XML 49 R42.htm IDEA: XBRL DOCUMENT
v3.24.2

Business Combinations - Summary of Unaudited Pro Forma Historical Results (Detail) - USD ($) $ / shares in Units, $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2024 | Jun. 30, 2023
Business Combinations [Abstract] |  |  |  |
Total revenues | $ 2,785.4 | $ 2,478.5 | $ 6,061.9 | $ 5,223.0
Net earnings attributable to controlling interests | $ 283.9 | $ 235.8 | $ 893.7 | $ 724.9
Basic net earnings per share | $ 1.3 | $ 1.1 | $ 4.1 | $ 3.38
Diluted net earnings per share | $ 1.27 | $ 1.07 | $ 4.02 | $ 3.32

X
- Definition Business acquisitions pro forma net income loss to controlling interest. + References No definition available. + Details
Name: | ajg_BusinessAcquisitionsProFormaNetIncomeLossToControllingInterest
Namespace Prefix: | ajg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (h)(2) -SubTopic 10 -Topic 805 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479328/805-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (h)(3) -SubTopic 10 -Topic 805 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479328/805-10-50-2 + Details
Name: | us-gaap_BusinessAcquisitionProFormaEarningsPerShareBasic
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (h)(2) -SubTopic 10 -Topic 805 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479328/805-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (h)(3) -SubTopic 10 -Topic 805 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479328/805-10-50-2 + Details
Name: | us-gaap_BusinessAcquisitionProFormaEarningsPerShareDiluted
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 805 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (h)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479328/805-10-50-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 805 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (h)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479328/805-10-50-2 + Details
Name: | us-gaap_BusinessAcquisitionsProFormaRevenue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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