Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deferred Tax Assets:
Net operating loss and tax credit carryforwards	$ 389	$ 477
Pension and postretirement benefits	68	86
Reserves not deductible until paid	15	14
Self insurance	4	2
Capitalized interest	8	7
Inventories	4	4
Share-based compensation	13	14
Other	9	7
Deferred tax assets before valuation allowance	510	611
Valuation allowance	(112)	(175)
Total deferred tax assets	398	436
Deferred Tax Liabilities:
Property, plant and equipment	157	153
Total deferred tax liabilities	157	153
Net deferred tax assets	$ 241	$ 283