Supplemental Disclosures to the Consolidated Statements of Cash Flows (Narrative) (Details) - Risk and Insurance Services - Guy Carpenter Reinsurance Group - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Oct. 31, 2023	Dec. 31, 2023
Loss Contingencies [Line Items]
Gain from the settlement	$ 58	$ 58
Litigation settlement, expense	$ 10