Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Year 1 Operating	$ 62
Year 2 Operating	54
Year 3 Operating	35
Year 4 Operating	12
Year 5 Operating	5
Later years, Operating Leases	49
Sublease rentals	0
Operating Leases, Future Minimum Payments Due	217
Operating Leases, Rent Expense, Net [Abstract]
Operating Leases, Rent Expense	$ 99	$ 87	$ 87