XML 106 R74.htm IDEA: XBRL DOCUMENT v3.8.0.1
Stock-Based Compensation Stock Options and Valuation Model (Details) - Long-Term Incentive Plans - Stock Options - USD ($)
$ / shares in Units, $ in Millions
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Stock-based compensation, stock options, overview      
Terms of award Stock options granted to key employees are exercisable over a specified period not in excess of ten years. Stock options generally vest over a period of three years from the date of grant. Stock options outstanding at December 31, 2017, expire between 2018 and 2026. However, vested stock options typically expire 30 days after the effective date of an employee’s termination of employment for reasons other than retirement. Employees who leave at the age of retirement have 90 days (or one year if they satisfy certain requirements) within which to exercise their vested stock options. The exercise price of options equals the market value of U.S. Cellular Common Shares on the date of grant.    
Minimum      
Stock-based compensation, stock options, overview      
Stock options expiration date Apr. 01, 2018    
Maximum      
Stock-based compensation, stock options, overview      
Stock options expiration date Apr. 01, 2026    
Common Shares      
Black Scholes valuation model assumptions      
Expected life   4 years 8 months 4 years 7 months
Expected annual volatility rate   30.50% 30.10%
Dividend yield   0.00% 0.00%
Risk-free interest rate   1.20% 1.20%
Estimated annual forfeiture rate   9.40% 9.70%
Stock compensation, stock option rollforward schedule, number of options      
Outstanding, begin of period 3,973,000    
Exercisable options, begin of period 1,937,000    
Granted options 0    
Exercised options (162,000)    
Forfeited options (74,000)    
Expired options (242,000)    
Outstanding, end of period 3,495,000 3,973,000  
Exercisable options, end of period 2,475,000 1,937,000  
Stock compensation, stock option rollforward schedule, other information      
Options outstanding, begin of period - weighted average exercise price $ 41.92    
Options exercisable, begin of period - weighted average exercise price 42.54    
Options exercised, weighted average exercise price 36.21    
Options forfeited, weighted average exercise price 41.62    
Options expired, weighted average exercise price 57.67    
Options outstanding, end of period - weighted average exercise price 41.10 $ 41.92  
Options exercisable, end of period - weighted average exercise price $ 40.79 42.54  
Options granted, weighted average grant date fair value   $ 12.77 $ 9.94
Aggregate intrinsic value, options exercised $ 1 $ 4 $ 2
Aggregate intrinsic value, options outstanding 3    
Aggregate intrinsic value, options exercisable $ 2    
Weighted average remaining contractual life, outstanding 6 years    
Weighted average remaining contractual life, exercisable 5 years 5 months