segments are the same as those of the Company. The Company organizes its segments based on customer type as follows: •Consumer and Small Business (CSB) - Customers in the CSB segment are comprised of residential homeowners, small business operators, and other individual consumers. The CSB segment primarily includes (i) revenue and operating costs from the sale, installation, servicing, and monitoring of integrated security and automation systems, as well as other offerings such as mobile security and home health solutions; (ii) other operating costs associated with support functions related to these operations; and (iii) general corporate costs and other income and expense items not included in the Commercial segment. Where applicable, results for the Company’s Canadian operations prior to its sale in the fourth quarter of 2019 are included in the CSB segment based on the primary customer market served in Canada. •Commercial - Customers in the Commercial segment are comprised of larger businesses with more expansive facilities (typically larger than 10,000 square feet) and/or multi-site operations, which often require more sophisticated integrated solutions. The Commercial segment primarily includes (i) revenue and operating costs from the sale, installation, servicing, and monitoring of integrated security and automation systems, fire detection and suppression systems, and other related offerings; (ii) other operating costs associated with support functions related to these operations; and (iii) dedicated corporate and other costs. Effective in the first quarter of 2021, the manner in which the Company’s Chief Executive Officer, who is the CODM, evaluates performance and makes decisions about how to allocate resources changed. Therefore, the Company now reports results in two operating and reportable segments, CSB and Commercial, rather than a single operating and reportable segment.
Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments	Long-Term Debt Instruments - The fair value of the Company’s debt instruments was determined using broker-quoted market prices, which represent prices based on quoted prices for similar assets or liabilities as well as other observable market data. The carrying amounts of debt outstanding, if any, under the Company’s revolving credit facility and receivables facility approximate fair values as interest rates on these borrowings approximate current market rates. The resulting fair values are classified as Level 2 fair value measurements.
Derivative
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments	Derivative Financial Instruments - Derivative financial instruments are reported at fair value as either assets or liabilities in the Condensed Consolidated Balance Sheets. These fair values are primarily calculated using discounted cash flow models that utilize observable inputs, such as quoted forward interest rates, and incorporate credit risk adjustments to reflect the risk of default by the counterparty or the Company. The resulting fair values are classified as Level 2 fair value measurements.
Cash and Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments	Cash Equivalents - Included in cash and cash equivalents are investments in money market mutual funds, which totaled $41 million and $143 million as of June 30, 2021 and December 31, 2020, respectively. These investments are classified as Level 1 fair value measurements, which represent unadjusted quoted prices in active markets for identical assets or liabilities.

Basis of Presentation and Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2021

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

amortization policy for Deferred SAC and SAS [Policy Text Block]

Subscriber system assets and any related deferred subscriber acquisition costs resulting from customer acquisitions are accounted for on a pooled basis based on the month and year of acquisition. The Company depreciates and amortizes its pooled subscriber system assets and related deferred subscriber acquisition costs using an accelerated method over the estimated life of the customer relationship, which is 15 years.

Deferred Subscriber Acquisition Costs [Policy Text Block]

Deferred subscriber acquisition costs represent selling expenses (primarily commissions) that are incremental to acquiring customers. Amortization expense relating to deferred subscriber acquisition costs, which is included in selling, general, and administrative expenses in the Condensed Consolidated Statements of Operations was $30 million and $23 million for the three months ended June 30, 2021 and 2020, respectively, and $59 million and $45 million for the six months ended June 30, 2021 and 2020, respectively.

Basis of Presentation

The condensed consolidated financial statements included herein are unaudited, but in the opinion of management, such financial statements include all adjustments, consisting of normal recurring adjustments, necessary to summarize fairly the Company’s financial position, results of operations, and cash flows for the interim periods presented. The interim results reported in these condensed consolidated financial statements should not be taken as indicative of results that may be expected for future interim periods or the full year. For a more comprehensive understanding of the Company and its interim results, these condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements included in its Annual Report on Form 10-K for the year ended December 31, 2020 (the “2020 Annual Report”), which was filed with the U.S. Securities and Exchange Commission (the “SEC”) on February 25, 2021. The Company’s accounting policies used in the preparation of these condensed consolidated financial statements do not differ from those used in the annual consolidated financial statements, unless otherwise noted.

The Condensed Consolidated Balance Sheet as of December 31, 2020 included herein was derived from the audited consolidated financial statements as of that date but does not include all the footnote disclosures from the annual consolidated financial statements.

The condensed consolidated financial statements include the accounts of ADT Inc. and its wholly-owned subsidiaries and have been prepared in U.S. dollars in accordance with GAAP. All intercompany transactions have been eliminated. Certain prior period amounts have been reclassified to conform with the current period presentation.

Segment Change

Effective in the first quarter of 2021, the manner in which the Company’s Chief Executive Officer, who is the chief operating decision maker (the “CODM”), evaluates performance and makes decisions about how to allocate resources changed. Therefore, the Company now reports results in two operating and reportable segments, Consumer and Small Business (“CSB”) and Commercial, rather than a single operating and reportable segment. Where applicable, prior periods have been

retrospectively adjusted to reflect the new operating and reportable segment structure. The accounting policies of the Company’s reportable segments are the same as those of the Company.

The Company organizes its segments based on customer type as follows:

•Consumer and Small Business (CSB) - Customers in the CSB segment are comprised of residential homeowners, small business operators, and other individual consumers. The CSB segment primarily includes (i) revenue and operating costs from the sale, installation, servicing, and monitoring of integrated security and automation systems, as well as other offerings such as mobile security and home health solutions; (ii) other operating costs associated with support functions related to these operations; and (iii) general corporate costs and other income and expense items not included in the Commercial segment.

Where applicable, results for the Company’s Canadian operations prior to its sale in the fourth quarter of 2019 are included in the CSB segment based on the primary customer market served in Canada.

•Commercial - Customers in the Commercial segment are comprised of larger businesses with more expansive facilities (typically larger than 10,000 square feet) and/or multi-site operations, which often require more sophisticated integrated solutions. The Commercial segment primarily includes (i) revenue and operating costs from the sale, installation, servicing, and monitoring of integrated security and automation systems, fire detection and suppression systems, and other related offerings; (ii) other operating costs associated with support functions related to these operations; and (iii) dedicated corporate and other costs.

Refer to Note 13 “Segment Information” for additional information on the Company’s segments.

COVID-19 Pandemic

During March 2020, the World Health Organization declared the outbreak of a novel coronavirus as a pandemic (the “COVID-19 Pandemic”). While responses have varied by individuals, businesses, and state and local municipalities, the COVID-19 Pandemic has had certain notable adverse impacts on general economic conditions, including the temporary closures of many businesses, increased governmental regulations, supply chain disruptions, and changes in consumer spending due to significant unemployment and other effects attributable to the COVID-19 Pandemic. In order to continue to both protect its employees and serve its customers, the Company has adjusted and is continuously evolving certain aspects of its operations, such as (i) detailed protocols for infectious disease safety for employees, (ii) employee daily wellness checks, and (iii) certain work from home actions, including for the majority of the Company’s call center professionals.

The Company considered the on-going and pervasive economic impact of the COVID-19 Pandemic in its assessment of its financial position, results of operations, cash flows, and certain accounting estimates as of and for the three and six months ended June 30, 2021. Due to the evolving and uncertain nature of the COVID-19 Pandemic, it is possible that the effects of the COVID-19 Pandemic could materially impact the Company’s estimates and condensed consolidated financial statements in future reporting periods.

Subscriber System Assets, Net

Subscriber System Assets, net and Deferred Subscriber Acquisition Costs, net

The Company capitalizes certain costs including equipment, installation, and other incremental costs associated with transactions in which the Company retains ownership of the security system, as well as selling expenses that are incremental to acquiring customers. These costs are recorded in subscriber system assets, net, and deferred subscriber acquisition costs, net, in the Condensed Consolidated Balance Sheets as these assets embody a probable future economic benefit as they contribute to the generation of future monitoring and related services revenue for the Company. Upon customer termination, the Company may retrieve such assets.

Subscriber system assets represent capitalized equipment and installation costs incurred in connection with transactions in which the Company retains ownership of the security system. Depreciation expense relating to subscriber system assets, which is included in depreciation and intangible asset amortization in the Condensed Consolidated Statements of Operations, was $124 million and $126 million for the three months ended June 30, 2021 and 2020, respectively, and $247 million and $259 million for the six months ended June 30, 2021 and 2020, respectively.

Financial Instruments

Fair Value of Financial InstrumentsThe Company’s financial instruments primarily consist of cash and cash equivalents, restricted cash and restricted cash equivalents, accounts receivable, retail installment contract receivables, accounts payable, debt, and derivative financial instruments. Due to their short-term and/or liquid nature, the fair values of cash, restricted cash, accounts receivable, and accounts payable approximate their respective carrying amounts

Cash and Cash Equivalents, Restricted Cash and Cash Equivalents

Cash and Cash Equivalents and Restricted Cash and Restricted Cash Equivalents

All highly liquid investments with original maturities of three months or less from the time of purchase are considered to be cash equivalents. Restricted cash and restricted cash equivalents are cash and cash equivalents that are restricted for a specific purpose and cannot be included in the general cash and cash equivalents account. Restricted cash and restricted cash equivalents are reflected in prepaid expenses and other current assets in the Condensed Consolidated Balance Sheets.

Retail Installment Contract Receivables

Retail Installment Contract Receivables, net - The fair value of the Company’s retail installment contract receivables was determined using a discounted cash flow model. The resulting fair value is classified as a Level 3 fair value measurement.

Derivative Financial Instruments

The Company's derivative financial instruments primarily consist of LIBOR-based interest rate swap contracts, which were entered into with the objective of managing exposure to variability in interest rates on the Company's debt. All interest rate swap contracts are reported in the Condensed Consolidated Balance Sheets at fair value. For interest rate swap contracts not designated as cash flow hedges, unrealized gains and losses are recognized in interest expense, net, in the Condensed Consolidated Statements of Operations. For interest rate swap contracts designated as cash flow hedges, unrealized gains and losses are recognized as a component of accumulated other comprehensive income (“AOCI”) in the Condensed Consolidated Balance Sheets and are reclassified into interest expense, net, in the same period in which the related interest on debt affects earnings. For interest rate swap contracts that have been de-designated as cash flow hedges and for which the forecasted cash flows are probable or reasonably possible of occurring, unrealized gains and losses previously recognized as a component of AOCI are reclassified into interest expense, net, in the same period in which the related interest on variable-rate debt affects earnings through the original maturity date of the related interest rate swap contracts. For interest rate swap contracts that have been de-designated as cash flow hedges and for which the forecasted cash flows are probable of not occurring, unrealized gains and losses previously recognized as a component of AOCI are immediately reclassified into interest expense, net. The cash flows associated with interest rate swap contracts that included an other-than-significant financing element at inception are reflected as cash flows from financing activities in the Condensed Consolidated Statements of Cash Flows.

Recently Adopted Accounting Pronouncements

Financial Accounting Standards Board Accounting Standards Update (“ASU”) 2020-06, Debt with Conversion and Other Options and Derivatives and Hedging - Contracts in Entity’s Own Equity, provides guidance to ease the potential burden of accounting for convertible instruments, derivatives related to an entity’s own equity, and the related earnings per share considerations. The Company early adopted the guidance as of January 1, 2021. The impact from adoption was not material.

ASU 2021-01, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting amends ASU 2020-04, which was disclosed in the Company’s 2020 Annual Report. ASU 2021-01 clarifies the scope and guidance of Topic 848 and allows derivatives impacted by the reference rate reform to qualify for certain optional expedients and exceptions for contract modifications and hedge accounting. The guidance is optional and is effective for a limited period of time through December 31, 2022. As of June 30, 2021, this guidance had no impact on the Condensed Consolidated Financial Statements. However, the Company will continue to evaluate this guidance.

Radio conversion costs

Radio conversion costs and radio conversion revenue are included in selling, general, and administrative expenses and monitoring and related services revenue, respectively, in the Condensed Consolidated Statements of Operations.

Segment Reporting, Policy

Segment Change

retrospectively adjusted to reflect the new operating and reportable segment structure. The accounting policies of the Company’s reportable segments are the same as those of the Company.

The Company organizes its segments based on customer type as follows:

Effective in the first quarter of 2021, the manner in which the Company’s Chief Executive Officer, who is the CODM, evaluates performance and makes decisions about how to allocate resources changed. Therefore, the Company now reports results in two operating and reportable segments, CSB and Commercial, rather than a single operating and reportable segment.

Debt

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial Instruments

Long-Term Debt Instruments - The fair value of the Company’s debt instruments was determined using broker-quoted market prices, which represent prices based on quoted prices for similar assets or liabilities as well as other observable market data. The carrying amounts of debt outstanding, if any, under the Company’s revolving credit facility and receivables facility approximate fair values as interest rates on these borrowings approximate current market rates. The resulting fair values are classified as Level 2 fair value measurements.

Derivative

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial Instruments

Derivative Financial Instruments - Derivative financial instruments are reported at fair value as either assets or liabilities in the Condensed Consolidated Balance Sheets. These fair values are primarily calculated using discounted cash flow models that utilize observable inputs, such as quoted forward interest rates, and incorporate credit risk adjustments to reflect the risk of default by the counterparty or the Company. The resulting fair values are classified as Level 2 fair value measurements.

Cash and Cash Equivalents [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial Instruments

Cash Equivalents - Included in cash and cash equivalents are investments in money market mutual funds, which totaled $41 million and $143 million as of June 30, 2021 and December 31, 2020, respectively. These investments are classified as Level 1 fair value measurements, which represent unadjusted quoted prices in active markets for identical assets or liabilities.