Restructuring Costs - Activity Related to Expenses Incurred and Cash Payments Made (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning Balance	$ 163
Expenses Incurred	215	$ 1,060
Cash Payments	(251)
Adjustments for Non-Cash Items	(41)
Restructuring Reserve, Ending Balance	86	163
Contract termination costs
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning Balance	81
Expenses Incurred	14	178
Cash Payments	(80)
Adjustments for Non-Cash Items	(1)
Restructuring Reserve, Ending Balance	14	81
Severance costs
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning Balance	52
Expenses Incurred	17	385
Cash Payments	(65)
Adjustments for Non-Cash Items	(3)
Restructuring Reserve, Ending Balance	1	52
Network decommissioning
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning Balance	30
Expenses Incurred	184	497
Cash Payments	(106)
Adjustments for Non-Cash Items	(37)
Restructuring Reserve, Ending Balance	$ 71	$ 30

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Section 45
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- Definition

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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- Definition

Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

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-Publisher FASB
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- Definition

Amount of expense (reversal of expense) which increases (decreases) the restructuring reserve from an adjustment to a previously accrued restructuring liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b)(2))
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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