Leases (Lease and Other Information) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Operating Lease, Cost	$ 272	$ 48	$ 378	$ 138
Short-term Lease, Cost	11	9	38	33
Sublease Income	(1)	(4)	(8)	(12)
Lease, Cost	282	53	408	159
Operating Lease, Payments	47	43	137	132
Right-of-use assets obtained in exchange for new operating lease liabilities	17	$ 33	372	$ 33
Other Noncurrent Assets [Member]
Operating Lease, Right-of-Use Asset	679		679		$ 575
Other Current Liabilities [Member]
Operating Lease, Liability, Current	192		192		158
Other Noncurrent Liabilities [Member]
Operating Lease, Liability, Noncurrent	$ 798		$ 798		$ 482