Leases - Supplemental Balance Sheet Information (Details) $ in Millions	Sep. 30, 2019 USD ($)
Leases [Abstract]
Operating Lease Right-of-Use Assets	$ 2,002
Current portion of operating lease liabilities	362
Long-Term Operating Lease Liabilities	1,763
Total operating lease liabilities	2,125
Property, Plant and Equipment, net	154
Current portion of long-term debt	11
Long-Term Debt	145
Total finance lease liabilities	$ 156
Weighted Average Remaining Lease Term - Operating leases	8 years 1 month 6 days
Weighted Average Remaining Lease Term - Finance leases	12 years 2 months 12 days
Weighted Average Discount Rate - Operating leases (percent)	3.10%
Weighted Average Discount Rate - Finance leases (percent)	3.89%