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Income Taxes - Operating and capital loss carryforwards available (Details) - Dec. 31, 2023 £ in Millions, $ in Millions | USD ($) | GBP (£)
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U.S. | Expiring 2024 - 2041 |  |
Operating and capital loss carryforwards [Line Items] |  |
Operating loss carryforwards | $ 10 |
United Kingdom |  |
Operating and capital loss carryforwards [Line Items] |  |
Operating loss carryforwards | $ 38 | £ 30

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- Definition Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-3 + Details
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