Shareholders' equity Repurchase of Common Shares (Details) - USD ($) $ in Millions	2 Months Ended	12 Months Ended
	Feb. 23, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased		14,925,028	27,644,500	3,584,150
Nov 2019 Stock Repurchase Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased				3,584,150
Common Shares repurchased				$ 516
July 2021 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased			27,644,500
Common Shares repurchased			$ 4,861
2022 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased		14,925,028
Common Shares repurchased		$ 3,014
Subsequent Event [Member] | 2022 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased	1,633,300
Common Shares repurchased	$ 347