XML 81 R71.htm IDEA: XBRL DOCUMENT v3.23.1

Commitments, Contingencies and Off-Balance Sheet Arrangements - Off-Balance Sheet Commitments (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2023 USD ($)
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Amount of Commitment Expiration by Period - 2023	$ 1.1
Amount of Commitment Expiration by Period - 2024	2.1
Amount of Commitment Expiration by Period - 2025	0.2
Amount of Commitment Expiration by Period - 2026	0.1
Amount of Commitment Expiration by Period - 2027	0.1
Amount of Commitment Expiration by Period - Thereafter	13.3
Total Amounts Committed	16.9
Financial Guarantees [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Amount of Commitment Expiration by Period - 2023	1.1
Amount of Commitment Expiration by Period - 2024	2.1
Amount of Commitment Expiration by Period - 2025	0.2
Amount of Commitment Expiration by Period - 2026	0.1
Amount of Commitment Expiration by Period - 2027	0.1
Total Amounts Committed	3.6
Letters of Credit [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Amount of Commitment Expiration by Period - Thereafter	13.3
Total Amounts Committed	$ 13.3

X

- Definition

Amount of Commitment Expiration Off-Balance Sheet Commitments

+ References

No definition available.

+ Details

Name:	ajg_AmountOfCommitmentExpirationOffBalanceSheetCommitments
Namespace Prefix:	ajg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Amount of Commitment Expiration Off-Balance Sheet Commitments Within Year Five

+ References

No definition available.

+ Details

Name:	ajg_AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearFive
Namespace Prefix:	ajg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Amount of Commitment Expiration Off-Balance Sheet Commitments Within Year Four

+ References

No definition available.

+ Details

Name:	ajg_AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearFour
Namespace Prefix:	ajg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Amount of Commitment Expiration Off-Balance Sheet Commitments Within Year One

+ References

No definition available.

+ Details

Name:	ajg_AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearOne
Namespace Prefix:	ajg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Amount of Commitment Expiration Off-Balance Sheet Commitments Within Year Thereafter

+ References

No definition available.

+ Details

Name:	ajg_AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearThereafter
Namespace Prefix:	ajg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Amount of Commitment Expiration Off-Balance Sheet Commitments Within Year Three

+ References

No definition available.

+ Details

Name:	ajg_AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearThree
Namespace Prefix:	ajg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Amount of Commitment Expiration Off-Balance Sheet Commitments Within Year Two

+ References

No definition available.

+ Details

Name:	ajg_AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearTwo
Namespace Prefix:	ajg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]

+ References

No definition available.

+ Details

Name:	ajg_CommitmentsContingenciesAndOffBalanceSheetArrangementsLineItems
Namespace Prefix:	ajg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_FinancialGuaranteeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis=ajg_LettersOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: