Divestitures of the Latin American and ILEC Businesses and Planned Divestiture of the EMEA Business - Additional Information (Details)							12 Months Ended
	Oct. 31, 2022 USD ($)	Oct. 03, 2022 USD ($) state	Oct. 31, 2021 USD ($)	Jul. 31, 2021 USD ($)	Jan. 31, 2021 USD ($)	Oct. 31, 2020 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Nov. 02, 2022 USD ($)	Aug. 01, 2022 USD ($)	Jul. 25, 2021 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on disposal							$ (700,000,000)	$ 0	$ 0
Goodwill					$ 0		12,657,000,000	15,986,000,000	18,870,000,000
Realized loss on foreign currency translation to gain on sale of business							(112,000,000)	0	0
Depreciation and amortization							3,239,000,000	4,019,000,000	4,710,000,000
Goodwill impairment			$ 0	$ 0	$ 0	$ 2,600,000,000	3,271,000,000	$ 0	$ 2,642,000,000
Pension Plans
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Reclassified of net actuarial loss and prior service credit, net of tax		$ 403,000,000
Purchaser of ILEC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Purchase obligation		$ 373,000,000
Purchase obligation period		3 years
Purchaser of ILEC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Purchase obligation		$ 67,000,000
Purchase obligation period		3 years
Disposal Group, Held-for-sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on disposal							(660,000,000)
Depreciation and amortization							51,000,000
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]
Deferred income tax liabilities											$ 129,000,000
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												$ 2,700,000,000
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		$ 7,500,000,000
Long term debt, net of discounts		1,500,000,000
Disposal Group, Held-for-sale, Not Discontinued Operations | EMEA Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net assets							1,823,000,000
Property, plant and equipment, net accumulated depreciation							1,873,000,000
Accumulated amortization							1,033,000,000
Deferred income tax liabilities							38,000,000
Goodwill impairment	$ 43,000,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Latin American Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on disposal							597,000,000
Indemnifications related to the sale of businesses							86,000,000
Net assets											1,900,000,000
Property, plant and equipment, net accumulated depreciation											1,700,000,000
Goodwill											245,000,000
Accumulated amortization											140,000,000
Deferred income tax liabilities											$ 154,000,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | ILEC Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on disposal							$ 176,000,000
Indemnifications related to the sale of businesses		89,000,000
Net assets		4,800,000,000
Property, plant and equipment, net accumulated depreciation		3,600,000,000
Goodwill		$ 2,600,000,000
Number of states in which the business is conducted | state		20
Consideration after closing adjustments		$ 400,000,000
Long term debt, net of discounts		1,400,000,000
Net proceeds from sales of colocation business and data centers		$ 5,600,000,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | EMEA 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										$ 1,800,000,000