Shareholders' equity Repurchase of Common Shares (Details) - USD ($) $ in Millions	2 Months Ended	12 Months Ended
	Feb. 22, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	May 19, 2022	Jul. 19, 2021	Feb. 01, 2021	Nov. 19, 2020
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased		11,825,600	14,925,028	27,644,500
Nov 2020 Stock Repurchase Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program authorized amount							$ 2,500	$ 1,500
2021 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased				27,644,500
Common Shares repurchased				$ 4,861
Stock repurchase program authorized amount						$ 5,000
2022 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased			14,925,028
Common Shares repurchased			$ 3,014
Stock repurchase program authorized amount					$ 2,500
July 2023 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased		11,825,600
Common Shares repurchased		$ 2,478
Stock repurchase program authorized amount					$ 5,000
Subsequent Event [Member] | July 2023 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased	269,450
Common Shares repurchased	$ 67