Income Taxes - Narrative (Details) £ in Millions, $ in Millions	12 Months Ended
Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2023 GBP (£)
Income Tax Reconciliation [Line Items]
Statutory rate of income taxes	21.00%	21.00%	21.00%
Income (losses) subject to tax in foreign jurisdictions	$ 32	$ 64	$ 33
Amount of expense for penalties related to a tax position	0	0	0
Cash payments for income taxes	201	242	212
AFG
Income Tax Reconciliation [Line Items]
Income tax penalties accrued	0	0
Maximum \| AFG
Income Tax Reconciliation [Line Items]
Unrecognized tax benefits that would impact the effective tax rate	1	1
Interest included in tax provision	1	1	$ 1
Interest on income taxes accrued	1	$ 1
United Kingdom
Income Tax Reconciliation [Line Items]
Operating loss carryforwards	$ 38			£ 30

Income Tax Reconciliation.

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- Definition

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
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- Definition

The portion of earnings or loss from continuing operations before income taxes that is attributable to foreign operations, which is defined as Income or Loss generated from operations located outside the entity's country of domicile.

+ References

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The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.

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Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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- Definition

Amount of statutory penalties accrued for a tax position claimed or expected to be claimed by the entity, in its tax return.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Amount of expense for penalties related to a tax position claimed or expected to be claimed in the tax return.

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Amount of interest expense accrued for an underpayment of income taxes.

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Amount of interest expense for an underpayment of income taxes.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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