Leases (Supplemental Information) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019 USD ($)
Leases [Abstract]
Operating cash flows from operating leases	$ 22
Right-of use assets obtained in exchange for new operating liabilities	6
Right-of-use asset	103
Lease liability balance: (in millions)
Short-term operating leases	47
Long-term operating leases	56
Total operating leases	$ 103
Weighted average remaining lease term	3 years 9 months 18 days
Weighted average discount rate	6.28%