Line of Business Information - Components of Other (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Segment Reporting Information [Line Items]
Repositioning charges	$ (89)
Income before income tax expense	969	$ 822
Repositioning charges	89
Compensation and employee benefits expenses	79
Occupancy costs associated with real estate footprint optimization	1
Information systems and communications
Segment Reporting Information [Line Items]
Client rescoping (expense impact)	(41)
Client rescoping (expense impact)	41
Other
Segment Reporting Information [Line Items]
Repositioning charges	(89)	0
Client rescoping (expense impact)	(41)	0
Income before income tax expense	(130)	0
Repositioning charges	89	0
Client rescoping (expense impact)	$ 41	$ 0