SCHEDULE II: Valuation And Qualifying Accounts (Schedule Of Valuation And Qualifying Accounts) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 404	$ 614	$ 650
Charged to Costs and Expenses	6	1	14
Charged to Other Accounts	69	69	9
Deductions	238	280	59
Balance at End of Period	241	404	614
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	404	614	650
Charged to Costs and Expenses	6	1	14
Charged to Other Accounts	69	69	9
Deductions	238	280	59
Balance at End of Period	$ 241	$ 404	$ 614