- Reconcilation (Details ) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
	Oct. 31, 2018	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment adjusted EBITDA										$ 8,771	$ 8,602	$ 6,056
Depreciation and amortization										(4,829)	(5,120)	(3,936)
Goodwill impairment	$ (2,700)				$ (6,500)	$ (2,700)			$ (2,700)	(6,506)	(2,726)	0
Share-based compensation										(162)	(186)	(111)
Total other expense, net										(2,040)	(2,133)	(1,469)
(Loss) income before income taxes										(4,766)	(1,563)	540
Income tax expense (benefit)										503	170	(849)
Net (loss) income		$ 223	$ 302	$ 371	$ (6,165)	$ (2,412)	$ 272	$ 292	$ 115	(5,269)	(1,733)	1,389
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment adjusted EBITDA										15,987	16,647	12,560
Unallocated amount to segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment adjusted EBITDA										(7,216)	(8,045)	(6,504)
Depreciation and amortization										(4,829)	(5,120)	(3,936)
Goodwill impairment										(6,506)	(2,726)	0
Other operating expenses										(7,216)	(8,045)	(6,504)
Operating (loss) income										(2,726)	570	2,009
Total other expense, net										$ (2,040)	$ (2,133)	$ (1,469)