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v3.20.4

Investment in associated companies - Consolidated Balance Sheets (Details) - USD ($) $ in Millions | 6 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2018 | Jul. 01, 2018 | Dec. 31, 2020 | Dec. 31, 2019
Schedule of Equity Method Investments [Line Items] |  |  |  |
Current assets |  |  | $ 1,062 | $ 1,773
Non-current assets |  |  | 2,899 | 7,506
Current liabilities |  |  | (6,545) | (770)
Non-current liabilities |  |  | (556) | (6,659)
Book value of investment |  |  | 248 | 389
Total impairment of investments in associated companies and joint ventures | $ 0 | $ 0 | 47 | 302
Cash proceeds from repayment of shareholder loans held in escrow |  |  | 2 | 9
Seadrill Partners |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Seadrill share of book equity |  |  |  | 1,305
Total impairment of investments in associated companies and joint ventures |  |  | 47 | 302
Seadrill Partners | Basis difference allocated to rigs |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Basis difference |  |  |  | (1,220)
Seadrill Partners | Basis difference allocated to contracts |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Basis difference |  |  |  | 37
Seadrill Partners | Seadrill Partners - Direct ownership investments |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Book value of investment |  |  | 0 | 122
Sebras Sapura and Seabras Sapura Holding |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Book value of investment |  |  | 224 | 221
Seabras Sapura |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Seadrill share of book equity |  |  | 361 | 338
Basis difference |  |  | (137) | (117)
Book value of investment |  |  | 103 | 98
Seabras Sapura | Basis difference allocated to rigs |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Basis difference |  |  | (351) | (369)
Seabras Sapura | Basis difference allocated to contracts |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Basis difference |  |  | 93 | 129
Seabras Sapura Holding |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Shareholder loans held as equity |  |  | 121 | 123
Book value of investment |  |  | 121 | 123
SeaMex |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Seadrill share of book equity |  |  | 230 | 236
Basis difference |  |  | (230) | (214)
Book value of investment |  |  | 0 | 22
SeaMex | Basis difference allocated to rigs |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Basis difference |  |  | (325) | (341)
SeaMex | Basis difference allocated to contracts |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Basis difference |  |  | 95 | 127
Sonadrill |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Seadrill share of book equity |  |  | 22 | 24
Book value of investment |  |  | 22 | 24
Gulfdrill |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Seadrill share of book equity |  |  | 2 | 0
Book value of investment |  |  | 2 | 0
Seadrill Partners |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Current assets |  |  |  | 833
Non-current assets |  |  |  | 4,847
Current liabilities |  |  |  | (533)
Non-current liabilities |  |  |  | (2,623)
Net Assets (2) |  |  |  | 2,524
Seabras Sapura |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Current assets |  |  | 207 | 195
Non-current assets |  |  | 1,474 | 1,495
Current liabilities |  |  | (541) | (510)
Non-current liabilities |  |  | (419) | (504)
Net Assets (2) |  |  | 721 | 676
SeaMex |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Current assets |  |  | 291 | 260
Non-current assets |  |  | 898 | 939
Current liabilities |  |  | (174) | (141)
Non-current liabilities |  |  | (555) | (586)
Net Assets (2) |  |  | 460 | 472
Sonadrill |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Current assets |  |  | 54 | 57
Non-current assets |  |  | 0 | 0
Current liabilities |  |  | (11) | (9)
Non-current liabilities |  |  | 0 | 0
Net Assets (2) |  |  | 43 | 48
Gulfdrill |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Current assets |  |  | 67 | 0
Non-current assets |  |  | 102 | 0
Current liabilities |  |  | (135) | 0
Non-current liabilities |  |  | (31) | 0
Net Assets (2) |  |  | $ 3 | $ 0

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