Income Taxes (Schedule Of Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Millions	3 Months Ended												12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	[1]	Sep. 30, 2018	[1]	Jun. 30, 2018	[1]	Mar. 31, 2018	[1]	Dec. 31, 2019	Dec. 31, 2018		Dec. 31, 2017
Income Tax Disclosure [Abstract]
Earnings (loss) from continuing operations before income taxes	$ (21)	$ 190	$ 219	$ (497)	$ 1,799		$ (105)		$ (486)		$ (264)		$ (109)	$ 944	[1]	$ 40
U.S. statutory income tax rate													21.00%	21.00%		35.00%
U.S. Tax Reform													0.00%	0.00%		957.00%
State income taxes													24.00%	5.00%		(2.00%)
Change in unrecognized tax benefits													(13.00%)	(2.00%)		(15.00%)
Audit settlements													15.00%	(2.00%)		0.00%
Other													(19.00%)	2.00%		2.00%
Deferred tax asset valuation allowance													0.00%	0.00%		(959.00%)
Effective income tax rate													28.00%	24.00%		18.00%

[1] Includes asset impairments of approximately $150 million in the second quarter of 2018. Additional discussion regarding asset impairments can be found in Note 5.