Segment Information - Reconciliation (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Total adjusted EBITDA	$ 2,157	$ 2,209
Depreciation and amortization	(1,150)	(1,160)
Total other expense, net	(355)	(547)
INCOME BEFORE INCOME TAXES	632	433
Income tax expense	157	119
Net income	475	314
Operating Segments
Segment Reporting Information [Line Items]
Total adjusted EBITDA	3,666	3,790
Operations and Other
Segment Reporting Information [Line Items]
Total adjusted EBITDA	(1,509)	(1,581)
Depreciation and amortization	(1,150)	(1,160)
Other operating expenses	(1,509)	(1,581)
Stock-based compensation	(20)	(69)
Operating income	987	980
Total other expense, net	$ (355)	$ (547)