Dividends (Details) - USD ($) $ in Millions		9 Months Ended
Mar. 31, 2017	Sep. 30, 2018	Sep. 30, 2017
Dividends [Abstract]
Dividends declared and paid to Qwest Services Corporation		$ 925	$ 800
Dividend of equity interest in limited liability company to Qwest Services Corporation	$ 12

Amount of paid and unpaid common stock dividends declared with the form of settlement in cash.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Name:	us-gaap_DividendsCommonStockCash
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration