Shareholders' equity Share Repurchases (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	May 19, 2022	Jul. 19, 2021	Feb. 01, 2021	Nov. 19, 2020
Nov 2019 Stock Repurchase Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased				22,877,400
Cost of shares repurchased				$ 3,956
Repurchase authorization remaining at end of period		$ 3,551		3,551
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		8,412,000
Cost of shares repurchased		$ 1,516
Repurchase authorization remaining at end of period		$ 3,551		$ 3,551
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			14,022,728
Cost of shares repurchased			$ 2,815
May 2022 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount					$ 2,500
Number of shares repurchased	3,676,528
Cost of shares repurchased	$ 685
Repurchase authorization remaining at end of period	$ 1,816		$ 1,816