Investments (Schedule Of Cost And Fair Value Of Equity Securities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Investments [Abstract]
Cost	$ 671	$ 666
Gross unrealized appreciation	18	28
Gross unrealized depreciation	(42)	(2)
Fair value	$ 647	$ 692

For an unclassified balance sheet, this item represents equity securities categorized neither as held-to-maturity nor trading.

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