Leases - Other Lease Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Cash paid for amounts included in the measurement of lease liabilities in operating cash flow	$ 259	$ 238	$ 240
Cash paid for amounts included in the measurement of lease liabilities in financing cash flows	26	19	15
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	89	32	38
Leased assets obtained in exchange for new lease liabilities	$ 64	$ 149	$ 221
Weighted-average remaining lease term (years)	8 years 3 months 18 days	10 years 1 month 6 days	9 years 7 months 6 days
Weighted-average remaining lease term (years)	1 year 8 months 12 days	1 year 7 months 6 days	2 years 4 months 24 days
Weighted-average discount rate (as a percent)	3.60%	4.30%	4.40%
Weighted-average discount rate (as a percent)	5.30%	6.70%	7.10%