Leases - Schedule of Leases Statement of Financial Position (Details) $ in Millions	Mar. 31, 2019 USD ($)
Leases [Abstract]
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentNet
Assets
ROU operating lease assets	$ 809
ROU finance lease assets	21
Total Leased Assets	830
Current
Operating lease	184
Finance lease	13
Noncurrent
Operating lease	651
Finance lease	17
Total leased liabilities	$ 865
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesAndOtherLiabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent