Commitments and Contingencies (Contingencies Narrative) (Details) $ / shares in Units, $ in Millions		12 Months Ended
	Nov. 09, 2016 USD ($)	Dec. 31, 2017 USD ($) item $ / shares	Dec. 31, 2016 USD ($)	Jan. 27, 2014 USD ($)
Loss Contingencies [Line Items]
Business Combination Contingent Consideration Arrangements, Contingent Value Right, Amount Per Share | $ / shares		$ 1.00
Deductible related to litigation and contingent value right		$ 18.0
Contingent value right, percentage multiplier		90.00%
Number of contingent value rights outstanding | item		264,544,053
Amount which CVR holders are no longer entitled to payment		$ 312.0
Contingent value right, period payable after final resolution		60 days
Business Combination, Contingent Consideration, Liability, Noncurrent		$ 256.0		$ 284.0
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability		4.0
Business Combination, Contingent Consideration, Liability, Current		0.0
Pending Litigation [Member] | Legal Matters Where Negative Outcome is Known or Probable [Member]
Loss Contingencies [Line Items]
Legal Fees		$ 2.0	$ 4.0
U.S. ex re. Baker vs. Community Health Systems, Inc. [Member]
Loss Contingencies [Line Items]
Judgment awarded	$ 1.9
Class Action Shareholder Federal Securities Cases [Member] | Pending Litigation [Member] | Litigation Matters For Which An Outcome Cannot Be Assessed [Member]
Loss Contingencies [Line Items]
Number of legal cases filed | item		3