Leases - Supplemental balance sheet information (Details) $ in Millions	Mar. 31, 2020 USD ($)
Leases [Abstract]
Operating Lease Right-of-Use Assets	$ 1,886
Current portion of operating lease liabilities	354
Long-Term Operating Lease Liabilities	1,660
Total operating lease liabilities	2,014
Property, Plant and Equipment, net	180
Current portion of long-term debt	15
Long-Term Debt	151
Total finance lease liabilities	$ 166
Weighted Average Remaining Lease Term (Years) - Operating leases	7 years 8 months 12 days
Weighted Average Remaining Lease Term (Years) - Finance leases	12 years 1 month 6 days
Weighted Average Discount Rate - Operating leases (percent)	3.03%
Weighted Average Discount Rate - Finance leases (percent)	2.86%