Restructuring Costs (Restructuring Activities) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Restructuring Reserve [Roll Forward]
Restructuring charges	$ 52	$ 38	$ 170	$ 96
Jardine Lloyd Thompson Group plc
Restructuring Reserve [Roll Forward]
Liability at beginning of period			146	69	$ 69
Restructuring charges			170		427
Cash payments			(215)		(193)
Non-cash charges			(28)		(157)
Liability at end of period	73		73		146
Jardine Lloyd Thompson Group plc | Severance
Restructuring Reserve [Roll Forward]
Liability at beginning of period			88	35	35
Restructuring charges			62		111
Cash payments			(111)		(58)
Non-cash charges			0		0
Liability at end of period	39		39		88
Jardine Lloyd Thompson Group plc | Real Estate Related Costs
Restructuring Reserve [Roll Forward]
Liability at beginning of period			56	34	34
Restructuring charges			63		195
Cash payments			(59)		(25)
Non-cash charges			(27)		(148)
Liability at end of period	33		33		56
Jardine Lloyd Thompson Group plc | Information Technology
Restructuring Reserve [Roll Forward]
Liability at beginning of period			0	0	0
Restructuring charges			7		15
Cash payments			(6)		(6)
Non-cash charges			(1)		(9)
Liability at end of period	0		0		0
Jardine Lloyd Thompson Group plc | Consulting and Other Outside Services
Restructuring Reserve [Roll Forward]
Liability at beginning of period			2	$ 0	0
Restructuring charges			38		106
Cash payments			(39)		(104)
Non-cash charges			0		0
Liability at end of period	$ 1		$ 1		$ 2