Equity Investments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	$ 487		$ 487		$ 470
Equity in earnings of unconsolidated affiliates	$ 21	$ 12	$ 39	$ 22
Four Hospitals in Las Vegas, Nevada [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	27.50%		27.50%
One Hospital in Las Vegas, Nevada [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	26.10%		26.10%
Three Hospitals in Macon Georgia, [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	38.00%		38.00%
HealthTrust [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	25.10%		25.10%