Recent Accounting Pronouncements - Supplemental Balance Sheet Information Related to Leases (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Operating lease assets:
Operating lease right-of-use assets	$ 290	$ 0
Other current liabilities	97	0
Operating lease liabilities	245	$ 0
Total Operating Lease Liabilities	342
Finance lease assets:
Land, buildings and equipment, net	16
Current portion of long-term debt	7
Long-term debt	10
Total Finance Lease Liabilities	$ 17