Leases Leases - Summary (Details) $ in Millions	Sep. 30, 2019 USD ($)
Leases [Abstract]
Operating Lease, Right-of-Use Asset	$ 526
Finance Lease, Right-of-Use Asset	503
Total Right-of-Use Asset	1,029
Operating Lease, Liability	574
Finance Lease, Liability	517
Total Lease Liabilities	$ 1,091