XML 78 R64.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Contracts with Customers - Summary of Expected Revenue Related to Performance Obligations 1 (Detail) $ in Millions | Dec. 31, 2023 USD ($)
--- | ---
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items] |
Expected revenue related to performance obligations | $ 706.2
Brokerage [Member] |
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items] |
Expected revenue related to performance obligations | 533.6
Risk Management [Member] |
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items] |
Expected revenue related to performance obligations | $ 172.6

X
- Definition Amount of transaction price allocated to performance obligation that has not been recognized as revenue. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (a) -SubTopic 10 -Topic 606 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479806/606-10-50-13 + Details
Name: | us-gaap_RevenueRemainingPerformanceObligation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=ajg_BrokerageSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=ajg_RiskManagementSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |