Income Taxes (Schedule Of Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Current income tax expense (benefit)	$ (27)	$ 12	$ (23)	$ 32
Deferred income tax expense (benefit)	20	(17)	(18)	$ (32)
Total income tax benefit	$ (7)	$ (5)	$ (41)
U.S. statutory income tax rate	21.00%	35.00%	21.00%	35.00%
State income taxes	(1.00%)	0.00%	0.00%	2.00%
Audit settlements	3.00%	0.00%	2.00%	0.00%
Other	(11.00%)	(7.00%)	(9.00%)	(3.00%)
Deferred tax asset valuation allowance	(11.00%)	(30.00%)	(8.00%)	(34.00%)
Effective income tax rate	1.00%	(2.00%)	6.00%	0.00%

Amount of current income tax expense (benefit) pertaining to taxable income (loss) from continuing operations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 9
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-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319

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-Publisher FASB
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Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations.

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the valuation allowance for deferred tax assets.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to income tax settlements. Including, but not limited to, domestic tax settlement, foreign tax settlement, state and local tax settlement, and other tax settlements.

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