Leases (Supplemental Cash Flow Information Related To Leases) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2019 USD ($)
Leases [Abstract]
Operating cash flows provided by operating leases	$ 52
Operating cash flows used by operating leases	(53)
Operating cash flows used by finance leases	(11)
Financing cash flows used by finance leases	(26)
Right-of-use assets obtained in exchange for lease liabilities, Operating leases	26
Right-of-use assets obtained in exchange for lease liabilities, Finance leases	$ 28