v3.24.0.1
Property, plant and equipment (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Property, plant and equipment    
Property, plant and equipment at beginning of period $ 449  
Additions from acquisition 34  
Property, plant and equipment at end of period 517 $ 449
Owned Assets    
Property, plant and equipment    
Property, plant and equipment at beginning of period 233  
Additions from acquisition 15  
Property, plant and equipment at end of period 252 233
Owned Assets | Network assets    
Property, plant and equipment    
Property, plant and equipment at beginning of period 18  
Property, plant and equipment at end of period 20 18
Owned Assets | Buildings and leasehold improvements    
Property, plant and equipment    
Property, plant and equipment at beginning of period 85  
Property, plant and equipment at end of period 84 85
Owned Assets | Computer equipment, furniture, and other    
Property, plant and equipment    
Property, plant and equipment at beginning of period 97  
Property, plant and equipment at end of period 111 97
Owned Assets | Assets under construction    
Property, plant and equipment    
Property, plant and equipment at beginning of period 33  
Property, plant and equipment at end of period 37 33
Right-of-use lease assets    
Property, plant and equipment    
Property, plant and equipment at beginning of period 449  
Property, plant and equipment at end of period 517 449
Right-of-use lease assets | Buildings and leasehold improvements    
Property, plant and equipment    
Property, plant and equipment at beginning of period 216  
Property, plant and equipment at end of period 265 216
At cost | Owned Assets    
Property, plant and equipment    
Property, plant and equipment at beginning of period 477 424
Additions 79 92
Additions from acquisition   3
Dispositions, retirements and other 10 (24)
Transfers 0 0
Foreign exchange 2 (18)
Property, plant and equipment at end of period 563 477
At cost | Owned Assets | Network assets    
Property, plant and equipment    
Property, plant and equipment at beginning of period 49 48
Additions 3 1
Additions from acquisition 0 0
Dispositions, retirements and other 0 (1)
Transfers 7 3
Foreign exchange 0 (2)
Property, plant and equipment at end of period 59 49
At cost | Owned Assets | Buildings and leasehold improvements    
Property, plant and equipment    
Property, plant and equipment at beginning of period 138 119
Additions 3 8
Additions from acquisition 10 2
Dispositions, retirements and other 1 (8)
Transfers 8 22
Foreign exchange 1 (5)
Property, plant and equipment at end of period 159 138
At cost | Owned Assets | Computer equipment, furniture, and other    
Property, plant and equipment    
Property, plant and equipment at beginning of period 257 231
Additions 19 22
Additions from acquisition 5 1
Dispositions, retirements and other 9 (15)
Transfers 35 27
Foreign exchange 1 (9)
Property, plant and equipment at end of period 308 257
At cost | Owned Assets | Assets under construction    
Property, plant and equipment    
Property, plant and equipment at beginning of period 33 26
Additions 54 61
Additions from acquisition 0 0
Dispositions, retirements and other 0 0
Transfers (50) (52)
Foreign exchange 0 (2)
Property, plant and equipment at end of period 37 33
At cost | Right-of-use lease assets    
Property, plant and equipment    
Property, plant and equipment at beginning of period 862 741
Additions 171 179
Additions from acquisition   5
Dispositions, retirements and other 23 (35)
Transfers 0 0
Foreign exchange 6 (28)
Property, plant and equipment at end of period 1,050 862
At cost | Right-of-use lease assets | Buildings and leasehold improvements    
Property, plant and equipment    
Property, plant and equipment at beginning of period 385 317
Additions 92 87
Additions from acquisition 19 2
Dispositions, retirements and other 13 (11)
Transfers 0 0
Foreign exchange 4 (10)
Property, plant and equipment at end of period 487 385
Accumulated depreciation | Owned Assets    
Property, plant and equipment    
Property, plant and equipment at beginning of period (244) (209)
Dispositions, retirements and other (10) (24)
Foreign exchange 1 (8)
Depreciation 76 67
Property, plant and equipment at end of period (311) (244)
Accumulated depreciation | Owned Assets | Network assets    
Property, plant and equipment    
Property, plant and equipment at beginning of period (31) (26)
Dispositions, retirements and other 0 1
Foreign exchange 0 (1)
Depreciation 8 7
Property, plant and equipment at end of period (39) (31)
Accumulated depreciation | Owned Assets | Buildings and leasehold improvements    
Property, plant and equipment    
Property, plant and equipment at beginning of period (53) (45)
Dispositions, retirements and other 1 8
Foreign exchange 1 (1)
Depreciation 22 17
Property, plant and equipment at end of period (75) (53)
Accumulated depreciation | Owned Assets | Computer equipment, furniture, and other    
Property, plant and equipment    
Property, plant and equipment at beginning of period (160) (138)
Dispositions, retirements and other 9 15
Foreign exchange 0 (6)
Depreciation 46 43
Property, plant and equipment at end of period (197) (160)
Accumulated depreciation | Owned Assets | Assets under construction    
Property, plant and equipment    
Property, plant and equipment at beginning of period 0 0
Dispositions, retirements and other 0 0
Foreign exchange 0 0
Depreciation 0 0
Property, plant and equipment at end of period 0 0
Accumulated depreciation | Right-of-use lease assets    
Property, plant and equipment    
Property, plant and equipment at beginning of period (413) (336)
Dispositions, retirements and other (23) (35)
Foreign exchange 2 (12)
Depreciation 141 124
Property, plant and equipment at end of period (533) (413)
Accumulated depreciation | Right-of-use lease assets | Buildings and leasehold improvements    
Property, plant and equipment    
Property, plant and equipment at beginning of period (169) (127)
Dispositions, retirements and other 13 11
Foreign exchange 1 (4)
Depreciation 65 57
Property, plant and equipment at end of period $ (222) $ (169)