Retirement Benefits (Amounts Recorded in the Consolidated Statements of Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Compensation and benefits expense	$ (5,282)	$ (4,280)	$ (4,312)
Other net benefit (credit) cost	(239)	(235)	(277)
Pension  Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Compensation and benefits expense	23	28	38
Other net benefit (credit) cost	(237)	(237)	(278)
Net benefit (credit) cost	(214)	(209)	(240)
Post-retirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Compensation and benefits expense	0	0	1
Other net benefit (credit) cost	(2)	2	1
Net benefit (credit) cost	$ (2)	$ 2	$ 2