Income Taxes (Reconciliation Of Income Tax Expense Based On Federal Statutory Rate To Amount Per Effective Tax Rate) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Abstract]
Taxes computed at federal statutory rate	$ 5,223	$ 5,299	$ 6,934
State and local income taxes - net of federal income tax benefit	738	509	416
Enactment date and measurement period adjustments from the Act	(718)	(20,271)	0
Tax on foreign investments	(466)	73	168
Mexico restructuring	0	0	(471)
Other - net	143	(318)	(568)
Total	$ 4,920	$ (14,708)	$ 6,479
Effective Tax Rate	19.80%	(97.20%)	32.70%
Statutory federal income tax rate	21.00%	35.00%	35.00%

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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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 tax exempt income, equity in earnings (loss) of an unconsolidated subsidiary, minority noncontrolling interest income (loss), tax holiday, disposition of a business, disposition of an asset, repatriation of foreign earnings, repatriation of foreign earnings jobs creation act of 2004, increase (decrease) in enacted tax rate, prior year income taxes, increase (decrease) in deferred tax asset valuation allowance, and other adjustments.

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