SCHEDULE II-VALUATION AND QUALIFYING ACCOUNTS (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowance for doubtful accounts
Movement in valuation and qualifying accounts
Balance at Beginning of Period	$ 397	$ 352	$ 369
Cost and Expenses	789	721	730
Deductions	(785)	(676)	(747)
Balance at End of Period	401	397	352
Valuation allowance for deferred tax assets
Movement in valuation and qualifying accounts
Balance at Beginning of Period	61	66	1,127
Cost and Expenses	(5)	(5)	(1,061)
Balance at End of Period	$ 56	$ 61	$ 66