Contingencies and Legal Claim Costs - Additional Information (Detail) - USD ($) $ in Millions							1 Months Ended	3 Months Ended		12 Months Ended
	Feb. 01, 2017	Jan. 17, 2017	Dec. 09, 2015	Dec. 01, 2015	Feb. 09, 2015	Jan. 24, 2013	Apr. 25, 2014	Mar. 31, 2014	Dec. 31, 2012	Dec. 31, 2016	Oct. 31, 2009
Loss Contingencies [Line Items]
Capital commitment in connection with purchase of hospitals											$ 450
Additional shortfall related to capital expenditures							$ 78
Legal claim costs			$ 434					$ 78	$ 175
Period of agreed capital commitments										5 years
Number of year under court-supervisor accounting for expenditures following the purchase										10 years
Percentage of legal claim costs			9.00%
Dispute settlement amount					$ 15
Net legal claim benefit										$ 246
Subsequent Event [Member]
Loss Contingencies [Line Items]
Capital commitment in connection with purchase of hospitals		$ 450
Period of agreed capital commitments		5 years
Percentage of legal claim costs				9.00%
Dispute settlement amount	$ 188
Reduction in accrual of claim		$ 290
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%