Financial Risk Management and Financial Instruments - Summary of Notional Principal of the Foreign Currency Exchange Contracts by Hedged Line Item in Statement of Operations (Details) - Dec. 31, 2018 - Cash Flow Hedges - Foreign Exchange Forwards € in Millions, £ in Millions, kr in Millions, $ in Millions, $ in Millions |
EUR (€) |
USD ($) |
AUD ($) |
GBP (£) |
SEK (kr) |
|---|---|---|---|---|---|
| Disclosure Of Financial Risk Management And Financial Instruments [Line Items] | |||||
| Notional amount in foreign currency | € 968 | $ 48 | $ 330 | £ 484 | kr 1,869 |
| Revenue | |||||
| Disclosure Of Financial Risk Management And Financial Instruments [Line Items] | |||||
| Notional amount in foreign currency | 27 | 187 | 282 | 1,112 | |
| Cost of Revenue | |||||
| Disclosure Of Financial Risk Management And Financial Instruments [Line Items] | |||||
| Notional amount in foreign currency | $ 21 | $ 143 | £ 202 | kr 757 |