Investments - Other Investments (Details) - USD ($) $ in Millions	1 Months Ended	6 Months Ended	12 Months Ended
Mar. 31, 2021	Jun. 30, 2023	Dec. 31, 2022	Dec. 31, 2021
Equity Method Investment, Aggregate Cost [Roll Forward]
Opening undistributed value of investment, beginning balance		$ 6.2	$ 3.9	$ 0.9
Investment in the period		0.4	2.0	3.2
Proceeds from Sale of Equity Method Investments			0.0	(0.5)
Closing value of investment, ending balance		7.0	6.2	3.9
Fair Value, Recurring [Member] \| Real estate fund (Dec 2017)
Equity Method Investment, Aggregate Cost [Roll Forward]
Investments, fair value		125.2	134.6	129.9
Equity Method Investment, Nonconsolidated Investee, Other
Equity Method Investment, Aggregate Cost [Roll Forward]
Unrealized Gain (Loss) on Investments		0.4	0.3	0.3
MVI
Equity Method Investment, Aggregate Cost [Roll Forward]
Opening undistributed value of investment, beginning balance		0.8	0.5	0.0
Investment in the period	$ 0.8	0.0	0.4	0.4
Proceeds from Sale of Equity Method Investments			0.0	0.0
Closing value of investment, ending balance		0.8	0.8	0.5
MVI \| Equity Method Investment, Nonconsolidated Investee, Other
Equity Method Investment, Aggregate Cost [Roll Forward]
Unrealized Gain (Loss) on Investments		0.0	(0.1)	0.1
Digital Re
Equity Method Investment, Aggregate Cost [Roll Forward]
Opening undistributed value of investment, beginning balance		0.2	0.2	0.4
Investment in the period		0.0	0.0	0.3
Proceeds from Sale of Equity Method Investments			0.0	(0.5)
Closing value of investment, ending balance		0.2	0.2	0.2
Digital Re \| Equity Method Investment, Nonconsolidated Investee, Other
Equity Method Investment, Aggregate Cost [Roll Forward]
Unrealized Gain (Loss) on Investments		0.0	0.0	0.0
Multi-Line Insurer
Equity Method Investment, Aggregate Cost [Roll Forward]
Opening undistributed value of investment, beginning balance		5.2	3.2	0.5
Investment in the period		0.4	1.6	2.5
Proceeds from Sale of Equity Method Investments			0.0	0.0
Closing value of investment, ending balance		6.0	5.2	3.2
Multi-Line Insurer \| Equity Method Investment, Nonconsolidated Investee, Other
Equity Method Investment, Aggregate Cost [Roll Forward]
Unrealized Gain (Loss) on Investments		$ 0.4	$ 0.4	$ 0.2

Equity Method Investment, Aggregate Cost [Roll Forward]

No definition available.

Name:	ahl_EquityMethodInvestmentAggregateCostRollForward
Namespace Prefix:	ahl_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the aggregate cost of investments accounted for under the equity method of accounting.

+ 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 210.5-02.12)
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_EquityMethodInvestmentAggregateCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258

+ Details

Name:	us-gaap_InvestmentsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The net cash outflow or inflow associated with the acquisition or sale of a business segment during the period.

+ References

No definition available.

+ Details

Name:	us-gaap_PaymentsForProceedsFromBusinessesAndInterestInAffiliates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow associated with the sale of equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3179-108585

+ Details

Name:	us-gaap_ProceedsFromSaleOfEquityMethodInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of unrealized gain (loss) on investment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

+ Details

Name:	us-gaap_UnrealizedGainLossOnInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=ahl_RealEstateFundDec2017Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis=us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ahl_MVIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ahl_DigitalRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ahl_MultiLineReinsurerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: