Retirement Benefits (Defined Benefit Plan Net Periodic Benefit Cost Amounts Recorded in Consolidated Statement of Income) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Defined Benefit Plan Disclosure [Line Items]
Compensation and benefits expense	$ (2,005)	$ (1,925)
Other net benefit credits	(43)	(67)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Compensation and benefits expense	6	6
Other net benefit credits	(44)	(67)
Net benefit credit	(38)	(61)
Postretirement Benefit Costs
Defined Benefit Plan Disclosure [Line Items]
Other net benefit credits	$ 1	$ 1