Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ 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 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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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

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregate amount of interest paid or due on all long-term debt.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.8)
-URI http://asc.fasb.org/extlink&oid=114873765&loc=SL114874048-224260

+ Details

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

- Details

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- Details

Name:	ahl_DebtCovenantTermsAxis=ahl_CallableNotesOption1Member
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- Details

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Data Type:	na
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- Details

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- Details

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- Details

Name:	srt_FederalHomeLoanBankAdvancesBranchOfFHLBBankAxis=srt_FederalHomeLoanBankOfDesMoinesMember
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Debt (Details) - USD ($)	3 Months Ended	9 Months Ended
Debt (Details) - USD ($)	Sep. 30, 2018	Sep. 30, 2018	Apr. 25, 2018	Jan. 09, 2018
Debt Instrument [Line Items]
Interest Expense, Long-term Debt	$ 10,000,000	$ 30,000,000
Senior notes
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 1,000,000,000
Debt Instrument, Interest Rate, Stated Percentage				4.125%
Senior notes \| Senior notes, price option 1 \| Treasury Rate
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		25.00%
Short-term debt \| Federal Home Loan Bank Advances
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			2.16%
Short-term debt \| Federal Home Loan Bank Advances \| Federal Home Loan Bank of Des Moines
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 183,000,000