Planned Divestiture of the Latin American and ILEC Businesses - Additional Information (Details) - USD ($) $ in Millions		3 Months Ended
	Mar. 31, 2022	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation and amortization		$ 808	$ 1,150
Disposal Group, Held-for-sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Long-term debt, net of discounts	$ 1,387	1,387		$ 1,377
Depreciation and amortization		170
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal		0
Disposal Group, Held-for-sale, Not Discontinued Operations | Embarq | Senior notes
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Long-term debt, net of discounts	1,400	1,400	$ 1,400	1,400
Disposal Group, Held-for-sale, Not Discontinued Operations | Latin American Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Long-term debt, net of discounts	0	0		0
Depreciation and amortization		49
Disposal Group, Held-for-sale, Not Discontinued Operations | Latin American Business | Level 3 Parent, LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration from disposal of business	2,700	2,700
Working capital, other purchase price adjustments and transaction expenses	50
Disposal Group, Held-for-sale, Not Discontinued Operations | ILEC Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration from disposal of business	7,500	7,500
Long-term debt, net of discounts	1,387	1,387		$ 1,377
Purchaser's transaction expenses	$ 1,700
Depreciation and amortization		$ 121