Goodwill and Other Intangibles (Amortized Intangible Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Gross Cost	$ 5,000	$ 4,728
Accumulated Amortization	2,280	2,098
Net Carrying Amount	2,720	2,630
Client relationships
Finite-Lived Intangible Assets [Line Items]
Gross Cost	4,614	4,337
Accumulated Amortization	1,937	1,761
Net Carrying Amount	2,677	2,576
Other
Finite-Lived Intangible Assets [Line Items]
Gross Cost	386	391
Accumulated Amortization	343	337
Net Carrying Amount	$ 43	$ 54