Operating Leases (Future Minimum Lease Payments) (Details) $ in Millions	Dec. 31, 2016 USD ($)
Leases, Operating [Abstract]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	$ 48
Operating Leases, Future Minimum Payments, Due in Two Years	37
Operating Leases, Future Minimum Payments, Due in Three Years	30
Operating Leases, Future Minimum Payments, Due in Four Years	33
Operating Leases, Future Minimum Payments, Due in Five Years	34
Operating Leases, Future Minimum Payments, Due Thereafter	244
Operating Leases, Future Minimum Payments Due	$ 426