Taxation (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Examination [Line Items]
Valuation allowance	$ 92	$ 83
Unrecognized Tax Benefits	64	76	$ 47
Income Tax Credits and Adjustments	26	31
Unrecognized tax benefits that would affect the effective tax rate	38	45
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	1	8	$ 5
Liabilities recorded for tax-related interest and penalties	14	$ 16
Domestic Tax Authority [Member]
Income Tax Examination [Line Items]
Net operating loss carry-forwards	$ 461
Switzerland
Income Tax Examination [Line Items]
Applicable income tax rates	19.70%	21.20%	7.83%
Foreign Tax Authority [Member]
Income Tax Examination [Line Items]
Foreign tax credit carry-forward	$ 156
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%