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		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
Revenues	$ 14,971	$ 15,276	$ 44,736	$ 43,688
Losses (equity) in earnings of affiliates	(10)	(35)	(29)	(78)
Adjusted segment EBITDA	2,902	3,224	8,888	9,495
Depreciation and amortization	749	716	2,219	2,125
Interest expense	446	398	1,288	1,168
Losses (gains) on sales of facilities	3	(1,047)	25	(1,057)
Losses on retirement of debt	0	0	78	12
Income before income taxes	1,704	3,157	5,278	7,247
National Group [Member]
Segment Reporting Information [Line Items]
Revenues	7,635	7,787	22,490	22,143
Losses (equity) in earnings of affiliates	(1)	(14)	(3)	(30)
Adjusted segment EBITDA	1,550	1,780	4,656	5,330
Depreciation and amortization	369	343	1,088	1,005
American Group [Member]
Segment Reporting Information [Line Items]
Revenues	6,599	6,767	19,872	19,562
Losses (equity) in earnings of affiliates	(13)	(14)	(31)	(38)
Adjusted segment EBITDA	1,389	1,604	4,417	4,698
Depreciation and amortization	309	295	914	884
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues	737	722	2,374	1,983
Losses (equity) in earnings of affiliates	4	(7)	5	(10)
Adjusted segment EBITDA	(37)	(160)	(185)	(533)
Depreciation and amortization	$ 71	$ 78	$ 217	$ 236