Shareholders' equity Share Repurchases (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Apr. 28, 2022	Mar. 31, 2022	Mar. 31, 2021	Jul. 19, 2021	Feb. 01, 2021	Nov. 19, 2020
Nov 2020 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount					$ 2,500	$ 1,500
Number of shares repurchased			3,110,000
Cost of shares repurchased			$ 519
Repurchase authorization remaining at end of period			$ 1,982
CB_Increase(Decrease)StockRepurchaseProgramAuthorizedAmount					$ 1,000
July 2021 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount				$ 5,000
Number of shares repurchased		4,869,900
Cost of shares repurchased		$ 1,001
Repurchase authorization remaining at end of period		$ 1,648
Subsequent Event [Member] | July 2021 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased	115,000
Cost of shares repurchased	$ 24
Repurchase authorization remaining at end of period	$ 1,624