Income Taxes (Schedule Of Reconciliation Of Gross Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Abstract]
Balance at beginning of year	$ 14	$ 8	$ 6	$ 4
Tax positions related to current year, Additions	2	1	1
Tax positions related to current year, Reductions	0	0	0
Tax positions related to prior years, Additions	4	1	1
Tax positions related to prior years, Reductions	0	0	0
Tax Adjustments, Settlements, and Unusual Provisions	0	0	0
Lapses in statutes of limitations	0	0	0
Balance at end of year	$ 14	$ 8	$ 6

Amount of increase (decrease) to previously recorded tax expense. Includes, but is not limited to, significant settlements of income tax disputes, and unusual tax positions or infrequent actions taken by the entity, including tax assessment reversal, and IRS tax settlement.

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Amount of unrecognized tax benefits.

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Amount of decrease in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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Income Taxes [Abstract]

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