Income Taxes (Reconciliation Of Provision (Benefit) For Income Taxes) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Taxes [Abstract]
Expected provision (benefit) at federal statutory rate	$ 507	$ 417	$ (403)
Increase (decrease) resulting from:
State income taxes, net of federal income tax effect	58	53	(44)
Nondeductible expenses	3	3	2
State rate redetermination	(48)	4	2
Other	5	9
Provision (benefit) for income taxes	$ 525us-gaap_IncomeTaxExpenseBenefit	$ 486us-gaap_IncomeTaxExpenseBenefit	$ (443)us-gaap_IncomeTaxExpenseBenefit

Income Tax Reconciliation State Rate Redetermination

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

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-Publisher FASB

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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Amount 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 nondeductible expenses.

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