Summary of Significant Accounting Policies (Components of Fixed Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Fixed assets, gross	$ 2,402	$ 2,436
Less-accumulated depreciation and amortization	(1,531)	(1,589)
Fixed assets, net	871	847	$ 856
Furniture and equipment
Property, Plant and Equipment [Line Items]
Fixed assets, gross	772	811
Land and buildings
Property, Plant and Equipment [Line Items]
Fixed assets, gross	372	385
Leasehold and building improvements
Property, Plant and Equipment [Line Items]
Fixed assets, gross	$ 1,258	$ 1,240