Goodwill and Other Intangibles (Amortized Intangible Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Gross Cost	$ 4,506	$ 4,353
Accumulated Amortization	2,008	1,816
Net Carrying Amount	2,498	2,537
Client relationships
Finite-Lived Intangible Assets [Line Items]
Gross Cost	4,133	3,993
Accumulated Amortization	1,683	1,508
Net Carrying Amount	2,450	2,485
Other
Finite-Lived Intangible Assets [Line Items]
Gross Cost	373	360
Accumulated Amortization	325	308
Net Carrying Amount	$ 48	$ 52