XML 83 R59.htm IDEA: XBRL DOCUMENT v3.20.1

Segment Reporting - Summary of the Schedule of the Company's gross written premiums based on the location of the insured risk (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Gross written premiums	$ 3,442.4	$ 3,446.9	$ 3,360.9
Australia/Asia
Segment Reporting Information [Line Items]
Gross written premiums	215.9	175.9	167.3
Caribbean
Segment Reporting Information [Line Items]
Gross written premiums	9.3	7.7	17.6
Europe
Segment Reporting Information [Line Items]
Gross written premiums	82.8	92.6	94.5
United Kingdom
Segment Reporting Information [Line Items]
Gross written premiums	295.7	290.1	258.3
United States & Canada
Segment Reporting Information [Line Items]
Gross written premiums	2,003.9	1,875.9	1,729.3
Worldwide excluding United States
Segment Reporting Information [Line Items]
Gross written premiums	63.0	70.1	88.1
Worldwide including United States
Segment Reporting Information [Line Items]
Gross written premiums	614.9	775.8	868.6
Others
Segment Reporting Information [Line Items]
Gross written premiums	$ 156.9	$ 158.8	$ 137.2

X

- Definition

Amount of direct and assumed premiums written.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 605
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547

+ Details

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

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

X

- Details

Name:	srt_StatementGeographicalAxis=srt_AsiaPacificMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_StatementGeographicalAxis=ahl_CaribbeanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_StatementGeographicalAxis=srt_EuropeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_StatementGeographicalAxis=country_GB
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_StatementGeographicalAxis=ahl_UnitedStatesAndCanadaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_StatementGeographicalAxis=us-gaap_NonUsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_StatementGeographicalAxis=ahl_WorldwideIncludingUnitedStatesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_StatementGeographicalAxis=ahl_OtherCountriesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: