Divestiture Of Northwest Operations (Narrative) (Details) - Predecessor [Member] - USD ($) $ in Millions		9 Months Ended
	May 01, 2020	Sep. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Gross proceeds from divestiture		$ 1,131
Net assets	$ 1,132
Property, plant, and equipment, Derecognized	1,084
Goodwill, Derecognized	658
Valuation allowance, Derecognized	603
Defined benefit pension and other postretirement benefit plan obligations, Derecognized	150
Loss on disposal of Northwest Operations		160
Northwest Operations [Member]
Defined Benefit Plan Disclosure [Line Items]
Gross proceeds from divestiture	1,352
Net proceeds	$ 1,131
Loss on disposal of Northwest Operations		$ 160