Leases (Narrative) (Details) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
---|---|---|
Operating Leased Assets [Line Items] | ||
Operating Lease, Right-of-Use Asset | $ 971 | |
Operating Lease, Liability, Current | 215 | $ 0 |
Operating Lease, Liability, Noncurrent | $ 781 | |
Minimum [Member] | ||
Operating Leased Assets [Line Items] | ||
Lessee, Operating Lease, Renewal Term | 1 month | |
Maximum [Member] | ||
Operating Leased Assets [Line Items] | ||
Lessee, Operating Lease, Renewal Term | 49 years |