Acquisitions and Divestitures (Acquisitions Narrative) (Details) $ / shares in Units, $ in Millions			3 Months Ended		6 Months Ended
	Apr. 01, 2016 USD ($) item	Mar. 01, 2016 USD ($) item	Jun. 30, 2016 USD ($) $ / shares	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) $ / shares	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Purchase of Interest by Parent					$ 2
Business Acquisition, Purchase Price Allocation, Goodwill			$ 6,926		$ 6,926		$ 8,965
Business Combination Contingent Consideration Arrangements, Contingent Value Right, Amount Per Share | $ / shares			$ 1.00		$ 1.00
Loss from early extinguishment of debt			$ (30)	$ (9)	$ (30)	$ (16)
Loss on Extinguishment of Debt, Net of Tax			(20)	(6)	$ (20)	(10)
Physicians' Specialty Hospital [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition					Apr. 01, 2016
Business Acquisition, Number of Licensed Hospital or Facility Beds | item	20
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	$ 2
Business Acquisition, Cost of Acquired Entity, Purchase Price	$ 14
Business Acquisition, Purchase Price Allocation, Goodwill			12		$ 12
Business Acquisition, Percentage of Voting Interests Acquired	80.00%
Business Combination, Assumed Noncontrolling Interest, Fair Value	$ 3
Business Acquisition, Cost of Acquired Entity, Cash Paid	$ 12
Indiana University Health [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition					Mar. 01, 2016
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		$ 8
Business Acquisition, Cost of Acquired Entity, Purchase Price		$ 104
Business Acquisition, Purchase Price Allocation, Goodwill			50		$ 50
Business Acquisition, Percentage of Voting Interests Acquired		80.00%
Business Combination, Assumed Noncontrolling Interest, Fair Value		$ 24
Business Acquisition, Cost of Acquired Entity, Cash Paid		$ 96
IU Health La Porte Hospital [Member]
Business Acquisition [Line Items]
Business Acquisition, Number of Licensed Hospital or Facility Beds | item		227
IU Health Starke Hospital [Member]
Business Acquisition [Line Items]
Business Acquisition, Number of Licensed Hospital or Facility Beds | item		50
Health Management Associates, Inc. [Member]
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs						1
Excluding Health Management Associates Inc [Member]
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs			1	$ 2	3	$ 5
Physician Practices Clinics and Other Ancillary Businesses [Member]
Business Acquisition [Line Items]
Business Combination, Assumed Noncontrolling Interest, Fair Value			6		6
Business Acquisition, Cost of Acquired Entity, Cash Paid					6
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment			4		4
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill			$ 8		$ 8