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Income Taxes - Operating and capital loss carryforwards available (Details) - Dec. 31, 2021 £ in Millions, $ in Millions | USD ($) | GBP (£)
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U.S. | Expiring 2022 - 2041 |  |
Operating and capital loss carryforwards [Line Items] |  |
Operating loss carryforwards | $ 56 |
United Kingdom |  |
Operating and capital loss carryforwards [Line Items] |  |
Operating loss carryforwards | $ 37 | £ 28

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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 -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32559-109319 + Details
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