Income Taxes (Reconciliation Of Taxes Computed At The Statutory Rate To Income Tax Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Provision for federal income tax, at statutory rate	$ 378	$ 195	$ 337
State income tax provision, net of federal income tax effect	26	1	17
Foreign income tax rate differential	(33)	(8)	(13)
Manufacturing deduction	(23)	(2)	(24)
Depletion	(7)	(2)	0
Noncontrolling interests	(9)	(7)	(7)
Tax on previously held shares of Axiall Corporation and certain other acquisition related items	0	(13)	0
Tax Act related adjustment	(591)	0	0
Changes in state apportionment and other state adjustments	2	(17)	0
Research and development expenditures and adjustments related to prior years' tax returns	(1)	(8)	0
Other, net	0	(1)	(12)
Provision for (benefit from) income taxes	$ (258)	$ 138	$ 298