Taxation (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Examination [Line Items]
Valuation allowance	$ 716	$ 916
Unrecognized Tax Benefits	73	67	$ 64
Income Tax Credits and Adjustments	19	21
Unrecognized tax benefits that would affect the effective tax rate	54	46
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	7	4	$ 1
Liabilities recorded for tax-related interest and penalties	25	18
Loss carry-forwards	149	104
Loss carry-forwards	149	$ 104
Investments
Income Tax Examination [Line Items]
Valuation allowance	441
Domestic Tax Authority [Member]
Income Tax Examination [Line Items]
Net operating loss carry-forwards	497
Loss carry-forwards	25
Loss carry-forwards	$ 25
Switzerland
Income Tax Examination [Line Items]
Applicable income tax rates	19.70%
Bermuda
Income Tax Examination [Line Items]
Applicable income tax rates	0.00%
UNITED STATES
Income Tax Examination [Line Items]
Applicable income tax rates	21.00%
UNITED KINGDOM
Income Tax Examination [Line Items]
Applicable income tax rates	23.50%