XML 78 R66.htm IDEA: XBRL DOCUMENT v3.21.2
Commitments and Contingencies Purchase Obligations (Details) - USD ($)
$ in Millions
1 Months Ended 6 Months Ended
Feb. 28, 2021
Jun. 30, 2021
Radio Conversion Purchase Commitments    
Long-term Purchase Commitment [Line Items]    
Purchase commitment, amount   $ 55
Customer Contract Purchase Commitments    
Long-term Purchase Commitment [Line Items]    
Purchase commitment, amount $ 67