Number Of Credit Facilities

No definition available.

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Namespace Prefix:	aon_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
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-Publisher FASB
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+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- 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_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Debt - Narrative (Details)	Dec. 31, 2022 EUR (€) credit_facility	Dec. 31, 2022 USD ($) credit_facility	Sep. 12, 2022 USD ($)	Feb. 28, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 02, 2021 USD ($)	Nov. 30, 2021 USD ($)	Aug. 23, 2021 USD ($)	Jan. 13, 2021 USD ($)
Debt Instrument [Line Items]
Number of credit facilities \| credit_facility	2	2
4.00% Senior Notes due November 2023 \| Senior Notes
Debt Instrument [Line Items]
Debt face value		$ 350,000,000
Debt interest rate percentage (as a percent)	4.00%	4.00%
2.20% Senior Notes due November 2022 \| Senior Notes
Debt Instrument [Line Items]
Debt face value					$ 500,000,000		$ 500,000,000
Debt interest rate percentage (as a percent)					2.20%
U. S. Program \| Commercial paper
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 1,000,000,000
European Program \| Commercial paper
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	€ 625,000,000	$ 665,000,000
Senior Notes \| 4.00% Senior Notes due November 2023
Debt Instrument [Line Items]
Debt interest rate percentage (as a percent)	4.00%	4.00%
Senior Notes \| 2.20% Senior Notes due November 2022
Debt Instrument [Line Items]
Debt interest rate percentage (as a percent)					2.20%
Senior Notes \| 5.00% Senior Notes due September 2032
Debt Instrument [Line Items]
Debt face value			$ 500,000,000
Debt interest rate percentage (as a percent)	5.00%	5.00%	5.00%
Senior Notes \| 2.85% Senior Notes due May 2027
Debt Instrument [Line Items]
Debt face value				$ 600,000,000
Debt interest rate percentage (as a percent)	2.85%	2.85%		2.85%
Senior Notes \| 3.90% Senior Notes due February 2052
Debt Instrument [Line Items]
Debt face value				$ 900,000,000
Debt interest rate percentage (as a percent)	3.90%	3.90%		3.90%
Senior Notes \| 2.60% Senior Notes due December 2031
Debt Instrument [Line Items]
Debt face value						$ 500,000,000
Debt interest rate percentage (as a percent)	2.60%	2.60%				2.60%
Senior Notes \| 2.05% Senior Notes due August 2031
Debt Instrument [Line Items]
Debt face value								$ 400,000,000
Debt interest rate percentage (as a percent)	2.05%	2.05%						2.05%
Senior Notes \| 2.90% Senior Notes due August 2051
Debt Instrument [Line Items]
Debt face value								$ 600,000,000
Debt interest rate percentage (as a percent)	2.90%	2.90%						2.90%
Senior Notes \| 2.80% Senior Notes due March 2021
Debt Instrument [Line Items]
Debt face value									$ 400,000,000
Debt interest rate percentage (as a percent)									2.80%
Line of Credit
Debt Instrument [Line Items]
Line of credit facility, available credit		$ 1,800,000,000
Line of Credit \| Credit Facility Expiring September 2026
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		1,000,000,000
Line of Credit \| Credit Facility Expiring October 2023
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 750,000,000