Segment and Geographic Information - Schedule of Geographic Distributions of Revenues, Equity in Earnings of Affiliates, Adjusted Segment EBITDA, Depreciation and Amortization and Assets (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Revenues	$ 14,945	$ 13,977
Equity in earnings of affiliates	(11)	(21)
Adjusted segment EBITDA	2,944	3,052
Depreciation and amortization	732	697
Interest expense	408	384
Gains on sales of facilities	(10)	(2)
Income before income taxes	1,814	1,973
National Group [Member]
Segment Reporting Information [Line Items]
Revenues	7,506	7,056
Equity in earnings of affiliates	(1)	(7)
Adjusted segment EBITDA	1,566	1,705
Depreciation and amortization	355	323
American Group [Member]
Segment Reporting Information [Line Items]
Revenues	6,616	6,291
Equity in earnings of affiliates	(9)	(12)
Adjusted segment EBITDA	1,486	1,501
Depreciation and amortization	301	293
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues	823	630
Equity in earnings of affiliates	(1)	(2)
Adjusted segment EBITDA	(108)	(154)
Depreciation and amortization	$ 76	$ 81