Leases - Supplemental Balance Sheet Information (Details) $ in Millions	Dec. 31, 2019 USD ($)
Assets:
ROU operating lease assets	$ 1,484
ROU finance lease assets	1,277
Total	2,761
Current
Operating lease	498
Finance lease	475
Total	973
Non-current
Operating lease	1,097
Finance lease	639
Total	$ 1,736
Weighted Average remaining lease term:
Operating leases	4 years 9 months 18 days
Finance leases	2 years 9 months 18 days
Weighted average remaining discount rate:
Operating leases	3.70%
Finance leases	6.50%