Leases (Lease and Other Information) (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Operating Lease, Cost	$ 45	$ 90
Short-term Lease, Cost	12	24
Sublease Income	(4)	(8)
Lease, Cost	53	106
Operating Lease, Payments	$ 44	$ 89
Operating Lease, Weighted Average Remaining Lease Term	7 years	7 years
Weighted Average Discount Rate, Percent (Deprecated 2019-01-31)	3.90%	3.90%
Other Noncurrent Assets [Member]
Operating Lease, Right-of-Use Asset	$ 637	$ 637
Other Current Liabilities [Member]
Operating Lease, Liability, Current	175	175
Other Noncurrent Liabilities [Member]
Operating Lease, Liability, Noncurrent	$ 524	$ 524