XML 52 R41.htm IDEA: XBRL DOCUMENT
v3.25.2

Business Combinations - Summary of Estimated Fair Values of Net Assets Acquired (Detail) $ in Millions | 3 Months Ended | 6 Months Ended | 282 Months Ended
--- | --- | --- | ---
Jun. 30, 2025 USD ($) acquisition | Jun. 30, 2024 acquisition | Jun. 30, 2025 USD ($) acquisition | Jun. 30, 2024 acquisition | Jun. 30, 2025 USD ($) company
Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items] |  |  |  |  |
Cash and cash equivalents | $ 93.5 |  | $ 93.5 |  | $ 93.5
Fiduciary assets | 593.7 |  | 593.7 |  | 593.7
Other current assets | 107.0 |  | 107.0 |  | 107.0
Fixed assets | 16.0 |  | 16.0 |  | 16.0
Noncurrent assets | 30.1 |  | 30.1 |  | 30.1
Goodwill | 1,027.7 |  | 1,027.7 |  | 1,027.7
Expiration lists | 935.7 |  | 935.7 |  | 935.7
Non-compete agreements | 21.6 |  | 21.6 |  | 21.6
Total assets acquired | 2,825.3 |  | 2,825.3 |  | 2,825.3
Fiduciary liabilities | 593.7 |  | 593.7 |  | 593.7
Current liabilities | 65.1 |  | 65.1 |  | 65.1
Noncurrent liabilities | 299.7 |  | 299.7 |  | 299.7
Total liabilities assumed | 958.5 |  | 958.5 |  | 958.5
Total net assets acquired | $ 1,866.8 |  | $ 1,866.8 |  | $ 1,866.8
Number of companies acquired | 36 | 30 | 56 | 58 | 770
W K Webster & Co Ltd February 1, 2025 (WKW) |  |  |  |  |
Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items] |  |  |  |  |
Cash and cash equivalents | $ 5.3 |  | $ 5.3 |  | $ 5.3
Fiduciary assets | 86.8 |  | 86.8 |  | 86.8
Other current assets | 16.7 |  | 16.7 |  | 16.7
Fixed assets | 1.1 |  | 1.1 |  | 1.1
Noncurrent assets | 2.2 |  | 2.2 |  | 2.2
Goodwill | 83.7 |  | 83.7 |  | 83.7
Expiration lists | 70.9 |  | 70.9 |  | 70.9
Non-compete agreements | 7.9 |  | 7.9 |  | 7.9
Total assets acquired | 274.6 |  | 274.6 |  | 274.6
Fiduciary liabilities | 86.8 |  | 86.8 |  | 86.8
Current liabilities | 11.8 |  | 11.8 |  | 11.8
Noncurrent liabilities | 21.8 |  | 21.8 |  | 21.8
Total liabilities assumed | 120.4 |  | 120.4 |  | 120.4
Total net assets acquired | 154.2 |  | 154.2 |  | 154.2
Case Group February 26, 2025 (CSG) |  |  |  |  |
Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items] |  |  |  |  |
Cash and cash equivalents | 5.6 |  | 5.6 |  | 5.6
Fiduciary assets | 0.0 |  | 0.0 |  | 0.0
Other current assets | 4.0 |  | 4.0 |  | 4.0
Fixed assets | 1.0 |  | 1.0 |  | 1.0
Noncurrent assets | 0.0 |  | 0.0 |  | 0.0
Goodwill | 49.5 |  | 49.5 |  | 49.5
Expiration lists | 36.2 |  | 36.2 |  | 36.2
Non-compete agreements | 7.3 |  | 7.3 |  | 7.3
Total assets acquired | 103.6 |  | 103.6 |  | 103.6
Fiduciary liabilities | 0.0 |  | 0.0 |  | 0.0
Current liabilities | 7.3 |  | 7.3 |  | 7.3
Noncurrent liabilities | 13.5 |  | 13.5 |  | 13.5
Total liabilities assumed | 20.8 |  | 20.8 |  | 20.8
Total net assets acquired | 82.8 |  | 82.8 |  | 82.8
Woodruff Sawyer & Co April 10, 2025 (WSC) |  |  |  |  |
Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items] |  |  |  |  |
Cash and cash equivalents | 61.9 |  | 61.9 |  | 61.9
Fiduciary assets | 465.3 |  | 465.3 |  | 465.3
Other current assets | 77.6 |  | 77.6 |  | 77.6
Fixed assets | 12.8 |  | 12.8 |  | 12.8
Noncurrent assets | 25.0 |  | 25.0 |  | 25.0
Goodwill | 658.1 |  | 658.1 |  | 658.1
Expiration lists | 673.4 |  | 673.4 |  | 673.4
Non-compete agreements | 2.4 |  | 2.4 |  | 2.4
Total assets acquired | 1,976.5 |  | 1,976.5 |  | 1,976.5
Fiduciary liabilities | 465.3 |  | 465.3 |  | 465.3
Current liabilities | 35.2 |  | 35.2 |  | 35.2
Noncurrent liabilities | 201.7 |  | 201.7 |  | 201.7
Total liabilities assumed | 702.2 |  | 702.2 |  | 702.2
Total net assets acquired | 1,274.3 |  | 1,274.3 |  | 1,274.3
Seventeen Other Acquisitions |  |  |  |  |
Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items] |  |  |  |  |
Cash and cash equivalents | 20.7 |  | 20.7 |  | 20.7
Fiduciary assets | 41.6 |  | 41.6 |  | 41.6
Other current assets | 8.7 |  | 8.7 |  | 8.7
Fixed assets | 1.1 |  | 1.1 |  | 1.1
Noncurrent assets | 2.9 |  | 2.9 |  | 2.9
Goodwill | 236.4 |  | 236.4 |  | 236.4
Expiration lists | 155.2 |  | 155.2 |  | 155.2
Non-compete agreements | 4.0 |  | 4.0 |  | 4.0
Total assets acquired | 470.6 |  | 470.6 |  | 470.6
Fiduciary liabilities | 41.6 |  | 41.6 |  | 41.6
Current liabilities | 10.8 |  | 10.8 |  | 10.8
Noncurrent liabilities | 62.7 |  | 62.7 |  | 62.7
Total liabilities assumed | 115.1 |  | 115.1 |  | 115.1
Total net assets acquired | $ 355.5 |  | $ 355.5 |  | $ 355.5
Number of companies acquired | acquisition |  |  | 17 |  |

X
- Definition Business Acquisition Actual Revenue And Pre Tax Income Loss [Line Items] + References No definition available. + Details
Name: | ajg_BusinessAcquisitionActualRevenueAndPreTaxIncomeLossLineItems
Namespace Prefix: | ajg_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Business Acquisitions Purchase Price Allocation Goodwill Amount + References No definition available. + Details
Name: | ajg_BusinessAcquisitionsPurchasePriceAllocationGoodwillAmount
Namespace Prefix: | ajg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Business combination recognized identifiable assets acquired and liabilities assumed cash and equivalents and restricted cash. + References No definition available. + Details
Name: | ajg_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalentsAndRestrictedCash
Namespace Prefix: | ajg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Business combination recognized identifiable assets acquired and liabilities assumed fiduciary assets current. + References No definition available. + Details
Name: | ajg_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFiduciaryAssetsCurrent
Namespace Prefix: | ajg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Business combination recognized identifiable assets acquired and liabilities assumed fiduciary liabilities current. + References No definition available. + Details
Name: | ajg_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFiduciaryLiabilitiesCurrent
Namespace Prefix: | ajg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Business combination, recognized identifiable assets acquired and liabilities assumed, intangible assets, expiration lists. + References No definition available. + Details
Name: | ajg_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsExpirationLists
Namespace Prefix: | ajg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Business combination, recognized identifiable assets acquired and liabilities assumed, intangible assets, non-compete agreements. + References No definition available. + Details
Name: | ajg_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsNonCompeteAgreements
Namespace Prefix: | ajg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of assets acquired at the acquisition date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479907/805-20-50-1 + Details
Name: | us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of other assets expected to be realized or consumed before one year or the normal operating cycle, if longer, acquired at the acquisition date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479907/805-20-50-1 + Details
Name: | us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of liabilities due within one year or within the normal operating cycle, if longer, assumed at the acquisition date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479907/805-20-50-1 + Details
Name: | us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of liabilities assumed at the acquisition date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479907/805-20-50-1 + Details
Name: | us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount recognized as of the acquisition date for the identifiable assets acquired in excess of (less than) the aggregate liabilities assumed. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 55 -Paragraph 37 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479303/805-10-55-37 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479907/805-20-50-1 + Details
Name: | us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of assets expected to be realized or consumed after one year or the normal operating cycle, if longer, acquired at the acquisition date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479907/805-20-50-1 + Details
Name: | us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of liabilities due after one year or the normal operating cycle, if longer, assumed at the acquisition date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479907/805-20-50-1 + Details
Name: | us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The amount of property, plant, and equipment recognized as of the acquisition date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 55 -Paragraph 37 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479303/805-10-55-37 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479907/805-20-50-1 + Details
Name: | us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The number of businesses acquired by the entity during the period. + References No definition available. + Details
Name: | us-gaap_NumberOfBusinessesAcquired
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=ajg_WKWebsterAndCoLtdMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=ajg_CaseGroupMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=ajg_WoodruffSawyerCoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=ajg_SeventeenOtherAcquisitionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |