Leases - Components of Lease Cost (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Finance lease cost
Amortization of right-of-use assets	$ 60	$ 47	$ 120	$ 89
Interest	4	3	7	5
Operating lease cost	344	274	684	520
Variable lease cost and other, net	57	21	117	70
Total lease cost	$ 465	$ 345	$ 928	$ 684
Weighted-average remaining lease term
Operating leases	12 years 7 months 6 days	13 years 1 month 6 days	12 years 7 months 6 days	13 years 1 month 6 days
Finance leases	15 years	15 years 3 months 18 days	15 years	15 years 3 months 18 days
Weighted-average discount rate
Operating leases	3.10%	3.50%	3.10%	3.50%
Finance leases	3.10%	3.20%	3.10%	3.20%