Leases (Lease Cost and Additional Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 374	$ 396
Short-term lease cost	4	3
Variable lease cost	144	138
Sublease income	(20)	(19)
Net lease cost	502	518
Operating cash outflows from operating leases	412	420
Right of use assets obtained in exchange for new operating lease liabilities	$ 348	$ 261
Real Estate Lease
Lessee, Lease, Description [Line Items]
Weighted-average remaining lease term – real estate	8 years 10 months 13 days	8 years 5 months 1 day
Weighted-average discount rate – real estate leases	2.72%	2.94%