Taxation (Reconciliation Of The Difference Between The Provision for Income Taxes and the Expected Tax Provision at Swiss Statutory Income Tax Rate) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Expected tax provision at Swiss statutory tax rate	$ 1,872	$ 1,274	$ 1,929
Taxes on earnings subject to rate other than Swiss statutory rate	(389)	(243)	(743)
Bermuda tax law enactment	(1,135)	0	0
Net withholding taxes	15	75	78
Other	148	133	5
Provision for income taxes	$ 511	$ 1,239	$ 1,269