Environmental (Schedule of Environmental Remediation Reserves) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Environmental Remediation Obligations [Abstract]
Document Period End Date	Dec. 31, 2019
Demerger obligations (Note 24)	$ 23	$ 26
Divestiture obligations (Note 24)	12	16
Active sites	13	14
US Superfund sites	11	11
Other environmental remediation liabilities	2	2
Total	$ 61	$ 69