Leases - Supplemental Balance Sheet Information (Details) $ in Millions	Jun. 30, 2019 USD ($)
Leases [Abstract]
Operating Lease Right-of-Use Assets	$ 2,031
Current portion of operating lease liabilities	373
Long-Term Operating Lease Liabilities	1,805
Total operating lease liabilities	2,178
Property, Plant and Equipment, net	67
Current portion of long-term debt	7
Long-Term Debt	86
Total finance lease liabilities	$ 93
Weighted Average Remaining Lease Term - Operating leases	8 years 6 months 21 days
Weighted Average Remaining Lease Term - Finance leases	11 years 9 months 3 days
Weighted Average Discount Rate - Operating leases (percent)	3.61%
Weighted Average Discount Rate - Finance leases (percent)	3.99%