XML 85 R69.htm IDEA: XBRL DOCUMENT v3.23.1

Investments - Aggregate Fair Value and Gross Unrealized Loss by Type of Security (Details) $ in Millions	Dec. 31, 2022 USD ($) security Security	Dec. 31, 2021 USD ($) security Security
Debt Securities, Available-for-sale [Line Items]
0-12 months, Fair Market Value	$ 2,321.4	$ 2,014.6
Gross unrealized losses, less than twelve months	(145.4)	(30.9)
Over 12 months, Fair Market Value	1,323.7	72.0
Over 12 months, Gross Unrealized Losses	(193.6)	(3.6)
Total, Fair Market Value	3,645.1	2,086.6
Total, Gross Unrealized Losses	$ (339.0)	$ (34.5)
Number of Securities | security	1,166	644
Fixed income securities — Available for sale
Debt Securities, Available-for-sale [Line Items]
0-12 months, Fair Market Value	$ 2,269.5	$ 2,010.2
Gross unrealized losses, less than twelve months	(145.0)	(30.9)
Over 12 months, Fair Market Value	1,323.7	72.0
Over 12 months, Gross Unrealized Losses	(193.6)	(3.6)
Total, Fair Market Value	3,593.2	2,082.2
Total, Gross Unrealized Losses	$ (338.6)	$ (34.5)
Number of Securities | Security	1,165	637
Short-term investments
Debt Securities, Available-for-sale [Line Items]
0-12 months, Fair Market Value	$ 51.9	$ 4.4
Gross unrealized losses, less than twelve months	(0.4)	0.0
Over 12 months, Fair Market Value	0.0	0.0
Over 12 months, Gross Unrealized Losses	0.0	0.0
Total, Fair Market Value	51.9	4.4
Total, Gross Unrealized Losses	$ (0.4)	$ 0.0
Number of Securities	1	7
U.S. government
Debt Securities, Available-for-sale [Line Items]
0-12 months, Fair Market Value	$ 741.1	$ 309.1
Gross unrealized losses, less than twelve months	(30.6)	(4.0)
Over 12 months, Fair Market Value	203.4	29.3
Over 12 months, Gross Unrealized Losses	(20.1)	(1.9)
Total, Fair Market Value	944.5	338.4
Total, Gross Unrealized Losses	$ (50.7)	$ (5.9)
Number of Securities | security	118	51
U.S. agency
Debt Securities, Available-for-sale [Line Items]
0-12 months, Fair Market Value	$ 7.1	$ 6.1
Gross unrealized losses, less than twelve months	(0.4)	0.0
Over 12 months, Fair Market Value	1.7	0.0
Over 12 months, Gross Unrealized Losses	0.0	0.0
Total, Fair Market Value	8.8	6.1
Total, Gross Unrealized Losses	$ (0.4)	$ 0.0
Number of Securities | security	5	5
Municipal
Debt Securities, Available-for-sale [Line Items]
0-12 months, Fair Market Value	$ 133.1	$ 29.7
Gross unrealized losses, less than twelve months	(7.1)	(0.5)
Over 12 months, Fair Market Value	16.4	0.0
Over 12 months, Gross Unrealized Losses	(2.3)	0.0
Total, Fair Market Value	149.5	29.7
Total, Gross Unrealized Losses	$ (9.4)	$ (0.5)
Number of Securities | security	59	20
Corporate
Debt Securities, Available-for-sale [Line Items]
0-12 months, Fair Market Value	$ 1,104.7	$ 804.6
Gross unrealized losses, less than twelve months	(77.6)	(11.7)
Over 12 months, Fair Market Value	568.2	23.6
Over 12 months, Gross Unrealized Losses	(91.5)	(1.3)
Total, Fair Market Value	1,672.9	828.2
Total, Gross Unrealized Losses	$ (169.1)	$ (13.0)
Number of Securities | security	701	400
Non-U.S. government-backed corporate
Debt Securities, Available-for-sale [Line Items]
0-12 months, Fair Market Value	$ 11.3	$ 114.4
Gross unrealized losses, less than twelve months	(0.5)	(1.9)
Over 12 months, Fair Market Value	99.0	0.0
Over 12 months, Gross Unrealized Losses	(8.3)	0.0
Total, Fair Market Value	110.3	114.4
Total, Gross Unrealized Losses	$ (8.8)	$ (1.9)
Number of Securities | security	16	10
Non-U.S government
Debt Securities, Available-for-sale [Line Items]
0-12 months, Fair Market Value	$ 63.8	$ 181.8
Gross unrealized losses, less than twelve months	(2.9)	(1.2)
Over 12 months, Fair Market Value	135.9	3.1
Over 12 months, Gross Unrealized Losses	(8.6)	0.0
Total, Fair Market Value	199.7	184.9
Total, Gross Unrealized Losses	$ (11.5)	$ (1.2)
Number of Securities | security	45	35
Agency mortgage-backed
Debt Securities, Available-for-sale [Line Items]
0-12 months, Fair Market Value	$ 202.8	$ 564.5
Gross unrealized losses, less than twelve months	(24.9)	(11.6)
Over 12 months, Fair Market Value	299.1	16.0
Over 12 months, Gross Unrealized Losses	(62.8)	(0.4)
Total, Fair Market Value	501.9	580.5
Total, Gross Unrealized Losses	$ (87.7)	$ (12.0)
Number of Securities | security	220	116

X

- Definition

Debt Securities, Available for Sale, Continuous Loss Position, Fair Market Value

+ References

No definition available.

+ Details

Name:	ahl_DebtSecuritiesAvailableForSaleContinuousLossPositionFairMarketValue
Namespace Prefix:	ahl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Debt Securities, Available for Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Market Value

+ References

No definition available.

+ Details

Name:	ahl_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerFairMarketValue
Namespace Prefix:	ahl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Debt Securities, Available for Sale Continuous Unrealized Loss Position Less Than Twelve Months Fair Market Value

+ References

No definition available.

+ Details

Name:	ahl_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsFairMarketValue
Namespace Prefix:	ahl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27337-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 5
-URI https://asc.fasb.org/extlink&oid=124269663&loc=SL82922890-210455

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27337-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 5
-URI https://asc.fasb.org/extlink&oid=124269663&loc=SL82922890-210455

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 55
-Paragraph 8
-URI https://asc.fasb.org/extlink&oid=121590138&loc=SL82922954-210456

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (a)(2)
-URI https://asc.fasb.org/extlink&oid=124269663&loc=SL82922888-210455

+ Details

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

X

- Definition

Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (b)(3)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI https://asc.fasb.org/extlink&oid=124269663&loc=SL82922888-210455

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
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_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

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

X

- Details

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

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_MunicipalBondsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ForeignCorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ForeignGovernmentDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: