v3.20.4
Tower Transaction (Narrative) (Details)
$ in Millions
12 Months Ended
Dec. 31, 2020
USD ($)
tower
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Other Liabilities [Line Items]      
Balance of tower assets $ 127,315 $ 130,128 $ 131,473
Depreciation expense $ 20,277 20,285 20,083
Crown Castle International      
Other Liabilities [Line Items]      
Number of wireless towers with exclusive rights to lease | tower 9,048    
Number of wireless towers subject to disposition | tower 627    
Cash from failed sale-leaseback $ 4,827    
Term of lease 28 years    
Approximate fixed future purchase option price on failed sale-leaseback $ 4,200    
Initial term 10 years    
Balance of tower assets $ 764 804  
Depreciation expense $ 39 $ 39 $ 39
Approximate annual interest rate - financing obligation 3.90%    
Lease payments $ 248    
Minimum lease payments - 2021 253    
Minimum lease payments - 2022 258    
Minimum lease payments - 2023 264    
Minimum lease payments - 2024 269    
Minimum lease payments - 2025 274    
Minimum lease payments - thereafter $ 856