Basis of Presentation and Significant Accounting Policies - Schedule of Net Operating Revenues (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Net operating revenues	$ 3,013	$ 3,025
Medicare
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Net operating revenues	693	756
Medicaid
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Net operating revenues	391	407
Managed Care and Other Third Party Payors
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Net operating revenues	1,915	1,832
Self-Pay
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Net operating revenues	$ 14	$ 30