Leases (Lease Cost and Additional Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 324	$ 343
Short-term lease cost	5	4
Variable lease cost	122	133
Sublease income	(11)	(17)
Net lease cost	440	463
Operating cash outflows from operating leases	379	380
Right of use assets obtained in exchange for new operating lease liabilities	$ 224	$ 196
Real Estate Lease
Lessee, Lease, Description [Line Items]
Weighted average remaining lease term – real estate	7 years 11 months 23 days	8 years 4 months 13 days
Weighted average discount rate – real estate leases	3.35%	2.90%