Leases Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions		Dec. 31, 2020	Dec. 31, 2019
Schedule of Lease Assets and Liabilities [Line Items]
Operating Lease, Right-of-Use Asset	[1]	$ 521	$ 555
Current operating lease liabilities	[2]	138	140
Noncurrent operating lease liabilities	[3]	391	426
Total operating lease liabilities		529	566
Finance Lease, Right-of-Use Asset, Gross		15	15
Finance Lease, Right-Of-Use Asset, Accumulated Depreciation		(10)	(8)
Finance Lease, Liability, Noncurrent		4	5
Finance Lease, Liability		5	9
Property, Plant and Equipment [Member]
Schedule of Lease Assets and Liabilities [Line Items]
Finance Lease, Right-of-Use Asset		5	7
Within One Year
Schedule of Lease Assets and Liabilities [Line Items]
Finance Lease, Liability, Current		1	4
Long-term Debt [Member]
Schedule of Lease Assets and Liabilities [Line Items]
Finance Lease, Liability, Noncurrent		$ 4	$ 5

[1] Included in other assets in the Consolidated Balance Sheet.

[2] Included in accrued and other current liabilities in the Consolidated Balance Sheet.

[3] Included in other noncurrent obligations in the Consolidated Balance Sheet.