Segment Reporting - Revenue by Major Category (Details) - USD ($) $ in Millions | 3 Months Ended |
Mar. 31, 2019 | Sep. 30, 2018 | Mar. 31, 2018 | Sep. 30, 2017 |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | $ 942.7 | | $ 909.9 | |
Total residential revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 654.2 | | 628.4 | |
Total residential fixed revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 481.1 | | 431.7 | |
Total subscription revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 448.4 | | 406.3 | |
Video | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 185.6 | | 165.7 | |
Broadband internet | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 205.5 | | 175.6 | |
Fixed-line telephony | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 57.3 | | 65 | |
Non-subscription revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 32.7 | | 25.4 | |
Total residential mobile revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 173.1 | | 196.7 | |
Service revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 150.7 | | 171.4 | |
Interconnect, equipment sales and other | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 22.4 | | 25.3 | |
Total B2B revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 288.5 | | 281.5 | |
Service revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 230.2 | | 222.9 | |
Subsea network revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 58.3 | | 58.6 | |
Mobile Handset | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 7 | | 12 | |
B2B Mobile Handset and Other Devices | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 4 | | 6 | |
Operating Segments | C&W | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 569.8 | | 585.5 | |
Operating Segments | C&W | Total residential revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 297.4 | | 316 | |
Operating Segments | C&W | Total residential fixed revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 143.4 | | 138.8 | |
Operating Segments | C&W | Total subscription revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 128.4 | | 123.3 | |
Operating Segments | C&W | Video | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 43.9 | | 42.7 | |
Operating Segments | C&W | Broadband internet | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 60.2 | | 53.7 | |
Operating Segments | C&W | Fixed-line telephony | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 24.3 | | 26.9 | |
Operating Segments | C&W | Non-subscription revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 15 | | 15.5 | |
Operating Segments | C&W | Total residential mobile revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 154 | | 177.2 | |
Operating Segments | C&W | Service revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 135 | | 155.1 | |
Operating Segments | C&W | Interconnect, equipment sales and other | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 19 | | 22.1 | |
Operating Segments | C&W | Total B2B revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 272.4 | | 269.5 | |
Operating Segments | C&W | Service revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 212.5 | | 209.9 | |
Operating Segments | C&W | Subsea network revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 59.9 | | 59.6 | |
Operating Segments | VTR/Cabletica | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 276.5 | | 263.8 | |
Operating Segments | VTR/Cabletica | Total residential revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 269 | | 257.9 | |
Operating Segments | VTR/Cabletica | Total residential fixed revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 249.9 | | 238.4 | |
Operating Segments | VTR/Cabletica | Total subscription revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 237.5 | | 230.9 | |
Operating Segments | VTR/Cabletica | Video | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 106.7 | | 99.7 | |
Operating Segments | VTR/Cabletica | Broadband internet | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 103.5 | | 96.6 | |
Operating Segments | VTR/Cabletica | Fixed-line telephony | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 27.3 | | 34.6 | |
Operating Segments | VTR/Cabletica | Non-subscription revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 12.4 | | 7.5 | |
Operating Segments | VTR/Cabletica | Total residential mobile revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 19.1 | | 19.5 | |
Operating Segments | VTR/Cabletica | Service revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 15.7 | | 16.3 | |
Operating Segments | VTR/Cabletica | Interconnect, equipment sales and other | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 3.4 | | 3.2 | |
Operating Segments | VTR/Cabletica | Total B2B revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 7.5 | | 5.9 | |
Operating Segments | VTR/Cabletica | Service revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 7.5 | | 5.9 | |
Operating Segments | VTR/Cabletica | Subsea network revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 0 | | 0 | |
Operating Segments | Liberty Puerto Rico | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 98.6 | | 61.8 | |
Operating Segments | Liberty Puerto Rico | Total residential revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 87.8 | | 54.5 | |
Operating Segments | Liberty Puerto Rico | Total residential fixed revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 87.8 | | 54.5 | |
Operating Segments | Liberty Puerto Rico | Total subscription revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 82.5 | | 52.1 | |
Operating Segments | Liberty Puerto Rico | Video | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 35 | | 23.3 | |
Operating Segments | Liberty Puerto Rico | Broadband internet | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 41.8 | | 25.3 | |
Operating Segments | Liberty Puerto Rico | Fixed-line telephony | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 5.7 | | 3.5 | |
Operating Segments | Liberty Puerto Rico | Non-subscription revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 5.3 | | 2.4 | |
Operating Segments | Liberty Puerto Rico | Total residential mobile revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 0 | | 0 | |
Operating Segments | Liberty Puerto Rico | Service revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 0 | | 0 | |
Operating Segments | Liberty Puerto Rico | Interconnect, equipment sales and other | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 0 | | 0 | |
Operating Segments | Liberty Puerto Rico | Total B2B revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 10.8 | | 7.3 | |
Operating Segments | Liberty Puerto Rico | Service revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 10.8 | | 7.3 | |
Operating Segments | Liberty Puerto Rico | Subsea network revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 0 | | 0 | |
Intersegment eliminations | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | (2.2) | | (1.2) | |
Intersegment eliminations | Total residential revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 0 | | 0 | |
Intersegment eliminations | Total residential fixed revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 0 | | 0 | |
Intersegment eliminations | Total subscription revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 0 | | 0 | |
Intersegment eliminations | Video | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 0 | | 0 | |
Intersegment eliminations | Broadband internet | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 0 | | 0 | |
Intersegment eliminations | Fixed-line telephony | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 0 | | 0 | |
Intersegment eliminations | Non-subscription revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 0 | | 0 | |
Intersegment eliminations | Total residential mobile revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 0 | | 0 | |
Intersegment eliminations | Service revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 0 | | 0 | |
Intersegment eliminations | Interconnect, equipment sales and other | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | 0 | | 0 | |
Intersegment eliminations | Total B2B revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | (2.2) | | (1.2) | |
Intersegment eliminations | Service revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | | $ (0.6) | | $ (0.2) |
Intersegment eliminations | Subsea network revenue | | | | |
Principal Transaction Revenue [Line Items] | | | | |
Revenue | $ (1.6) | | $ (1) | |