Leases Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Operating Leased Assets [Line Items]
Operating Lease, Right-of-Use Asset	$ 1,100	$ 1,000
Operating Lease, Liability, Current	251	215
Operating Lease, Liability, Noncurrent	$ 862	$ 781
Minimum [Member]
Operating Leased Assets [Line Items]
Lessee, Operating Lease, Renewal Term	10 months
Maximum [Member]
Operating Leased Assets [Line Items]
Lessee, Operating Lease, Renewal Term	49 years