Leases Comparative Information (Details) $ in Millions	Dec. 31, 2018 USD ($)
Leases [Abstract]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	$ 640
Operating Leases, Future Minimum Payments, Due in Two Years	631
Operating Leases, Future Minimum Payments, Due in Three Years	628
Operating Leases, Future Minimum Payments, Due in Four Years	623
Operating Leases, Future Minimum Payments, Due in Five Years	619
Operating Leases, Future Minimum Payments, Due Thereafter	8,054
Operating Leases, Future Minimum Payments Due	$ 11,195