Accrued Expenses - Summary of Other Accrued Expenses (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Professional liability risks	$ 508	$ 477
Defined contribution benefit plans	549	547
Right-of-use operating lease	392	379
Taxes other than income	361	343
Interest	353	315
Government stimulus refund liability	79	83
Other	1,080	1,096
Other accrued expenses	$ 3,322	$ 3,240