Goodwill, Customer Relationships and Other Intangible Assets - Additional Information (Details)							1 Months Ended	3 Months Ended	12 Months Ended
	Oct. 31, 2021 USD ($) reporting_unit	Jul. 31, 2021 USD ($) reporting_unit	Jan. 31, 2021 USD ($)	Jan. 01, 2021 USD ($)	Oct. 31, 2020 USD ($) reporting_unit	Oct. 31, 2019 reporting_unit	Jan. 31, 2021 reporting_unit	Mar. 31, 2019 USD ($)	Dec. 31, 2021 USD ($) segment $ / shares	Dec. 31, 2020 USD ($) $ / shares	Dec. 31, 2019 USD ($) $ / shares	Aug. 03, 2021 USD ($)	Jan. 01, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible assets, gross (including goodwill)									$ 38,500,000,000
Impairment of indefinite-lived intangible assets									$ 0	$ 0
Number of reportable segments | segment									2
Number of reporting units | reporting_unit	5	5			8	8	5
Goodwill impairment	$ 0	$ 0	$ 0		$ 2,600,000,000			$ 6,500,000,000	$ 0	2,642,000,000	$ 6,506,000,000
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets									1,300,000,000	1,700,000,000	1,700,000,000
Net income (loss)									$ 2,033,000,000	$ (1,232,000,000)	$ (5,269,000,000)
Basic earnings (loss) per common share (in dollars per share) | $ / shares									$ 1.92	$ (1.14)	$ (4.92)
Diluted earnings (loss) per common share (in dollars per share) | $ / shares									$ 1.91	$ (1.14)	$ (4.92)
Weighted average cost of capital, percentage					7.60%
Cost of debt, after tax, percentage					2.50%
Cost of equity, percentage					10.70%
Control premium, percent					33.00%			4.10%					4.50%
Acquired finite-lived intangible assets, weighted average useful life									7 years
Measurement Input, Revenue Multiple
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment, measurement input					2.3
Measurement Input, Revenue Multiple | Minimum
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment, measurement input					2.0			2.1
Measurement Input, Revenue Multiple | Maximum
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment, measurement input					5.5			4.9
Measurement Input, EBITDA Multiple
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment, measurement input					5.7
Measurement Input, EBITDA Multiple | Minimum
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment, measurement input					4.8			4.9
Measurement Input, EBITDA Multiple | Maximum
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment, measurement input					12.5			9.8
Mass Markets
Finite-Lived Intangible Assets [Line Items]
Goodwill, impairment percent	277.00%	150.00%
NA Business
Finite-Lived Intangible Assets [Line Items]
Goodwill, impairment percent	8.00%	24.00%
EMEA
Finite-Lived Intangible Assets [Line Items]
Goodwill, impairment percent	57.00%	58.00%				5.00%
Weighted average cost of capital, percentage					8.00%
Cost of debt, after tax, percentage					2.90%
Cost of equity, percentage					11.20%
LATAM
Finite-Lived Intangible Assets [Line Items]
Goodwill, impairment percent	100.00%	100.00%			74.00%	63.00%
Weighted average cost of capital, percentage					14.30%
Cost of debt, after tax, percentage					6.90%
Cost of equity, percentage					18.80%
APAC
Finite-Lived Intangible Assets [Line Items]
Goodwill, impairment percent	125.00%	134.00%			23.00%	38.00%
Weighted average cost of capital, percentage					10.10%
Cost of debt, after tax, percentage					3.90%
Cost of equity, percentage					14.00%
NA GAM
Finite-Lived Intangible Assets [Line Items]
Goodwill, impairment percent					46.00%	55.00%
Consumer
Finite-Lived Intangible Assets [Line Items]
Goodwill, impairment percent						44.00%
Small and Medium Business
Finite-Lived Intangible Assets [Line Items]
Goodwill, impairment percent						41.00%
Enterprise
Finite-Lived Intangible Assets [Line Items]
Goodwill, impairment percent					2.00%	53.00%
Wholesale
Finite-Lived Intangible Assets [Line Items]
Goodwill, impairment percent						46.00%
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Acquired finite-lived intangible assets, weighted average useful life									8 years
Capitalized software
Finite-Lived Intangible Assets [Line Items]
Acquired finite-lived intangible assets, weighted average useful life									4 years
Trade names
Finite-Lived Intangible Assets [Line Items]
Acquired finite-lived intangible assets, weighted average useful life									1 year
Reclassification of Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets									$ 22,000,000
Net income (loss)									$ (17,000,000)
Basic earnings (loss) per common share (in dollars per share) | $ / shares									$ (0.02)
Diluted earnings (loss) per common share (in dollars per share) | $ / shares									$ (0.02)
Reclassification of Intangible Assets | Right-of-way assets
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets				$ 268,000,000
Remaining amortization period				9 years
Reclassification of Intangible Assets | Right-of-way assets | Disposal Group, Held-for-sale, Not Discontinued Operations
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets												$ 169,000,000