Noncontrolling Interests (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Change Due to Net Income Attributable to Parent and Effects of Changes, Net [Abstract]
Net income (loss) attributable to TDS shareholders	$ 46	$ (181)	$ 119	$ (134)
Transfers to noncontrolling interests
Change in TDS' Capital in excess of par value from U.S. Cellular's issuance of U.S. Cellular shares			(22)	(12)
Change in TDS' Capital in excess of par value from U.S. Cellular's repurchases of U.S. Cellular shares			0	0
Purchase of ownership in subsidiaries from noncontrolling interests			0	0
Net transfers to noncontrolling interests			(22)	(12)
Change from net income (loss) attributable to TDS and transfers to noncontrolling interests			$ 97	$ (146)

This element represents the total net income attributable to the parent for the period and the effect of net changes during the period impacting the parent's ownership interest in a subsidiary as it relates to the total (consolidated) equity attributable to the parent. The changes to the parent's ownership interest in a subsidiary represented by this element did not result in a deconsolidation of the subsidiary from the consolidated financial statements.

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Represents a sale (new stock issuance) by a subsidiary to noncontrolling interests (third parties, parties directly or indirectly unrelated to parent) during the period. The capital transaction by subsidiary does not result in a loss of control by the parent, but does effect a change in total (consolidated) equity attributable to the parent.

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- Definition

The increase (decrease) during the period impacting the parent's ownership interest in a subsidiary as it relates to the total (consolidated) equity attributable to the parent. The changes to the parent's ownership interest in a subsidiary represented by this element did not arise in a deconsolidation of the subsidiary from the consolidated financial statements.

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Represents the purchase by the parent of an additional equity interest in a subsidiary during the period, thereby effecting a change in total (consolidated) equity attributable to the parent. The purchase of the additional equity interest represented by this element increases the parent's controlling interest in the subsidiary.

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Represents the repurchase of equity (treasury stock) by a subsidiary during the period, thereby effecting a change in total (consolidated) equity attributable to the parent; but not deconsolidation by the parent.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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