Fair Value Measurements (Schedule Of Unrealized Gains Losses Related To Available-For-Sale Investments) (Details) (USD $) In Millions	Sep. 30, 2011		Dec. 31, 2010
Schedule of Available-for-sale Securities [Line Items]
Amounts excluded from the total fair value	$ 169		$ 185
U.S. Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	377		509
Total Unrealized Gains	432		529
Total Unrealized Losses	(11)		(2)
Total Fair Value	798	[1]	1,036	[1]
Non-U.S. Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	201		180
Total Unrealized Gains	119		170
Total Unrealized Losses	(9)		(1)
Total Fair Value	311	[1]	349	[1]
U.S. Government And Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	764		571
Total Unrealized Gains	101		55
Total Unrealized Losses			(2)
Total Fair Value	865	[1]	624	[1]
Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	63		119
Total Unrealized Gains	2		1
Total Unrealized Losses			(1)
Total Fair Value	65	[1]	119	[1]
Other Fixed-Income Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	91		65
Total Unrealized Gains	3		1
Total Unrealized Losses
Total Fair Value	94	[1]	66	[1]
Securities (Assets) [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,496		1,444
Total Unrealized Gains	657		756
Total Unrealized Losses	(20)		(6)
Total Fair Value	$ 2,133	[1]	$ 2,194	[1]

[1] Excludes $169 million and $185 million at September 30, 2011 and December 31, 2010, respectively, primarily related to deferred taxes on appreciation of investment value.