Contingencies and Legal Claim Costs - Additional Information (Detail) $ in Millions					3 Months Ended			9 Months Ended
	Feb. 09, 2015 USD ($)	Apr. 25, 2014 USD ($)	Jan. 24, 2013 USD ($)	Oct. 28, 2011 Cases	Sep. 30, 2015 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2012 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Jul. 31, 2012 Hospital	Oct. 31, 2009 USD ($)
Loss Contingencies [Line Items]
Number of claims filed | Cases				3
Capital commitments in connection with purchase of hospitals											$ 450
Additional shortfall related to capital expenditures		$ 78
Legal claim costs					$ 77	$ 78	$ 175	$ 77	$ 78
Period of agreed capital commitments								5 years
Number of year under court-supervisor accounting for expenditures following the purchase								10 years
Dispute settlement amount	$ 15
Pending Litigation [Member]
Loss Contingencies [Line Items]
Accrued liabilities in connection with litigation					$ 382			$ 382
Health Care Foundation of Greater Kansas City [Member] | Pending Litigation [Member]
Loss Contingencies [Line Items]
Judgment award by the court			$ 162
Plaintiff attorneys fees award								$ 12
Percentage of legal claim costs					9.00%	9.00%	9.00%	9.00%
Florida [Member]
Loss Contingencies [Line Items]
Number of owned and operated hospitals reviewed | Hospital										8
Florida [Member] | Qui Tam Action [Member]
Loss Contingencies [Line Items]
Number of owned and operated hospitals reviewed | Hospital										2