Schedule II-Valuation And Qualifying Accounts (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Allowance For Loss On Receivables [Member]
Balance at Beginning of Period	$ 52		$ 51		$ 49
Acquired Balances	0		0		0
Charged (Credited) to Costs and Expenses	31		19		19
Charged to Other Accounts	22	[1]	(1)	[1]	2	[1]
Deductions or Write-offs	(20)		(17)		(19)
Balance at End of Period	85		52		51
Deferred Tax Asset Valuation Allowance [Member]
Balance at Beginning of Period	(28)		(30)		(28)
Acquired Balances	0		0		0
Charged (Credited) to Costs and Expenses	0		2		(2)
Charged to Other Accounts	0	[1]	0	[1]	0	[1]
Deductions or Write-offs	0		0		0
Balance at End of Period	$ (28)		$ (28)		$ (30)

[1] Represents changes in retroactive membership adjustments to premiums revenue and contractual allowances adjustments to services revenue as more fully described in Note 2 to the consolidated financial statements