v3.26.1
Segment and Geographic Information - Schedule of Geographic Distributions of Revenues, Equity in Earnings or Losses of Affiliates, Adjusted Segment EBITDA, Depreciation and Amortization (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Segment Reporting Information [Line Items]          
Revenues $ 20,230 $ 18,605 $ 39,339 $ 36,926  
Salaries and benefits 8,290 8,138 16,573 16,135  
Supplies 2,886 2,844 5,739 5,608  
Other operating expenses 5,043 3,793 9,223 7,638  
Equity in earnings of affiliates (16) (19) (25) (37)  
Depreciation and amortization 944 863 1,874 1,723  
Interest expense 599 568 1,183 1,115  
Losses (gains) on sales of facilities (10) 3 (9) 2  
Income before income taxes 2,494 2,415 4,781 4,742  
Assets 63,250   63,250   $ 60,720
Operating Segments [Member]          
Segment Reporting Information [Line Items]          
Adjusted segment EBITDA 4,380 4,201 8,491 8,213  
Eliminations and Reconciling Items [Member]          
Segment Reporting Information [Line Items]          
Corporate and Other 353 352 662 631  
Depreciation and amortization 944 863 1,874 1,723  
Interest expense 599 568 1,183 1,115  
Losses (gains) on sales of facilities (10) 3 (9) 2  
Income before income taxes 2,494 2,415 4,781 4,742  
National Group [Member] | Operating Segments [Member]          
Segment Reporting Information [Line Items]          
Revenues 5,251 5,200 10,572 10,265  
Salaries and benefits 1,965 1,919 3,931 3,878  
Supplies 773 755 1,536 1,496  
Other operating expenses 1,330 1,255 2,664 2,488  
Equity in earnings of affiliates (1) 0 (1) 0  
Operating expenses 4,067 3,929 8,130 7,862  
Adjusted segment EBITDA 1,184 1,271 2,442 2,403  
Depreciation and amortization 238 223 474 449  
Assets 13,589   13,589   13,596
Atlantic Group [Member] | Operating Segments [Member]          
Segment Reporting Information [Line Items]          
Revenues 7,573 6,122 13,936 12,289  
Salaries and benefits 2,293 2,246 4,579 4,462  
Supplies 934 935 1,878 1,849  
Other operating expenses 2,520 1,590 4,215 3,166  
Equity in earnings of affiliates (1) (1) (2) (2)  
Operating expenses 5,746 4,770 10,670 9,475  
Adjusted segment EBITDA 1,827 1,352 3,266 2,814  
Depreciation and amortization 298 275 596 549  
Assets 19,374   19,374   17,945
American Group [Member] | Operating Segments [Member]          
Segment Reporting Information [Line Items]          
Revenues 6,582 6,493 13,148 12,824  
Salaries and benefits 2,287 2,216 4,564 4,412  
Supplies 1,084 1,067 2,143 2,087  
Other operating expenses 1,859 1,649 3,690 3,360  
Equity in earnings of affiliates (17) (17) (32) (31)  
Operating expenses 5,213 4,915 10,365 9,828  
Adjusted segment EBITDA 1,369 1,578 2,783 2,996  
Depreciation and amortization 296 277 591 556  
Assets 21,385   21,385   21,217
Corporate and Other [Member]          
Segment Reporting Information [Line Items]          
Revenues 824 790 1,683 1,548  
Depreciation and amortization 112 $ 88 213 $ 169  
Assets $ 8,902   $ 8,902   $ 7,962