Goodwill and Other Intangible Assets - Schedule of Changes in the Net Carrying Amount of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Oct. 30, 2025
Goodwill [Roll Forward]
Balance at the beginning of the period	$ 15,234	$ 8,414
Goodwill related to current year acquisitions	531	7,125
Goodwill related to current year disposals	(405)	(82)
Goodwill related to prior year acquisitions	(21)
Foreign currency translation and other	458	(223)
Balance at the end of the period	15,797	15,234
Disposed of by Sale | NFP Acquisition
Goodwill [Roll Forward]
Goodwill			$ 398
Risk Capital
Goodwill [Roll Forward]
Balance at the beginning of the period	8,785	6,227
Goodwill related to current year acquisitions	478	2,768
Goodwill related to current year disposals	(7)	(50)
Goodwill related to prior year acquisitions	(11)
Foreign currency translation and other	306	(160)
Balance at the end of the period	9,551	8,785
Human Capital
Goodwill [Roll Forward]
Balance at the beginning of the period	6,449	2,187
Goodwill related to current year acquisitions	53	4,357
Goodwill related to current year disposals	(398)	(32)
Goodwill related to prior year acquisitions	(10)
Foreign currency translation and other	152	(63)
Balance at the end of the period	$ 6,246	$ 6,449