Acquisitions and Divestitures (Acquisitions Narrative) (Details)		3 Months Ended		6 Months Ended
	Jun. 01, 2019 USD ($) item	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Business Acquisition [Line Items]
Business combination acquisition related costs		$ 2,000,000		$ 3,000,000	$ 1,000,000
Goodwill		4,494,000,000		4,494,000,000		$ 4,559,000,000
Maximum [Member]
Business Acquisition [Line Items]
Business combination acquisition related costs			$ 1,000,000
Physician Practices Clinics and Other Ancillary Businesses [Member]
Business Acquisition [Line Items]
Business acquisition, cost of acquired entity, purchase price				7,000,000
Purchase price allocation, property and equipment		4,000,000		4,000,000
Business acquisition, purchase price allocation, intangible assets, other than goodwill		$ 3,000,000		$ 3,000,000
Northwest Mississippi Medical Center [Member]
Business Acquisition [Line Items]
Business acquisition, cost of acquired entity, purchase price	$ 7,000,000
Business acquisition number of licensed beds | item	181
Business acquisition cash paid for operating assets	$ 2,000,000
Business acquisition liabilities assumed	5,000,000
Goodwill	$ 0