Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- 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.

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No definition available.

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- Definition

Number of shares authorized for issuance under share-based payment arrangement.

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Stock-Based Compensation - TDS excluding UScellular, Valuation model (Details) - TDS Parent Company - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
TDS Long-Term Incentive Plans \| Stock Options
Black Scholes valuation model assumptions
Expected life	6 years 2 months 12 days	6 years 2 months 12 days	6 years 3 months 18 days
Expected annual volatility rate	35.00%	29.00%	28.60%
Dividend yield	3.60%	2.10%	2.50%
Risk-free interest rate	0.50%	2.40%	2.90%
Common Shares \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period	3 years
Common Shares \| TDS Long-Term Incentive Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved	17,025,000
Common Shares \| TDS Long-Term Incentive Plans \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Common Shares \| Non-Employee Directors' Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved	182,000
Common Shares \| Maximum \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	10 years
Terminated Employees \| Common Shares \| TDS Long-Term Incentive Plans \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	30 days
Retired Employees \| Common Shares \| Minimum \| TDS Long-Term Incentive Plans \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	90 days
Retired Employees \| Common Shares \| Maximum \| TDS Long-Term Incentive Plans \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	1 year