Income Taxes (Schedule Of Net Deferred Tax Assets) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Income Taxes [Abstract]
Deferred tax assets	$ 16,181		$ 14,383
Deferred tax liabilities	(12,939)		(10,736)
Valuation allowance	(101)		(105)
Net deferred tax assets	$ 3,141	[1]	$ 3,542	[1]

[1] Of the deferred tax asset for net operating loss and credit carryovers, $336 expires in years ending from December 31, 2012 through December 31, 2031 and $152 may be carried over indefinitely.