Accounts receivable - Age Analysis of Accounts Receivable (Details) - USD ($) $ in Millions |
Dec. 31, 2022 |
Dec. 31, 2021 |
|---|---|---|
| Credit risk | ||
| Customer accounts receivable – billed, net of allowance for doubtful accounts | $ 222 | $ 211 |
| Accounts receivable – unbilled | 201 | 175 |
| Other receivables | 5 | 28 |
| Total | 428 | 414 |
| Less than 30 days past billing date | ||
| Credit risk | ||
| Customer accounts receivable – billed, net of allowance for doubtful accounts | 154 | 162 |
| 30-60 days past billing date | ||
| Credit risk | ||
| Customer accounts receivable – billed, net of allowance for doubtful accounts | 44 | 39 |
| 61-90 days past billing date | ||
| Credit risk | ||
| Customer accounts receivable – billed, net of allowance for doubtful accounts | 12 | 3 |
| More than 90 days past billing date | ||
| Credit risk | ||
| Customer accounts receivable – billed, net of allowance for doubtful accounts | $ 12 | $ 7 |