Commitments and Contingencies - Additional Information (Details) - USD ($)		3 Months Ended			12 Months Ended
	Jun. 01, 2018	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Commitments And Contingencies [Line Items]
Physician recruiting commitment, physician income guarantee period					12 months
Physician recruiting commitment, period of recoverability of physician income guarantee for noncommitment					3 years
Physician recruiting commitment, maximum potential future payments in excess of liability recorded					$ 17,000,000
Malpractice loss contingency, historical claims period used by actuary to estimate liability	20 years
Malpractice Loss Contingency, Discount Rate					1.80%	2.60%	3.10%
Malpractice Loss Contingency, Accrual, Discounted		$ 612,000,000			$ 602,000,000	$ 612,000,000
Malpractice Loss Contingency, Accrual, Undiscounted		663,000,000			629,000,000	663,000,000
Malpractice Loss Contingency, Accrual, Discounted, Current		169,000,000			177,000,000	169,000,000
Expenses related to settlement of professional liability claim					50,000,000
Recovery of full settlement amount					50,000,000
Change in estimate reserve for professional liability claims					0
Change in settlement liability claims estimate amount		$ 0	$ 20,000,000	$ 70,000,000
Pending Litigation [Member] | Litigation Matters Where Negative Outcome Is Reasonably Possible [Member]
Commitments And Contingencies [Line Items]
Attorneys' fees and other costs incurred					3,000,000	$ 21,000,000	$ 2,000,000
Professional and general liability self-insured claims reported prior to June 1, 2002, per occurrence [Member]
Commitments And Contingencies [Line Items]
Malpractice loss contingency, self-insured retention					1,000,000
Professional and general liability self-insured reported from June 1, 2002 through June 1, 2003, per occurrence [Member]
Commitments And Contingencies [Line Items]
Malpractice loss contingency, self-insured retention					2,000,000
Professional and general liability self-insured reported from June 1, 2003 and before June 1, 2005, per occurrence [Member]
Commitments And Contingencies [Line Items]
Malpractice loss contingency, self-insured retention					4,000,000
Professional and general liability self-insured claims reported on or after June 1, 2005, per occurrence [Member]
Commitments And Contingencies [Line Items]
Malpractice loss contingency, self-insured retention					5,000,000
Professional and general liability claims reported on or after June 1, 2014 [Member]
Commitments And Contingencies [Line Items]
Malpractice loss contingency, self-insured retention					10,000,000
Professional and general liability claims reported on or after June 1, 2003 [Member]
Commitments And Contingencies [Line Items]
Malpractice Insurance, Maximum Coverage Per Incident					95,000,000
Professional and general liability claims incurred and reported after January 1, 2008 [Member]
Commitments And Contingencies [Line Items]
Malpractice Insurance, Maximum Coverage Per Incident					145,000,000
Professional and general liability claims incurred and reported after June 1, 2010 [Member]
Commitments And Contingencies [Line Items]
Malpractice Insurance, Maximum Coverage Per Incident					195,000,000
Professional and general liability claims reported on or after June 1, 2015 [Member]
Commitments And Contingencies [Line Items]
Malpractice Insurance, Maximum Coverage Per Incident					215,000,000
Integrated occurrence claims reported on or after June 1, 2014 [Member]
Commitments And Contingencies [Line Items]
Malpractice Insurance, Annual Coverage Limit					50,000,000
Integrated occurrence claims reported on or after June 1, 2015 through June 1, 2020 [Member]
Commitments And Contingencies [Line Items]
Malpractice Insurance, Annual Coverage Limit					75,000,000
Integrated occurrence claims reported between June 1,2020 and May 31, 2021 [Member]
Commitments And Contingencies [Line Items]
Malpractice Insurance, Annual Coverage Limit					75,000,000
Professional and general liability self-insured claims under certain policy terms until Company total aggregate coverage is met if first aggregate layer becomes fully utilized [Member]
Commitments And Contingencies [Line Items]
Malpractice loss contingency, self-insured retention					10,000,000
Triad professional and general liability self-insured claims during 2007 [Member]
Commitments And Contingencies [Line Items]
Malpractice loss contingency, self-insured retention					$ 10,000,000
Maximum
Commitments And Contingencies [Line Items]
Malpractice loss contingency, average lag period from occurrence to settlement					4 years
Malpractice loss contingency, settled claims as percent of total liability					1.00%
Malpractice loss contingency, self-insured retention					$ 15,000,000
Maximum | Professional And General Liability Claims Incurred And Reported On Or After June 1, 2008 [Member]
Commitments And Contingencies [Line Items]
Malpractice loss contingency, self-insured retention					15,000,000
Maximum | Triad professional and general liability self-insured claims after December 31, 2006 [Member]
Commitments And Contingencies [Line Items]
Malpractice loss contingency, self-insured retention					$ 5,000,000
Minimum
Commitments And Contingencies [Line Items]
Malpractice loss contingency, average lag period from occurrence to settlement					3 years
Malpractice loss contingency, self-insured retention					$ 10,000,000
Minimum | Professional and general liability self-insured claims under certain policy terms until Company total aggregate coverage is met if first aggregate layer becomes fully utilized [Member]
Commitments And Contingencies [Line Items]
Malpractice loss contingency, self-insured retention					15,000,000
Minimum | Triad professional and general liability self-insured claims after December 31, 2006 [Member]
Commitments And Contingencies [Line Items]
Malpractice loss contingency, self-insured retention					$ 1,000,000
Northwest Health - La Porte [Member]
Commitments And Contingencies [Line Items]
Capital commitment, future period after acquisition for completing open capital improvement projects month and year					2021-03
Capital commitment, post-acquisition estimated cost of replacement hospital					$ 126,000,000
Northwest Health - La Porte [Member] | Maximum
Commitments And Contingencies [Line Items]
Capital commitment, future period after acquisition for completing open capital improvement projects					5 years
Northwest Health – Starke [Member]
Commitments And Contingencies [Line Items]
Capital commitment, future period after acquisition for completing open capital improvement projects date					Sep. 30, 2026
Capital commitment, post-acquisition estimated cost of replacement hospital					$ 15,000,000
Northwest Health – Starke [Member] | Maximum
Commitments And Contingencies [Line Items]
Capital commitment, future period after acquisition for completing open capital improvement projects					5 years