Basis of Presentation and Significant Accounting Policies (Schedule of Net Operating Revenue) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Net operating revenues	$ 3,025	$ 3,376
Medicare [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Net operating revenues	756	889
Medicaid [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Net operating revenues	407	428
Managed Care And Other Third Party Payors [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Net operating revenues	1,832	2,025
Self-Pay [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Net operating revenues	$ 30	$ 34