XML 183 R171.htm IDEA: XBRL DOCUMENT v3.20.4
Pension benefits - Expected Annual Pension Plan Contributions Under Defined Benefit Plans (Details)
$ in Millions
Dec. 31, 2020
USD ($)
Defined Benefit Plan, Expected Future Employer Contributions [Abstract]  
2021 $ 1
2022 1
2023 1
2024 1
2025-2030 3
Total payments expected during the next 10 years $ 7