Summary of Cash, Cash Equivalents and Restricted Cash Reported In Condensed Consolidated Statements of Cash Flows (Parenthetical) (Detail)	3 Months Ended
Mar. 31, 2021
Minimum
Cash And Cash Equivalents Period Increase Decrease [Line Items]
Short -term cash investments interest rate	0.20%
Maximum
Cash And Cash Equivalents Period Increase Decrease [Line Items]
Short -term cash investments interest rate	0.35%

Cash and cash equivalents period increase decrease.

No definition available.

Name:	uhs_CashAndCashEquivalentsPeriodIncreaseDecreaseLineItems
Namespace Prefix:	uhs_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration