Face (par) amount of debt instrument at time of issuance.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

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Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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Period Type:	duration

- Definition

Face (par) amount of the original debt instrument that was repurchased.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585

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Period Type:	duration

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Long-Term Debt - Additional Information (Details) - USD ($)		9 Months Ended
	Sep. 25, 2019	Sep. 30, 2019	Oct. 25, 2019	Oct. 24, 2019	Oct. 17, 2019
6.125% Senior Notes due 2021 \| Senior Notes \| Subsequent Event
Long-term debt
Repurchased face amount			$ 240,000,000
Stated interest rate			6.125%
Senior Notes, 5.75% Due 2022
Long-term debt
Stated interest rate		5.75%
Senior Notes, 5.75% Due 2022 \| Senior Notes \| Subsequent Event
Long-term debt
Repurchased face amount					$ 600,000,000
Stated interest rate					5.75%
Level 3 Financing, Inc. \| 6.125% Senior Notes due 2021
Long-term debt
Stated interest rate		6.125%
Repayments of debt		$ 400,000,000
Level 3 Financing, Inc. \| 6.125% Senior Notes due 2021 \| Senior Notes
Long-term debt
Repurchased face amount	$ 240,000,000
Stated interest rate	6.125%
Level 3 Financing, Inc. \| 4.625% Senior Notes Due 2027 \| Senior Notes
Long-term debt
Stated interest rate	4.625%
Long term debt	$ 1,000,000,000.0
Level 3 Financing, Inc. \| Senior Notes, 5.75% Due 2022 \| Senior Notes
Long-term debt
Repurchased face amount	$ 600,000,000
Stated interest rate	5.75%
Level 3 Financing, Inc. \| 5.375% Senior Notes Due 2022 \| Senior Notes
Long-term debt
Stated interest rate	5.375%
Repayments of debt	$ 160,000,000
Long term debt	$ 1,000,000,000
Level 3 Financing, Inc. \| 5.375% Senior Notes Due 2022 \| Senior Notes \| Subsequent Event
Long-term debt
Repurchased face amount			$ 160,000,000
Stated interest rate			5.375%
Long term debt				$ 1,000,000,000.0