Acquisitions and Divestitures (Schedule of Purchase Price Allocation) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill	$ 4,559	$ 4,723	$ 6,521
Hospitals and Significant Practices Acquired [Member]
Business Acquisition [Line Items]
Current assets			7
Property and equipment			69
Goodwill			57
Intangible assets			10
Other long-term assets			3
Liabilities			(10)
Noncontrolling interests			(28)
Total identifiable net assets			$ 108