Variable Interest Entities - Narrative (Details) - USD ($)	9 Months Ended
	Sep. 30, 2018		Sep. 30, 2017	Dec. 31, 2017
Variable Interest Entity [Line Items]
Assets	$ 9,719,000,000	[1]	$ 9,210,000,000	$ 9,295,000,000	[1]
Investment in unconsolidated entities, maximum exposure	4,000,000			$ 4,000,000
Capital contributions, loans or advances	92,000,000		724,000,000
Net income attributable to noncontrolling interests, net of tax
Variable Interest Entity [Line Items]
Out-of-period adjustment	6,000,000
Net income attributable to TDS shareholders
Variable Interest Entity [Line Items]
Out-of-period adjustment	(6,000,000)
USCC EIP LLC
Variable Interest Entity [Line Items]
Capital contributions, loans or advances	$ 66,000,000		$ 701,000,000
King Street Wireless Out Of Period Adjustment
Variable Interest Entity [Line Items]
Immaterial error correction	During the nine months ended September 30, 2018, U.S. Cellular recorded out-of-period adjustments attributable to 2016 and 2017 due to errors in the application of accounting guidance applicable to the calculation of Noncontrolling interests with redemption features related to King Street Wireless, Inc. These out-of-period adjustments had the impact of increasing Net income attributable to noncontrolling interests, net of tax, by $8 million and decreasing Net income attributable to U.S. Cellular shareholders by $8 million for the nine months ended September 30, 2018. U.S. Cellular determined that these adjustments were not material to any of the periods impacted.
Aquinas Wireless, L.P.
Variable Interest Entity [Line Items]
Assets	$ 0

[1] The consolidated total assets as of September 30, 2018 and December 31, 2017, include assets held by consolidated variable interest entities (VIEs) of $831 million and $765 million, respectively, which are not available to be used to settle the obligations of TDS. The consolidated total liabilities as of September 30, 2018 and December 31, 2017, include certain liabilities of consolidated VIEs of $17 million and $21 million, respectively, for which the creditors of the VIEs have no recourse to the general credit of TDS. See Note 10 — Variable Interest Entities for additional information.