Segment Information - Reconciliation (Details ) - USD ($)					3 Months Ended	12 Months Ended
	Oct. 31, 2021	Jul. 31, 2021	Jan. 31, 2021	Oct. 31, 2020	Mar. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Depreciation and amortization						$ (4,019,000,000)	$ (4,710,000,000)	$ (4,829,000,000)
Goodwill impairment	$ 0	$ 0	$ 0	$ (2,600,000,000)	$ (6,500,000,000)	0	(2,642,000,000)	(6,506,000,000)
Stock-based compensation						(120,000,000)	(175,000,000)	(162,000,000)
OPERATING INCOME (LOSS)						4,285,000,000	962,000,000	(2,726,000,000)
Total other expense, net						(1,584,000,000)	(1,744,000,000)	(2,040,000,000)
INCOME (LOSS) BEFORE INCOME TAXES						2,701,000,000	(782,000,000)	(4,766,000,000)
Income tax expense						668,000,000	450,000,000	503,000,000
NET INCOME (LOSS)						2,033,000,000	(1,232,000,000)	(5,269,000,000)
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment adjusted EBITDA						14,332,000,000	15,017,000,000	15,652,000,000
Operations and Other
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Depreciation and amortization						(4,019,000,000)	(4,710,000,000)	(4,829,000,000)
Goodwill impairment						0	(2,642,000,000)	(6,506,000,000)
Operations and other expenses						(5,908,000,000)	(6,528,000,000)	(6,881,000,000)
Stock-based compensation						(120,000,000)	(175,000,000)	(162,000,000)
OPERATING INCOME (LOSS)						4,285,000,000	962,000,000	(2,726,000,000)
Total other expense, net						$ (1,584,000,000)	$ (1,744,000,000)	$ (2,040,000,000)