Statement of Cash Flows, Supplemental Disclosures (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Item Effected [Line Items]
Cash paid for interest, net of amounts capitalized	$ 222	$ 204
Income Taxes Paid, Net	2	3
Property, plant and equipment acquired with accounts payable and accrued liabilities	5	21
Right-of-Use Assets Obtained in Exchange for Operating and Finance Lease Liabilities	11	38
Accounting Standards Update 2016-02 [Member]
Item Effected [Line Items]
Cumulative Effect of Implementation of Topic 842	$ 0	$ 84