Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2018
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 3,773
Acquisitions and Dispositions	(21)
Charged to Costs and Expenses	3,054
Write-offs	(2,936)
Balance at End of Year	$ 3,870
Patient accounts receivable, net of allowance for doubtful accounts		$ 2,258	$ 2,352
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Patient accounts receivable, net of allowance for doubtful accounts				$ 3,900