Available-For-Sale Investments (Fair Value And Gross Unrealized Losses Of Investments By Length Of Time In Continuous Unrealized Loss Position) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2011		Dec. 31, 2010
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of securities in a loss position	22		22
12 months or greater, Fair value	$ 41		$ 45
12 months or greater, Unrealized losses	(20)	[1]	(20)	[1]
Total, Fair value	41		45
Total, Unrealized losses	(20)		(20)
Long Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of securities in a loss position	22		22
12 months or greater, Fair value	41		45
12 months or greater, Unrealized losses	(20)	[1]	(20)	[1]
Total, Fair value	41		45
Total, Unrealized losses	$ (20)		$ (20)

[1] Unrealized losses in securities less than 12 months were not significant