XML 104 R94.htm IDEA: XBRL DOCUMENT
v3.25.3

DISCONTINUED OPERATIONS - Components of Loss From Discontinued Operations (Details) - USD ($) $ in Millions |  | 3 Months Ended | 9 Months Ended
--- | --- | --- | ---
Sep. 12, 2024 | Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |
Loss on sale of ATC TIPL |  |  |  | $ 0.0 | $ (1,245.5)
Loss from discontinued operations, net of taxes |  | $ 0.0 | $ (1,208.5) | 0.0 | (978.3)
Discontinued Operations, Disposed of by Sale | ATC TIPL |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |
Revenue |  | 0.0 | 234.1 | 0.0 | 911.2
Cost of operations |  | 0.0 | (131.8) | 0.0 | (473.8)
Depreciation, amortization and accretion |  | 0.0 | (14.3) | 0.0 | (96.0)
Selling, general, administrative and development expense |  | 0.0 | (30.0) | 0.0 | (58.7)
Other operating expense |  | 0.0 | (5.7) | 0.0 | (6.7)
Loss on sale of ATC TIPL |  | 0.0 | (1,245.5) | 0.0 | (1,245.5)
Operating loss |  | 0.0 | (1,193.2) | 0.0 | (969.5)
Interest income |  | 0.0 | 4.4 | 0.0 | 30.7
Interest expense |  | 0.0 | (2.0) | 0.0 | (7.6)
Other income, net |  | 0.0 | 0.2 | 0.0 | 46.5
Loss from discontinued operations before taxes |  | 0.0 | (1,190.6) | 0.0 | (899.9)
Income tax provision |  | 0.0 | (17.9) | 0.0 | (78.4)
Loss from discontinued operations, net of taxes |  | $ 0.0 | (1,208.5) | $ 0.0 | (978.3)
Reclassification of cumulative translation adjustment | $ 1,100.0 |  | $ 1,100.0 |  | $ 1,072.3

X
- Definition Discontinued Operation, Cumulative Foreign Currency Translation Gains (Losses), Net Of Tax + References No definition available. + Details
Name: | amt_DiscontinuedOperationCumulativeForeignCurrencyTranslationGainsLossesNetOfTax
Namespace Prefix: | amt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Disposal Group, Including Discontinued Operation, Other Income (Expense), Net + References No definition available. + Details
Name: | amt_DisposalGroupIncludingDiscontinuedOperationOtherIncomeExpenseNet
Namespace Prefix: | amt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Disposal Group, Including Discontinued Operation, Other Operating Expense + References No definition available. + Details
Name: | amt_DisposalGroupIncludingDiscontinuedOperationOtherOperatingExpense
Namespace Prefix: | amt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Disposal Group, Including Discontinued Operation, Selling, General, Administrative And Development Expense + References No definition available. + Details
Name: | amt_DisposalGroupIncludingDiscontinuedOperationSellingGeneralAdministrativeAndDevelopmentExpense
Namespace Prefix: | amt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount after tax of gain (loss) not previously recognized resulting from the disposal of a discontinued operation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5C -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5C Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3B Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-1 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3 + Details
Name: | us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount before tax of income (loss) from a discontinued operation. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 220 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(12)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477250/944-220-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3A -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3A Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3B Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-4 Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-1 Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3 Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(14)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2 + Details
Name: | us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of tax expense (benefit) related to a discontinued operation. Includes, but is not limited to, tax expense (benefit) related to income (loss) from operations during the phase-out period, tax expense (benefit) related to gain (loss) on disposal, tax expense (benefit) related to gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and tax expense (benefit) related to adjustments of a prior period gain (loss) on disposal. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 6.I.7) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479360/740-10-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-10 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482659/740-20-45-2 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3A -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3A Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5C -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5C Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3B Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-4 Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-1 + Details
Name: | us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of costs of goods sold attributable to disposal group, including, but not limited to, discontinued operation. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-7 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSold
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of depreciation and amortization expense attributable to disposal group, including, but not limited to, discontinued operation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortization
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of interest expense attributable to disposal group, including, but not limited to, discontinued operation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section S99 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480781/205-20-S99-3 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-6 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-7 + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of interest income attributable to disposal group, including, but not limited to, discontinued operation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of operating income (loss) attributable to disposal group, including, but not limited to, discontinued operation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of revenue attributable to disposal group, including, but not limited to, discontinued operation. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-7 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount after tax of income (loss) from a discontinued operation including the portion attributable to the noncontrolling interest. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 220 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(12)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477250/944-220-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 270 -Name Accounting Standards Codification -Section 45 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477349/740-270-45-3 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-7 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3A -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3A Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5C -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5C Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3B Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-4 Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-1 Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3 + Details
Name: | us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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 Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 360 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3A -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482099/360-10-50-3A Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 360 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3A -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482099/360-10-50-3A + Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_DisposalGroupClassificationAxis=us-gaap_DiscontinuedOperationsDisposedOfBySaleMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=amt_ATCTIPLMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |