Basis of Presentation and Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Jan. 01, 2016
Allowance for Doubtful Accounts, Policy [Abstract]
Number of days from the date of discharge over which all accounts are reserved 100%			365 days
Electronic Health Records Reimbursement, Policy [Abstract]
Electronic health records incentive reimbursement under HITECH	$ 31	$ 55	$ 49	$ 81
Electronic Health Records Incentive Reimbursement, Cash Received	18	10	102	65
Reclassification of debt issuance costs					$ 266
Accounting for the Impairment or Disposal of Long-Lived Assets [Abstract]
Write-down of long-lived assets	239
Long-lived assets at certain of the hospitals intended to sell	169
Impairment of Long-Lived Assets Held-for-use	70
Electronic Health Records Incentive Reimbursements [Member]
Electronic Health Records Reimbursement, Policy [Abstract]
Deferred Revenue	$ 4	$ 21	$ 4	$ 21