Taxation (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Examination [Line Items]
Valuation allowance	$ 916	$ 92
Unrecognized Tax Benefits	67	64	$ 76
Income Tax Credits and Adjustments	21	26
Unrecognized tax benefits that would affect the effective tax rate	46	38
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	4	1	$ 8
Liabilities recorded for tax-related interest and penalties	18	$ 14
Investments
Income Tax Examination [Line Items]
Valuation allowance	815
Domestic Tax Authority [Member]
Income Tax Examination [Line Items]
Net operating loss carry-forwards	$ 346
Switzerland
Income Tax Examination [Line Items]
Applicable income tax rates	19.70%	19.70%	21.20%	7.83%
Foreign Tax Authority [Member]
Income Tax Examination [Line Items]
Foreign tax credit carry-forward	$ 76
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	19.00%